Bulletin of the American Physical Society
64th Annual Meeting of the APS Division of Plasma Physics
Volume 67, Number 15
Monday–Friday, October 17–21, 2022; Spokane, Washington
Session GO07: Laboratory Plasma AstrophysicsLive Streamed
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Chair: Sergey Lebedev, Imperial College London Room: 401 ABC |
Tuesday, October 18, 2022 9:30AM - 9:42AM |
GO07.00001: Energy partition in high-Mach number collisionless shock experiments at NIF Frederico Fiuza, George F Swadling, Colin J Bruulsema, Anna Grassi, Alexis Marret, Drew P Higginson, Hye-Sook Park, Bradley B Pollock, Wojciech Rozmus, Dmitri D Ryutov, Anatoly Spitkovsky, Arno V Vanthieghem Recent developments in high-energy-density laser facilities, such as NIF, are now enabling studies of high-Mach number collisionless shocks in the laboratory [1]. We will present the results of recent NIF experiments where Thomson scattering is used to characterize the evolution of the plasma density, temperature, and velocity during shock formation. In particular, we will discuss measurements of the electron and ion temperatures as function of time and connect those with models for how the kinetic energy of the plasma flows is partitioned between ions and electrons in a high Mach number collisionless shock. |
Tuesday, October 18, 2022 9:42AM - 9:54AM |
GO07.00002: High Repetition Rate Mapping of the Collisonless Coupling Between a Super-Alfvénic Piston Plasma and Magnetized Ambient Plasma Robert S Dorst, Ari Le, Carmen G Constantin, Jessica J Pilgram, Derek B Schaeffer, Stephen T Vincena, Shreekrishna Tripathi, Dan Winske, Misa Cowee, David J Larson, Christoph Niemann We present two-dimensional mapping of a super-Alfvénic (MA > 1) carbon, laser produced plasma (LPP) as it couples to an ambient, magnetized helium plasma through collisionless, collective processes. The data was acquired during recent experiments performed on the Large Plasma Device (LAPD) at the University of California, Los Angeles as part of a series of experiments recreating conditions observed in Earth’s magnetosphere for study in the laboratory. The Laminar coupling is investigated by utilizing laser induced fluorescence to measure the phase-space evolution of the LPP ions in conjunction with magnetic field traces that measure the energy departed into the ambient ions. The acquisition of this data requires a high repetition rate (~ 1 Hz) as each dataset represent thousands of laser shots in order to fully investigate the two-dimensional region of interest. The data is compared to fully kinetic, 2D3V PIC simulations in order to provide a framework in which we can understand the coupling and contextualize our results in the astrophysical environment. |
Tuesday, October 18, 2022 9:54AM - 10:06AM |
GO07.00003: Progress towards collisionless shock experiments in a magnetised, pulsed power-driven ambient plasma Danny R Russell, Jack W Halliday, Stefano Merlini, Lee G Suttle, Vicente Valenzuela-Villaseca, Derek B Schaeffer, Sergey V Lebedev Magnetised collisionless shocks are ubiquitous in astrophysical plasmas and have been shown to accelerate energetic particles. The collisionless nature of these shocks raises many interesting questions including how energy is partitioned and how particles are accelerated to high energies [2]. This is an active field of research which includes scaled laboratory experiments. Significant progress has been made in recent years [3], however, one of the main challenges for laboratory experiments is sustaining shocks for long enough that these processes can be observed. |
Tuesday, October 18, 2022 10:06AM - 10:18AM |
GO07.00004: Laser-driven high Mach number collisionless shock experiments on NIF and Omega Hye-Sook Park, Ellie Tubman, Frederico Fiuza, Drew P Higginson, David J Larson, Mario J Manuel, Kasper Moczulski, Brad B Pollock, Michael M Pokornik, George F Swadling, Petros Tzeferacos High Mach number astrophysical plasmas can create collisionless shocks via plasma instabilities and turbulence that are responsible for magnetic field generations and cosmic ray acceleration. Recently, many laboratory experiments were successful to observe the Weibel instabilities, self-generated magnetic fields, collisionless shock formation as well as non-thermal