In this bachelor's thesis, isotope effects for pedestal instabilities have been studied based on an ASDEX Upgrade H-Mode scenario. This was done using the JOREK code for extended MHD simulations, including the ion diamagnetic drift and the establishment of ExB flows. Simulations with single toroidal harmonics were performed for multiple times during the build-up of the pedestal, to assess the evolution of the linear stability of modes occurring near the edge. When changing the average ion masses from 2.0 to 2.5 and 3.0, the variations were small, and MHD's momentum equation was shown to be the major cause for them. As a second step, simulations with multiple toroidal harmonics were performed to simulate an Edge Localized Mode (ELM) crash, again comparing between the average ion masses of 2.0, 2.5, and 3.0. The resulting variations of heat and particle losses were compared to JET results. The experimental differences between ion masses could not be reproduced. Together with the fact that the simulations' pedestal for an average ion mass of 2.5 and 3.0 was not matched to the experiment, this indicates that other effects, such as small-scale turbulences, must be included - for example, by adapting the simulations' transport coefficients - to explain the experimental differences.
{"title":"Magneto-Hydrodynamic Simulations of Pedestal Instabilities for Tokamak Plasmas with Different Ion Masses","authors":"Matthias Rosenthal","doi":"arxiv-2408.04518","DOIUrl":"https://doi.org/arxiv-2408.04518","url":null,"abstract":"In this bachelor's thesis, isotope effects for pedestal instabilities have\u0000been studied based on an ASDEX Upgrade H-Mode scenario. This was done using the\u0000JOREK code for extended MHD simulations, including the ion diamagnetic drift\u0000and the establishment of ExB flows. Simulations with single toroidal harmonics\u0000were performed for multiple times during the build-up of the pedestal, to\u0000assess the evolution of the linear stability of modes occurring near the edge.\u0000When changing the average ion masses from 2.0 to 2.5 and 3.0, the variations\u0000were small, and MHD's momentum equation was shown to be the major cause for\u0000them. As a second step, simulations with multiple toroidal harmonics were\u0000performed to simulate an Edge Localized Mode (ELM) crash, again comparing\u0000between the average ion masses of 2.0, 2.5, and 3.0. The resulting variations\u0000of heat and particle losses were compared to JET results. The experimental\u0000differences between ion masses could not be reproduced. Together with the fact\u0000that the simulations' pedestal for an average ion mass of 2.5 and 3.0 was not\u0000matched to the experiment, this indicates that other effects, such as\u0000small-scale turbulences, must be included - for example, by adapting the\u0000simulations' transport coefficients - to explain the experimental differences.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141941532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We study the nonlinear theory of small-amplitude electron-acoustic solitons (EASs) in a relativistic astrophysical magnetoplasma consisting of two-temperature electrons: a sparse population of relativistic nondegenerate classical electrons and a group of fully degenerate dense relativistic electrons (main constituent) immersed in a static magnetic field with a neutralizing stationary ion background. By using the multiple-scale reductive perturbation technique with the Lorentz transformation, the Zakharov-Kuznetsov (ZK) and the modified Zakharov-Kuznetsov (mZK) equations are derived to describe the evolution of EASs in two different regimes of relativistic degeneracy: $r_{d0}<50$ and $r_{d0}gtrsim50$. The characteristics of the plane soliton solutions of ZK and mZK equations and the soliton energy are studied. We show that the solitons moving at an angle $alpha$ to the external magnetic field can be unstable under transverse long-wavelength perturbations. The growth rates of instabilities are obtained and analyzed with the effects of the relativity parameter $beta_{rm{cl}}=k_BT_{rm{cl}}/m_ec^2$ and the degeneracy parameter $r_{d0}$, where $k_B$ is the Boltzmann constant and $T_{rm{cl}}$ is the temperature of classical electrons. Interestingly, the ZK solitons, even if it is stable for the first-order perturbations, can be unstable in the second-order correction. Furthermore, while the first-order growth rates of perturbations for ZK solitons tend to vanish as $alpharightarrow 38^circ$, that for the mZK soliton goes to zero as $alpharightarrow 90^circ$. However, depending on the angle $alpha$, the growth rates are found to be reduced either by increasing the values of $beta_{rm{cl}}$ or by decreasing the values of $r_{d0}$. The applications of our results to astrophysical plasmas, such as those in the environments of white dwarfs are discussed.
