arXiv - PHYS - Plasma Physics最新文献_第2页

FreeMHD: validation and verification of the open-source, multi-domain, multi-phase solver for electrically conductive flows FreeMHD：验证和核查用于导电流的开源、多域、多相求解器

arXiv - PHYS - Plasma Physics Pub Date : 2024-09-13 DOI: arxiv-2409.08950

Brian Wynne, Francisco Saenz, Jabir Al-Salami, Yufan Xu, Zhen Sun, Changhong Hu, Kazuaki Hanada, Egemen Kolemen

{"title":"FreeMHD: validation and verification of the open-source, multi-domain, multi-phase solver for electrically conductive flows","authors":"Brian Wynne, Francisco Saenz, Jabir Al-Salami, Yufan Xu, Zhen Sun, Changhong Hu, Kazuaki Hanada, Egemen Kolemen","doi":"arxiv-2409.08950","DOIUrl":"https://doi.org/arxiv-2409.08950","url":null,"abstract":"The extreme heat fluxes in the divertor region of tokamaks may require an\u0000alternative to solid plasma-facing components, for the extraction of heat and\u0000the protection of the surrounding walls. Flowing liquid metals are proposed as\u0000an alternative, but raise additional challenges that require investigation and\u0000numerical simulations. Free surface designs are desirable for plasma-facing\u0000components (PFCs), but steady flow profiles and surface stability must be\u0000ensured to limit undesirable interactions with the plasma. Previous studies\u0000have mainly used steady-state, 2D, or simplified models for internal flows and\u0000have not been able to adequately model free-surface liquid metal (LM)\u0000experiments. Therefore, FreeMHD has been recently developed as an open-source\u0000magnetohydrodynamics (MHD) solver for free-surface electrically conductive\u0000flows subject to a strong external magnetic field. The FreeMHD solver computes\u0000incompressible free-surface flows with multi-region coupling for the\u0000investigation of MHD phenomena involving fluid and solid domains. The model\u0000utilizes the finite-volume OpenFOAM framework under the low magnetic Reynolds\u0000number approximation. FreeMHD is validated using analytical solutions for the\u0000velocity profiles of closed channel flows with various Hartmann numbers and\u0000wall conductance ratios. Next, experimental measurements are then used to\u0000verify FreeMHD, through a series of cases involving dam breaking, 3D magnetic\u0000fields, and free-surface LM flows. These results demonstrate that FreeMHD is a\u0000reliable tool for the design of LM systems under free surface conditions at the\u0000reactor scale. Furthermore, it is flexible, computationally inexpensive, and\u0000can be used to solve fully 3D transient MHD flows.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"75 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257458","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}

引用次数: 0

Production and magnetic self-confinement of $e^-e^+$ plasma by an extremely intense laser pulse incident on a structured solid target 结构化固体靶上入射的极强激光脉冲产生 $e^-e^+$ 等离子体并使其磁性自约束

arXiv - PHYS - Plasma Physics Pub Date : 2024-09-13 DOI: arxiv-2409.09131

Alexander Samsonov, Alexander Pukhov

{"title":"Production and magnetic self-confinement of $e^-e^+$ plasma by an extremely intense laser pulse incident on a structured solid target","authors":"Alexander Samsonov, Alexander Pukhov","doi":"arxiv-2409.09131","DOIUrl":"https://doi.org/arxiv-2409.09131","url":null,"abstract":"We propose an all-optical, single-laser-pulse scheme for generating dense,\u0000relativistic, strongly-magnetized electron-positron pair plasma. The scheme\u0000involves the interaction of an extremely intense ($I gtrsim\u0000SI{e24}{watt/cm^2}$) circularly polarized laser pulse with a solid-density\u0000target containing a conical cavity. Through full-scale three-dimensional\u0000particle-in-cell (PIC) simulations that account for quantum electrodynamical\u0000effects, it is shown that this interaction results in two significant outcomes:\u0000first, the generation of quasi-static axial magnetic fields reaching tens of\u0000gigagauss due to the inverse Faraday effect; and second, the production of\u0000large quantities of electron-positron pairs (up to $num{e13}$) via the\u0000Breit-Wheeler process. The $e^-e^+$ plasma becomes trapped in the magnetic\u0000field and remains confined for hundreds of femtoseconds, far exceeding the\u0000laser timescale. The dependency of pair plasma parameters, as well as the\u0000efficiency of plasma production and confinement, is discussed in relation to\u0000the properties of the laser pulse and the target. Realizing this scheme\u0000experimentally would enable the investigation of physical processes relevant to\u0000extreme astrophysical environments.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257457","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}

