Bulletin of the American Physical Society
60th Annual Meeting of the APS Division of Plasma Physics
Volume 63, Number 11
Monday–Friday, November 5–9, 2018; Portland, Oregon
Session TO8: Plasma Acceleration: Computation, Beam Driven, Mid-IR lasers |
Hide Abstracts |
Chair: Jessica Shaw, Laboratory for Laser Energetics, Rochester, NY Room: OCC C120-122 |
Thursday, November 8, 2018 9:30AM - 9:42AM |
TO8.00001: Implementation of a Finite Difference Algorithm into QuickPIC Fei Li, Weiming An, Lance Hildebrand, Yujian Zhao, Viktor K Decyk, Warren B Mori The 3D parallel quasi-static PIC code, QuickPIC [1-3], has been widely used for making discoveries in plasma-based accelerator (PBA) research for many years. The current code is written based on the full spectral (FFT) algorithm framework of UPIC [4,5]. We report on a recent update to QuickPIC where an option for using a finite difference (FD) algorithm has been implemented. In this presentation, we will show the comparison between FD and the full spectral method for PBA simulations. The implementation of FD algorithm lays the foundation for many other improvements of QuickPIC planned in the future, including the parallelization of the 2D part of the code using a multi-dimensional partition, a multigrid Poisson solver, and mesh (static and adaptive) refinement. [1] C. Huang et al., J. Comp. Phys. 217, 658 (2006). |
Thursday, November 8, 2018 9:42AM - 9:54AM |
TO8.00002: Recent developments on QuickPIC Open Source Weiming An, Viktor K Decyk, Lance Hildebrand, Yujian Zhao, Fei Li, Warren B Mori Since 2017, QuickPIC has been an open source code on Github [1]. QuickPIC is a 3D parallel quasi-static PIC code for efficiently simulating the plasma based accelerator (PBA), which is typically 1000 times faster than using a normal 3D PIC code. It is developed based on the framework UPIC. QuickPIC has been widely used in studying PBA problems [2,3,4]. The open source QuickPIC was written in an object-oriented way using Fortran 2003, while most of the lower level subroutines that developed based on UPIC are written in Fortran 77. In this presentation, we will introduce recent development of QuickPIC, including vectorization algorithm for the Intel KNL cpu, the new JSON style input file, new particle beam initializations and new plasma initializations. We will also introduce some important classes in the upper level of the code, including the beam class, the species2d class and the simulation class, which would be important for people who are interested in developing QuickPIC. |
Thursday, November 8, 2018 9:54AM - 10:06AM |
TO8.00003: Integrating the Lorentz Force Law for Highly-Relativistic Particle-in-Cell Simulations Adam Vincent Higuera, John Robert Cary Integrating the Relativistic Lorentz Force Law for plasma simulations is an area of current research. In particular, recent research indicates that interaction with laser fields of relativistic intensity is particularly problematic for current integration techniques. Here is presented a special-purpose integrator yielding improved accuracy for particle trajectories in fields of highly-relativistic intensity, and convergence studies of VSim particle-in-cell simulations showing improved accuracy and performance for laser-plasma acceleration problems. |
Thursday, November 8, 2018 10:06AM - 10:18AM |
TO8.00004: Warp-X: a new exascale computing platform for plasma simulations Jean-Luc Vay, Ann Almgren, John Bell, Guillaume Blaclard, Lixin Ge, Dave Grote, Mark J Hogan, Haithem Kallala, Remi Lehe, Andrew Myers, Cho Ng, Jaehong Park, Olga Shapoval, Maxence Thévenet, Henri Vincenti, Weiqun Zhang Plasmas involve very complex phenomena, often across large ranges of space and time scales, driving the development of computer simulation codes with novel algorithms that run on the largest available supercomputers. As part of U.S. DOE’s Exascale Computing Project, a team from LBNL, SLAC and LLNL is developing a new powerful plasma accelerator simulation tool. The new software will harness the power of future exascale supercomputers for the exploration of outstanding questions in the physics of acceleration and transport of particle beams in chains of plasma channels for the realization of compact and affordable high-energy physics colliders, many spinoff applications of plasma accelerators and other plasma applications. We will present the various components of the codes such as the new Particle-In-Cell Scalable Application Resource (PICSAR) and the redesigned adaptive mesh refinement library AMReX, combined with redesigned elements of the Warp code, in the new WarpX software. The status, examples of applications to plasma acceleration of electrons or ions and to plasma mirrors, and future developments, will be discussed. |
