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)
(click on the image for a larger version)
Date: 2020 January 12
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