引用次数: 0

Dephasing of ion beams as Magnetic Vortex Acceleration regime transitions into a bubble-like field structure 磁涡流加速系统过渡到气泡状场结构时离子束的消相现象

arXiv - PHYS - Plasma Physics Pub Date : 2024-09-13 DOI: arxiv-2409.09156

Sahel Hakimi, Stepan S. Bulanov, Axel Huebl, Lieselotte Obst-Huebl, Kei Nakamura, Anthony Gonsalves, Thomas Schenkel, Jeroen van Tilborg, Jean-Luc Vay, Carl B. Schroeder, Eric Esarey, Cameron R. Geddes

{"title":"Dephasing of ion beams as Magnetic Vortex Acceleration regime transitions into a bubble-like field structure","authors":"Sahel Hakimi, Stepan S. Bulanov, Axel Huebl, Lieselotte Obst-Huebl, Kei Nakamura, Anthony Gonsalves, Thomas Schenkel, Jeroen van Tilborg, Jean-Luc Vay, Carl B. Schroeder, Eric Esarey, Cameron R. Geddes","doi":"arxiv-2409.09156","DOIUrl":"https://doi.org/arxiv-2409.09156","url":null,"abstract":"The interaction of an ultra-intense laser pulse with a near critical density\u0000target results in the formation of a plasma channel, a strong azimuthal\u0000magnetic field and moving vortices. An application of this is the generation of\u0000energetic and collimated ion beams via Magnetic Vortex Acceleration. The\u0000optimized regime of Magnetic Vortex Acceleration is becoming experimentally\u0000accessible with new high intensity laser beamlines coming online and advances\u0000made in near critical density target fabrication. The robustness of the\u0000acceleration mechanism with realistic experimental conditions is examined with\u0000three-dimensional simulations. Of particular interest is the acceleration\u0000performance with different laser temporal contrast conditions, in some cases\u0000leading to pre-expanded target profiles prior to the arrival of the main pulse.\u0000Preplasma effects on the structure of the accelerating fields is explored,\u0000including a detailed analysis of the ion beam properties and the efficiency of\u0000the process. Improved scaling laws for the MVA mechanism, including the laser\u0000focal spot size effects, are presented.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257460","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}

引用次数: 0

Model-free Rayleigh weight from x-ray Thomson scattering measurements 从 X 射线汤姆逊散射测量得出的无模型瑞利权重

arXiv - PHYS - Plasma Physics Pub Date : 2024-09-13 DOI: arxiv-2409.08591

Tobias Dornheim, Hannah M. Bellenbaum, Mandy Bethkenhagen, Stephanie B. Hansen, Maximilian P. Böhme, Tilo Döppner, Luke B. Fletcher, Thomas Gawne, Dirk O. Gericke, Sebastien Hamel, Dominik Kraus, Michael J. MacDonald, Zhandos A. Moldabekov, Thomas R. Preston, Ronald Redmer, Maximilian Schörner, Sebastian Schwalbe, Panagiotis Tolias, Jan Vorberger

