The Role of Mesoscale Plasma Sheet Dynamics in Ring Current Formation

During geomagnetically active periods ions are transported from the magnetotail into the inner magnetosphere and accelerated to energies of tens to hundreds of keV. These energetic ions, of mixed composition with the most important species being H+ and O+, become the dominant source of plasma pressu...

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Autores principales:	K. A. Sorathia, A. Michael, V.G. Merkin, A.Y. Ukhorskiy, D. L. Turner, J.G. Lyon, J. Garretson, M. Gkioulidou , F.R. Toffoletto
Formato:	article
Lenguaje:	EN
Publicado:	Frontiers Media S.A. 2021
Materias:	plasma sheet ring current buoyancy mesoscale bursty bulk flows injections Astronomy QB1-991 Geophysics. Cosmic physics QC801-809
Acceso en línea:	https://doaj.org/article/defcb15cee294a3d9580290a46367e55
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spelling	oai:doaj.org-article:defcb15cee294a3d9580290a46367e552021-12-02T17:50:55ZThe Role of Mesoscale Plasma Sheet Dynamics in Ring Current Formation2296-987X10.3389/fspas.2021.761875https://doaj.org/article/defcb15cee294a3d9580290a46367e552021-11-01T00:00:00Zhttps://www.frontiersin.org/articles/10.3389/fspas.2021.761875/fullhttps://doaj.org/toc/2296-987XDuring geomagnetically active periods ions are transported from the magnetotail into the inner magnetosphere and accelerated to energies of tens to hundreds of keV. These energetic ions, of mixed composition with the most important species being H+ and O+, become the dominant source of plasma pressure in the inner magnetosphere. Ion transport and acceleration can occur at different spatial and temporal scales ranging from global quasi-steady convection to localized impulsive injection events and may depend on the ion gyroradius. In this study we ascertain the relative importance of mesoscale flow structures and the effects of ion non-adiabaticity on the produced ring current. For this we use: global magnetohydrodynamic (MHD) simulations to generate self-consistent electromagnetic fields under typical driving conditions which exhibit bursty bulk flows (BBFs); and injected test particles, initialized to match the plasma moments of the MHD simulation, and subsequently evolved according to the kinetic equations of motion. We show that the BBFs produced by our simulation reproduce thermodynamic and magnetic statistics from in situ measurements and are numerically robust. Mining the simulation data we create a data set, over a billion points, connecting particle transport to characteristics of the MHD flow. From this we show that mesoscale bubbles, localized depleted entropy regions, and particle gradient drifts are critical for ion transport. Finally we show, using identical particle ensembles with varying mass, that O+ non-adiabaticity creates qualitative differences in energization and spatial distribution while H+ non-adiabaticity has non-negligible implications for loss timescales.K. A. SorathiaA. MichaelV.G. MerkinA.Y. UkhorskiyD. L. TurnerJ.G. LyonJ. GarretsonM. Gkioulidou F.R. ToffolettoFrontiers Media S.A.articleplasma sheetring currentbuoyancymesoscalebursty bulk flowsinjectionsAstronomyQB1-991Geophysics. Cosmic physicsQC801-809ENFrontiers in Astronomy and Space Sciences, Vol 8 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	plasma sheet ring current buoyancy mesoscale bursty bulk flows injections Astronomy QB1-991 Geophysics. Cosmic physics QC801-809
spellingShingle	plasma sheet ring current buoyancy mesoscale bursty bulk flows injections Astronomy QB1-991 Geophysics. Cosmic physics QC801-809 K. A. Sorathia A. Michael V.G. Merkin A.Y. Ukhorskiy D. L. Turner J.G. Lyon J. Garretson M. Gkioulidou F.R. Toffoletto The Role of Mesoscale Plasma Sheet Dynamics in Ring Current Formation
description	During geomagnetically active periods ions are transported from the magnetotail into the inner magnetosphere and accelerated to energies of tens to hundreds of keV. These energetic ions, of mixed composition with the most important species being H+ and O+, become the dominant source of plasma pressure in the inner magnetosphere. Ion transport and acceleration can occur at different spatial and temporal scales ranging from global quasi-steady convection to localized impulsive injection events and may depend on the ion gyroradius. In this study we ascertain the relative importance of mesoscale flow structures and the effects of ion non-adiabaticity on the produced ring current. For this we use: global magnetohydrodynamic (MHD) simulations to generate self-consistent electromagnetic fields under typical driving conditions which exhibit bursty bulk flows (BBFs); and injected test particles, initialized to match the plasma moments of the MHD simulation, and subsequently evolved according to the kinetic equations of motion. We show that the BBFs produced by our simulation reproduce thermodynamic and magnetic statistics from in situ measurements and are numerically robust. Mining the simulation data we create a data set, over a billion points, connecting particle transport to characteristics of the MHD flow. From this we show that mesoscale bubbles, localized depleted entropy regions, and particle gradient drifts are critical for ion transport. Finally we show, using identical particle ensembles with varying mass, that O+ non-adiabaticity creates qualitative differences in energization and spatial distribution while H+ non-adiabaticity has non-negligible implications for loss timescales.
format	article
author	K. A. Sorathia A. Michael V.G. Merkin A.Y. Ukhorskiy D. L. Turner J.G. Lyon J. Garretson M. Gkioulidou F.R. Toffoletto
author_facet	K. A. Sorathia A. Michael V.G. Merkin A.Y. Ukhorskiy D. L. Turner J.G. Lyon J. Garretson M. Gkioulidou F.R. Toffoletto
author_sort	K. A. Sorathia
title	The Role of Mesoscale Plasma Sheet Dynamics in Ring Current Formation
title_short	The Role of Mesoscale Plasma Sheet Dynamics in Ring Current Formation
title_full	The Role of Mesoscale Plasma Sheet Dynamics in Ring Current Formation
title_fullStr	The Role of Mesoscale Plasma Sheet Dynamics in Ring Current Formation
title_full_unstemmed	The Role of Mesoscale Plasma Sheet Dynamics in Ring Current Formation
title_sort	role of mesoscale plasma sheet dynamics in ring current formation
publisher	Frontiers Media S.A.
publishDate	2021
url	https://doaj.org/article/defcb15cee294a3d9580290a46367e55
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The Role of Mesoscale Plasma Sheet Dynamics in Ring Current Formation

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