Bulletin of the American Physical Society
49th Annual Meeting of the Division of Plasma Physics
Volume 52, Number 11
Monday–Friday, November 12–16, 2007; Orlando, Florida
Session YP8: Poster Session IX: Supplemental and Postdeadline 
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Room: Rosen Centre Hotel Grand Ballroom, 9:30am  12:30pm 

YP8.00001: SUPPLEMENTAL 

YP8.00002: The basic evolution of the angular momentum density in a fieldtheoretical model of vorticity transport Florin Spineanu, Madalina Olimpia Vlad, Saddrudin Benkadda The structure of the vortical flow of twodimensional plasmas and fluids evolves under the constraint imposed by the selforganization of the vorticity field, as shown by the extremum of an action functional obtained from the equivalent pointlike vortices models. We formulate a fieldtheoretical model that provides the explicit form of the Lagrangian density and of the equations of motion for the vorticity. In this model the density of the angular momentum results from the field of vorticity and it is possible to infer nondissipative evolutions of the angular momentum from the trend of generating coherent states of the vorticity. The transport of angular momentum exhibits aspects similar to the socalled nonlocal transport in plasma and also to resilient radial profiles in stable stationary vortices. This can be a significant contribution to angular momentum transport in 2D plasmas, fluids, accreation discs, etc. [Preview Abstract] 

YP8.00003: Possible mechanisms for dust grain acceleration in plasmas Padma Kant Shukla, Lennart Stenflo, Bengt Eliasson There exists conclusive evedince of charged dust grain acceleration in tokamak edges as well as in cosmic plasmas. Our objective here is to present an evaluative description of dust particle acceleration in magnetized dusty plasmas. Possible acceleration mechanisms involve ion drag force caused by plasma flow as well as strong ambipolar electric fields created by the ponderomotive force of large amplitude waves in magnetolasmas. Spatiotemporal scales over which the dust grain acceleration occurs are discussed. [Preview Abstract] 

YP8.00004: Nonlinear Interactions in Dense Quantum Plasmas Padma Shukla The purpose of this talk is to discuss some important collective processes in dense quantum plasmas, which are ubiquitous in micromechanical systems and ultrasmall electronic devices, in nanowires, in biophotonics, in intense lasersolid density plasma interaction experiments, as well as in astrophysical and cosmological environments. Tn dense quantum plasmas, which obey the FermiDirac distributions, there are new pressure laws and new quantum forces. The latter are responsible for novel collective interactions at nanoscales in the Fermi plasma. We shall describe the underlying models for dense quantum plasmas and shall discuss new aspects of the quantum fluid turbulence as well as the formation of nanostructures (quantum electron holes and quantum electron vortices) associated with nonlinear plasmonic oscillations. The results of computer simulations reveal interesting dynamics of quantum electron vortices. Furthermore, the nonlinear interactions between intense photons and plasmons exhibit the trapping of localized photons into quantum electron holes. The relevance of our investigation to laboratory experiments and astrophysical settings is discussed. [Preview Abstract] 

YP8.00005: ABSTRACT WITHDRAWN 

YP8.00006: Vorticity Stabilization of Magnetized Plasma in an Alfven Black Hole. Friedwardt Winterberg As in an acoustic black hole where the fluid is moving faster than the speed of sound and where the sound waves are swept along, in an Alfven black hole where the plasma is moving faster than the Alfven velocity, the Alfven waves are swept along and are eliminated as the cause of the magnetohydrodynamic instabilities. To realize an Alfven black hole, it is proposed to bring a plasma into rapid rotation through radially arranged lumped parameter transmission lines intersecting the plasma under an oblique angle, with the rotational velocity exceeding the Alfven velocity. The rotating plasma slides frictionless over magnetic mirror fields directed towards the rotating plasma, with the mirror fields generated by magnetic solenoids positioned at the end of each transmission line. It is then shown that, with this configuration one can realize a thermonuclear dynamo, which also can serve as the analogue of a magnetar. [Preview Abstract] 

YP8.00007: Global Plasma Oscillation Regime and Its Suppression on TCV Elina Asp, Victor Udintsev, Timothy P. Goodman, Olivier Sauter, Gianpaolo Turri In the Tokamak \`{a} Configuration Variable (R/a = 0.88 m/ 0.24 m, B$_{T}$ $<$ 1.54 T), global plasma oscillations are found to exist in fully noninductive plasmas featuring eITBs with strong ECRH/ECCD. This phenomenon is akin to the socalled Oscillatory, or Oregime, first observed in LHCD plasmas on Tore Supra. In TCV, the Oregime is linked to the evolution of the MHD modes in the reversed magnetic shear plasmas. It is demonstrated that the Oregime can be effectively suppressed by ECCDinduced local current density perturbation or by adding an Ohmic current perturbation. In these experiments MHD activity is modified through current density profile tailoring rather than local deposition within an island. The suppression of the Oregime usually leads to improved energy confinement, which is characterized by exceeding the RebutLalliaWatkins scaling, to obtain H$_{RLW}$ above 3.5. The detection of the MHD modes by various diagnostics (ECE, SXR, Mirnov coils etc) has aided in the correct identification of rational qsurfaces and in understanding their role in the evolution of the Oregime. The evolution of the safety factor during the Oregime has been studied by means of CQL3D/ASTRA simulations and will be presented. [Preview Abstract] 

YP8.00008: Ratchet and curvature pinch in turbulent plasmas Madalina Olimpia Vlad, Florin Spineanu, Saddrudin Benkadda We have shown that the gradient of the confining magnetic field, grad(B), generates a pinch (average velocity) in turbulent plasmas. It is a ratchet type process that appears in test particle approach due to the modification of guiding center trajectories. The ratchet pinch depends on the characteristics of the turbulence and changes its orientation along grad(B) from antiparallel to parallel when trajectory trapping or eddying appears. Another effect of grad(B) is the compressibility of the ExB velocity field, which was shown to produce a pinch parallel with grad(B), the curvature pinch. The influence of grad(B) on trajectories is neglected in the derivation od the curvature pinch. We determine here the evolution of particle density taking into account both effects. We include in the model particle collisions and plasma rotation and determine their effects on the transport and on the peaking factor. The results are compared with the experimental data on impurity transport in tokamak plasmas. [Preview Abstract] 

YP8.00009: Convex optimation of a pulsed inductive plasma thruster model Sam Adhikari Exhaust velocity and efficiency are represented as a function of nondimensionalized set of coupled circuit equations and a momentum equation in a pulsed inductive plasma thruster model. Convex optimization techniques are used to maximize efficiency and to determine the optimal criteria. Statistical estimation techniques are used to optimally match the acceleration timescale to circuit's natural period. Vector optimization techniques allow the estimation of optimal fraction of the propellant loaded near the inductive acceleration coil to maximize performance. [Preview Abstract] 

YP8.00010: Assessment of the LiWall plasma regime for DD fusion Leonid E. Zakharov, Englen A. Azizov, John Sheffield The lithium plasma facing components pump out the plasma particles and eliminate the cold particles, which enter it in the conventional wall situation. Together with core plasma fueling by neutral beam injection this provides flat plasma temperature, eliminates the turbulence associated with the temperature gradient, and leads to the best possible confinement regime. The Reference Transport Model (RTM), which assumes all transport coefficients equal to the ion thermoconductivity $\chi_i=\chi_e=D=\chi^{neo}_i$ can describe the LiWall confinement quantitatively. Implementation of the LiWall regime would make the path to the DT fusion straightforward. It is only the inability of the current fusion program to move beyond the outdated concept, which prevents the progress in DT fusion with the LiWall regime. In this regime, at a given beta, the confinement $\tau_E\propto T^{3/2}$ is very favorable for DD fusion as well. The question, studied here using the RTM, is if it is possible to maintain the plasma in the hotion mode by NBI, while expelling the fusion products and keeping the radiation from electrons limited. Realization of DD fusion could be of great interest because of its independence from tritium fuel and possible use for transmutation of radioactive waste. [Preview Abstract] 

YP8.00011: The theory of the failure of magnetic fusion Leonid E. Zakharov In the physics of the 20th century, fusion represents an extraordinary failure which eroded expectations of society on an ``unexhaustible'' energy source. The question is if these 50 years of research did really prove that fusion will be forever a ``carrot'' on a stick and always 35 years from its implementation. When a person is asking fusion people why this program is full of broken promises, he (besides conventional complaints on the lack of funding) is typically getting the answer that the problem itself is the most difficult one that physics ever faced. In the FSU, such characterizations were done as early as in the 60s by Lev Artsimovich, the leader in the field. This view is only partially applicable in the 21st century. Since the times of Artsimovich, fusion, as a ``difficult'' problem, has been converted into the ``complicated'' one. The presented theory makes a clear distinction between these two kinds of problems, which require significantly different management approaches, and explains the current stagnation in magnetic fusion by the lack of understanding this crucial difference. [Preview Abstract] 

YP8.00012: Dynamic hohlraums as xray sources in highenergy density science J.F. Hansen, S.G. Glendinning, R.F. Heeter A new laser driven dynamic hohlraum (LDDH) backlighter has been evaluated using 10 of 60 beams of the Omega laser. The LDDH is filled with krypton that implodes to create an xray flash that satisfies requirements imposed by future experiments: (1) the flash spectrum extends $>$ 5.5 keV, well above the maximum xray energy ($\sim $3.5 keV) obtained from the previously ``best'' opacity backlighters (uranium Mshell emission backlighters); (2) the spectrum is smooth and featureless (intensity variation $<$6{\%} RMS), allowing absorption spectrometry through experimental samples; (3) the flash size is sufficiently small ($<$50 $\mu $m) for projection backlighting through future samples; (4) the flash is bright enough (and twice as bright as imploding hydrogenfilled capsules) for gated spectrometer measurements; and (5) the flash duration is optimized ($\approx $100 ps) for current and future generations of spectrometers. This enables opacity and temperature measurements through absorption spectrometry of materials in LTE at temperatures $>$150 eV, a crucial regime for future astrophysics and ignition fusion experiments at NIF. [Preview Abstract] 

