Kinetic models of equilibrium structures in space plasmas

In the space plasma environments, there are a variety of electromagnetic structures, including current sheets, magnetic holes and flux ropes, for which scales range from fluid down to ion or even electron kinetic scales. Our understanding of these structures, especially their electromagnetic field p...

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Main Authors: Jinghuan Li, Fan Yang, Xuzhi Zhou
Format: Article
Language:zho
Published: Editorial Office of Reviews of Geophysics and Planetary Physics 2022-09-01
Series:地球与行星物理论评
Subjects:
Online Access:https://www.sjdz.org.cn/en/article/doi/10.19975/j.dqyxx.2022-017
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author Jinghuan Li
Fan Yang
Xuzhi Zhou
author_facet Jinghuan Li
Fan Yang
Xuzhi Zhou
author_sort Jinghuan Li
collection DOAJ
description In the space plasma environments, there are a variety of electromagnetic structures, including current sheets, magnetic holes and flux ropes, for which scales range from fluid down to ion or even electron kinetic scales. Our understanding of these structures, especially their electromagnetic field profiles and particle distributions, has been greatly improved due to the recent improvement in spacecraft technologies and enhancement in the observational database. To fully achieve the three-dimensional configurations of these structures, it is insufficient to use only the observations but also the theoretical models and numerical simulations. This paper briefly reviews the general framework of constructing theoretical models over these structures, which are self-consistent equilibrium solutions of Vlasov-Maxwell equations. In this framework, to ensure the satisfaction of the equilibrium Vlasov equation, particle distribution is expressed as a function of the particle invariant's motion. The moments of the particle distributions are then substituted into the Maxwell equations to solve the profiles of electromagnetic fields, which are further used to determine the particle phase space densities that can be compared directly to spacecraft observations. In recent years, this framework has been widely applied in the modeling and reconstruction of electromagnetic structures, demonstrating the ubiquitous presence of kinetic equilibrium structures in space plasmas. Moreover, the self-consistent models can be used as initial conditions of kinetic simulations. Finally, we discuss the open questions and future directions in studying kinetic structures in space plasmas.
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spelling doaj.art-36f513b0d6294d348d9b0ba365a6a6442023-03-28T07:02:35ZzhoEditorial Office of Reviews of Geophysics and Planetary Physics地球与行星物理论评2097-18932022-09-0153553254310.19975/j.dqyxx.2022-0172022-017Kinetic models of equilibrium structures in space plasmasJinghuan Li0Fan Yang1Xuzhi Zhou2School of Earth and Space Sciences, Peking university, Beijing 100871, ChinaSchool of Earth and Space Sciences, Peking university, Beijing 100871, ChinaSchool of Earth and Space Sciences, Peking university, Beijing 100871, ChinaIn the space plasma environments, there are a variety of electromagnetic structures, including current sheets, magnetic holes and flux ropes, for which scales range from fluid down to ion or even electron kinetic scales. Our understanding of these structures, especially their electromagnetic field profiles and particle distributions, has been greatly improved due to the recent improvement in spacecraft technologies and enhancement in the observational database. To fully achieve the three-dimensional configurations of these structures, it is insufficient to use only the observations but also the theoretical models and numerical simulations. This paper briefly reviews the general framework of constructing theoretical models over these structures, which are self-consistent equilibrium solutions of Vlasov-Maxwell equations. In this framework, to ensure the satisfaction of the equilibrium Vlasov equation, particle distribution is expressed as a function of the particle invariant's motion. The moments of the particle distributions are then substituted into the Maxwell equations to solve the profiles of electromagnetic fields, which are further used to determine the particle phase space densities that can be compared directly to spacecraft observations. In recent years, this framework has been widely applied in the modeling and reconstruction of electromagnetic structures, demonstrating the ubiquitous presence of kinetic equilibrium structures in space plasmas. Moreover, the self-consistent models can be used as initial conditions of kinetic simulations. Finally, we discuss the open questions and future directions in studying kinetic structures in space plasmas.https://www.sjdz.org.cn/en/article/doi/10.19975/j.dqyxx.2022-017electromagnetic structureskinetic equilibriummagnetic holesflux ropes
spellingShingle Jinghuan Li
Fan Yang
Xuzhi Zhou
Kinetic models of equilibrium structures in space plasmas
地球与行星物理论评
electromagnetic structures
kinetic equilibrium
magnetic holes
flux ropes
title Kinetic models of equilibrium structures in space plasmas
title_full Kinetic models of equilibrium structures in space plasmas
title_fullStr Kinetic models of equilibrium structures in space plasmas
title_full_unstemmed Kinetic models of equilibrium structures in space plasmas
title_short Kinetic models of equilibrium structures in space plasmas
title_sort kinetic models of equilibrium structures in space plasmas
topic electromagnetic structures
kinetic equilibrium
magnetic holes
flux ropes
url https://www.sjdz.org.cn/en/article/doi/10.19975/j.dqyxx.2022-017
work_keys_str_mv AT jinghuanli kineticmodelsofequilibriumstructuresinspaceplasmas
AT fanyang kineticmodelsofequilibriumstructuresinspaceplasmas
AT xuzhizhou kineticmodelsofequilibriumstructuresinspaceplasmas