{"title":"Transverse instability of electron-acoustic solitons in a relativistic degenerate astrophysical magnetoplasma","authors":"A. P. Misra, A. Abdikian","doi":"arxiv-2408.04404","DOIUrl":"https://doi.org/arxiv-2408.04404","url":null,"abstract":"We study the nonlinear theory of small-amplitude electron-acoustic solitons\u0000(EASs) in a relativistic astrophysical magnetoplasma consisting of\u0000two-temperature electrons: a sparse population of relativistic nondegenerate\u0000classical electrons and a group of fully degenerate dense relativistic\u0000electrons (main constituent) immersed in a static magnetic field with a\u0000neutralizing stationary ion background. By using the multiple-scale reductive\u0000perturbation technique with the Lorentz transformation, the Zakharov-Kuznetsov\u0000(ZK) and the modified Zakharov-Kuznetsov (mZK) equations are derived to\u0000describe the evolution of EASs in two different regimes of relativistic\u0000degeneracy: $r_{d0}<50$ and $r_{d0}gtrsim50$. The characteristics of the plane\u0000soliton solutions of ZK and mZK equations and the soliton energy are studied.\u0000We show that the solitons moving at an angle $alpha$ to the external magnetic\u0000field can be unstable under transverse long-wavelength perturbations. The\u0000growth rates of instabilities are obtained and analyzed with the effects of the\u0000relativity parameter $beta_{rm{cl}}=k_BT_{rm{cl}}/m_ec^2$ and the degeneracy\u0000parameter $r_{d0}$, where $k_B$ is the Boltzmann constant and $T_{rm{cl}}$ is\u0000the temperature of classical electrons. Interestingly, the ZK solitons, even if\u0000it is stable for the first-order perturbations, can be unstable in the\u0000second-order correction. Furthermore, while the first-order growth rates of\u0000perturbations for ZK solitons tend to vanish as $alpharightarrow 38^circ$,\u0000that for the mZK soliton goes to zero as $alpharightarrow 90^circ$. However,\u0000depending on the angle $alpha$, the growth rates are found to be reduced\u0000either by increasing the values of $beta_{rm{cl}}$ or by decreasing the\u0000values of $r_{d0}$. The applications of our results to astrophysical plasmas,\u0000such as those in the environments of white dwarfs are discussed.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141941371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tobias Dornheim, Panagiotis Tolias, Zhandos Moldabekov, Jan Vorberger
We investigate the short wavelength limit of the dynamic Matsubara local field correction $widetilde{G}(mathbf{q},z_l)$ of the uniform electron gas based on direct emph{ab initio} path integral Monte Carlo (PIMC) results over an unprecedented range of wavenumbers, $qlesssim20q_textnormal{F}$, where $q_textnormal{F}$ is the Fermi wavenumber. We find excellent agreement with the analytically derived asymptotic limit by Hou emph{et al.}~[textit{Phys.~Rev.~B}~textbf{106}, L081126 (2022)] for the static local field correction and empirically confirm the independence of the short wavelength limit with respect to the Matsubara frequency $z_l$. In the warm dense matter regime, we find that the onset of the quantum tail in the static local field correction closely coincides with the onset of the algebraic tail in the momentum distribution function and the corresponding empirical criterion reported by Hunger emph{et al.}~[textit{Phys.~Rev.~E} textbf{103}, 053204 (2021)]. In the strongly coupled electron liquid regime, our calculations reveal a more complicated non-monotonic convergence towards the $qtoinfty$ limit that is shaped by the spatial structure in the system. We expect our results to be of broad interest for a number of fields including the study of matter under extreme conditions, the development of improved dielectric theories, and the construction of advanced exchange--correlation functionals for thermal density functional theory.
