Bulletin of the American Physical Society
63rd Annual Meeting of the APS Division of Plasma Physics
Volume 66, Number 13
Monday–Friday, November 8–12, 2021; Pittsburgh, PA
Session TO05: Computational and Analytical Techniques for Lasers and BeamsOn Demand
|
Hide Abstracts |
Chair: David Blackman, University of California San Diego Room: Rooms 306-307 |
Thursday, November 11, 2021 9:30AM - 9:42AM |
TO05.00001: WarpX Exascale Update - New Platforms, Functionality and Applications Axel Huebl, Ann Almgren, Ligia D Amorim, John B Bell, Kevin N Gott, Revathi Jambunathan, Remi Lehe, Andrew Myers, Michael Rowan, Olga Shapoval, Weiqun Zhang, Yinjian Zhao, Edoardo Zoni, Jean-Luc Vay, Lixin Ge, Cho Ng, Mark J Hogan, David P Grote, Maxence Thévenet, Luca Fedeli, Neil Zaim, Henri Vincenti, Peter Scherpelz, Phil Miller, Michael Kieburtz, Kevin Zhu, Roelof E Groenewald, Lorenzo Giacomel We present the latest results on the development of WarpX, an advanced electromagnetic particle-in-cell code from the U.S. Exascale Computing Project. With the introduction of the first Exascale machines, we present results on new GPU architectures. We also give an overview of new algorithms and functionalities, including scalable in situ analysis and visualization, new applications beyond laser-plasma accelerators and the development of an international open source ecosystem around WarpX. |
Thursday, November 11, 2021 9:42AM - 9:54AM |
TO05.00002: Lorentz-boosted LWFA simulations: developments in simulation of self-injection and flying focus laser pulses Jacob Pierce, Kyle G Miller, Fei Li, Xinlu Xu, Frank S Tsung, Warren B Mori, Bernardo F Malaca, Jorge Vieira, John P Palastro, Dustin H Froula Given the high cost of full-resolution PIC simulations of LWFA, Lorentz-boosted simulations present an attractive path forward for simulation of new concepts in LWFA. Although boosted frame simulations have become more robust over the past decade through the development of new electromagnetic field solvers and algorithms dedicated to the suppression of the numerical Cherenkov instability, accurate modeling of self-injection in nonlinear wakes using boosted LWFA simulations remains a challenge because of the drastic reduction in macroparticle statistics. We present comparison lab frame and boosted frame simulations of downramp injection using OSIRIS. In addition, there is recent interest in studying how “flying focus” laser pulses could be used to overcome dephasing in LWFA. We describe a generalized antenna implemented in OSIRIS for a flying focus laser as well as boosted frame simulations of LWFA for such laser pulses. Analogous lab-frame simulations are very challenging. |
Thursday, November 11, 2021 9:54AM - 10:06AM |
TO05.00003: Overcoming timestep limitations in boosted-frame Particle-In-Cell simulations of plasma-based acceleration Olga Shapoval, Remi Lehe, Maxence Thevenet, Edoardo Zoni, Yinjian Zhao, Jean-Luc Vay Explicit electromagnetic Particle-In-Cell (PIC) codes are typically limited by the Courant-Friedrichs-Lewy (CFL) condition, which implies that the timestep multiplied by the speed of light must be smaller than the smallest cell size.In the case of boosted-frame PIC simulations of plasma-based acceleration, this limitation can be a major hindrance as the cells are often very elongated along the longitudinal direction and the timestep is thus limited by the small, transverse cell size. This entails many small-timestep PIC iterations, and can limit the potential speed-up of the boosted-frame technique. Here, by using a CFL-free analytical spectral solver, and by mitigating additional numerical instabilities that arise at large timestep, we show that it is possible to overcome traditional limitations on the timestep and thereby realize the full potential of the boosted-frame technique over a much wider range of parameters. |
Thursday, November 11, 2021 10:06AM - 10:18AM |
