Time-dependent perpendicular transport of fast charged particles in a turbulent magnetic field

F. Fraschetti, J. R. Jokipii

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

We present an analytic derivation of the temporal dependence of the perpendicular transport coefficient of charged particles in magnetostatic turbulence, for times smaller than the time needed for charged particles to travel the turbulence correlation length. This time window is left unexplored in most transport models. In our analysis all magnetic scales are taken to be much larger than the particle gyroradius, so that perpendicular transport is assumed to be dominated by the guiding center motion. Particle drift from the local magnetic field lines (MFLs) and magnetic field line random walk are evaluated separately for slab and three-dimensional (3D) isotropic turbulence. Contributions of wavelength scales shorter and longer than the turbulence coherence length are compared. In contrast to the slab case, particles in 3D isotropic turbulence unexpectedly diffuse from local MFLs; this result questions the common assumption that particle magnetization is independent of turbulence geometry. Extensions of this model will allow for a study of solar wind anisotropies.

Original languageEnglish (US)
Article number83
JournalAstrophysical Journal
Volume734
Issue number2
DOIs
StatePublished - Jun 10 2011

Keywords

  • ISM: magnetic fields
  • cosmic rays
  • turbulence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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