{"title":"Short wavelength limit of the dynamic Matsubara local field correction","authors":"Tobias Dornheim, Panagiotis Tolias, Zhandos Moldabekov, Jan Vorberger","doi":"arxiv-2408.04669","DOIUrl":"https://doi.org/arxiv-2408.04669","url":null,"abstract":"We investigate the short wavelength limit of the dynamic Matsubara local\u0000field correction $widetilde{G}(mathbf{q},z_l)$ of the uniform electron gas\u0000based on direct emph{ab initio} path integral Monte Carlo (PIMC) results over\u0000an unprecedented range of wavenumbers, $qlesssim20q_textnormal{F}$, where\u0000$q_textnormal{F}$ is the Fermi wavenumber. We find excellent agreement with\u0000the analytically derived asymptotic limit by Hou emph{et\u0000al.}~[textit{Phys.~Rev.~B}~textbf{106}, L081126 (2022)] for the static local\u0000field correction and empirically confirm the independence of the short\u0000wavelength limit with respect to the Matsubara frequency $z_l$. In the warm\u0000dense matter regime, we find that the onset of the quantum tail in the static\u0000local field correction closely coincides with the onset of the algebraic tail\u0000in the momentum distribution function and the corresponding empirical criterion\u0000reported by Hunger emph{et al.}~[textit{Phys.~Rev.~E} textbf{103}, 053204\u0000(2021)]. In the strongly coupled electron liquid regime, our calculations\u0000reveal a more complicated non-monotonic convergence towards the $qtoinfty$\u0000limit that is shaped by the spatial structure in the system. We expect our\u0000results to be of broad interest for a number of fields including the study of\u0000matter under extreme conditions, the development of improved dielectric\u0000theories, and the construction of advanced exchange--correlation functionals\u0000for thermal density functional theory.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141941531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jeremy J. Williams, Daniel Medeiros, Stefan Costea, David Tskhakaya, Franz Poeschel, René Widera, Axel Huebl, Scott Klasky, Norbert Podhorszki, Leon Kos, Ales Podolnik, Jakub Hromadka, Tapish Narwal, Klaus Steiniger, Michael Bussmann, Erwin Laure, Stefano Markidis
Large-scale HPC simulations of plasma dynamics in fusion devices require efficient parallel I/O to avoid slowing down the simulation and to enable the post-processing of critical information. Such complex simulations lacking parallel I/O capabilities may encounter performance bottlenecks, hindering their effectiveness in data-intensive computing tasks. In this work, we focus on introducing and enhancing the efficiency of parallel I/O operations in Particle-in-Cell Monte Carlo simulations. We first evaluate the scalability of BIT1, a massively-parallel electrostatic PIC MC code, determining its initial write throughput capabilities and performance bottlenecks using an HPC I/O performance monitoring tool, Darshan. We design and develop an adaptor to the openPMD I/O interface that allows us to stream PIC particle and field information to I/O using the BP4 backend, aggressively optimized for I/O efficiency, including the highly efficient ADIOS2 interface. Next, we explore advanced optimization techniques such as data compression, aggregation, and Lustre file striping, achieving write throughput improvements while enhancing data storage efficiency. Finally, we analyze the enhanced high-throughput parallel I/O and storage capabilities achieved through the integration of openPMD with rapid metadata extraction in BP4 format. Our study demonstrates that the integration of openPMD and advanced I/O optimizations significantly enhances BIT1's I/O performance and storage capabilities, successfully introducing high throughput parallel I/O and surpassing the capabilities of traditional file I/O.