particle acceleration [1,2]. The collisionless shocks come in two flavors: one in unmagnetized and the other in magnetized background conditions. Various experimental platforms are developed to study both cases using optical Thomson scattering, particle spectrometers, and proton radiography diagnostics on Omega and NIF. Experimental measurements are compared with the electromagnetic hybrid simulation codes, in which the target and background ions are treated kinetically with particle-in-cell methods and the charge-neutralizing electrons are treated as an inertia-less adiabatic fluid [3]. This paper will present the recent results from these experiments. |
Tuesday, October 18, 2022 10:18AM - 10:30AM |
GO07.00005: Observations of high-MA, magnetized, collisionless shocks on the OMEGA facility. Eleanor Tubman, David J Larson, Michael Pokornik, Kasper Moczulski, George F Swadling, Bradley B Pollock, Mario Manuel, Drew P Higginson, Frederico Fiuza, Petros Tzeferacos, Hye-Sook Park Magnetized collisionless (λmfp>> Lshock) shocks are created throughout the universe including within super-nova remnants and the Earth’s atmosphere. These shocks can generate energized, ionized particles and radiation belts. The radiation belts exist for longer durations and extend over greater distances than predicted by models, which is of particular concern for shocks driven close to the Earth where satellites can be affected. Designing a laboratory experiment where a high MA (=vA/v >5) shock is produced within magnetized conditions, allows benchmarking of HANE (High Altitude Nuclear Explosion) models, and helps develop a better understanding of the underlying physics. |
Tuesday, October 18, 2022 10:30AM - 10:42AM |
GO07.00006: Kinetic Study of Quasi-Parallel Shock formation and particle acceleration Yu Zhang, Peter V Heuer, Jonathan R Davies, Chuang Ren, Derek B Schaeffer Quasi-parallel collisionless shocks (in which the shock normal is approximately parallel to the background magnetic field) are believed to be the most efficient accelerators in the universe. Compared to quasi-perpendicular shocks, quasi-parallel shocks are more difficult to form in the laboratory and to simulate because of their large spatial scales and long formation times. Our 2-D particle-in-cell simulations show that the early stage of quasi-parallel shock formation is achievable at the National Ignition Facility, and that particles accelerated by diffusive shock acceleration are expected to be observable experimentally. Repetitive ion acceleration by crossings of shock front, a key feature of DSA, is seen in the simulations. Collisionless dissipation mechanisms and particle spectra for different magnetic field angles to the shock normal will be presented. |
Tuesday, October 18, 2022 10:42AM - 10:54AM |
GO07.00007: Modeling of Young Stellar Objects through the study of magnetized rear-driven plasma jets from thin foil targets Pablo Perez-Martin, Michal Šmíd, Victorien Bouffetier, Florian-Emanuel Brack, Petr Cagas, Michal Červenák, Fabian Donat, Pavel Gajdos, Zhiyu He, Milan Holec, Grigory Kagan, Lenka Hronová, Kakolee F Kaniz, Michaela Kozlova, Florian Kroll, Huiya Liu, Xiayun Pan, Irene Prencipe, Gabriel Schaumann, Sushil K Singh, Manfred Sobiella, Bhuvana Srinivasan, Jamil Stafford, Jinren Sun, Zhiyong Xie, Jun Xiong, Panzheng Zhang, Yan Zhang, Francisco Suzuki-Vidal, Miroslav Krůs, Lei Ren, Ning Kang, Katerina Falk Plasma jets can be found in astrophysical systems (Accretion disks[1][2], Polars [3] or Young Stellar Objects [4]), but they are also useful as a platform to study plasma properties and transport effects. On a experiment at the PALS facility, we have studied the formation and propagation of rear-driven, collisional plasma jets from different foil thicknesses and materials when subject to an intense external magnetic field. |
Tuesday, October 18, 2022 10:54AM - 11:06AM |