Thursday, November 8, 2018 10:18AM - 10:30AM |
TO8.00005: FLASHForward - A Future-Oriented Plasma Wakefield Accelerator Research and Development Facility at FLASH Alexander Knetsch, Alexander Aschikhin, Simon Bohlen, Gregory Boyle, Theresa Karoline Bruemmer, John Dale, Richard D'Arcy, Brian Foster, Matthew James Garland, Lars Goldberg, Pau Gonzalez Caminal, Olena Kononenko, Peng Kuang, Vladyslav Libov, Timon J Mehrling, Martin Meisel, Pardis Niknejadi, Alberto Martinez de la Ossa, Charlotte A.J. Palmer, Kristjan Poder, Paul Pourmoussavi, Martin Quast, Jan-Hendrik Roeckemann, Lucas Schaper, Bernhard Schmidt, Sarah Schroeder, Matthew J V Streeter, Jan-Patrick Schwinkendorf, Bridget Sheeran, Gabriele Tauscher, Stephan Wesch, Paul Viktor Winkler, Johann Zemella, Ming Zeng, Jens Osterhoff Due to high accelerating electric fields in the range of several GV/m, beam-driven plasma wakefield accelerators (PWFAs) have outstanding potential to transform technologies, such as the design of future electron-positron colliders and free-electron lasers. At DESY in Hamburg, the FLASHForward project has recently started operation and will develop further important capabilities in future. The plasma is generated in a capillary gas cell either by gas discharge or by using a femtosecond pulse from the 25 TW Ti:Sa laser system to ionize the gas. The laser provides an ionizing main laser arm and a transverse probe laser arm. The electron bunch from the FLASH linear acclerator has energy up to 1.25 GeV and delivers up to a few kA peak current. The facility has exceptional capabilities to longitudinally shape the electron bunch, allowing plasma waves to be excited in the nonlinear blowout regime for a variety of experiments. These include the generation of high-quality electron bunches (internal injection) and post-acceleration of electron bunches form FLASH (external injection). The first interaction of the electron beam with a plasma wake has been demonstrated in June 2018, beginning the exploitation of the great potential of the FLASHForward Plasma Wakefield accelerator. |
Thursday, November 8, 2018 10:30AM - 10:42AM |
TO8.00006: Asymmetric wakes and hosing theory in PWFA Lance Hildebrand, Weiming An, Xinlu Xu, Yujian Zhao, Mark J Hogan, Vitaly Yakimenko, Chandrashekhar Joshi, Warren B Mori In PWFA and LWFA experiments, the wakefields are generally made by asymmetric beams and the beams may have some transverse offset or tilt. Yet little theoretical work has been done in understanding wake structures in these scenarios. Here, we will investigate using 3D QuickPIC simulations the wake structure excited by particle beams (a two-bunch PWFA scenario) where there is transverse spot size asymmetry in the drive or witness beam, or where the witness beam has some offset or tilt with respect to the drive beam. In the back of the nonlinear wake, i.e., bubble, where the witness bunch experiences the highest acceleration, there may be severe hosing. In this regime, we modify the non-linear hosing equations where some of the original assumptions break down. An alternative derivation for these equations using an azimuthal mode expansion may be discussed. |
Thursday, November 8, 2018 10:42AM - 10:54AM |
TO8.00007: Emittance Evolution in a Single Stage Plasma Wake FieldAccelerator with Plasma Ramps Yujian Zhao, Weiming An, Lance Hildebrand, Xinlu Xu, Mark J Hogan, Vitaly Yakimenko, Chan Joshi, Warren B Mori Emittance growth of the accelerated beam can be controlled when the beam is matched inside wake of a drive beam in the plasma wake field accelerator (PWFA). When there is a plasma density up ramp at the entrance and a plasma density down ramp at the exit, the initial matching condition for the accelerated beam can be calculated for a given plasma density profile. However, the real beam parameters at the entrance of the plasma may differ from the ideal matched condition. We use QuickPIC simulations to study the initial beam parameters’ influence on the beam emittance growth by changing the initial focal positon, the initial value of the beta star, the initial energy and the initial energy spread of the trailing beam. In the end, we give the comparison between the theoretical analysis |
