Non-Maxwellianity of Ion Velocity Distributions in the Earth's Magnetosheath

Fuente: arXiv
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Main Authors: Richard, Louis, Servidio, Sergio, Svenningsson, Ida, Artemyev, Anton V., Klein, Kristopher G., Yordanova, Emiliya, Chasapis, Alexandros, Pezzi, Oreste, Khotyaintsev, Yuri V.
Format: Preprint
Published: 2025
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author Richard, Louis
Servidio, Sergio
Svenningsson, Ida
Artemyev, Anton V.
Klein, Kristopher G.
Yordanova, Emiliya
Chasapis, Alexandros
Pezzi, Oreste
Khotyaintsev, Yuri V.
author_facet Richard, Louis
Servidio, Sergio
Svenningsson, Ida
Artemyev, Anton V.
Klein, Kristopher G.
Yordanova, Emiliya
Chasapis, Alexandros
Pezzi, Oreste
Khotyaintsev, Yuri V.
contents We analyze the deviations from local thermodynamic equilibrium (LTE) of the ion velocity distribution function (iVDF) in collisionless plasma turbulence. Using data from the Magnetospheric Multiscale (MMS) mission, we examine the non-Maxwellianity of 439,685 iVDFs in the Earth's magnetosheath. We find that the iVDFs' anisotropies and the high-order non-bi-Maxwellian features are widespread and can be significant. Our results show that the complexity of the iVDFs is strongly influenced by the ion plasma beta and turbulence intensity, with high-order non-LTE features emerging in the presence of large-amplitude magnetic field fluctuations. Furthermore, our analysis indicates that turbulence-driven magnetic curvature contributes to the isotropization of the iVDFs by scattering the ions, emphasizing the complex interaction between turbulence and the velocity distribution of charged particles in collisionless plasmas.
format Preprint
id arxiv_https___arxiv_org_abs_2504_05502
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Non-Maxwellianity of Ion Velocity Distributions in the Earth's Magnetosheath
Richard, Louis
Servidio, Sergio
Svenningsson, Ida
Artemyev, Anton V.
Klein, Kristopher G.
Yordanova, Emiliya
Chasapis, Alexandros
Pezzi, Oreste
Khotyaintsev, Yuri V.
Plasma Physics
We analyze the deviations from local thermodynamic equilibrium (LTE) of the ion velocity distribution function (iVDF) in collisionless plasma turbulence. Using data from the Magnetospheric Multiscale (MMS) mission, we examine the non-Maxwellianity of 439,685 iVDFs in the Earth's magnetosheath. We find that the iVDFs' anisotropies and the high-order non-bi-Maxwellian features are widespread and can be significant. Our results show that the complexity of the iVDFs is strongly influenced by the ion plasma beta and turbulence intensity, with high-order non-LTE features emerging in the presence of large-amplitude magnetic field fluctuations. Furthermore, our analysis indicates that turbulence-driven magnetic curvature contributes to the isotropization of the iVDFs by scattering the ions, emphasizing the complex interaction between turbulence and the velocity distribution of charged particles in collisionless plasmas.
title Non-Maxwellianity of Ion Velocity Distributions in the Earth's Magnetosheath
topic Plasma Physics
url https://arxiv.org/abs/2504.05502