YP8.00013: Theoretical approach to the ground state of spherically confined Yukawa plasmas Christian Henning, Michael Bonitz, Alexander Piel, Patrick Ludwig, Henning Baumgartner Recently spherical 3D dust crystals (aka Yukawa balls) were discovered [1], which allow direct observation of strong correlation phenomena and the structure of which is well explained by computer simulations of charged Yukawa interacting particles within an external parabolic confinement [2]. Here we present an analytical approach to the ground state of these systems using the minimization of the system's energy. Applying the nonlocal meanfield approximation we show that screening has a dramatic effect on the density profile, which can be derived explicitly [3]. In addition the local density approximation allows for the inclusion of correlations, which further improves the results in the regime of large screening [4]. Comparisons with MD simulations of Yukawa balls show excellent agreement.\newline [1] O. Arp et al. Phys. Rev. Lett. 93, 165004 (2004)\newline [2] M. Bonitz et al., Phys. Rev. Lett. 96, 075001 (2006)\newline [3] C. Henning et al., Phys. Rev. E 74, 056403 (2006)\newline [4] C. Henning at al., Phys. Rev. E (2007) [Preview Abstract] 

YP8.00014: Stability of Ultrathin Solid Targets in the Radiation Pressure Dominated Regime with Circular Polarization C. Bellei, R.G. Evans, S. Atzeni, A.P.L. Robinson, S. Kar, M. Zepf The stability of ultrathin (thickness $<<$ laser wavelength) solid targets illuminated by circularly polarized laser pulses is studied in a regime where the radiation pressure is the dominant acceleration mechanism, by means of 2D3V PIC simulations (Osiris code). The Osiris simulations show that the foil exhibits an instability very similar to the classical RayleighTaylor instability even though the foil material is not collisional. Indeed, it is found that the mechanism of ion bunch formation leads to the growth of unstable modes that become nonlinear in a few laser cycles and have a detrimental effect for the production of monoenergetic ions. The possibility of tailoring the laser intensity profile in order to inhibit the bunch formation and therefore decrease the growth of the instability will be also discussed. [Preview Abstract] 

YP8.00015: Perturbation Theory For A Maximal Gyrokinetic Ordering A.M. Dimits We develop a perturbation theory for a maximal gyrokinetic ordering. By working with a lowestorder gyrocenter position variable that is relative to the aggregate local ExB displacement, and a particular gauge condition for the electromagnetic (4)potential, the PoincareCartan 1form can be cast in such a way that its perturbed parts depend on the electricfield shear and time derivative, and not directly on the electrostatic field nor the potential. This permits the perturbation theory to be carried out in an optimal ordering in which the small parameter is the change in local ExB velocity across a particle's gyroorbit divided by its perpendicular velocity (or the relative orbit squeezing parameter), and which does not necessitate any separation of the electrostatic potential into equilibrium and perturbed parts. Existing results (Hahm `96; Qin et. al., 20062007) can be obtained via subsidiary orderings. [Preview Abstract] 

YP8.00016: Simulation studies of FRC with rotating magnetic field current drive E.V. Belova, R.C. Davidson The HYM code has been modified to include the effects of rotating magnetic field (RMF) current drive. Initial 3D twofluid and hybrid simulations have been performed for evenparity RMF and different plasma parameters. Simulations show that the RMF pushes the plasma radially inward, resulting in a reduced plasma density outside the separatrix. Lower plasma density and larger RMF amplitudes result in faster RMF field penetration, in agreement with previous studies [R. Milroy, Phys. Plasmas 8, 2804 (2001)]. Effects of the applied RMF field on particle confinement have been studied using 3D test particle simulations. Simulations of stationary RMFs show that for relatively large ion Larmor radius ($S^*<20$), there is very little difference between even and oddparity RMFs in terms of the ion losses. The rate of particle losses is larger in larger FRCs, and increases with the RMF amplitude. In contrast, highfrequency RMF can reduce ion losses provided $\omega_{rmf} \gg \omega_{ci}$, and the RMF is of evenparity. The improved particle confinement is related to ponderomotive forces due to the rapidly oscillating, inhomogeneous electromagnetic field. It is also found that highfrequency, oddparity RMFs force particles away from the midplane toward the FRC ends. [Preview Abstract] 

YP8.00017: A Vertical ECE Diagnostic for TCV L. Porte, S. Coda, S. Alberti, R. Bertizzolo, R. Chavan, JM. Mayor, V. Udintsev, A. Simonetto With ECRH power density unrivalled in the fusion community, TCV is in a unique position to study fastelectron dynamics in regimes where quasilinear effects dominate. TCV is equipped with a comprehensive suite of ECE heterodyne radiometers that covers the first three ECE harmonics. A new vertical line of sight will be installed which will allow measurements to be made whose interpretation is straightforward and yields direct information on the fast electron energy distribution. The line will be equipped with a glass ceramic (MACOR) beam dump mounted in the vacuum vessel while the focussing optics will be placed in air behind a quartz window. An oversized, corrugated transmission line will transport the radiation from the tokamak to the radiometers. The diagnostic layout and the physics potential will be described. [Preview Abstract] 

YP8.00018: An Improved Collision Algorithm for Explicit and Hybrid Implicit PIC Simulations Larissa A. Cottrill, Andreas Kemp, Max Tabak Since its acclimation from the ion beam community, the LSP code has been used to model a wide range of laserplasma configurations relevant to fast ignition research. Given the high density, low temperature regimes of interest for some of these problems, there has been an increased concern for the role collisionality might play in hot electron beam transport and how one would appropriately model this in an electromagnetic hybridimplicit particleincell code such as LSP. Although a number of scattering models exist in the literature and in practice, there are always underlying concerns for computational efficiency and kinematic accuracy. This work will present a new collision algorithm for the LSP code that will improve upon the inter and intraspecies collision algorithms that currently exist within the code. Comparisons between various aspects of the old and new models will be presented for several beamplasma problems of interest. This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract W7405ENG48. [Preview Abstract] 

YP8.00019: Evolution of Nongyrotropic Pressure in Collisionless Magnetic Reconnection Haihong Che, J. Drake, M. Swisdak From the view of statistics, we separate the nongyrotropic pressure into two multiplied parts: the gyrotropic pressure and the correlation function in particle velocity space. The gyrotropic pressure is related to the heating process. The correlation is determined by the chaotic motion at xline or by the turbulent process, which depend on the type of the instabilities. We perform both 3D low and high temperature magnetic reconnection particle simulations. The low temperature develop a Buneman instability around xline while the turbulence is absent in the high temperature simulation. Our simulations show that 1) the resonant chaotic motion occur at xline while the width of electron current sheet is in the order of electron Lamour radius, which build up a significant correlation in electron velocity space. The contribution to correlation from the turbulence is small because the instabilities occur in our simulation are uncorrelated in the nongyrotropic space. 2) The anomalous heating also enhance the role of nongyrotropic pressure . The heating caused by turbulence is much more effective than the heating caused by the chaotic motion. [Preview Abstract] 

YP8.00020: 1 D analysis of Radiative Shock damping by lateral radiative losses. Michel Busquet, JeanPhilippe Colombier, Chantal Stehle It has been shown theoretically and experimentally [1] that the radiative precursor in front of a strong shock in hiZ material is slowed down by lateral radiative losses. The 2D simulation showed that the shock front and the precursor front remain planar, with an increase of density and a decrease of temperature close to the walls. The damping of the precursor is obviously sensitive to the fraction of selfemitted radiation reflected by the walls (the albedo). In order to perform parametric studies we include the albedo controlled lateral radiative losses in the 1D hydrocode MULTI (created by Ramis et al [2]) both in terms of energy balance and of spectral diagnostic. \newline \newline [1] Gonzales et al, Laser Part. Beams 24, 16 (2006) ; Busquet et al, High Energy Density Physics (2007), doi: 10.1016/j.hedp.2007.01.002 \newline [2] Ramis et al, Comp. Phys. Comm., \textbf{49} (1988), 475 [Preview Abstract] 

YP8.00021: Beam plasma electromagnetic instabilities in a smooth density gradient:Applications to ICF fast ignition Antoine Bret, Claude Deutsch We detail a calculation of the integrated growth rate(GR) of an instability in a weakly varying plasma density gradient using a WKBlike approximation.We justify such an assumption in the fast ignitor scenario context.Our formalism includes 2 stream, filamentation and 2stream/filamentation instabilities.The latter features an appropriate mixture of the separate two former ones.It is also the fastest.We demonstrate that filamentation is damped through the density gradient whereas 2stream and 2stream/filamentation saturate even before being submitted to the density gradient. [Preview Abstract] 

YP8.00022: Structural transitions in spherical 3D screened Coulomb crystals Michael Bonitz, Daniel Asmus, Volodymir Golubnichiy, Henning Baumgartner, Patrick Ludwig After the first observation of 3D Coulomb crystals [2], the particularly interesting structures of spherical concentric shells were found in experiment and simulations [3], and it was then demonstrated that the Coulomb interaction between the dust particles is screened [4]. Here, we extend this work by performing extensive molecular dynamics simulations to calculate the ground states of mesoscopic Coulomb balls ($N\le 60$) in a wide range of screening parameters. The ground states interesting structural transitions, such as the changes of the shell population with the screening parameter as well as the particle number. We present a phase diagram where a general trend to increased inner shell populations with increased screening can be seen.\newline [1] R. W. Hasse et al., Phys. Rev. A 44, 4506 (1991)\newline [2] O. Arp et al., Phys. Rev. Lett. 93, 165004 (2004)\newline [3] P. Ludwig et al., Phys. Rev. E 71, 046403 (2005)\newline [4] M. Bonitz,et al., Phys. Rev. Lett. 96, 075001 (2006) [Preview Abstract] 

