Numerical studies on electron magnetohydrodynamics tearing mode instability

The 2D electron-magnetohydrodynamics (EMHD) dominant tearing mode in an electron-skin-depth-scale current sheet (ECS) is further studied. The resistive diffusion is proved to be insignificant at the scale. Electron inertia leads to the expansion of the “inner region” as well as a wider saturation is...

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Autores principales:	Wenping Guo, Jiaqi Wang, Dongjian Liu
Formato:	article
Lenguaje:	EN
Publicado:	AIP Publishing LLC 2021
Materias:	Physics QC1-999
Acceso en línea:	https://doaj.org/article/aa3d686a59d74fd185d9285755dbf033
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spelling	oai:doaj.org-article:aa3d686a59d74fd185d9285755dbf0332021-12-01T18:52:06ZNumerical studies on electron magnetohydrodynamics tearing mode instability2158-322610.1063/5.0066269https://doaj.org/article/aa3d686a59d74fd185d9285755dbf0332021-11-01T00:00:00Zhttp://dx.doi.org/10.1063/5.0066269https://doaj.org/toc/2158-3226The 2D electron-magnetohydrodynamics (EMHD) dominant tearing mode in an electron-skin-depth-scale current sheet (ECS) is further studied. The resistive diffusion is proved to be insignificant at the scale. Electron inertia leads to the expansion of the “inner region” as well as a wider saturation island and the invalidity of the boundary layer approximation. The unstable tearing mode index Δ′ thus decreases dramatically from that in classical asymptotic theory. As for nonlinear evaluation, the inverse spectral cascade and the flattening of the m = 0 anti-parallel asymptotic magnetic field will result in an m = 1 final island after nonlinear coupling in a long ECS. A rapid normal saturation transition is observed and only expected for a larger wave number due to the growth rate dependence on the wave number being a single humped function. A linear analysis of the EMHD tearing mode is also presented for the force-free equilibrium. With a strong guide field, it shows that the tearing mode can be suppressed by the shear flow. Nonlinear simulation results with specific parameters then showed that the dynamic structures in the current sheet are consistent with the observation in the Earth’s turbulent magnetosheath.Wenping GuoJiaqi WangDongjian LiuAIP Publishing LLCarticlePhysicsQC1-999ENAIP Advances, Vol 11, Iss 11, Pp 115206-115206-11 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Physics QC1-999
spellingShingle	Physics QC1-999 Wenping Guo Jiaqi Wang Dongjian Liu Numerical studies on electron magnetohydrodynamics tearing mode instability
description	The 2D electron-magnetohydrodynamics (EMHD) dominant tearing mode in an electron-skin-depth-scale current sheet (ECS) is further studied. The resistive diffusion is proved to be insignificant at the scale. Electron inertia leads to the expansion of the “inner region” as well as a wider saturation island and the invalidity of the boundary layer approximation. The unstable tearing mode index Δ′ thus decreases dramatically from that in classical asymptotic theory. As for nonlinear evaluation, the inverse spectral cascade and the flattening of the m = 0 anti-parallel asymptotic magnetic field will result in an m = 1 final island after nonlinear coupling in a long ECS. A rapid normal saturation transition is observed and only expected for a larger wave number due to the growth rate dependence on the wave number being a single humped function. A linear analysis of the EMHD tearing mode is also presented for the force-free equilibrium. With a strong guide field, it shows that the tearing mode can be suppressed by the shear flow. Nonlinear simulation results with specific parameters then showed that the dynamic structures in the current sheet are consistent with the observation in the Earth’s turbulent magnetosheath.
format	article
author	Wenping Guo Jiaqi Wang Dongjian Liu
author_facet	Wenping Guo Jiaqi Wang Dongjian Liu
author_sort	Wenping Guo
title	Numerical studies on electron magnetohydrodynamics tearing mode instability
title_short	Numerical studies on electron magnetohydrodynamics tearing mode instability
title_full	Numerical studies on electron magnetohydrodynamics tearing mode instability
title_fullStr	Numerical studies on electron magnetohydrodynamics tearing mode instability
title_full_unstemmed	Numerical studies on electron magnetohydrodynamics tearing mode instability
title_sort	numerical studies on electron magnetohydrodynamics tearing mode instability
publisher	AIP Publishing LLC
publishDate	2021
url	https://doaj.org/article/aa3d686a59d74fd185d9285755dbf033
work_keys_str_mv	AT wenpingguo numericalstudiesonelectronmagnetohydrodynamicstearingmodeinstability AT jiaqiwang numericalstudiesonelectronmagnetohydrodynamicstearingmodeinstability AT dongjianliu numericalstudiesonelectronmagnetohydrodynamicstearingmodeinstability
_version_	1718404712622981120

Numerical studies on electron magnetohydrodynamics tearing mode instability

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