{"title":"Enabling High-Throughput Parallel I/O in Particle-in-Cell Monte Carlo Simulations with openPMD and Darshan I/O Monitoring","authors":"Jeremy J. Williams, Daniel Medeiros, Stefan Costea, David Tskhakaya, Franz Poeschel, René Widera, Axel Huebl, Scott Klasky, Norbert Podhorszki, Leon Kos, Ales Podolnik, Jakub Hromadka, Tapish Narwal, Klaus Steiniger, Michael Bussmann, Erwin Laure, Stefano Markidis","doi":"arxiv-2408.02869","DOIUrl":"https://doi.org/arxiv-2408.02869","url":null,"abstract":"Large-scale HPC simulations of plasma dynamics in fusion devices require\u0000efficient parallel I/O to avoid slowing down the simulation and to enable the\u0000post-processing of critical information. Such complex simulations lacking\u0000parallel I/O capabilities may encounter performance bottlenecks, hindering\u0000their effectiveness in data-intensive computing tasks. In this work, we focus\u0000on introducing and enhancing the efficiency of parallel I/O operations in\u0000Particle-in-Cell Monte Carlo simulations. We first evaluate the scalability of\u0000BIT1, a massively-parallel electrostatic PIC MC code, determining its initial\u0000write throughput capabilities and performance bottlenecks using an HPC I/O\u0000performance monitoring tool, Darshan. We design and develop an adaptor to the\u0000openPMD I/O interface that allows us to stream PIC particle and field\u0000information to I/O using the BP4 backend, aggressively optimized for I/O\u0000efficiency, including the highly efficient ADIOS2 interface. Next, we explore\u0000advanced optimization techniques such as data compression, aggregation, and\u0000Lustre file striping, achieving write throughput improvements while enhancing\u0000data storage efficiency. Finally, we analyze the enhanced high-throughput\u0000parallel I/O and storage capabilities achieved through the integration of\u0000openPMD with rapid metadata extraction in BP4 format. Our study demonstrates\u0000that the integration of openPMD and advanced I/O optimizations significantly\u0000enhances BIT1's I/O performance and storage capabilities, successfully\u0000introducing high throughput parallel I/O and surpassing the capabilities of\u0000traditional file I/O.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141941372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Xie, Y. Sun, M. Jia, A. Loarte, Y. Q. Liu, C. Ye, S. Gu, H. Sheng, Y. Liang, Q. Ma, H. Yang, C. A. Paz-Soldan, G. Deng, S. Fu, G. Chen, K. He, T. Jia, D. Lu, B. Lv, J. Qian, H. H. Wang, S. Wang, D. Weisberg, X. Wu, W. Xu, X. Yan, Y. Yu, Q. Zang, L. Zeng, T. Zhang, C. Zhou, Z. Zhou, B. Wan, the EAST Team
We report the suppression of Type-I Edge Localized Modes (ELMs) in the EAST tokamak under ITER baseline conditions using $n = 4$ Resonant Magnetic Perturbations (RMPs), while maintaining energy confinement. Achieving RMP-ELM suppression requires a normalized plasma beta ($beta_N$) exceeding 1.8 in a target plasma with $q_{95}approx 3.1$ and tungsten divertors. Quasi-linear modeling shows high plasma beta enhances RMP-driven neoclassical toroidal viscosity torque, reducing field penetration thresholds. These findings demonstrate the feasibility and efficiency of high $n$ RMPs for ELM suppression in ITER.