YP8.00023: Diamagnetic loop for KSTAR. JunGyo Bak, SangGon Lee, EunMie Ka Three sets of diamagnetic loop (DL), at different locations, are designed to measure diamagnetic flux during a plasma discharge in the KSTAR machine. Each set consists of two concentric poloidal loops, and it is used for the diamagnetic flux measurement with the compensation of a ripple from to the power supply producing a toroidal field and a pickup signal from the poloidal field due to the misalignment in the installation. One set is installed on inner wall of the vacuum vessel for the flux measurement at the first plasma in the KSTAR machine. It is located at a toroidal angle in the vacuum vessel, and the gap distance between inner and outer loops is 2 cm. An accurate position measurement of the two loops is done by using a laser tracker system after the installation. The \textit{insitu} calibration of the loops is done from the toroidal flux measurement. In the measurement, the electric current of less than 100A is applied to the toroidal field coils. In this work, present status of the DL for the initial measurement in the KSTAR machine will be presented. [Preview Abstract] 

YP8.00024: Mix Calculations of DoubleShell capsule implosions on Omega and NIF N.D. Delamater, G.R. Magelssen, M.A. Gunderson, D.C. Wilson, I.L. Tregillis Recently, Los Alamos has renewed its effort [1] to design and evaluate doubleshell capsules as an alternative to the singleshell cryogenic NIF design. [2] The recent work by Livermore is being used as a starting point. [34] One to two megajoules of laser energy is used as input into the designs being considered. 1D and 2D integrated calculations of both the NIF capsule design and the doubleshell design recently fielded on Omega will be presented. The unmixed calculations for a NIF design give ignition with moderate gain $<$ 10. Calculations of the Omega double shell design are shown and application of the Omega experiments to the scaled up NIF double shell ignition design is discussed. Sensitivity to mix effects in these implosions with respect to overall yield, implosion hydro, asymmetry and imploded capsule core xray emission is investigated using a multifluid interpenetration model. [5,6] Work supported by US DOE/NNSA, performed at LANL, operated by LANS LLC under Contract DEAC5206NA25396 [1] W. S. Varnum et al., Phys. Rev. Lett. 84, 5153 (2000). [2] D. A. Callahan et al., Phys. of Plasmas 13, 56307 (2005). [3] P. A. Amendt et al., Phys. Rev. Lett. 94, 65004 (2005). [4] J. L. Milovich et al., Phys. of Plasmas 11, 1552 (2004). [5] A.J. Scannapieco and B. Cheng, Phys. Lett. A., 299, 49 (2002). [6] D.C. Wilson, et al., Phys. of Plasmas 11, 2723 (2004) [Preview Abstract] 

YP8.00025: Simulation Studies of the Pulse Line Ion Accelerator Enrique Henestroza, Roxanne Martinez The Heavy Ion Fusion Science Virtual National Laboratory has been studying the Pulse Line Ion Accelerator (PLIA) concept, motivated by the desire for an inexpensive way to accelerate intense short pulse heavy ion beams to regimes of interest for studies of high energy density matter and fusion ignition conditions. The PLIA uses a slowwave structure based on a helical winding, on which a voltage pulse is launched and propagated to generate the accelerating fields. The PLIA has the ability to accelerate ion bunches to energies much greater than the peak applied voltage and over distances much larger than the voltage pulse ramp length; furthermore, the PLIA can axially confine the heavy ion beam bunch. These properties make it a good candidate for a high intensity, short bunch injector. We will present selfconsistent numerical simulation studies of the beam dynamics in the PLIA. [Preview Abstract] 

YP8.00026: Simulations of Radiation Flow in Inhomogeneous Foams M.A. Gunderson, P. Keiter, J. Foster, P. Rosen, A. Comley, M. Taylor Radiation flow through inhomogeneous materials has been of great interest in many areas, including astrophysics applications. However, experiments to study this phenomenon have proven very challenging. The experiment is made up of a scaleone OMEGA halfraum with an attached gold tube filled with various foamgold mixtures or pure foams. While we have had success in modeling the pure foam and the fine gold particle (less than 0.5 micron) ``atomically'' loaded foams, Mband radiation from the halfraum was preheating the inhomogeneous mixture. By increasing the gold particle sizes from 12 microns up to 59 microns, it appears that this problem has been mitigated. Gated xray imagers filtered to look at both 300 and 500 eV spectral bands were used as the primary diagnostic in determining the location of the temperature front through diagnostics slots in the gold tube. Comparisons between experimental data and simulations will be shown with the pure foam and ``atomically'' loaded foamgold mixtures as the bounding cases. Work supported by US DOE/NNSA, performed at LANL, operated by LANS LLC under Contract DEAC5206NA25396. [Preview Abstract] 

YP8.00027: A Unified Theory of Toroidal Momentum Transport and Momentum Transport Bifurcations by Drift Wave Turbulence P.H. Diamond, C. McDevitt, O.D. Gurcan, T.S. Hahm, V. Naulin We present a unified theory of toroidal momentum transport, treating both resonant and nonresonant particle contributions. A general momentum conservation theorem is proved, which relates momentum density evolution to the resonant particle momentum flux, the wave momentum flux and a refractive force due to straining of wave packets. The wave momentum flux is calculated using a ChapmenEnskog like expansion of the wave kinetic equation. The results are used to explain a new class of momentum transport bifurcation. Possible origins of hysteresis are discussed. [Preview Abstract] 

YP8.00028: Low velocity ion stopping of relevance to the US beamtarget program Claude Deutsch, Romain Popoff We focus attention on the stopping mechanisms involved in the recently proposed US beamtarget program devoted to the production of warm dense matter through pulsed ion beams linearly accelerated and impacting thin solid foils in Bragg peak conditions.We concentrate on moderate or low ion projectile velocities Vp $<$ Vth, target thermal electron velocity. Ion projectile energy loss in the very low and Vp linear regime is investigated in a novel and statistical physics approach in terms of particle diffusion coefficients. Beam target interaction in the presence of an arbitrarily strong magnetic field is also considered. [Preview Abstract] 

YP8.00029: Using Half of NIF to Tune FullScale Ignition Hohlraums Nelson Hoffman, Douglas Wilson, Robert Goldman If fusion ignition is to be achieved at NIF, the symmetry of drive radiation incident on the ignition capsule must be superb. Thus techniques for diagnosing and verifying drive symmetry are highly important. Here we describe how half of the NIF facility (i.e., only 96 laser beams, expected to be available in 2008) can be used to tune drive symmetry in fullscale ignition hohlraums during the first several steps (the ``foot'') of the ignition pulse, in a manner similar to what will be done with full 192beam NIF. This is possible because the foot requires less than half of the energy and power NIF can deliver, so half the beams each running at twice the power can deliver the fullscale energy during the foot, although not during the final, highestpower step. Only modest compromises are necessary due to the slightly different illumination geometry with 96 beams. We propose a set of symmetry capsules imploding at properly chosen times, allowing foot tuning by beam phasing, thus expediting final foot tuning with 192 beams. [Preview Abstract] 

YP8.00030: An advanced Xray imaging crystal spectrometer for tokamak plasmas Sang Gon Lee, Jun Kyo Bak, Min Gap Bog, Uk Won Nam, Myung Kook Moon, Jong Kyu Cheon An advanced Xray imaging crystal spectrometer (XICS) utilizing a segmented positionsensitive two dimensional (2D) multiwire proportional counter and timetodigital converter (TDC) based delayline readout data acquisition system is under development. The XICS provides spatially and temporally resolved measurements of the ion and electron temperatures, toroidal rotation velocity, impurity chargestate distributions, and ionization equilibrium. Recently, a prototype of twosegmented detector with a F1 chip TDC based delayline readout and supporting electronics successfully demonstrated to improve the photon countrate capability of the XICS system. Based on this improvement, further developments including four and eightsegment detectors and supporting electronics are possible. Furthermore, a vacuum brazing technique for a small thin beryllium window has been successfully developed. This vacuum brazing technique will be applied to the detector development in order to increase detector performances as compared to the typical epoxybonding method. The current development status of the advanced Xray imaging crystal spectrometer will be presented. [Preview Abstract] 

YP8.00031: PIC simulations of cone surface roughness and angle dependence in high intensity laser/microcone interaction Nathalie Le Galloudec, Emmanuel d'Humieres, Byoung Ick Cho, Jens Osterholz, Todd Ditmire, Yasuhiko Sentoku It has been recently demonstrated that compared to a typical flat target, microcone targets can increase laser energy absorption and energetic electrons temperature when irradiated by a high intensity laser. These increases are very promising for numerous applications of high intensity laser plasma interaction, like proton acceleration or isochoric heating. Using ParticleinCell simulations, we have analyzed the role of cone surface roughness and cone angle in changing the characteristics of the produced energetic electrons population. Our results are compared to experiments done at UT Austin with the Thor laser (0.5 J, 40 fs, 800 nm, 7 microns focal spot). Based on these results, we propose new microcone designs to increase the efficiency of laser energy deposition. [Preview Abstract] 

