Cosmic-ray diffusion in a sectored magnetic field in the distant heliosheath

Abstract

Very high intensities of galactic cosmic rays measured by Voyager 1 in the heliosheath appear to be incompatible with the presence of a modulation "wall" near the heliopause produced by a pile up of the heliospheric magnetic field. We propose that the modulation wall is a structure permeable to cosmic rays as a result of a sectored magnetic field topology compressed by plasma slowdown on approach to the heliopause and stretched to high latitudes by latitudinal flows in the heliosheath. The tightly folded warped current sheet permits efficient cosmic-ray transport in the radial direction via a drift-like mechanism. We show that when stochastic variations in the sector widths are taken into account, particle transport becomes predominantly diffusive both along and across the magnetic sectors. Using a test-particle model for cosmic rays in the heliosheath we investigate the dependence of the diffusion coefficients on the properties of the sector structure and on particle energy.

32 pages, 11 figures

References in corpus (1)

• Sudden Intensity Increases and Radial Gradient Changes of Cosmic Ray MeV Electrons and Protons Observed at Voyager 1 beyond 111 AU in the Heliosheath

Cited by in corpus (4)

• Heliosheath Processes and the Structure of the Heliopause: Modeling Energetic Particles, Cosmic Rays, and Magnetic Fields
• Modulation of Galactic Cosmic Rays in the Inner Heliosphere over Solar Cycles
• Multiple current sheet systems in the outer heliosphere: Energy release and turbulence
• Transient Heliosheath Modulation