TO05.00004: A Particle-In-Cell Code Comparison for Laser Ion Acceleration: EPOCH, LSP, and WarpX Joseph R Smith, Chris Orban, Nashad Rahman, Brendan McHugh, Ricky Oropeza, Enam Chowdhury There are now more Particle-in-Cell (PIC) codes than ever before that researchers use to simulate intense laser-plasma interactions. To date, there have been relatively few direct comparisons of these codes in the literature, especially for relativistic intensity lasers interacting with thin overdense targets. To address this we perform a code comparison of three PIC codes: EPOCH, LSP, and WarpX for the problem of laser-driven ion acceleration in a 2D(3v) geometry. We examine the plasma density, ion energy spectra, and laser-plasma coupling of the three codes and find strong agreement. We also run the same simulation 20 times with different random seeds to explore statistical fluctuations of the outputs. We then compare the execution times and memory usage of the codes (without “tuning” to improve performance) using between 1 and 48 processors on one node. We provide input files to encourage larger and more frequent code comparisons in this field. |
Thursday, November 11, 2021 10:18AM - 10:30AM |
TO05.00005: A Hybrid Nodal-Staggered Pseudo-Spectral Electromagnetic Particle-In-Cell Method with Finite-Order Centering Edoardo Zoni, Remi Lehe, Olga Shapoval, Daniel Belkin, Neil Zaïm, Luca Fedeli, Henri Vincenti, Jean-Luc Vay Electromagnetic particle-in-cell (PIC) codes are widely used to perform computer simulations of a variety of physical systems, including fusion plasmas, astrophysical plasmas, plasma wakefield particle accelerators, and secondary photon sources driven by ultra-intense lasers. In a PIC code, Maxwell's equations are solved on a grid with a numerical method of choice. This talk focuses on pseudo-spectral analytical time-domain (PSATD) algorithms and presents a novel hybrid PSATD PIC scheme that combines the respective advantages of standard nodal and staggered methods. The novelty of the hybrid scheme consists in using finite-order centering of grid quantities between nodal and staggered grids, in order to combine the solution of Maxwell's equations on a staggered grid with the deposition of charges and currents and the gathering of electromagnetic forces on a nodal grid. The correctness and performance of the novel hybrid scheme are assessed by means of numerical tests that employ different classes of PSATD equations in a variety of physical scenarios. It is shown that the novel hybrid scheme offers significant numerical and computational advantages, compared to purely nodal or staggered methods, for all the test cases presented. |
Thursday, November 11, 2021 10:30AM - 10:42AM |
TO05.00006: HiPACE++: a portable, scalable 3D quasistatic particle-in-cell code Severin Diederichs, Carlo Benedetti, Axel Huebl, Remi Lehe, Andrew Myers, Alexander Sinn, Jean-Luc Vay, Weiqun Zhang, Maxence Thevenet Modeling plasma wakefield accelerators is a computationally challenging task. Using cost-reducing algorithms like the quasistatic approximation allows for efficient modeling of demanding plasma wakefield accelerator scenarios. In this work, we present the performance-portable, 3D quasistatic particle-in-cell code HiPACE++. It adopts modern HPC practices like a performance-portability layer, continuous integration, standard I/O formats, and is open-source (https://github.com/Hi-PACE/hipace). Owing to careful memory management within the quasistatic algorithm, it demonstrates orders of magnitude speed-up on modern GPU-equipped supercomputers compared to its CPU-only predecessor HiPACE. We present a novel quasistatic pipeline algorithm, based on a temporal domain decomposition, which provides near-ideal scaling up to hundreds of GPUs. HiPACE++ enables efficient modeling of plasma wakefield accelerators both on state-of-the-art supercomputers as well as GPU-equipped laptops. |
Thursday, November 11, 2021 10:42AM - 10:54AM |
TO05.00007: Hybrid quantum-classical simulations of relativistic charged fluids in electromagnetic fields Julien Zylberman, Nuno F Loureiro, Fabrice F Debbasch Extreme plasmas, which are both quantum and relativistic, are relevant in several contexts ranging from Astrophysics to Inertial Fusion and High-Energy-Density Physics. I will present the first steps in a research program aiming at simulating these plasmas on quantum computers. The approach is based on the Dirac equation and relies on two key results. First, a generalization of the so-called Madelung transform shows that the Dirac equation actually describes a quantum relativistic fluid of spin 1/2 particles. Second, the Dirac equation can be discretized into quantum walks, which are a standard tool of quantum computing and also constitute a universal quantum computational primitive. Our first results are simulations of shocks of extreme fluids immersed in a uniform electric field. The simulations have been first performed on a classical computer, but we have also developed a new quantum-classical hybrid algorithm tailor-made for current Noisy Intermediate-Scale Quantum (NISQ) computers and run the simulations on IBM’s quantum processors. The next steps, including the introduction of self-consistent electromagnetic fields, will be also discussed. |