YP8.00032: Modelling of hydrodynamics instabilities including the non local heat transport Marina OlazabalLoume, JeanLuc Feugeas, Philippe Nicolai, Javier Sanz Experimental works [T. Sakaiya {\it et al.}, Phys. Rev. Lett. 88, 145003 (2002)] have shown that the growth rate of ablative RayleighTaylor instability is well reproduced by the simulation that solves the nonlocal heat transport. Furthermore, it has been recently pointed out [V. N. Goncharov {\it et al.}, Phys. Plasmas 13, 012702 (2006)]that non local heat transport modifies characteristic lengths needed in hydrodynamic instabilities models. This work presents a new way to take into account the non local effects in hydrodynamic instabilities modelling. The simulations are performed with a code dedicated to the linear stability study of unsteady flows [M. OlazabalLoum\'e {\it et al.}, J. Phys. IV France 133 (2006)]. The code calculates a onedimensional basic solution and its first order 3D perturbation in Lagrangian formalism. It integrates a multidimensionnal non local model based on the approach of [JF. Luciani {\it et al.}, Phys. Rev. Lett. {\bf 51}, 1664 (1983)] and [E. Epperlein et al., Phys. Fluids B {\bf 3}, 3082 (1991)]. [Preview Abstract] 

YP8.00033: Transition From TwoFluid to Resistive MHD Tearing Instability in Slab and Cylindrical Geometries V.V. Mirnov, A. Cole, C.C. Hegna, S.C. Prager We report new results on the physics of twofluid tearing instabilities with particular focus on analytically understanding the transition between the twofluid and singlefluid MHD regimes. Linear eigenfunctions and quasilinear dynamo terms are calculated in both slab and cylindrical geometry with specific emphasis on edgeresonant m=0 tearing modes in the Madison Symmetric Torus (MST) reversed field pinch experiment. A twofluid quasilinear theory was originally derived for a sheared slab in [1] and generalized to cylindrical geometry in [2], where the effects of current gradient and field line curvature were analyzed in the electron MHD approximation. To investigate the transition between the different regimes, we extend the previous work to include the effects of ion motion. This allows us to analytically follow the transition from a twofluid to singlefluid regime. The growth rates and eigenmode profiles are obtained to allow comparison with twofluid MHD codes, and for interpretation of recent MST measurements of Hall reconnection. *Supported by the U.S.DoE and NSF. [1] V. V. Mirnov, C. C. Hegna, S. C. Prager, Plasma Physics Report 29, 612 (2003) [2] V.V. Mirnov, C.C. Hegna, S.C. Prager, C.R. Sovinec, H. Tian, Proc. of 21st IAEA FEC, Chengdu, China, TH/P318 (2006) [Preview Abstract] 

YP8.00034: Designs for subscale hohlraum energetics experiments on the National Ignition Facility N.B. Meezan, D.A. Callahan, M.J. Edwards, D.E. Hinkel, B.K. Spears, S.H. Glenzer, L.J. Suter The 96beam energetics campaign on the National Ignition Facility will use subscale targets to emulate the plasma conditions and laserplasma interaction (LPI) behavior of ignition hohlraums. These ``plasma emulator'' targets are geometrically scaled by a scalefactor s. To lowest order, the laser pulse shapes are also directly scaled (time $t \propto s$ and power $P \propto s^2$); however, finetuning the pulse can improve the hohlraum emulator quality. The plasma density inside the hohlraum depends strongly on the mass ablated from the capsule during the foot, so we try to match this to the ignition value, $m_{96}\left(t\right) = s^3 m_{ignition}\left(st\right)$. Matching the ablated mass leads to ignitionlike hohlraum plasma conditions. Linear gain analysis predicts LPI behavior in the emulator hohlraum that is qualitatively and quantitatively similar to that of an ignition hohlraum. [Preview Abstract] 

YP8.00035: Threedimensional measurements of earlytime symmetry in gasfilled hohlraums with the reemission ball technique G.R. Magelssen, N.D. Delamater, J.J. MacFarlane, O.L. Landen The reemission ball technique has been used in the past to measure early time capsule symmetry for experiments done on NOVA.[12] Livermore scientists are now pursuing this concept to study early time symmetry on NIF.[3] Here we review some unpublished results using this method.[4] The results include reemission measurements in methanefilled hohlraums irradiated by lasers with kinoform phase plates. They also include three dimensional measurements of asymmetries due to beam power imbalance and from diagnostic holes. Comparisons between experimental data and calculations will be shown. New results will also be presented. Reemission measurements made within spherical hohlraums will be shown. Finally, a method used to increase the time of the reemit measurement will be discussed and experimental results given. 1. G. R. Magelssen et al., Phys. Rev. E 57, pg. 4663 (1998). 2. N. D. Delamater et al., Phys. Rev. E 53, 5240 (1996). 3. Don Meeker, J. Edwards, private communication, LLNL. 4. G. R. Magelssen et al., Abstract 1998 APS meeting; G. R. Magelssen et al., ``ThreeDimensional measurements of early time radiation asymmetry in methanefilled hohlraums,'' LAUR073742. [Preview Abstract] 

YP8.00036: An explicit Hall MHD algorithm using the discontinuous Galerkin method John Loverich The discontinuous Galerkin method is a numerical wave propagation scheme that can achieve arbitrarily higher order accuracy. The method has received considerable attention from the numerical fluid dynamics community recently. In this paper an explicit discontinuous Galerkin Hall MHD algorithm is presented. The algorithm works in the high beta regime and can be used to simulate collisionless reconnection and fast instabilities in a Zpinch. Error wave propagation is used to correct divergence errors. The scheme uses auxiliary variables to treat the higher order derivatives that result from the Hall and diamagnetic drift terms. Hall MHD results are compared with full twofluid results and show good agreement. The explicit scheme is a first step in producing an implicit discontinuous Galerkin algorithm that does not suffer the time step restriction of the Whistler wave. [Preview Abstract] 

YP8.00037: Development of Generator of HighVelocity Gas Jet by using a Compact Toroid Injector D. Liu, N. Fukumoto, T. Takahashi, J. Miyazawa, Y. Kikuchi, M. Nagata Fueling expreiments by supersonic gas jets has been conducted on several tokamaks. The ability of gas jets, however, is not enough to penetrate into the plasma core. Rozhansky et al have proposed a new technique for acceleration of jet by a plasma gun to enhance the ability [1]. The jet has been successfully accelerated to 100 km/s, resulting in penetration into the plasma core on GlobusM. We have so far developed compact toroid (CT) injectors as a kind of plasma gun, and performed CT injection experiments. We have therefore considered generation of such a gas jet by using a CT injector. The preliminary experiment has been carried out to generate fast gas jets by CT injection into a plasma neutralizer cell with a singlestage CT injector at the University of Hyogo. The typical CT parameters are: 1$\sim $4 x 10$^{21}$ m$^{3}$ in electron density and 30$\sim $70 km/s in velocity. The neutralization efficiency of CT plasma has been also estimated by calculation. The technique will be applied to a CT injector of SPICA for an advanced fueler into LHD. \newline [1] V. Rozhansky et al, Proc. 33rd EPS Conf. on Plasma Phys., Roma, 2006, 30I, P4.107 (2006). [Preview Abstract] 

YP8.00038: Platform development of xray absorptionbased temperature measurements above 100eV on the OMEGA laser Jonathan Workman, P. Keiter, T. Tierney, H. Tierney, K. Belle, G. Magelssen, R. Peterson, C. Fryer, A. Comley, M. Taylor Experiments were performed on the OMEGA laser system at the University of Rochester to measure radiation temperature in hohlraumheated foams. Using xray absorption spectroscopy in the 36keV xray range allows temperature determination in the range of 50200eV. Uranium, bismuth and gold Mshell xray emission were used as broadband backlighters. Backlighter absorption through heated chlorinated foam and scandium tracers were used to determine temperatures. The development of this technique in the temperature range of 100200eV will be used for platform development of future NIF experiments. We will present timeintegrated and timeresolved measurements of xray emission from the backlighter materials as well as absorption measurements trough the heated tracer materials. We will also present future directions in the development of this platform. [Preview Abstract] 

YP8.00039: Sensitivity of DoubleShell Ignition Capsules to Asymmetric Drive I.L. Tregillis, G.R. Magelssen, N.D. Delamater, M.A. Gunderson, N.M. Hoffman Doubleshell (DS) targets [1] present an alternative approach to ignition via the cryogenic singleshell point design [2]. Although these targets present unique fabrication challenges, they embody many attractive features, including noncryogenic fielding and low threshold temperatures ($\sim$4 keV) for volume ignition [34]. We have used 2D radiationhydrodynamic modeling to survey the behavior of DS targets under asymmetric temperature drive in rugby vacuum hohlraums. The yield is robust against deviations from symmetric illumination, varying smoothly as a function of the imposed $P_{2}$ and $P_{4}$ amplitudes. Ignition occurs even when 10\% or more of the drive is contained in Legendre $P_{2}$ or $P_{4}$ components, with yield reductions on the order of 50\% for the most extreme cases investigated here. \\ \\ $[$1$]$ P. Amendt et al., Phys. of Plasmas 9, 2221 (2002) \\ $[$2$]$ D. A. Callahan et al., Phys. of Plasmas 13, 56307 (2005) \\ $[$3$]$ P. Amendt et al., Phys. Rev. Lett. 94, 65004 (2005) \\ $[$4$]$ W. S. Varnum et al., Phys. Rev. Lett. 84, 5153 (2000) [Preview Abstract] 

YP8.00040: Suppression of Weibel Instabilities in Advanced Fast Ignition Laser Fusion Pellets by Two ConeGuided Relativistic Laser Beams V. Stefan I propose utilization of two coneguided relativistic laser beams in antiparallel interaction with the fusion pellet as a novel approach for the suppression of Weibel instabilities in the core of advanced fast ignition pellets.\footnote{M. Tabak, J. Hammer, M.E. Glinsky, W.L. Kruer, S. C. Wilks, J. Woodworth, E. M. Campbell, and M.D. Perry, Phys. Plasmas 1 (5), 1626 (1994).} The propagation of generated suprathermal electron beam toward the core may lead to the appearance of colossal ($\sim $10MG), small scale (L$\sim$velocity of light/local electron plasma frequency\footnote{V. Stefan, Suppression of Weibel Instabilities by HighHarmonic Electron Bernstein Modes in Advanced Fast Ignition Laser Fusion Pellets.APS2006. October 30November 3, 2006; Philadelphia, Pennsylvania.} magnetic fields. This would suppress the transport of magnetic fields into the core of the pellet and may eliminate the difficulties in the nonlinearrelativistic treatment of magnetized core plasma. [Preview Abstract] 

