Plasma β scaling of anisotropic magnetic field fluctuations in the solar wind flux tube

Aveek Sarkar, Amitava Bhattacharjee, Fatima Ebrahimi

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Based on various observations, it has been suggested that at 1 AU, solar wind consists of "spaghetti"-like magnetic field structures that have the magnetic topology of flux tubes. It is also observed that the plasma fluctuation spectra at 1 AU show a plasma β dependence. Reconciling these two sets of observations and using the Invariance Principle, Bhattacharjee et al. suggested that the plasma inside every flux tube may become unstable with respect to pressure-driven instabilities and gives rise to fluctuation spectra that depend on the local plasma β. The present work is the first direct numerical simulation of such a flux tube. We solve the full magnetohydrodynamic equations using the DEBS code and show that if the plasma inside the flux tube is driven unstable by spatial inhomogeneities in the background plasma pressure, the observed nature of the fluctuating power spectra agrees reasonably well with observations, as well as the analytical prediction of Bhattacharjee et al.

Original languageEnglish (US)
Article number65
JournalAstrophysical Journal
Volume783
Issue number2
DOIs
StatePublished - Mar 10 2014

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • instabilities
  • magnetohydrodynamics (MHD)
  • plasmas
  • solar wind
  • turbulence

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