High-rigidity Forbush decreases: due to CMEs or shocks?

Arunbabu, K. P., H. M. Antia, S. R. Dugad, S. K. Gupta, Y. Hayashi, S. Kawakami, P. K. Mohanty, T. Nonaka, A. Oshima, and P. Subramanian, High-rigidity Forbush decreases: due to CMEs or shocks?, A&A, 555, A139 (2013) (ADS)

The cartoon

(click on the image for a larger version)

This cartoon illustrates the interaction of Galactic cosmic rays with the volume of a CME flux rope as it expands through the heliosphere. It reminds us of the usual assumption of diffusive propagation, rather than the rigorous trapping for a picture such as that of Elliot. Galactic cosmic rays of course play no role in flare physics directly, but the "Forbush [1] Decrease", as shown, can certainly help to define the geometry of the CME flux rope.

      Beware of nonlinear geometry here; both the Earth and the Sun appear distinctly oval in this cartoon! And very, very disproportionate...


[1] Forbush Decrease

Date: 2020 January 12