View in EDS

Ion Interaction With Rotational Discontinuities: The Role of Polarization Electric Fields in Ion Heating.

Saved in:
Bibliographic Details
Title: Ion Interaction With Rotational Discontinuities: The Role of Polarization Electric Fields in Ion Heating.
Authors: Tonoian, David1 (AUTHOR) david.tonoian@utdallas.edu, Zhang, Xiao‐Jia1 (AUTHOR), Artemyev, Anton2 (AUTHOR), Ebert, Robert W.3,4 (AUTHOR), Allegrini, Frederic3,4 (AUTHOR)
Source: Journal of Geophysical Research. Space Physics. Jun2026, Vol. 131 Issue 6, p1-23. 23p.
Subject Terms: Polarization (Electricity), Plasma heating, Current sheets, Solar wind, Plasma physics, Magnetotails, Ion migration & velocity
Abstract: Ion energization and magnetic field energy dissipation within kinetic‐scale plasma structures is an important problem of space plasma physics. A representative category of such structures consists of magnetic field discontinuities (or thin current sheets), which are widely observed in the solar wind and planetary magnetotails. As these discontinuities move through the ambient plasma, they generate convection electric fields that accelerate ions interacting with them. This acceleration process can be further modified by polarization electric fields that arise due to ion and electron decoupling around strong magnetic field gradients. We investigate ion interactions with moving polarized discontinuities in four distinct space plasma environments: the magnetotails of Earth and Mars, magnetodisk of Jupiter, and the near‐Earth solar wind. Using multi‐mission data sets, we characterize the convection and polarization electric fields by the magnitude of plasma flows along the discontinuity, vflow ${v}_{\mathit{flow}}$, and the electron‐to‐ion temperature ratio Te/Ti ${T}_{e}/{T}_{i}$. Discontinuities in Earth's magnetotail and Jovian magnetodisk are typically slow (vflow ${v}_{\mathit{flow}}$ smaller than the ion thermal velocity) and feature hot ions Te/Ti<1 $\left({T}_{e}/{T}_{i}< 1\right)$, whereas solar wind discontinuities are fast (vflow ${v}_{\mathit{flow}}$ exceeding the ion thermal velocity) and dominated by hot electrons Te/Ti>1 $\left({T}_{e}/{T}_{i} > 1\right)$. Martian magnetotail discontinuities can exhibit intermediate properties between these two regimes. We develop a theoretical model describing ion interactions with moving polarized discontinuities and quantify the respective roles of convection and polarization electric fields in ion acceleration. Main model predictions are compared with spacecraft observations and discussed in the context of heavy ion energization across the four examined space plasma systems. Key Points: We investigate the effects of polarization electric fields on ion heating in current sheetsWe examine current sheets observed in the magnetotails of Earth and Mars, magnetodisk of Jupiter, as well as in the near‐Earth solar windWe show that polarization electric fields can significantly alter the heating of cold, heavy ions in these current sheets [ABSTRACT FROM AUTHOR]
Copyright of Journal of Geophysical Research. Space Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: GreenFILE
Description
Abstract:Ion energization and magnetic field energy dissipation within kinetic‐scale plasma structures is an important problem of space plasma physics. A representative category of such structures consists of magnetic field discontinuities (or thin current sheets), which are widely observed in the solar wind and planetary magnetotails. As these discontinuities move through the ambient plasma, they generate convection electric fields that accelerate ions interacting with them. This acceleration process can be further modified by polarization electric fields that arise due to ion and electron decoupling around strong magnetic field gradients. We investigate ion interactions with moving polarized discontinuities in four distinct space plasma environments: the magnetotails of Earth and Mars, magnetodisk of Jupiter, and the near‐Earth solar wind. Using multi‐mission data sets, we characterize the convection and polarization electric fields by the magnitude of plasma flows along the discontinuity, vflow ${v}_{\mathit{flow}}$, and the electron‐to‐ion temperature ratio Te/Ti ${T}_{e}/{T}_{i}$. Discontinuities in Earth's magnetotail and Jovian magnetodisk are typically slow (vflow ${v}_{\mathit{flow}}$ smaller than the ion thermal velocity) and feature hot ions Te/Ti<1 $\left({T}_{e}/{T}_{i}< 1\right)$, whereas solar wind discontinuities are fast (vflow ${v}_{\mathit{flow}}$ exceeding the ion thermal velocity) and dominated by hot electrons Te/Ti>1 $\left({T}_{e}/{T}_{i} > 1\right)$. Martian magnetotail discontinuities can exhibit intermediate properties between these two regimes. We develop a theoretical model describing ion interactions with moving polarized discontinuities and quantify the respective roles of convection and polarization electric fields in ion acceleration. Main model predictions are compared with spacecraft observations and discussed in the context of heavy ion energization across the four examined space plasma systems. Key Points: We investigate the effects of polarization electric fields on ion heating in current sheetsWe examine current sheets observed in the magnetotails of Earth and Mars, magnetodisk of Jupiter, as well as in the near‐Earth solar windWe show that polarization electric fields can significantly alter the heating of cold, heavy ions in these current sheets [ABSTRACT FROM AUTHOR]
ISSN:21699380
DOI:10.1029/2025JA034909