Mirror instability in the turbulent solar wind
Abstract
The relationship between a decaying strong turbulence and the mirror instability in a slowly expanding plasma is investigated using two-dimensional hybrid expanding box simulations. We impose an initial ambient magnetic field perpendicular to the simulation box, and we start with a spectrum of large-scale, linearly-polarized, random-phase Alfvenic fluctuations which have energy equipartition between kinetic and magnetic fluctuations and vanishing correlation between the two fields. A turbulent cascade rapidly develops, magnetic field fluctuations exhibit a Kolmogorov-like power-law spectrum at large scales and a steeper spectrum at sub-ion scales. The imposed expansion (taking a strictly transverse ambient magnetic field) leads to generation of an important perpendicular proton temperature anisotropy that eventually drives the mirror instability. This instability generates large-amplitude, nonpropagating, compressible, pressure-balanced magnetic structures in a form of magnetic enhancements/humps that reduce the perpendicular temperature anisotropy.
Cite
@article{arxiv.1703.07377,
title = {Mirror instability in the turbulent solar wind},
author = {P. Hellinger and S. Landi and L. Matteini and A. Verdini and L. Franci},
journal= {arXiv preprint arXiv:1703.07377},
year = {2017}
}
Comments
ApJ, 7 pages, 9 figures. arXiv admin note: text overlap with arXiv:1508.03159