{"title":"Model-free Rayleigh weight from x-ray Thomson scattering measurements","authors":"Tobias Dornheim, Hannah M. Bellenbaum, Mandy Bethkenhagen, Stephanie B. Hansen, Maximilian P. Böhme, Tilo Döppner, Luke B. Fletcher, Thomas Gawne, Dirk O. Gericke, Sebastien Hamel, Dominik Kraus, Michael J. MacDonald, Zhandos A. Moldabekov, Thomas R. Preston, Ronald Redmer, Maximilian Schörner, Sebastian Schwalbe, Panagiotis Tolias, Jan Vorberger","doi":"arxiv-2409.08591","DOIUrl":"https://doi.org/arxiv-2409.08591","url":null,"abstract":"X-ray Thomson scattering (XRTS) has emerged as a powerful tool for the\u0000diagnostics of matter under extreme conditions. In principle, it gives one\u0000access to important system parameters such as the temperature, density, and\u0000ionization state, but the interpretation of the measured XRTS intensity usually\u0000relies on theoretical models and approximations. In this work, we show that it\u0000is possible to extract the Rayleigh weight -- a key property that describes the\u0000electronic localization around the ions -- directly from the experimental data\u0000without the need for any model calculations or simulations. As a practical\u0000application, we consider an experimental measurement of strongly compressed Be\u0000at the National Ignition Facility (NIF) [D\"oppner emph{et al.},\u0000textit{Nature} textbf{618}, 270-275 (2023)]. In addition to being interesting\u0000in their own right, our results will open up new avenues for diagnostics from\u0000emph{ab initio} simulations, help to further constrain existing chemical\u0000models, and constitute a rigorous benchmark for theory and simulations.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257459","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}

引用次数: 0

$Etimes B$ shear suppression of microtearing based transport in spherical tokamaks 球形托卡马克中基于微撕裂传输的剪切抑制

arXiv - PHYS - Plasma Physics Pub Date : 2024-09-12 DOI: arxiv-2409.08216

B. S. Patel, M. R. Hardman, D. Kennedy, M. Giacomin, D. Dickinson, C. M. Roach

{"title":"$Etimes B$ shear suppression of microtearing based transport in spherical tokamaks","authors":"B. S. Patel, M. R. Hardman, D. Kennedy, M. Giacomin, D. Dickinson, C. M. Roach","doi":"arxiv-2409.08216","DOIUrl":"https://doi.org/arxiv-2409.08216","url":null,"abstract":"Electromagnetic microtearing modes (MTMs) have been observed in many\u0000different spherical tokamak regimes. Understanding how these and other\u0000electromagnetic modes nonlinearly saturate is likely critical in understanding\u0000the confinement of a high $beta$ spherical tokamak (ST). Equilibrium $Etimes\u0000B$ sheared flows have sometimes been found to significantly suppress low\u0000$beta$ ion scale transport in both gyrokinetic simulations and in experiment.\u0000This work aims to understand the conditions under which $Etimes B$ sheared\u0000flow impacts on the saturation of MTM simulations. Two experimental regimes are\u0000examined from MAST and NSTX, on surfaces that have unstable MTMs. The MTM\u0000driven transport on a local flux surface in MAST is shown to be more resilient\u0000to suppression via $Etimes B$ shear, compared to the case from NSTX where the\u0000MTM transport is found to be significantly suppressed. This difference in the\u0000response to flow shear is explained through the impact of magnetic shear,\u0000$hat{s}$ on the MTM linear growth rate dependence on ballooning angle,\u0000$theta_0$. At low $hat{s}$, the growth rate depends weakly on $theta_0$, but\u0000at higher $hat{s}$, the MTM growth rate peaks at $theta_0 = 0$, with regions\u0000of stability at higher $theta_0$. Equilibrium $Etimes B$ sheared flows act to\u0000advect the $theta_0$ of a mode in time, providing a mechanism which suppresses\u0000the transport from these modes when they become stable. The dependence of\u0000$gamma^{MTM}$ on $theta_0$ is in qualitative agreement with a recent theory\u0000[M.R. Hardman et al (2023)] at low $beta$ when $qsim1$, but the agreement\u0000worsens at higher $q$ where the theory breaks down. This work highlights the\u0000important role of the safety factor profile in determining the impact of\u0000equilibrium $Etimes B$ shear on the saturation level of MTM turbulence.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"66 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142196015","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}

