What are the bright loop-top kernels in soft X-ray flares?

Phillips, K. J. H., J. Jakimiec, M. Tomczak, R. Falewicz, and A. Fludra, What are the bright loop-top kernels in soft X-ray flares?, Advances in Space Research, 26, 1773-1776 (2001) (ADS)

The cartoon

(click on the image for a larger version)

The loop-top concentrations of hot plasma shown by soft X-ray imaging of both flare and quiescent coronal loops remains a bit perplexing, and not enough work has been done on the 3D geometry of these optically-thin phenomena. Here is an idea sidestepping this issue, suggesting (following Jakimiec) that turbulence can trap not only particles but also plasma at loop tops. Note that this cartoon implicitly identifies the loop top with low plasma beta, since there is no obvious embolism to be seen.

Date: 2020 September 28