YP8.00041: Dose Prediction in Plasma Ion Implantation Marcel Risch, Michael Bradley The exact knowledge of the plasma ion current, and hence the implanted dose, is essential for materials processing, but the measurement of those quantities requires complex instrumentation. We present the computation of the ion current and dose from the sampled negative voltage pulse applied to the electrode and plasma parameters obtained by virtue of Langmuir probe measurements. Firstly, we solved the equations of the Lieberman model for the sheath width and the plasma ion current, including errors, as a function of time. Then, integration of the ion current over the duration of the voltage pulse yielded the dose and its error limits. We will compare the plasma current predictions to the plasma current measured by a Faraday cup and the dose calculation will be verified by nuclear reaction analysis (NRA). The numerical methods were proven fairly accurate and are thus a valuable tool for materials engineering. [Preview Abstract] 

YP8.00042: POSTDEADLINE 

YP8.00043: A Test Suite for Magnetoinertial Fusion Jason Cassibry, Seth Thompson, Nilesh Dhote, Ron Kirkpatrick, Charles Knapp, S.T. Wu We present a set of hydrodynamic and magnetohydrodynamic problems that will provide a set of test cases for those interested in modeling magnetoinertial fusion (MIF) plasmas. We describe several problems in cylindrical and spherical geometries, including the Noh problem, selfsimilar converging shocks, and magnetohydrodynamic imploding shocks. We use these models to provide physical insights into implosion dynamics of targets in the MIF parameter space. We verify MACH2 and SPH against selected cases. [Preview Abstract] 

YP8.00044: ABSTRACT WITHDRAWN 

YP8.00045: ABSTRACT WITHDRAWN 

YP8.00046: Alpha Deposition in Magnetoinertial Fusion Targets Seth Thompson, Nilesh Dehote, Jason Cassibry, Ronald Kirkpatrick, Charles Knapp, S.T. Wu We performed a Monte Carlo simulation for plasmas with closed field line topology to quantify alpha deposition in magnetoinertial fusion (MIF) targets. It was assumed that the bornon position and initial velocity vector of an alpha particle is isotropic. The total energy deposited via scattering collisions is determined for a single alpha particle. This process is then repeated to achieve a statistical average. This quantity is volume averaged to get the fractional energy deposited in a target with a given set of conditions. Results were obtained for purely azimuthal, uniform and extended to field reversed configurations. LindlWidner diagrams were generated to identify fusion ignition regions in the MIF parameter space. [Preview Abstract] 

YP8.00047: Status of RF Heating and Current Drive Systems for KSTAR YoungSoon Bae, Jinhyun Jeong, Seungil Park, Moohyun Cho, Won Namkung, JongGu Kwak, JaeSung Yoon, YeongDuk Bae, SonJong Wang, SukKwon Kim, ChulKew Hwang, SungKyu Kim The heating and current drive systems consisting of neutral beam injection (NBI) and radio frequency (RF) systems will be used for the KSTAR whose construction will be completed by August, 2007. The KSTAR RF heating and current drive systems are composed of ion cyclotron range of frequencies (ICRF), lower hybrid current drive (LHCD) system, and electron cyclotron heating (ECH) system. The KSTAR adopts the ECHassisted startup for the flexibility and reliability of the operation regime using 84 GHz, 500 kW gyrotron. For the KSTAR first plasma scheduled at June, 2008, two RF heating systems, 84 GHz ECH and 2560 MHz ICRF systems, will be used for the preionization to reduce the loop voltage and the wall discharge cleaning, respectively. This paper describes the status of the KSTAR RF heating and current drive systems and the initial test results using dummy load. Also, the upgrade plan of the KSTAR RF heating and current drive systems will be presented as well as the key features and the relevant technological issues for the long pulse operation. [Preview Abstract] 

YP8.00048: Extremely Nonsinusoidal Emissions and Fast Electron Phenomena from Strong Laser Pulses Obliquely PIncident on SharpEdged Plasmas T.W. Johnston, L. Nikolic, Y. Tyshetskiy, F. Vidal High laser harmonic light [1] emerges when the Vulcan petawatt laser's subps laser pulses are obliquely incident on slab targets with extremely low prepulse energy. Similar work is in progress with the ALLS 200 TW TiSaph laser at INRS EMT. (Pulses are 24 fs at 10 Hz with 10$^{10}$ contrast, even without plasma mirrors). 2D PIC (OSIRIS code at INRS) results on basic mechanism(s) resemble those of Gibbon [2], Naumova et al. [3] and Thaury et al. [4]. The very large and asymmetric electromagnetic ``spikes'' which account for the high harmonic content are produced by extremely concentrated 2D plasma surface currents. The connection between our 2D PIC results (also those in [3] and 1D PIC results [2,4] using the GibbonBourdier moving 1D formalism[2] is also discussed, as are the fast electrons, including some related quasisteady magnetic fields. [1] B. Dromey et al Nature Phys. Lett., 2, 456459 (2006) [2] Paul Gibbon, Phys. Rev. Lett. 76, 50 (1996) [3] N. Naumova, et al., Phys. Rev. Lett. 93, 195003 (2004). [4] C. Thaury, et al., Nature Phys. 3, 424 (2007) [Preview Abstract] 

YP8.00049: Semianalytical solution of initialvalue problems Jan Scheffel A fully spectral weighted residual method for solution of general initial value partial differential equations has been developed [1]. All time, spatial and physical parameter domains are represented by Chebyshev series, enabling global semianalytical solutions. The method avoids time step limitations. The spectral coefficients are determined by iterative solution of a linear or nonlinear system of algebraic equations, for which a globally convergent root solver has been developed. Accuracy is controlled by the number of included Chebyshev modes in each dimension. The computational efficiency is shown to increase through the use of subdomains. It is shown by example that the method may be used for efficient solution of nonlinear initial value problems in fluid mechanics and magnetohydrodynamics. [1] J. Scheffel, ``Semianalytical solution of initialvalue problems,'' TRITAALF200403, Royal Institute of Technology, Stockholm, Sweden, 2004. [Preview Abstract] 

YP8.00050: Stability and growth rates of ideal localized interchange modes Maxim Umansky Stability of cylindrical localized ideal pressuredriven interchange plasma modes is revisited. Converting the underlying eigenvalue problem into the form of the Schrodinger equation gives a new simple way to derive the Suydam stability criterion and find the growth rates of unstable modes, using physical arguments and calculations based on elementary quantum mechanics. Near the marginal stability limit the growth rate is exponentially small and the mode has a double peak structure. [Preview Abstract] 

YP8.00051: Laserinducedfluorescence in the sheath of a thermionic Ar/O$_2$ Plasma. Sebastian Enge, Fara Aziz, Alf K\"ohn, Eberhard Holzhauer, Ulrich Stroth In most technical plasma processes, the ion impinging energy has an important influence on the process quality. The ions gain their energy from the potential drop in the sheath region. To modify the ion energy, the substrate can be biased with a radiofrequency voltage. Furthermore, in plasma etching processes negative ions influence the sheath potential and thus the ion energy. Therefore information on the ion velocity distribution function (ivdf) in the sheath region is needed to improve the quality of plasma processing. For the investigation of the ivdf in the sheath region, a laserinducedfluorescence diagnostic is installed on a doubleplasma device. The diode laser used has an optical output of 25~mW at 668.6~nm and a modehopfree tuning range of 20~GHz. It is modulated with an acoustic optical modulator. The fluorescence light is collected with a PMT. For data acquisition, a 24bit 100~kS/s PC card is used. In the first step the sheath potential has been studied in DC discharges for different fractions of negative ions in the Argon plasma. The experimental setup and first results on the sheath profile will be presented. [Preview Abstract] 

YP8.00052: Measurement of nonlinear energy transfer in twodimensional plasma turbulence Peter Manz, Mirko Ramsich, Ulrich Stroth An important questions concerning the turbulent cascade is how energy is transfered among the scales. In threedimensional fluid turbulence the energy cascades from large to small scales. Whereas in twodimensional fluid turbulence the transfer is in the opposite direction, via an inverse cascade in, while the enstrophy is transferred by a direct cascade. In magnetised plasmas the turbulence can be assumed twodimensional. In this work the turbulent energy cascade in simulated and experimental data from toroidally confined plasmas is studied by bispectral methods, which base on the model of threewave interaction. General properties of the twodimensional HasegawaWakatani turbulence are recovered, which are the analytically known growth rate, dispersion relation and the direction of the energy transfer. The results from measurements in density and potential fluctuations by using a 2D probe array in the torsatron TJK are in good agreement with the simulated data from the HasegawaWakatani turbulence. The density fluctuations, which are advected by the vorticity, show free energy transfer to smaller scales, while the $E\times B$ energy of the potential fluctuations is transferred as an inverse cascade to larger scales. [Preview Abstract] 

YP8.00053: Parametrics for Molecular Deuterium Concentrations in the Source Region of the UWIEC Device Using an Ion Acoustic Wave Diagnostic D.R. Boris, G.A. Emmert The ion source region of the UWInertial Electrostatic Confinement device is comprised of a filament assisted DC discharge plasma that exists between the wall of the IEC vacuum chamber and the grounded spherical steel grid that makes up the anode of the IEC device. A 0dimensional rate equation calculation of the molecular deuterium ion species concentration has been applied utilizing varying primary electron energy, and neutral gas pressure. By propagating ion acoustic waves in the source region of the IEC device the concentrations of molecular deuterium ion species have been determined for these varying plasma conditions, and high D$_{3}^{+}$ concentrations have been verified. This was done by utilizing the multispecies ion acoustic wave dispersion relation, which relates the phase speed of the multispecies ion acoustic wave, $v_{ph}$, to the sum in quadrature of the concentration weighted ion acoustic sound speeds of the individual ion species. [Preview Abstract] 

YP8.00054: Neoclassical Conductivity and Fraction of Trapped Particles for Damavand Tokamak. Fatemeh Dini, Sina Khorasani The Spitzer or classical conductivity is the conductivity of cylindrical plasma column\textbf{. }The neoclassical theory, taking into account the toroidal geometry of the plasma, predicts under certain conditions the existence of socalled banana particles, which are trapped in the magnetic field and do not contribute to the plasma conductivity. Here, the best proposed expression for the neoclassical conductivity in terms of fraction trapped particle has been used. A standard model for the Damavand Tokamak plasma equilibrium, with largeaspectratio and elongation (A$\sim $5.1, k$\sim $1.2), is considered for evaluating averaged magnetic field in flux coordinates. Analytical and numerical calculations have been obtained using integration of ellipticity function within the approximation of large aspect ratio and zeroshift of flux surfaces for Damavand Tokamak. [Preview Abstract] 

YP8.00055: Long time electron cloud instability simulation using QUICKPIC with pipelining algorithm Bing Feng We proposed a novel algorithm, which uses pipelining to reduce the simulation time for beamelectron cloud interaction. In the pipelining algorithm the processors are divided into subgroups, and during the simulation different groups will be on consecutive time steps. The pipelining algorithm is applied to the fully parallelized ParticleInCell (PIC) code QuickPIC to overcome the limit of the number of processors that can be used at each time step. With the new algorithm, the accuracy of the simulation is preserved; and the speed of the simulation is improved by a factor proportional to the number of processors available. The long term beam evolution results for the CERNLHC using the QuickPIC with pipelining algorithm are presented. [Preview Abstract] 

YP8.00056: Penumbral Dynamics and its Manifestation in the Overlying Chromosphere Margarita Ryutova, Thomas Berger, Theodor Tarbell, Zoe Frank, Alan Title Mature sunspots are usually surrounded by penumbra  a dense conglomerate of a random interlaced flux tubes with varying inclinations. High resolution observations show a fine substructure of penumbral filaments and new regularities in their dynamics. These regularities fit well our recent model of penumbra based on cascading reconnection events occurring in the system of noncollinear flux tubes. Each act of reconnection generates twist in the reconnected filaments and facilitates the onset of a screw pinch instability, consistent with the observations showing that individual filaments are cylindrical helices with a pitch/radius ratio providing their stability. In addition, the postreconnection products produce a slingshot effect that generates oblique shocks and leads to appearence of a lateral jets. Here we report high resolution (120180 km) high cadence (1530 sec) observations taken with the Solar Optical Telescope (SOT) on the Hinode satellite. Coaligned multihour movies taken simultaneously in several wavelengths show detailed behavior of penumbra filaments and their effect on the overlying chromosphere. We confirm the ubiquitous nature of penumbral microjets recently discovered by SOT instrument (Katsukawa et al. 2007, AAS 210, 94.13), and present quantitative analysis of chromospheric jets based on our recent model of penumbra. [Preview Abstract] 

YP8.00057: A Simulation Study of Hall Effect on Double Tearing Modes Zhiwei Ma, Chenglong Zhang, Jiaqi Dong The Hall magnetohydrodynamics (MHD) simulation is carried out to study the dynamic process of a double tearing mode. The results indicated that the growth rates in the earlier nonlinear and transition phases agree with previous results. With further development of reconnection, the current sheet thickness is much smaller than the ion inertia length, which leads to a strong influence of the Hall effects. As a result, the reconnection in the late nonlinear phase exhibits an explosive nature with a time scale nearly independent of resistivity. A localized and severely intensified current density is observed and the maximum kinetic energy is over one order of magnitude higher in Hall MHD than in resistive MHD. [Preview Abstract] 

YP8.00058: Investigation of Xray lasers on the SOKOLP facility at RFNCVNIITF D.S. Gavrilov, A.V. Andriyash, D.A. Vikhlyaev, S.A. Gorokhov, D.A. Dmitrov, A.L. Zapysov, A.G. Kakshin, I.A. Kapustin, E.A. Loboda, V.A. Lykov, V.Yu. Politov, A.V. Potapov, V.A. Pronin, G.N. Rykovanov, V.N. Sukhanov, A.S. Tischenko, A.A. Ugodenko, O.V. Chefonov The experiments [1] have demonstrated generation of the laser Xradiation (LXR) $\lambda $=326A on 3p3s transitions of Nelike Ti ions at sequential irradiation of the targets by two laser pulses, focused into a narrow line. The small signal gain equaled 30cm$^{1}$. The intensity was 0.5$\cdot $10$^{12}$ W/cm$^{2}$ in the prepulse of 0.4ns and 10$^{14}$ W/cm$^{2}$ in the master pulse of 4ps (delay 1.5 ns). The dependence of LXR yield on the laser energy is demonstrated to have an exponential form. The traveling pumping wave mode was realized using the reflective echelon and the LXR yield is as great as 5fold. The latest experiments have demonstrated the LXR generation on 4d4p of Nilike molybdenum $\lambda $=189A. The development of LXR generation model, and numerical codes which allow for the quanta delay effects, quanta refraction in plasma with heavy density gradient, and also the saturation effect have made it possible to describe the experimental dependence of the output LXR yield on the active medium length. Good quantitative agreement is also evident when estimating the output LXR yield on Nelike Ti ions. [1]Andriyash Quantum Electronics 36 511 [Preview Abstract] 

YP8.00059: Laser heating of solid matter by light pressuredriven shocks at ultrarelativistic intensities K. Akli, M. Key, A. Kemp, S. Hansen, R. Stephens, R. Freeman, F. Beg, D. Clark, D. Hey, S. Hatchett, K. Highbarger, E. Giraldez, J. Green, G. Gregori, K. Lancaster, T. Ma, A. Mackinnon, P. Norreys, P. Patel, C. Stoeckl, W. Theobald, R. Weber, L. Van Woerkom, N. Patel, M. Storm Heating by irradiation of a solid surface in vacuum with 5x10$^{20}$ Wcm$^{2}$, 0.8 ps, 1.05 micron wavelength laser light is studied by xray spectroscopy of the Kshell emission from thin layers of Ni, Mo and V. A surface layer is heated to $\sim $5 keV with an axial temperature gradient of 0.6 $\mu $m scale length. Images of Ni Ly$\alpha $ show the hot region has a $\sim $25 $\mu $m diameter. These data are consistent with collisional particleincell simulations using preformed plasma density profiles from hydrodynamic modeling, which show that the more than 100 \textit{Gbar }light pressure compresses the preformed plasma and drives a shock into the solid heating a thin layer. [Preview Abstract] 

YP8.00060: Microwave Soliton Generation and Propagation in a Cylindrical Partially Plasma Filled Waveguide Seyed MoradAli Hashemi A perfect electrical conductor (PEC) cylindrical waveguide with a radius of r$_{1}$ is considered as the main part of a basic microwave generator model in the cylindrical geometry which supports the axial movement of an electron beam of radius r$_{2 }\le $ r$_{1}$ inside it. Using fluid theory of plasma, it has been shown that this structure is capable of supporting nonlinear Schr\"{o}dinger (NLS) soliton generation and propagation. The wave equation for the vector potential \textbf{A} has been derived using plasma dispersion relation. The equation has then been separated into two different equations in the transverse and axial directions, considering a solution in the form of a function of transverse variables multiplied by another time dependent function of axial variable, the latter itself having two components: a fast oscillation with a slowly varying amplitude. Once $\beta $, the propagation constant in the axial direction, obtained by applying boundary conditions in the former equation, the latter equation can be manipulated by imposing a perturbation on the dielectric constant. This will result in a perturbation on propagation constant which in turn will induce to the calculations the nonlinear term required for NLS equation in the form of a pondermotive force, completing derivation of the required NLS equation supporting the soliton formation and propagation. [Preview Abstract] 

YP8.00061: Direct Observation of Electron Bernstein Wave on the Internal Coil Device MiniRT Eiichi Yatsuka, Daisuke Sakata, Kiyotake Kinjo, Junji Morikawa, Yuichi Ogawa Electron Bernstein Wave (EBW) heating is one of the most promising methods of producing and heating of overdense plasma, i.e., the plasma density is higher than a cutoff density. Overdense plasma was observed with steep density gradient by ECH (2.45GHz, 2.5kW) in internal coil device MiniRT. Directly measurements of electric field with electron cyclotron range of frequency were carried out, in order to investigate the basic characteristics of mode conversion to EBW. An extra microwave (1.0$\sim $2.1GHz, 10W) has been injected with an excitation antenna, and has been directly measured with a receiver antenna inside the plasma column. With the combination of floating and levitation coils, which are located inside and above the vacuum vessel, we can produce a separatrix configuration with a steep density gradient, which is one of important parameters on the EBW mode conversion. With appropriate magnetic configuration and density profile, we can see a characteristic of a short wavelength related with the EBW. In addition, the reversal of phase variation can be observed. Since the EBW is backward wave (direction of phase velocity is opposite to that of group velocity), these experimental results suggest the direct measurement of the EBW. [Preview Abstract] 

