Bulletin of the American Physical Society
Annual Meeting of the APS Four Corners Section
Volume 62, Number 17
Friday–Saturday, October 20–21, 2017; Fort Collins, CO
Session L6: Plasma Physics II: Laser Plasma Interactions, Shocks and Confinement |
Hide Abstracts |
Chair: Michael Ware, Brigham Young University Room: Lory Student Center 322 |
Saturday, October 21, 2017 11:10AM - 11:22AM |
L6.00001: Ultra high energy density plasmas generated by highly relativistic laser nanowire interactions Reed Hollinger, Y. Wang, S. Wang, A. Rockwood, J. Glasby, V. Shlyaptsev, J.J. Rocca, M.G. Capeluto, V. Kaymak, A. Pukhov The interaction of high aspect ratio, ordered nanowire arrays with clean, ultrashort laser pulses of relativistic intensity provides a unique combination of nearly complete optical absorption and increased light penetration into near solid density matter. Previous experiments have shown that irradiation of Ni and Au nanowires at intensities of 5x10$^{\mathrm{18}}$Wcm$^{\mathrm{-2}}$ generate multi-keV, near solid density plasmas in which the ionization state reaches Ni$^{\mathrm{+26}}$ and Au$^{\mathrm{+52}}$ charge states$^{\mathrm{1\thinspace }}$at depths of 5$\mu $m$^{\mathrm{\thinspace }}$suggesting the creation of volumetrically heated matter$^{\mathrm{2}}$. Here we present the first results of the irradiation of Ag nanowire arrays with highly relativistic laser pulses of intensities up to 5x10$^{\mathrm{21}}$Wcm$^{\mathrm{-2}}$. Time integrated x-ray spectra show the presence of He-like and Li-like emission. Results of experiments conducted with a variety of different nanowire diameters will be presented and compared to three dimensional particle in cell (3D-PIC) simulations. $^{\mathrm{1}}$Purvis et al Nature Photonics 7, 769 (2013).~$^{\mathrm{2}}$Bargsten et al Sci. Advances Vol. 3 No. 1 (2017) [Preview Abstract] |
Saturday, October 21, 2017 11:22AM - 11:34AM |
L6.00002: Fusion neutron generation in deuterated nanowire arrays irradiated by femtosecond pulses of relativistic intensity Chase Calvi, Alden Curtis, Jim Tinsley, Reed Hollinger, Shoujun Wang, Alex Rockwood, Yong Wang, Conrad Buss, Vyacheslav Shlyaptsev, Alexander Pukhov, Vural Kaymak, Jorge Rocca We have demonstrated a new dense fusion environment created by irradiating arrays of deuterated nanostructures with Joule--level pulses from a compact ultrafast Ti:Saphire laser. The irradiation of ordered deuterated polyethylene nanowires arrays with femtosecond pulses of relativistic intensity is shown to create ultra-high energy density plasmas in which deuterons (D) are accelerated to MeV energies, efficiently driving D-D fusion reactions and ultrafast neutron pulses. We have measured up to 2 x 10$^{\mathrm{6}}$ fusion neutrons/Joule, a 500 times increase respect to flat solid targets, a record yield for Joule-level lasers, and have also observed a rapid increase in neutron yield with laser pulse energy. We present results of a first experiments conducted at intensities \textgreater 1 x 10 $^{\mathrm{21}}$ W cm$^{\mathrm{-2}}$ that has generated \textgreater 1 x 10 $^{\mathrm{7}}$ fusion neutrons per shot. This material is based on work supported by the Air Force Office of Scientific Research under award number FA9560-14-10232, and by NSTec. [Preview Abstract] |
Saturday, October 21, 2017 11:34AM - 11:46AM |
L6.00003: Laser ionized plasma sources for plasma wakefield accelerators Robert Ariniello, Michael Litos Plasma wakefield accelerators (PWFA) have demonstrated multi-GeV/m accelerating gradients making them an attractive option for future particle accelerators. However, current PWFAs tend to increase the particle beam's emittance (area of the beam in transverse phase-space) as the beam propagates through the plasma. The emittance can be preserved by correctly focusing the beam into and out of the plasma. One technique is to carefully control the plasma density along the beam axis such that the Coulomb force from the ion column focuses the beam at a carefully prescribed rate into the plasma. We present simulations of an optical system capable of producing nearly arbitrary on axis plasma density profiles in a $1\times16\,\mathrm{cm}^{-3}$ Argon gas using an ultrafast Ti:sa laser pulse. Our simulations demonstrate that suitable plasma columns with lengths of up to a meter can be generated via laser ionization. Additionally, we examine how the laser pulse is distorted by refraction off of the ionizing plasma column. [Preview Abstract] |
Saturday, October 21, 2017 11:46AM - 11:58AM |
L6.00004: Dynamics of phase-flip transition with changing coupling strength between two inductively coupled glow discharge plasmas Neeraj Chaubey, Subroto Mukherjee, Abhijit Sen The dynamics of a phase-flip transition as a function of the coupling strength is studied between two inductively coupled glow discharge plasma sources. The self-sustained oscillations are produced in two independent systems that are then inductively coupled to each other through externally wound copper wires. It is observed that with the progressive increase in the oscillation frequency of one of the systems while keeping the other system parameters fixed, the coupled oscillations of the two systems abruptly jump from an in-phase to an anti-phase state. This transition is found to be dependent on the positions of the externally wound wires which determines the mutual coupling strength. When the wound wire bunch on one of the systems is placed at a distance of 6 cms away from the cathode (i.e on the plasma column) and the wire bunch on the other system near the electrode sheath area then a small entrainment region is observed without any phase-flip transition while when the wires are placed on top of the plasma column then a larger entrainment region is observed with a phase-flip transition. Model calculations to understand these observations are carried out using a coupled set of Van der Pol equations and results are found to be in good match with the experimental results. [Preview Abstract] |
Saturday, October 21, 2017 11:58AM - 12:10PM |
L6.00005: Improving Confinement Techniques of a non-neutral Plasma Bryce Spencer, Bryan Peterson We are currently working on improving the confinement in our pure ion, non-neutral plasma with a rotating wall. Our desire is to achieve a sufficient level of containment to measure the frequencies of radial modes of oscillation in the plasma without losing a large amount of charged particles. We are varying the rotating wall plasma confinement system by changing the frequency and the amplitude of the rotating wall signal. We will present our analysis from our data that we have collected and possible future modifications and data analysis techniques to improve our ability to confine a plasma with sufficient density to make quality measurements. [Preview Abstract] |
Saturday, October 21, 2017 12:10PM - 12:22PM |
L6.00006: Analytic approximations for an axisymmetric strong shock wave Mark W. Coffey, Liam Pocher, Dan Borovina, Jonathan Mace, Charles Durfee The modelling of shock waves has many applications, including to electrostatic discharge phenomena. We recall the similarity solution for a radially expanding strong shock, consisting of normalized pressure, velocity, and mass density. The numerical solution of coupled ordinary differential equations with appropriate boundary conditions yields these quantities as a function of the scaled radial position of the shock front. Based upon such numerical results, we then present approximate analytic relations between the various normalized quantities. Various derived quantities follow from such a model, including the total energy per unit length delivered by the shock. [Preview Abstract] |
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