GO07.00008: Diagnostic development for energetic electron measurements on the Facility for Laboratory Reconnection Experiment Jongsoo Yoo, Hantao Ji, Peiyun Shi, Stephen P Majeski, Derek J Thuecks The Facility for Laboratory Reconnection Experiment (FLARE) will have capabilities to access reconnection regimes with multiple X-lines after the current power system upgrade. FLARE can provide unique opportunities to study energetic particle generation during magnetic reconnection in astrophysically-relevant plasmas, since regimes with multiple X-lines require a large Lunquist number and normalized system size. Here we review previous laboratory and space measurements of energetic particles. Then, we discuss possible diagnostics for energetic electron measurements on FLARE, which include a Thomson scattering system with a notch filter, soft X-ray tomography, whistler wave absorption diagnostic, and electron energy analyzer. We also discuss how we use these diagnostics to determine dominant acceleration mechanisms during reconnection. |
Tuesday, October 18, 2022 11:06AM - 11:18AM |
GO07.00009: Stochastic Acceleration of Heavy Ions in a Magnetized and Turbulent Plasma Thomas I Campbell, Charles D Arrowsmith, Charlotte A Palmer, Archie F Bott, Abel Blazevic, Dennis Schumacher, Paul Neumayer, Martin Metternich, Haress Nazary, Vincent Bagnoud, Brian Reville, Konstantin Beyer, Laura Chen, Subir Sarkar, Alexander A Schekochihin, Tony Bell, Robert Bingham, Christopher Spindloe, Oliver Karnbach, Francesco Miniati, Scott Feister, Don Q Lamb, Kasper Moczulski, Anthony Scopatz, Petros Tzeferacos, Gianluca Gregori The exact mechanism that enables the acceleration of highly energetic charged particles in the Universe, cosmic rays (CR), remains controversial. Although many processes may result in CR acceleration, turbulence is generally accepted to be essential to energizing the ions and electrons in the interstellar medium. Indeed, the original mechanism of CR acceleration proposed by Fermi theorised that energetic charged particles gain energy in random scattering events with magnetized clouds. Given that the standard origin mechanism for these B fields is the turbulent dynamo mechanism, clearly a key process governing CR acceleration is related to how charged particles interact with stochastic B fields embedded in turbulent plasma. We have performed an experiment at GSI to investigate the interaction of fast heavy ions and turbulent magnetized plasma. Two opposing plastic targets, with textured surfaces, were laser-driven such that ablated plasma collided in the central region, creating a turbulent, magnetized plasma. As this occurs, collimated pulses of ions from UNILAC traverse the central region and the change in their energy profile is extracted from their time-of-flight (ToF). Our ToF data shows that the mean energy of ion pulses crossing the turbulent magnetized plasma increases. Our experimental results are supported by 3D magneto-hydrodynamics simulations. |
Tuesday, October 18, 2022 11:18AM - 11:30AM |
GO07.00010: Chemical Modeling of a Pulsed Glow Discharge Plasma at Low Temperature with Applications to Saturn's Moon Titan David Dubois, Alexander Raymond, Ella Sciamma-O'Brien, Farid Salama The Cassini spacecraft measured the molecular mass of ions for the first time in the atmosphere of Saturn’s largest moon, Titan[1]. These observations uncovered the complexity of Titan’s upper atmospheric chemistry, which results in the production of radicals, ions and aerosols[2]. Photochemical models have helped explain the gas phase chemistry involved in the production of organic aerosols[3]. Alongside those models, laboratory experiments have helped fill gaps in the reaction networks through detailed studies of the effects of precursors and energy source(s) on the chemical pathways leading to aerosol production. Here we present a new study using an existing 1D model[4], which simulates the plasma chemistry in the Titan Haze Simulation (THS) experiment developed on the COsmic Simulation Chamber (COSmIC) at NASA Ames Research Center. THS uses a pulsed plasma discharge in the stream of a supersonic jet expansion to simulate the different steps in Titan’s atmospheric chemistry at low (~150 K) Titan-like temperature[5]. Using newly published reaction rates[3], we have updated the model and report new computational results and their comparison to experimental mass spectra obtained with THS in two gas mixing ratio conditions (N2-CH4 and N2-CH4-C2H4) relevant to Titan's ionosphere. |
Tuesday, October 18, 2022 11:30AM - 11:42AM |
