On the Generation of Compressible Mirror-mode Fluctuations in the Inner Heliosheath

TL;DR

This study uses quasilinear theory and MHD modeling to investigate the generation of mirror-mode fluctuations and associated density variations in the inner heliosheath, based on Voyager 1 data.

Contribution

It extends previous studies by analyzing the entire inner heliosheath and predicts the presence of compressible mirror-mode fluctuations using theoretical and modeling approaches.

Findings

Mirror-mode fluctuations are likely present in the inner heliosheath.

Density fluctuations associated with magnetic fluctuations are computed.

Results provide inputs for future turbulence transport models.

Abstract

Measurements made with the Voyager 1 spacecraft indicate that significant levels of compressive fluctuations exist in the inner heliosheath. Some studies have already been performed with respect to the mirror-mode instability in the downstream region close to the solar wind termination shock, and here we extend the investigation to the whole inner heliosheath. We employ quasilinear theory and results from a global magnetohydrodynamic model of the heliosphere to compute the time evolution of both the temperature anisotropy and the energy density of the corresponding magnetic fluctuations, and we demonstrate their likely presence in the inner heliosheath. Furthermore, we compute the associated, locally generated density fluctuations. The results can serve as inputs for future models of the transport of compressible turbulence in the inner heliosheath.