Nonlinear Mirror Modes in Space Plasmas

TL;DR

This paper reviews the observational and simulation-based studies of nonlinear mirror modes in space plasmas, focusing on magnetic structures, instability effects, and the influence on ion temperature anisotropy in the solar wind.

Contribution

It provides a comprehensive review of satellite observations, numerical simulations, and models of mirror instability and its nonlinear evolution in space plasmas.

Findings

Mirror structures are linked to the mirror instability in high-beta regions.

Simulations show the nonlinear evolution constrains ion temperature anisotropy.

The mirror instability influences ion heating in the solar wind.

Abstract

Since the first observations by Kaufmann et al.\ (1970), special attention has been paid to static pressure-balanced structures in the form of magnetic holes or humps observed in regions of the solar wind and of planetary magnetosheaths where the $\beta$ parameter is relatively large and the ion perpendicular temperature exceeds the parallel one. Although alternative interpretations have been proposed, these structures are usually viewed as associated with the mirror instability discovered in 1957 by Vedenov and Sagdeev. After reviewing observational results provided by satellite missions, high-resolution numerical simulations of the Vlasov--Maxwell equations together with asymptotic and phenomenological models of the nonlinear dynamics near the instability threshold are discussed. The constraining effect of the mirror instability on the temperature anisotropy associated with a dominant perpendicular ion heating observed in the solar wind is reported, and recent simulations of this phenomenon based on an elaborated fluid model including low-frequency kinetic effects are briefly mentioned.