YP8.00062: Magnetohydrodynamic Waves Driven by CW AM Modulation of Helicon Plasmas Saeid Houshmandyar, Alex Hansen, Earl Scime Nonlinearly interacting, lowfrequency, magnetohydrodynamic waves, and the resultant cascade of energy to larger perpendicular or parallel wave numbers, have been suggested as a possible explanation for electron and/or ion heating in the expanding solar corona. In experiments undertaken in HELIX (Hot hELIcon eXperiment), we have explored the possibility of exciting large amplitude, lowfrequency waves in a high density helicon plasma through the continuouswave AM modulation of the rf antenna of a helicon plasma source. Magnetic fluctuation measurements indicate that low frequency waves are excited in helium helicon plasmas at the AM modulation frequency. We will present measurements of the parallel and perpendicular wave numbers obtained from ensembleaveraged measurements as a function of AM frequency, background magnetic field strength, and neutral gas pressure. No resonant behavior is observed for AM frequencies close to the helium ion cyclotron frequency. [Preview Abstract] 

YP8.00063: Turbulent transport of energetic particles in global gyrokinetic particle simulations Wenlu Zhang, Viktor Decyk, Yasutaro Nishimura, Zhihong Lin Multispecies capability has been added to the gyrokinetic toroidal code (GTC), which has been applied to study the behavior of energetic particles in burning plasmas. The effect of microscopic iontemperaturegradient (ITG) turbulence on energetic particles transport is investigated using the large scale gyrokinetic particle simulations. [Preview Abstract] 

YP8.00064: Nonextensive ThomasFermi model Bhimsen Shivamoggi, Evgeny Martinenko Nonextensive ThomasFermi model was father investigated in the following directions: Heavy atom in strong magnetic field. following Shivamoggi work on the extension of Kadomtsev equation we applied nonextensive formalism to father generalize TF model for the very strong magnetic fields (of order 10e12 G). The generalized TF equation and the binding energy of atom were calculated which contain a new nonextensive term dominating the classical one. The binding energy of a heavy atom was also evaluated. ThomasFermi equations in N dimensions which is technically the same as in Shivamoggi (1998) ,but behavior is different and in interesting 2 D case nonextesivity prevents from becoming linear ODE as in classical case. Effect of nonextensivity on dielectrical screening reveals itself in the reduction of the envelope radius. It was shown that nonextesivity in each case is responsible for new term dominating classical thermal correction term by order of magnitude, which is vanishing in a limit q$>$1. Therefore it appears that nonextensive term is ubiquitous for a wide range of systems and father work is needed to understand the origin of it. [Preview Abstract] 

YP8.00065: Plasma dynamics in DUSTWHEEL F. Greiner, S. Knist, A. Piel The new experiment DUSTWHEEL consists of a set of 24 watercooled magnets, which produce a steadystate magnetic field of {\bf B} $\le$ 0.7T that is homogeneous over a length of L~=~1~m. DUSTWHEEL has a special design for the investigation of drift or flute modes under the influence of a dusty plasma environment. In contrast to other plasma constituents dust particles are strongly affected by gravitation. To deal with this the magnets of DUSTWHEEL are suspended in a wheelshaped cage, which allows tilting the entire experiment. In this way, the angle between the magnetic field direction and gravity can be chosen at will. This allows exciting dust flows by a variation of the residual component of gravity. The plasma in DUSTWHEEL is produced by means of a capacitive high frequency discharge at 13.56 MHz. The low density plasma has a Gaussian shaped density profile with a peak density of $4~10^{14} ~m^{3}$. The electron temperature is nearly constant with a value of circa $4~eV$. A detailed analysis of density and potential fluctuations using Langmuir probes shows a turbulent plasma state with almost no mode like behavior. As a control parameter to get different dynamic states a biasing voltage can be applied to the plasma. In this way the plasma can also be driven to modelike states. Amplitude and structure Analysis reveals that the structures have drift wave dynamics. So, DUSTWHEEL is ready to put dust inside and study the modification of drift waves. [Preview Abstract] 

YP8.00066: Photoelectron Plasma for Antiproton Cooling in Antihydrogen Production Benjamin Levitt A new photocathode electron source has been developed for antiproton cooling for antihydrogen production in the ATRAP2 Penning trap apparatus. Tennanosecond pulses of photoelectrons liberated by intense UV laser pulses from a thin gold layer are captured into a singlecomponent plasma. Up to a billion electrons are accumulated using a series of laser pulses, more than are needed for efficient p cooling. The method is demonstrated within an enclosed vacuum space that is entirely at 4 K, and is thus compatible with the exceptional cryogenic vacuum that is desirable for the longterm storage of antihydrogen. The pitfalls of other electron accumulation methods are entirely avoided, including the particle heating and declining efficiency of field emission point loading, and the heat load and contamination of thermionic emission methods. We also report on other recent ATRAP results, including antiproton stability and antihydrogen production inside a quadrupole PenningIoffe trap. [Preview Abstract] 

YP8.00067: Quantification of factors contributing to the xray spot produced by the paraxial diode with a plasmafilled drift cell David Short, Dale Welch The paraxial diode with a plasmafilled drift cell is currently under investigation as a focusing element for the HRF at AWE Aldermaston. The long term xradiographic goal is for an xray dose of 1000 Rads@1m in a 2mm spot. To meet this the plasmafilled drift cell needs to provide complete space charge and current neutralization. In this manner the electrons will focus ballistically meeting at a common focus within the plasma drift cell [1]. However, any time variation in current neutralization, due to a finite magnetic diffusivity, will result in some degree of focal sweep and an increased spot size at the high Z target. The work presented here will attempt to quantify this factor and any other effects that impact the spot on the high Z target. Computer simulations are carried using the particle in cell code Lsp [2]. An idealized beam injection into the drift cell was used to examine the effect perfect entrance conditions would have on the focusing spot. The findings indicate that the plasmafilled paraxial using a flat plate cathode is likely to give a total time integrated spot of around 3mm. Updates on the latest simulations are also discussed. [1]. D.Welch \textit{et al}. Transport of a relativistic electron beam in gas and plasmafilled focusing cells for xradiography, Phys.Plasmas, \textbf{11}, pp 751760 (2004) [2]. Lsp is a software product of Mission Research Corporation, www.mrcabq.com [Preview Abstract] 

YP8.00068: Remarks on the Scaling of Kurtosis with Squared Skewness J.A. Krommes Recent analysis of density fluctuations in TORPEX\footnote{B. Labit \emph{et al.}, Universal statistical properties of driftinterchange turbulence in TORPEX plasmas, Phys.\ Rev.\ Lett. \textbf{98}, 255002 (2007).} support the relationship $K = aS^2 + b$ between the skewness $S$ and (excess) kurtosis $K$, where $a \approx 1.5$ and $b \approx 0.2$. (A realizability constraint is $K \ge S^2  2$.) Remarkably, essentially the same result has been shown to hold for a global dataset of fluctuations of seasurface temperature,\footnote{P. Sura and P. D. Sardeshmukh, A global view of nonGaussian SST variability, J. Phys.\ Oceanogr.(2007), in press.} and a simple theoretical (nonlinear Langevin) model has been proposed\footnotemark[3] that leads to $a = 3/2$ and $b = 0$. This is obviously suggestive, but it is a challenge to justify the Langevin model in detail for magnetized plasma turbulence. Previous results on higherorder statistics,\footnote{J. A. Krommes, NonGaussian statistics, classical field theory, and realizable Langevin models, Phys.\ Rev.\ E \textbf{53}, 4865 (1996).} dimensionally compatible with $K \sim S^2$, are reviewed and an attempt is made to derive $a$ and $b$ for a model involving coupled modes and linear waves. The extent to which the values of $a$ and $b$ are sensitive discriminants for details of the underlying turbulence is discussed. [Preview Abstract] 

YP8.00069: Stability Analysis of Laser Driven Radiative Shocks in High Energy Density Plasmas Robert Lunsford, J. Martin Laming, Jacob Grun, Charles Manka, Sergei Nikitin, Gelu Comanescu An experiment has been undertaken at the Naval Research Laboratory which looks to investigate the applicability of present analytic models to various multidimensional radiative instabilities within the interstellar medium. The primary focus at this juncture is the examination of a velocity dependant cooling instability thought to cause amplitude fluctuations within the overall shock propagation velocity. The PHAROS laser at NRL is utilized to create the relevant shock front by ablative deconstruction of an aluminized Mylar foil placed at the front of a tunnel within a PMMA block. This primary front launches secondary shocks into the walls of the tunnel and the pressure gradient created within the PMMA is recorded utilizing dark field shadowgraphy on a SIM8 multichannel high speed framing camera. It is a deviation from linearity in this secondary front which can be interpreted as a instability in the propagation velocity. [Preview Abstract] 

YP8.00070: Electron Acoustic Waves Inside a Plasma Sheath Around a Hypersonic Vehicle Vladimir Sotnikov High plasma density inside a plasma sheath around a hypersonic vehicle prevents electromagnetic waves with the frequencies below the local plasma frequency to propagate in this layer. This creates serious communication problems. One of the possibilities to mitigate this problem is to create two temperature electron plasma inside a sheath to allow electron acoustic waves to propagate through a plasma layer. Excitation, propagation and attenuation of electron acoustic waves inside a plasma sheath in the presence of an electron beam will be discussed. [Preview Abstract] 

YP8.00071: Plasma Dynamics of Translation process of Fieldreversed Configuration Ken Sakuraba To form high performance FRC plasmas with electron density of 10$^{20}$m$^{3}$ and low background neutral particles, a fieldreversed theta pinch device, called NUCTEIII, modified and a confinement region with a quasistationary magnetic field is installed. A FRC translation experiment with superAlfvenic velocity started. Initial experiment results are presented. FRC plasma, which has electron density of $\sim $2.5x10$^{21}$ m$^{3}$, total temperature of 200 eV, poloidal flux of 0.5 mWb, separatrix radius of 0.05 m, plasma volume of 4x10$^{3}$ m$^{3}$, has been translated with the first path velocity of 150 km/s, and the second path one of 50 km/s and settled down after two times reflections. Plasma volume, poloidal flux and separatrix radius of settled down FRC become $\sim $4x10$^{2}$ m$^{3}$, 0.23 mWb and $\sim $0.1 m, respectively. The plasma had a lifetime of about 0.1ms and terminated by the growth of n=2 rotational instability. The velocity was yet a half of Alfven one. High performance FRC plasma, which is formed on TCS, has not yet obtained. By the excluded flux and visible light optical measurements, dynamics of the translation process has been investigated. [Preview Abstract] 

