The Role of Pressure Anisotropy in Cosmic Ray Hydrodynamics

Zweibel, EllenĀ G., The Role of Pressure Anisotropy in Cosmic Ray Hydrodynamics, arXiv e-prints, arXiv:1910.03052 (2019) (ADS)

The cartoon

(click on the image for a larger version)

A technical cartoon illustrating a calculation of the effects of cosmic-ray pressure anisotropy. This is for non-solar applications, of course, since cosmic-ray pressure does not usually play a structural role in the inner heliosphere. But we are still curious about the propagation of cosmic rays near the Sun, since these dominate its γ-ray emission at all times, and have many other interesting properties during solar particle events. Here the upper panel shows the distortion of a flux tube with lower Alfvén speed from a cosmic-ray source to the left. Generally the heliosphere presents a region of increasing Alfvén speed as GCRs enter it, but there is considerable structure due to streamers and active regions that will perturb the "flow" of the cosmic-ray "fluid" - that's the kind of language that people use, believe it or not.

      The perspective representation looks a little bit off here. The idea was to increase the cosmic-ray pressure in one thin flux tube (colored) which can then expand into its surrounding flux tubes. But the top layer of this bundle looks eccentric to the Archivist.

Date: 2019 December 20