GO07.00011: An Experimental Investigation of Rubble Pile Charging In A Vacuum Environment Graeson Griffin, Jorge A Martinez Ortiz, Calvin Carmichael, Parker J Adamson, Lorin S Matthews, Truell W Hyde Dust particle charging occurs naturally across a diverse set of physics ranging from protoplanetary disk agglomeration to dust interactions on the lunar surface. As such, the underlying physics for charging individual dust particles and dust agglomerates must be clearly understood. Much of the time, this is most easily accomplished by the study of monomer piles [1]. The structure of monomer piles is relevant in various astrophysical contexts, such as studying the fine-grained rims observed around chondrules and dust interactions on airless bodies. These dynamics are important to such diverse physics issues as maintaining a human presence on the lunar surface for extended periods or understanding how the solar system formed. Dust particle charging can occur due to partially ionized environments, secondary photoelectron emission from solar radiation, or collisional charging [2]. All of these must be considered when studying astrophysical contexts such as studies of the Martian surface, dust aggregates in protoplanetary disks, or lunar regolith transport. Unfortunately, the question of how dust particle charging affects monomer pile dynamics remains largely unanswered. This presentation will present an experimental method for characterizing micron-sized particles on a surface and exploring dust particle charging under differing conditions. |
Tuesday, October 18, 2022 11:42AM - 11:54AM |
GO07.00012: Laboratory study of quadratic Zeeman effect in hydrogen Vladimir V Ivanov, Roberto C Mancini, Noah A Huerta, Kyle Swanson, Donald E Winget, Michael H Montgomery, Igor E Golovkin, Haritha Hariharan, Zethran Berbel The Zeeman effect is widely used for measurement of magnetic fields in laboratory and astrophysical plasmas. Magnetic fields in atmospheres of magnetic White Dwarf stars are in the range of 1 MG - 1 GG. The quadratic Zeeman effect results in the additional split and shift of of hydrogen lines in magnetic fields > 2 MG. Balmer lines were studied in magnetic fields produced by a 1 MA Zebra pulse power generator at the University of Nevada, Reno. The magnetic field was generated on the surface of rod loads. A layer of CH oil on the load center was a source of hydrogen. Hydrogen was excited and backlit by black body emission from the rod with a temperature of ~0.6 eV. Zeeman splitting of H-alpha and H-beta absorption lines was studied with a grating spectrometer and intensified CCD camera. A spectral shift of the central component of the triplet indicated the quadratic Zeeman effect in hydrogen . For the first time the quadratic Zeeman effects in hydrogen have been studied in a laboratory setting. |
Tuesday, October 18, 2022 11:54AM - 12:06PM |
GO07.00013: Modelling radiative collapse in high energy density systems using static mesh refinement Nikita Chaturvedi, Jeremy P Chittenden, Jack D Hare Radiative collapse occurs in dense plasmas where radiative loss drops the thermal pressure below the compressional magnetic pressure, leading to a runaway collapse to very small scale lengths. This is hypothesised to occur in the reconnection layer formed between two adjacent exploding wire arrays, driven by strong currents from Z facility at Sandia National Laboratories. In this regime, the reconnection layer can reach high enough densities and temperatures to radiatively cool and ultimately collapse to a very small region. |
Tuesday, October 18, 2022 12:06PM - 12:18PM |
GO07.00014: Increasing Angular Momentum in Pulsed-Power Driven quasi-Keplerian Rotating Plasma Experiments Vicente Valenzuela-Villaseca, Lee G Suttle, Francisco Suzuki-Vidal, Stefano Merlini, S. Reza Mirfayzi, Jack W Halliday, Danny R Russell, Jeremy P Chittenden, Jack D Hare, Mark E Koepke, Eric G Blackman, Sergey V Lebedev We present new results from the Rotating Plasma Experiment (RPX) platform developed on the MAGPIE pulsed-power generator (1.4 MA, 500 ns drive time). RPX was designed to simulate aspects of astrophysical accretion disks in the laboratory by driving quasi-Keplerian, differentially rotating plasmas by an off-radial inward-convergence of 8 magnetized ablation flows generated by a wire array Z pinch [1,2]. |
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