我们报告了在ITER基线条件下使用$n = 4$共振磁扰动（RMPs）抑制EASTtokamak中的I型边缘局部模（ELMs），同时保持能量约束的情况。实现RMP-ELM抑制要求目标等离子体中的归一化等离子体β（$beta_N$）超过1.8，q_{95}approx 3.1$和钨分流器。准线性建模显示，高等离子体β能增强RMP驱动的新古典环形粘滞力矩，降低场穿透阈值。这些发现证明了在热核实验堆中使用高 n$ RMP 抑制 ELM 的可行性和效率。
{"title":"Suppression of Edge Localized Modes in ITER Baseline Scenario in EAST using Edge Localized Magnetic Perturbations","authors":"P. Xie, Y. Sun, M. Jia, A. Loarte, Y. Q. Liu, C. Ye, S. Gu, H. Sheng, Y. Liang, Q. Ma, H. Yang, C. A. Paz-Soldan, G. Deng, S. Fu, G. Chen, K. He, T. Jia, D. Lu, B. Lv, J. Qian, H. H. Wang, S. Wang, D. Weisberg, X. Wu, W. Xu, X. Yan, Y. Yu, Q. Zang, L. Zeng, T. Zhang, C. Zhou, Z. Zhou, B. Wan, the EAST Team","doi":"arxiv-2408.03272","DOIUrl":"https://doi.org/arxiv-2408.03272","url":null,"abstract":"We report the suppression of Type-I Edge Localized Modes (ELMs) in the EAST\u0000tokamak under ITER baseline conditions using $n = 4$ Resonant Magnetic\u0000Perturbations (RMPs), while maintaining energy confinement. Achieving RMP-ELM\u0000suppression requires a normalized plasma beta ($beta_N$) exceeding 1.8 in a\u0000target plasma with $q_{95}approx 3.1$ and tungsten divertors. Quasi-linear\u0000modeling shows high plasma beta enhances RMP-driven neoclassical toroidal\u0000viscosity torque, reducing field penetration thresholds. These findings\u0000demonstrate the feasibility and efficiency of high $n$ RMPs for ELM suppression\u0000in ITER.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"99 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141941369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Rososhek, B. R. Kusse, W. M. Potter, N. J. Wilson, E. S. Lavine, D. A. Hammer
An imaging refractrometer can be used to describe the properties of a high-energy density plasma by analyzing the transverse intensity distribution of a laser beam that has passed through the plasma. The output of the refractrometer can be directly calibrated in terms of beam deflection angles using ray transfer matrix analysis. This paper describes a novel way to calibrate the refractrometer output in terms of the spatial wavenumbers of the transverse intensity distribution of the laser beam. This is accomplished by replacing the plasma with a gridded structure that modulates the transverse intensity of the beam, producing an intensity distribution with a known Fourier Transform. This calibration technique will generate a one-to-one mapping of deflection angle to wavenumber and will enable measurement of the size of Fourier space available to the system. The spectrum of wavenumbers generated when the laser beam passes through a high-energy density plasma may contain information about the types of density fluctuation that are present in the plasma.
{"title":"Wavenumber Calibration for an Imaging Refractometer","authors":"A. Rososhek, B. R. Kusse, W. M. Potter, N. J. Wilson, E. S. Lavine, D. A. Hammer","doi":"arxiv-2408.02660","DOIUrl":"https://doi.org/arxiv-2408.02660","url":null,"abstract":"An imaging refractrometer can be used to describe the properties of a\u0000high-energy density plasma by analyzing the transverse intensity distribution\u0000of a laser beam that has passed through the plasma. The output of the\u0000refractrometer can be directly calibrated in terms of beam deflection angles\u0000using ray transfer matrix analysis. This paper describes a novel way to\u0000calibrate the refractrometer output in terms of the spatial wavenumbers of the\u0000transverse intensity distribution of the laser beam. This is accomplished by\u0000replacing the plasma with a gridded structure that modulates the transverse\u0000intensity of the beam, producing an intensity distribution with a known Fourier\u0000Transform. This calibration technique will generate a one-to-one mapping of\u0000deflection angle to wavenumber and will enable measurement of the size of\u0000Fourier space available to the system. The spectrum of wavenumbers generated\u0000when the laser beam passes through a high-energy density plasma may contain\u0000information about the types of density fluctuation that are present in the\u0000plasma.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141941373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ivan Ostrovsky, Gilad Hurvitz, Eli Bograd, Eli Flaxer, Soumitra Hazra, Sharly Fleischer
A sensitive optical diffractometry method is developed and utilized for advanced tomography of laser-induced air plasma formations. Using transverse diffractometry and Supergaussian plasma distribution modelling we extract the main parameters of the plasma being the plasma density, width and shape with 20 micrometer spatial resolution throughout the plasma formation. The experimentally recorded diffraction patterns fitted by the Supergaussian plasma model are found to capture unprecedentedly delicate traits in the evolution of the plasma from its effective birth and on. Key features in the spatial evolution of the plasma such as the 'escape position', the 'turning point' and the refocusing dynamics of the beam are identified and explored in details. Our work provides experimental and theoretical access into the highly nonlinear dynamics of laser-induced air plasma.