Thursday, November 8, 2018 10:54AM - 11:06AM |
TO8.00008: FACET Beam Ionization Injection Technique Advantages and Challenges Ligia Diana Pinto de Almeida Amorim, Navid Vafaei-Najafabadi, Kenneth A Marsh, Christopher E Clayton, Weiming An, Frank Shih-Yu Tsung, Warren B Mori, Chandrashekhar Joshi, Wei Lu, Carl A. Lindstrom, Erik Adli, James Allen, Christine I Clarke, Sebastien Corde, Spencer J Gessner, Michael Dennis Litos, Brendan O'Shea, Joel T Frederico, Selina Z. Green, Nate Lipkowitz, Gerald Yocky, Mark J Hogan, Vitaly Yakimenko Beam-driven Plasma Wakefield Accelerators (PWFAs) can sustain accelerating gradients that surpass those of standard accelerators. In the PWFA technique called “Beam Induced Ionization Injection” (BIII) a mismatched beam excites the wakefields while performing betatron oscillations. During each betatron cycle, the beam space charge fields exceed the high ionization thresholds of gas impurities and inject their electrons into the wake’s accelerating phase. By correctly positioning the impurity gas, it is possible to produce a single, high-quality accelerated beam. Moreover, if the impurity section encompasses several cycles, a multi-colored beam of electrons with narrow energy spread can be generated. Although BIII can produce low energy spread beams through beam-loading, the required charge ionizes and injects an additional low quality “inception beam”. Here we will discuss different BIII scenarios modeled with Particle in Cell code OSIRIS [R.A.Fonseca et al., LNCS (2331) 342, 2002]. We will show the BIII formation of single accelerated beams, multi-colored beams and the impact of “inception beams” on beam quality. |
Thursday, November 8, 2018 11:06AM - 11:18AM |
TO8.00009: Optical measurements and simulations of nanosecond-scale plasma channel evolution excited by beam-driven plasma wakes at FACET Rafal Zgadzaj, Michael C Downer, Alexander Sosedkin, Konstantin V. Lotov, Thales Silva, Jorge M Vieira, Mark J Hogan, Vitaly Yakimenko Energy density contained in highly nonlinear “blowout” regime plasma wakes can reach electron rest energy density (~nemc2) [1]. The ns, and longer, dynamics of the subsequent redistribution and diffusion of this enormous energy density sets ultimate repetition rates for plasma accelerators. Although simulations have predicted unique structure and dynamics of such “ion wakes,” [1-3] experiments have not yet explored this long-term evolution. We report optical measurements of cylindrically symmetric ion channel structures emerging from broken plasma wakes generated in singly self-ionized lithium (Li) plasma (ne=8e16cm-3) by SLAC’s 20GeV, 2nC electron bunches (σx=σy=30µm, σz=50µm), that show the plasma column remains peaked on axis and grows continuously in radius from < 10 µm at ∆t < 10 ps after passage of the drive bunch to several hundred µm at ∆t = 1.5 ns. Strongly refracting plasma column persists at ms delays. Simulations using the fully relativistic PIC code OSIRIS [3] and the quasi-static LCODE [1], model the evolving plasma column to ∆t ~ 1 ns, yielding a density profile consistent with measurements. [1] K. V. Lotov et al., Phys. Rev. Lett. 112, 194801 (2014) [2] A. Sahai et al., ArXiv.1504.03735 (2015) [3] J. Vieira et al., Phys. Rev. Lett. 109, 145005 (2012) |
Thursday, November 8, 2018 11:18AM - 11:30AM |
