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

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.
Authors:
 [1] ; ;  [2]
  1. Space Science Center, University of New Hampshire, Durham, NH 03824 (United States)
  2. Department of Astrophysical Sciences and Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States)
Publication Date:
OSTI Identifier:
22351332
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 783; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANISOTROPY; COMPUTERIZED SIMULATION; FLUCTUATIONS; INSTABILITY; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; PLASMA PRESSURE; SCALING; SOLAR WIND; SPECTRA; TURBULENCE