引用次数: 0

Two-plasmon decay instability and 3/2 harmonic generation in inhomogeneous magnetized plasma 非均质磁化等离子体中的双等离子衰减不稳定性和 3/2 谐波生成

arXiv - PHYS - Plasma Physics Pub Date : 2024-09-12 DOI: arxiv-2409.07982

S. S. Ghaffari-Oskooei, A. A. Molavi Choobini

引用次数: 0

Probing the radiation-dominated regime of laser-plasma interaction in multi-beam configurations of petawatt lasers 在多波束配置的 petawatt 激光器中探测激光与等离子体相互作用的辐射主导机制

arXiv - PHYS - Plasma Physics Pub Date : 2024-09-12 DOI: arxiv-2409.08134

T. Liseykina, E. Peganov, S. Popruzhenko

引用次数: 0

Design Optimization of Nuclear Fusion Reactor through Deep Reinforcement Learning 通过深度强化学习优化核聚变反应堆的设计

arXiv - PHYS - Plasma Physics Pub Date : 2024-09-12 DOI: arxiv-2409.08231

Jinsu Kim, Jaemin Seo

引用次数: 0

Universal Diffusion in Coulomb Crystals 库仑晶体中的普遍扩散

arXiv - PHYS - Plasma Physics Pub Date : 2024-09-11 DOI: arxiv-2409.07513

M. E. Caplan, D. Yaacoub

引用次数: 0

Sub-cycle Nanotip Field Emission of Electrons Driven by Air Plasma Generated THz Pulses 空气等离子体产生的太赫兹脉冲驱动电子的亚周期纳米尖端场发射

arXiv - PHYS - Plasma Physics Pub Date : 2024-09-11 DOI: arxiv-2409.07196

Benjamin Colmey, Rodrigo T. Paulino, David G. Cooke

{"title":"Sub-cycle Nanotip Field Emission of Electrons Driven by Air Plasma Generated THz Pulses","authors":"Benjamin Colmey, Rodrigo T. Paulino, David G. Cooke","doi":"arxiv-2409.07196","DOIUrl":"https://doi.org/arxiv-2409.07196","url":null,"abstract":"Terahertz pulses generated by two-color laser plasmas have reported peak\u0000field strengths exceeding MV/cm, and when illuminating metal nanotips the\u0000near-field enhancement at the tip apex should result in extremely high bunch\u0000charges and electron energies via sub-cycle cold field emission. Here, electron\u0000emission from tungsten nanotips driven by THz pulses generated by a long\u0000filament air-plasma are reported. Electron energies up to 1.1 keV and bunch\u0000charges up to 2x$10^5$ electrons per pulse were detected, well below values\u0000expected for peak field calculated via the time averaged Poynting vector.\u0000Investigations revealed a failure in the use of the time-averaged Poynting\u0000vector when applied to long filament THz pulses, due to spatio-temporal\u0000restructuring of the THz pulse in the focus. Accounting for this restructuring\u0000significantly reduces the field strength to approximately 160 ~kV/cm,\u0000consistent with the observed electron bunch charges, peak energies and their\u0000dependence on the tip position in the THz focus. Despite these findings, our\u0000results surpass previous THz plasma-driven electron generation by an order of\u0000magnitude in both electron energy and bunch charge and a path to increasing\u0000these by an additional order of magnitude by modification of the THz optics is\u0000proposed.","PeriodicalId":501274,"journal":{"name":"arXiv - PHYS - Plasma Physics","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142196029","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}

引用次数: 0