{"title":"Tomographic diffractometry of laser-induced plasma formations","authors":"Ivan Ostrovsky, Gilad Hurvitz, Eli Bograd, Eli Flaxer, Soumitra Hazra, Sharly Fleischer","doi":"arxiv-2408.02772","DOIUrl":"https://doi.org/arxiv-2408.02772","url":null,"abstract":"A sensitive optical diffractometry method is developed and utilized for\u0000advanced tomography of laser-induced air plasma formations. Using transverse\u0000diffractometry and Supergaussian plasma distribution modelling we extract the\u0000main parameters of the plasma being the plasma density, width and shape with 20\u0000micrometer spatial resolution throughout the plasma formation. The\u0000experimentally recorded diffraction patterns fitted by the Supergaussian plasma\u0000model are found to capture unprecedentedly delicate traits in the evolution of\u0000the plasma from its effective birth and on. Key features in the spatial\u0000evolution of the plasma such as the 'escape position', the 'turning point' and\u0000the refocusing dynamics of the beam are identified and explored in details. Our\u0000work provides experimental and theoretical access into the highly nonlinear\u0000dynamics of laser-induced air plasma.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"165 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141941370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mario Imbrogno, Claudio Meringolo, Sergio Servidio, Alejandro Cruz-Osorio, Benoît Cerutti, Francesco Pegoraro
Turbulence in classical fluids is characterized by persistent structures that emerge from the chaotic landscape. We investigate the analogous process in fully kinetic plasma turbulence by using high-resolution, direct numerical simulations in two spatial dimensions. We observe the formation of long-living vortices with a profile typical of macroscopic, magnetically dominated force-free states. Inspired by the Harris pinch model for inhomogeneous equilibria, we describe these metastable solutions with a self-consistent kinetic model in a cylindrical coordinate system centered on a representative vortex, starting from an explicit form of the particle velocity distribution function. Such new equilibria can be simplified to a Gold-Hoyle solution of the modified force-free state. Turbulence is mediated by the long-living structures, accompanied by transients in which such vortices merge and form self-similarly new metastable equilibria. This process can be relevant to the comprehension of various astrophysical phenomena, going from the formation of plasmoids in the vicinity of massive compact objects to the emergence of coherent structures in the heliosphere.
{"title":"Long-living Equilibria in Kinetic Astrophysical Plasma Turbulence","authors":"Mario Imbrogno, Claudio Meringolo, Sergio Servidio, Alejandro Cruz-Osorio, Benoît Cerutti, Francesco Pegoraro","doi":"arxiv-2408.02656","DOIUrl":"https://doi.org/arxiv-2408.02656","url":null,"abstract":"Turbulence in classical fluids is characterized by persistent structures that\u0000emerge from the chaotic landscape. We investigate the analogous process in\u0000fully kinetic plasma turbulence by using high-resolution, direct numerical\u0000simulations in two spatial dimensions. We observe the formation of long-living\u0000vortices with a profile typical of macroscopic, magnetically dominated\u0000force-free states. Inspired by the Harris pinch model for inhomogeneous\u0000equilibria, we describe these metastable solutions with a self-consistent\u0000kinetic model in a cylindrical coordinate system centered on a representative\u0000vortex, starting from an explicit form of the particle velocity distribution\u0000function. Such new equilibria can be simplified to a Gold-Hoyle solution of the\u0000modified force-free state. Turbulence is mediated by the long-living\u0000structures, accompanied by transients in which such vortices merge and form\u0000self-similarly new metastable equilibria. This process can be relevant to the\u0000comprehension of various astrophysical phenomena, going from the formation of\u0000plasmoids in the vicinity of massive compact objects to the emergence of\u0000coherent structures in the heliosphere.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141941374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jeremy J. Williams, Daniel Medeiros, Ivy B. Peng, Stefano Markidis
Optimizing iPIC3D, an implicit Particle-in-Cell (PIC) code, for large-scale 3D plasma simulations is crucial for space and astrophysical applications. This work focuses on characterizing iPIC3D's communication efficiency through strategic measures like optimal node placement, communication and computation overlap, and load balancing. Profiling and tracing tools are employed to analyze iPIC3D's communication efficiency and provide practical recommendations. Implementing optimized communication protocols addresses the Geospace Environmental Modeling (GEM) magnetic reconnection challenges in plasma physics with more precise simulations. This approach captures the complexities of 3D plasma simulations, particularly in magnetic reconnection, advancing space and astrophysical research.