YP8.00072: ECRH and its Effects on Neoclassical Transport in a Stellarator JaeChun Seol, C.C. Hegna, J.D. Callen A direct loss flux can be generated from energetic electron population in a stellarator. Thus energetic electron populations can substantially modify the neoclassical transport properties in stellarators. A model accounting for this change in transport is developed assuming the presence of electron cyclotron resonance heating (ECRH). The quasilinear diffusion coefficient for second harmonic X mode ECRH is developed for a bumpy stellarator. Care is taken in accounting for the pitchangle dependence of the quasilinear diffusion coefficient since application to experiments with narrow resonance zones is of interest. For trapped particles in a three dimensional configuration, collisionless loss zones exist in velocity space. Radiofrequency (rf) waves accelerate trapped electrons into the direct loss zone in bumpy stellarators and produce a direct loss flux. An analytic expression for this loss flux is derived; it is proportional to the rf field strength and the value of the zeroth order distribution function at the minimum speed for collisionless loss. The direct loss flux of electrons is another source of a nonambipolar particle flux in bumpy stellarators. This additional nonambipolar flux modifies the ambipolarity equation which generally has multiple roots for the radial electric field. An electron root (large positive $E_r$) is easily obtained if the electrons are in the $1/\nu$ regime and the ions are in the $\nu$ regime. [Preview Abstract] 

YP8.00073: Identification of the parametricmodulational instability of the drift wavezonal flow system in a cylindrical magnetized plasma Y. Nagashima, S.I. Itoh, S. Shinohara, M. Fukao, A. Fujisawa, T. Nishizima, K. Terasaka, M. Kawaguchi, Y. Kawai, G.R. Tynan, P.H. Diamond, M. Yagi, S. Inagaki, T. Yamada, T. Maruta, K. Kamataki, K. Itoh We present observation of the parametricmodulational instability of the drift wavezonal flow system in the Large Mirror device of Kyushu University. Linear dispersion relations of observed fluctuations are consistent with theoretical predictions of mesoscale residual zonal flow and microscale driftwave. Oscillation of the zonal flow potential is synchronized at modulations of amplitude, radial wavenumber, and turbulence Reynolds stress per mass density of the driftwave. The bispectral analysis reveals nonlinear energy transfer from the driftwave into the zonal flow at a radial location where the zonal flow forms a shear structure. Nonlocal energy transfer to turbulence via ``zonal flow channel'' is also discussed. [Preview Abstract] 

YP8.00074: Application of Optical Emission Diagnostics to Study Effects of Foils on Self Magnetic Pinch EBeam Diode Operations. A.D. Heathcote, A.D.J. Critchley, M.D. Johnston Optical diagnostics are being developed and deployed at AWE to explore the limiting physics of electron beam diodes used for flash xray radiography. Photodiode and imaging systems have been used to observe plasma emission from the diode anode cathode (AK) gap during xray production ($\sim $100 ns) and for several microseconds beyond. There is currently a paucity of experimental data [1] direct from AK gap plasmas; these data are needed to enhance understanding of the limiting physics of the diode geometries. Spatially and spectrally resolved intensity data from the AK gap of self magnetic pinch (SMP) diodes has been collected and is presented. This has been used to study the role of foils used within the diode assembly and their role in inhibiting diode impedance collapse [2] for improved integrated dose output. [1]  Martin P, Short D, Jones A  Theory Underpinning Ongoing Fundamental Pinch Physics Research at AWE, November 2005 to August 2006. Ref: AWE/HD02/B/0607/812. [2]  I. Crotch et al., ``Self Magnetic Pinch Diode Experiments at AWE'',14th IEEE Int. Pulsed Power Conf., 2003, pp. 507509. [Preview Abstract] 

YP8.00075: A New Shearing Interferometer for Cylindrical Wire Array Experiments S. Pikuz, T. Schelkovenko, P. Schrafel, B. Kusse In standard shearing interferometry, part of a single probing beam passes through a perturbing medium and is then split into two beams. A linear shift results in an overlap, interference and a fringe pattern yielding the perturbing medium density profile. The probing beam needs to be larger than the perturbing medium so that part of it passes through a well separated, low density region. During early time axial views of imploding cylindrical wire arrays the low and high density regions are not well separated. The low density regions lie in between the high density regions that are near the initial wire positions. In addition, the probing beam diameter is comparable to the array diameter. In this case a linear translation will not work but the overlap can be accomplished by an azimuthal rotation of one beam with respect to the other. Such an azimuthal shearing interferometer has been bench tested with encouraging results. A refined version has been set up on the COBRA experiment to give time resolved, radial and azimuthal electron density profiles during early time, cylindrical wire array implosions. [Preview Abstract] 

YP8.00076: Plasma operation in a divertor tokamak with all tungsten plasma facing components R. Neu, W. Bobkov, R. Dux, T. Eich, H. Greuner, O. Gruber, A. Herrmann, L. Horton, A. Kallenbach, M. Kaufmann, P. Lang, C. F. Maggi, H.W. Mueller, R. Pugno, T. Puetterich, V. Rohde, W. Schustereder, A.C.C. Sips, J. Stober, W. Suttrop, M. Wischmeier, H. Zohm To investigate plasma wall interaction with tungsten plasma facing components and its implications in a divertor tokamak, ASDEX Upgrade has been completely equipped with W coated tiles. A range of tools has been developed to allow for discharges with good confinement combined with acceptable W concentrations. After the implementation of W ICRH and guardlimiters, they were identified as the main W sources during operation of ICRH. This is attributed to the acceleration of intrinsic impurities in the rectified parasitic electrical field leading to an increased W sputtering yield. During the last vent deposited layers were removed from the W surfaces and the startup of the 2007 campaign was performed without prior boronization. Although all primary carbon sources are removed, almost no reduction of the C concentrations is observed up to now. HModes with $H \approx 1$ and a moderate W content could be obtained soon after the first pulse with auxiliary heating and detailed investigations on the W influxes and their impact were performed. [Preview Abstract] 

YP8.00077: Observation of Recurring PhaseInversions in Radiatively Heated SingleMode Sinusoidal Perturbations N.E. Lanier, J. Workman, S.D. Crockett, R.L. Holmes, R.N. Mulford, B. Patterson, D. Schmidt, D. Swift, P. Graham, A. Moore Experiments studying the hydrodynamic evolution of radiatively heated singlemode perturbations have been conducted at the OMEGA laser facility. An epoxy layer with a sinusoidal interface is embedded in foam and heated with tin $L$shell radiation. As the epoxy expands, an optional shock, with independently controlled strength and timing, is introduced. The resulting hydrodynamic behavior is radiographically. Experimental data along with threedimensional RAGE simulations are used to generate a more complete picture of this preheatinduced evolution. When preheated, the initial expansion of the sinusoidal perturbation forms a complex set of shocks and an interface that quickly becomes nonlinear. The interaction of these preheatinduced shocks result in density gradients, whose phase, with respect to the initial perturbation, oscillates in time. In this experiment, when the shock propagates through the evolving layer, these density gradients are the dominant influence on postshock hydrodynamic behavior. This work is sponsored by U. S. DOE under Contract No. DEAC5206NA25396. [Preview Abstract] 

YP8.00078: Outline for a Spheromak Proof of Principle Experiment Simon Woodruff, Angus Macnab A possible means for reducing reactor core complexity and size (and hence cost) could lie with research into the Spheromak concept: a plasma ring with no coils linking the plasma.~ Much progress has been made in the last 20 years, and now tokamaklike confinement is being reported, with work focusing on understanding betalimits, transport and novel means of generating magnetic fields both in sustained and pulsed scenarios.~ Spheromak research is maturing, with many experiments integrated into a national program to resolve well defined critical physics issues.~ This poster summarizes the work from the last 20 years both as a historical overview and an outline of the present status.~ A natural consequence is to suggest the possibility of a NextStep Spheromak, or advanced Proof of Principle device that will build on recent success and address many of the remaining critical issues in preparation for a Spheromak BPX.~~ [Preview Abstract] 

YP8.00079: Two Stage Proton Acceleration from Ultrathin Foils via High Intensity, High Contrast Laser Pulses S.A. Reed, T. Matsuoka, S.S. Bulanov, V. Chvykov, A. Brantov, V. Bychenkov, G. Kalinchenko, C. McGuffey, P. Rousseau, V. Yanovsky, D. Litzenberg, K. Krushelnick, A. Maksimchuk Laser driven proton acceleration from submicron targets using high intensity (4x10$^{20 }$W/cm$^{2})$, high contrast (10$^{11})$ laser pulses has been investigated. PIC simulations show two distinct acceleration stages: first, a charge separation at the target front due to the laser's ponderomotive force, and second, the rear TNSA mechanism. The two acceleration stages were experimentally distinguished through target selection. The maximum proton energy observed for hydrogen containing targets (CH) was two times higher than for nonhydrogen containing targets (Si$_{3}$N$_{4})$. For H containing targets the protons are accelerated first by the pondermotive potential, propagate through the target and receive additional acceleration from the rear sheath, whereas Si$_{3}$N$_{4 }$only receives TNSA thus yielding lower proton energy. [Preview Abstract] 
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