Thursday, November 11, 2021 10:54AM - 11:06AM Not Participating |
TO05.00008: Digital Engineering Approach to the Development of Novel USPL Mid-IR Laser Systems Wes C Erbsen, Adrian P Lucero, Andreas Schmitt-Sody, Jennifer Elle, Christopher Urbina The exploitation of the Model-Based Systems Engineering (MBSE) approach to laser design enabled the rapid development and deployment of our Mid-IR USPL system, while mitigating technical risk, reducing cost, and strengthening our organic engineering capability. This was facilitated by a paradigm shift from the traditional "Design-Build-Test" methodology, in which the final product is developed by incrementally building out the system in the lab, to the "Model-Analyze-Build" MBSE approach, where the system design is defined by recursively modifying the model inside of a comprehensive Digital Ecosystem. This shift in strategy is enabled by the creation of a modular open systems architecture which supports end-to-end laser development throughout the entire engineering lifecycle. The "connective tissue" between various design tools and simulations enables dynamic interoperability in a seamless information space, which facilitates rapid updates to the system design in response to changing requirements. Here we present our results, challenges, and lessons learned from leveraging the MBSE approach to system design applied to “one-off” laser systems. |
Thursday, November 11, 2021 11:06AM - 11:18AM |
TO05.00009: A curious case of high absorption in moderately relativistic intensity laser interactions Chris Orban, Nashad Rahman, Ricky Oropeza, Joseph R Smith Laser interactions at intensities where electron motion is only moderately relativistic typically involve lower absorption than other regimes because (1) the plasma is hot enough that collisional effects are minimal and (2) the intensity is not so high that relativistic absorption becomes important. Due to these effects, it is often the case that of order 80% of the laser light is reflected from near-solid-density targets in this regime. An interesting exception to this rule is when two laser pulses simultaneously irradiate a target from two different angles. In a recent paper from our group particle-in-cell simulations indicate that this configuration can potentially double the absorption. In this talk I will discuss physical reasons why this approach enhances absorption and whether it can be of any use in laser fusion. |
Thursday, November 11, 2021 11:18AM - 11:30AM |
TO05.00010: Accelerating predictive modeling of laser-driven ion acceleration with deep learning Jason Chou, Tailin Wu, Sophia Kivelson, Jacqueline H Yau, Rex Ying, E. Paulo Alves, Jure Leskovec, Frederico Fiuza Fully kinetic simulations are commonly used to model the physics of intense laser-plasma interactions and ion acceleration. These methods offer an accurate description of the plasma microphysics, but at significant computational cost, which has limited the reach of 3D simulations and the ability to develop predictive simulations of laser-driven secondary sources. In this work, we explore deep learning-based methods for accelerating the modeling of nonlinear, many-body systems, with a focus on laser-driven ion acceleration. We aim to learn efficient, low-dimensional representations of the phase-space structure of the plasma and their associated evolution operators. In addition, we aim to incorporate fundamental symmetries in the machine learned representations to ensure physical consistency and generalizability. We will discuss results obtained based on data from high-fidelity particle-in-cell simulations and show the potential of the new methods for accelerating the modeling of laser-driven ion acceleration systems. |
Thursday, November 11, 2021 11:30AM - 11:42AM |