TO8.00010: CO2-laser-driven laser-wakefield acceleration experiments at Brookhaven's Accelerator Test Facility James Welch, Rafal Zgadzaj, Michael C Downer, Lígia Diana Amorim, Mael Flament, Pietro Iapozzuto, Jiayang Yan, Navid Vafaei-Najafabadi, Vladimir N Litvinenko, Prabhat Kumar, Roman V. Samulyak, Chaojie Zhang, Wei Lu, Warren B Mori, Chan Joshi, Mikhail Polyanskiy, Christina Swinson, Marcus Babzien, Karl Kusche, Mikhail Fedurin, Igor Pogorelsky Advances in CO2 lasers[1] open mid-IR wavelengths for laser wakefield accelerators, a regime favorable at low plasma densities ne[2], with large accelerating structures enabling precise external lepton injection and optical[3] and electron[4] probing of wake density and field structure. The AE71 project at BNL's Accelerator Test Facility is devoted to these studies. We report optical measurements of the plasma density structure, amplitude and dynamics of self-modulated wakes driven by CO2 laser pulses (4ps, 2J, focus w0≈25µm)[5] in H2 (0.4<ne<3e18cm-3), observed by collective Thomson scattering (CTS) of a 532nm, 4ps, probe. 1st and 2nd order CTS sidebands were studied vs. ne, pump-probe time delay ∆t, drive laser peak power P, and focus position within the gas jet. Simulations, detailed in other co-author presentations at this DPP, explain key observations, including unexpected spectral splitting of sidebands at ∆t~0, ~10ps wake lifetimes, and wake amplitude dependence on ne and P. [1] M.N. Polyanskiy et al. Optica 2, 675 (2015) [2] I. Pogorelsky et al, Plasma Phys. Control. Fusion 56, 084017 (2014) [3] S. P. LeBlanc et al., Phys. Rev. Lett. 77, 5381 (1996) [4] C. Zhang et al., Plasma Phys. Control. Fusion 60, 044013 (2018) [5] N. Andreev, Phys. Rev. STAB 6, 041301 (2003) |
Thursday, November 8, 2018 11:30AM - 11:42AM |
TO8.00011: Numerical study of long CO2 laser pulse interactions with hydrogen plasma at ATF Navid Vafaei-Najafabadi, Ligia Diana Amorim, Jiayang Yan, Pietro Iapozzuto, Mael Flament, Yichao Jing, Vladimir N Litvinenko, Roman V. Samulyak, Prabhat Kumar, Igor Pogorelsky, Christina Swinson, Marcus Babzien, Karl Kusche, Mikhail Polyanskiy, Mikhail Fedurin, Mark A Palmer, Rafal Zgadzaj, James R Welch, Michael C Downer, Chan Joshi, Warren B Mori, Wei Lu Laser-driven plasma Wakefield Accelerators (LWFAs) can sustain accelerating gradients that greatly surpass those of standard accelerators. Long (~ps) and intense (>TW) laser pulses have been employed in LWFAs to generate bright, hard x-rays which are of interest for imaging and diagnosing warm-dense matter. We explore the LWFA regime using a long TW class CO2 (~10.6µm) laser to excite wakefields in a hydrogen plasma in the experiment AE71 at the ATF facility of the Brookhaven National Laboratory. In that experiment, the laser encompasses hundreds of plasma skin depths allowing for three different regimes of laser and plasma interaction: laser self-modulation, laser disruption along with transversely spread out plasma bubbles and laser self-channeling. In this talk, numerical results will be presented to show the main properties of those laser and plasma interactions for different configurations experimentally tested as well as the effects imprinted on the frequency-doubled Nd:YAG and electron beam probes. The simulations were done using the Particle in Cell code OSIRIS [R.A.Fonseca, LNCS (2331) 342, 2002]. |
Thursday, November 8, 2018 11:42AM - 11:54AM |
TO8.00012: Observation of arrest of Kerr self-focusing in a 10 μm filament in air at 1 TW/cm2 clamped intensity Sergei Tochitsky, Eric Welch, Mikhail Polyanskiy, Igor Pogorelsky, Paris Panagiotopoulos, Miroslav Kolesik, Ewan M Wright, Stephan W Koch, Jerome V Moloney, Jeremy Pigeon, Chan Joshi In this paper we demonstrate for the first time self-guiding of a 10.2 μm ~1TW CO2 laser pulse in the atmosphere over at least 30 meters (~20 ZR). We observe that when the peak power of such pulses exceeds ~870 GW, a centimeter-diameter single filament is formed in air. We call such a single filament a megafilament because it confines an ~1TW laser pulse with several Joules of energy and its cross-section is 104 times larger than a typical near-IR single filament. The clamped intensity of ~1 TW/cm2 for the long-wave infrared light confined in this megafilament was measured to be much smaller than that required for the tunnel ionization of O2/N2. By anchoring the experimental data with numerical simulations based on the concept of many-body interactions in the atmospheric pressure gas, we find that Kerr self-focusing at such a low laser intensity is arrested by a new and different ionization mechanism due to many-body Coulomb ionization . The amount of free carriers produced inside of the filament is rather small (≤1013cm-3) but sufficient to effectively decrease the molecular polarizability during the laser pulse.