{"title":"Characterizing the Performance of the Implicit Massively Parallel Particle-in-Cell iPIC3D Code","authors":"Jeremy J. Williams, Daniel Medeiros, Ivy B. Peng, Stefano Markidis","doi":"arxiv-2408.01983","DOIUrl":"https://doi.org/arxiv-2408.01983","url":null,"abstract":"Optimizing iPIC3D, an implicit Particle-in-Cell (PIC) code, for large-scale\u00003D plasma simulations is crucial for space and astrophysical applications. This\u0000work focuses on characterizing iPIC3D's communication efficiency through\u0000strategic measures like optimal node placement, communication and computation\u0000overlap, and load balancing. Profiling and tracing tools are employed to\u0000analyze iPIC3D's communication efficiency and provide practical\u0000recommendations. Implementing optimized communication protocols addresses the\u0000Geospace Environmental Modeling (GEM) magnetic reconnection challenges in\u0000plasma physics with more precise simulations. This approach captures the\u0000complexities of 3D plasma simulations, particularly in magnetic reconnection,\u0000advancing space and astrophysical research.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141941375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A recent neutron analysis of experiments conducted at the National Ignition Facility (NIF) has revealed deviations from the Maxwellian distributions in the ion relative kinetic energy of burning plasmas, with the surprising emergence of supra-thermal deuterium and tritium (DT) ions that fall outside the predictions of macroscopic statistical hydrodynamic models. Our hybrid-particle-in-cell simulations, incorporating the newly-developed model of large-angle collisions, suggest this could be attributed to the increased significance of large-angle collisions among DT ions and (alpha)-particles in the burning plasma. Extensive investigations into the implications of large-angle collisions in the burning plasma have yield several key findings, including an ignition moment promotion by (sim 10, {rm ps}), the presence of supra-thermal ions below an energy threshold, and a hotspot expansion rate about six times faster than expected. Furthermore, we have established the congruency between the NIF neutron spectral moment analysis and our simulations. Our researches on large-angle collisions in burning plasmas offer new insights for experiment interpretation and update our understanding for new designs of inertial confinement fusions.
{"title":"Large-Angle Collisions in Burning Plasmas of Inertial Confinement Fusions","authors":"Y. H. Xue, D. Wu, J. Zhang","doi":"arxiv-2408.01948","DOIUrl":"https://doi.org/arxiv-2408.01948","url":null,"abstract":"A recent neutron analysis of experiments conducted at the National Ignition\u0000Facility (NIF) has revealed deviations from the Maxwellian distributions in the\u0000ion relative kinetic energy of burning plasmas, with the surprising emergence\u0000of supra-thermal deuterium and tritium (DT) ions that fall outside the\u0000predictions of macroscopic statistical hydrodynamic models. Our\u0000hybrid-particle-in-cell simulations, incorporating the newly-developed model of\u0000large-angle collisions, suggest this could be attributed to the increased\u0000significance of large-angle collisions among DT ions and (alpha)-particles\u0000in the burning plasma. Extensive investigations into the implications of\u0000large-angle collisions in the burning plasma have yield several key findings,\u0000including an ignition moment promotion by (sim 10, {rm ps}), the presence\u0000of supra-thermal ions below an energy threshold, and a hotspot expansion rate\u0000about six times faster than expected. Furthermore, we have established the\u0000congruency between the NIF neutron spectral moment analysis and our\u0000simulations. Our researches on large-angle collisions in burning plasmas offer\u0000new insights for experiment interpretation and update our understanding for new\u0000designs of inertial confinement fusions.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141941376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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