Journal Article

Plasma Acceleration by Magnetic Tension Forces in the Martian Magnetotail: MAVEN Observations

Mazelle, Christian, Ma, Yingjuan, Gruesbeck, Jacob R, DiBraccio, Gina A, Dubinin, Eduard, Xu, Shaosui, Hanley, Kathleen G, Mitchell, David L, Fowler, Christopher M, Espley, Jared R, Ruhunusiri, Suranga, Halekas, Jasper S, Modolo, Ronan, Lillis, Robert J, Romanelli, Norberto, Curry, Shannon M

2025

Overview

The Martian magnetotail is a dynamic region where several processes contribute to plasma acceleration. Here, we analyze ∼5 ${\\sim} 5$ years of Mars Atmosphere and Volatile EvolutioN (MAVEN) data to evaluate the role of magnetic tension forces in driving plasma acceleration within current sheets in the tail. Based on magnetic field measurements, we identify 547 current sheet crossings that follow a Harris profile and find that the median observed current sheet density is ∼ ${\\sim} $110 nA m−2 ${\\mathrm{m}}^{-2}$, with a typical sheet width of ∼ ${\\sim} $100 km. We estimate a median normalized |〈Bn〉| $\\vert \\langle {B}_{n}\\rangle \\vert $ of ∼ ${\\sim} $0.1, and J×Bn $\\mathbf{J}\\times {\\mathbf{B}}_{n}$ force of ∼10−16 ${\\sim} 1{0}^{-16}$ N m−3 ${\\mathrm{m}}^{-3}$, capable of accelerating planetary ions within the sheets to ∼ ${\\sim} $1 keV over ∼ ${\\sim} $2 RM ${\\mathrm{R}}_{M}$. We also analyze plasma energization signatures in nine high‐Bn ${\\mathbf{B}}_{n}$ case studies and find they can be explained by work done by J×Bn $\\mathbf{J}\\times {\\mathbf{B}}_{n}$, although observed ion differential streaming suggests additional forces may be present.

• Publisher: John Wiley & Sons, Inc
• Subject: Current sheets / Magnetic field / Magnetic fields / Magnetotails / Mars / Mars atmosphere / Planetary magnetotails / Plasma / Plasma acceleration / Streaming / Tension