TO05.00011: Electromagnetic Transparency in strongly magnetized plasmas Devshree Mandal, Ayushi Vashistha, LAXMAN P GOSWAMI, Amita Das Plasma being a collection of charged particles interacts with Electromagnetic fields and can display wide ranging of scattering, absorption, reflection and transmission of the wave. It is shown here with the help of PIC simulations, that a plane laser pulse is able to propagate unhindered inside the plasma in the presence of a very strong magnetic field. The study has been conducted for a configuration for which the applied external magnetic field is normal to the laser electric field. The applied magnetic field is strong to magnetize even the heavier ion species. The plasma in this case behaves like a vacuum for the propagation of the EM field. The phenomena is understood by realising that when the applied magnetic field is strong, the resonance and cut-off points approach each other, and as a result, the width of stop-band gets reduced. Thus, the EM wave is allowed to propagate inside the medium. In this case, even though charges move, there is no current generated in the medium, nor does any charge separation occurs. Thus, the source in the Maxwells equation which alters the vacuum dielectric behaviour is totally absent. This study is relevant in astrophysical scenario where plasmas are often threaded with strong magnetic fields. |
Thursday, November 11, 2021 11:42AM - 11:54AM |
TO05.00012: Three-Dimensional Modeling of Capillary Discharge Plasmas for Acceleration and Control of Particle Beams Nathan M Cook, Abdourahmane Diaw, Evan Carlin, Stephen Coleman, Edward C Hansen, Petros Tzeferacos, Paul Moeller, Rob Nagler Next generation accelerators aim to achieve unparalleled beam quality, stability, and average power, for which dramatic improvements to the flexibility, control, and precision of beamline components is required. Capillary discharge plasmas are a subset of structured plasma systems which offer strategic advantages over traditional beamline technologies for accelerating stages, focusing elements, energy compensators, and diagnostics. We present simulations of capillary discharge plasmas in 2D and 3D geometries using FLASH, a publicly-available multi-physics code with sophisticated magneto-hydrodynamic capabilities. We explore novel geometric configurations of capillary structures for use as a laser-plasma accelerator stage, and examine differences in the plasma density steady state resulting from structure, gas, and discharge parameters. We model laser energy deposition to generate sub-channels for the guiding of intense pulses. Lastly, we investigate the use of capillaries for active plasma lenses and present results from benchmark studies. These results are compared against simulation and experimental studies. |
Thursday, November 11, 2021 11:54AM - 12:06PM |
TO05.00013: On stochastic electron motion in colliding plane waves Alexey R Knyazev, Sergei Krasheninnikov The stochastic dynamics of an electron in counterpropagating linearly polarized laser beams is analyzed using a recently developed 3/2-dimensional Hamiltonian approach. |
Thursday, November 11, 2021 12:06PM - 12:18PM |
TO05.00014: On QED plasma framework Mikhail V Medvedev Ultra-magnetized plasmas where the magnetic field strength exceeds the Schwinger (critical) field become of great scientific interest, thank to the current advances in laser-plasma experiments and astrophysical observations of magnetar emission. These advances demand better understanding of how quantum electrodynamics (QED) effects that are present in ultra-strong-field environments affect plasma dynamics. Interestingly, magnetars -- neutron stars with magnetic fields of ~1e15 Gauss or greater -- do exist and QED effects on their magnetospheric plasma cannot be ignored. In particular, Maxwell's equations become nonlinear in the strong-QED regime. This effect has neither been incorporated in plasma codes, nor systematically considered in theoretical studies. Here we present the `QED plasma framework' which will allow for such studies. We present the derivation of the general equation of linear plasma modes in QED-plasma with arbitrarily strong magnetic field. We also precent an illustrative example of low-frequency modes in the ultra-magnetized cold plasma. These results can be important for understanding of a magnetospheric pair plasma of a magnetar and for future laser-plasma experiments. |
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