Formation of Rotational Discontinuities in Compressive three-dimensional MHD Turbulence
Abstract
Measurements of solar wind turbulence reveal the ubiquity of discontinuities. In this study, we investigate how the discontinuities, especially rotational discontinuities (RDs), are formed in magnetohydrodynamic (MHD) turbulence. In a simulation of the decaying compressive three-dimensional (3-D) MHD turbulence with an imposed uniform background magnetic field, we detect RDs with sharp field rotations and little variations of magnetic field intensity as well as mass density. At the same time, in the de Hoffman-Teller (HT) frame, the plasma velocity is nearly in agreement with the Alfv\'{e}n speed, and is field-aligned on both sides of the discontinuity. We take one of the identified RDs to analyze in details its 3-D structure and temporal evolution. By checking the magnetic field and plasma parameters, we find that the identified RD evolves from the steepening of the Alfv\'{e}n wave with moderate amplitude, and that steepening is caused by the nonuniformity of the Alfv\'{e}n speed in the ambient turbulence.
Keywords
Cite
@article{arxiv.1504.05348,
title = {Formation of Rotational Discontinuities in Compressive three-dimensional MHD Turbulence},
author = {Liping Yang and Lei Zhang and Jiansen He and Chuanyi Tu and Linghua Wang and Eckart Marsch and Xin Wang and Shaohua Zhang and Xueshang Feng},
journal= {arXiv preprint arXiv:1504.05348},
year = {2015}
}
Comments
Five figures enclosed. Submitted to Astrophys. J., Under referring