A comparative study of four-field and fully compressible magnetohydrodynamic turbulence in the solar wind

Date

1999-11-01

Department

Program

Citation of Original Publication

Bhattacharjee, A., Ng, C. S., Ghosh, S., and Goldstein, M. L. (1999), A comparative study of four-field and fully compressible magnetohydrodynamic turbulence in the solar wind, J. Geophys. Res., 104(A11), 24835–24843, doi:10.1029/1999JA900327.

Rights

This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
Public Domain Mark 1.0

Subjects

Abstract

A four-field system of equations has been recently derived from the compressible magnetohydrodynamic (MHD) equations to describe turbulence in the solar wind. These equations apply to a plasma permeated by a spatially varying mean magnetic field when the plasma beta is of the order unity or less. In the presence of spatial inhomogeneities, the four-field equations predict pressure fluctuations of the order of the Mach number of the turbulence, as observed by Helios 1 and 2. It is shown that inhomogeneities that occur only in the form of pressure-balanced structures cannot account for density fluctuations as large as the Mach number of the turbulence. Numerical predictions from the four-field and compressible MHD equations are compared using the same initial condition. The comparison shows that the predictions of the four-field model are qualitatively consistent with the predictions of the compressible MHD model and suggests that the four-field model is a viable model of compressible turbulence in the solar wind.