|
Thursday, November 8, 2018 11:54AM - 12:06PM |
TO8.00013: Comparison of broadband microwave generation from single and two-color ultrafast mid-IR laser-produced plasmas in atmosphere Alexander Englesbe, Robert Schwartz, Anastasia Korolov, Daniel Woodbury, Jennifer Elle, Adrian Lucero, Remington Reid, Serge Kalmykov, Hugh Pohle, Ki-Yong Kim, Howard Michael Milchberg, Karl Michael Krushelnick, Andreas Schmitt-Sody Nonlinear propagation of a high power ultrashort laser pulse through a transparent medium creates a plasma that radiates broadband electromagnetic waves. We present a direct comparison between the absolute emitted microwave frequency spectrum for plasmas produced with a ultrashort pulse at a wavelength of 3.9 microns focused in air, and a two-color pulse consisting of the 3.9 micron fundamental superimposed with its second harmonic. Comparison of the microwave emission for the single and two-color cases may reflect different current generation mechanisms in the plasma, namely the ponderomotive force, and direct current driven by the temporal asymmetry of the laser field oscillation that is enabled in a two-color scheme. The frequency content of the microwaves is measured as a function of viewing angle relative to the laser propagation direction up to a real-time bandwidth of 70 GHz. The frequency spectra are compensated for the instrument response of the receiver so that the absolute electric field amplitude incident on the receiver aperture is known. |
Thursday, November 8, 2018 12:06PM - 12:18PM |
TO8.00014: Plasma-assisted light bullets and wavelength scaling of laser filamentation in the long-wavelength infrared Rostislav Igorevitch Grynko, Garima Chaudhary Nagar, Bonggu Shim We model laser filamentation in ZnSe in the mid-infrared (Mid-IR, wavelengths λ = 4 and 6 µm) and the long-wavelength infrared (LWIR, λ = 8 and 10 µm) using carrier-resolved unidirectional pulse propagation equations (UPPE) [1]. We predict an unprecedented propagation regime at λ = 8 µm that supports light bullets [2], which are spatio-temporally non-spreading electromagnetic pulses. Furthermore, in contrast to the previous report in air in the mid-IR [3], we predict that LWIR light bullets in solids critically rely on plasma-mediated dispersion, which dynamically evolves during multiphoton and tunneling ionization as peak plasma densities reach ρ ∼ 6.6 x 1018 cm-3. Finally, the plasma-assisted light bullets propagate with sub-cycle pulse durations and peak intensities I ∼ 1.1 x 1012 W/cm2, making them useful for high-harmonic generation and attosecond pulse generation. [1] M. Kolesik and J. V. Moloney, Phys. Rev. E 70, 036604 (2004). [2] Y. Silberberg, Opt. Lett. 15, 1282 (1990). [3] P. Panagiotopoulos, P. Whalen, M. Kolesik, and J. V. Moloney, Nat. Photon. 9, 543 (2015). |
Thursday, November 8, 2018 12:18PM - 12:30PM |
TO8.00015: Computational Investigation of Laser Polarization on Filament Properties Ryan Phillips, Andreas Schmitt-Sody, Jennifer Elle, Serge Youri Kalmykov, John Palastro Ultrashort pulse laser filaments are a unique source of ultra-broadband radiation, from the visible spectrum to terahertz (THz) and radio frequencies (RF). Experimental investigation has found that there is a polarization dependence on the amount of RF radiation produced by an atmospheric laser filament. To explain the experimental results, the polarization properties of a filamenting 800nm ultra short laser pulse are examined computationally. Using a delayed rotational response model for the refractive index contribution of the atmospheric gases and a paraxial enveloped wave equation solver, a computational finite differences investigation is carried out. The intent is to develop an understanding of how the input laser polarization alters the laser interaction with the filament and by extension how properties such as RF/THz yield and laser energy conversion efficiency are affected. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700