Work

Ion temperature anisotropy limits from magnetic curvature scattering in magnetotail reconnection jets

Year: 2026

Type: article

Abstract: In collisionless plasmas, relaxation of the deviations of ion velocity distribution functions (VDFs) from local thermodynamic equilibrium occurs through particle interactions with electromagnetic fields. In particular, in the Earth's magnetotail, the deviations of the ion VDFs, typically consisting of multiple components, from the equilibrium must be limited to maintain stability of the current sheet. Curvature scattering is a leading candidate mechanism to limit such deviations, but its role remains insufficiently understood. We investigate the limits of ion temperature anisotropy in a magnetotail-like configuration by modeling a quasi-1D current sheet with a finite magnetic field curvature and three ion populations. We derive analytical thresholds for anisotropy based on current sheet stability and validate against spacecraft observations and numerical simulations. Our findings demonstrate that curvature scattering imposes limits on ion anisotropies, thereby maintaining the stability of the current sheet.

Source: Physics of Plasmas

DOI: 10.1063/5.0313635

Authors: Louis Richard, Anton V. Artemyev, Cecilia Norgren, Xin An, Sergei R. Kamaletdinov, Yuri V. Khotyaintsev

Institutions: Swedish Institute of Space Physics, University of California, Los Angeles, University of Bergen, Uppsala University

Language: English

Topic: Ionosphere and magnetosphere dynamics

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid