Double Coronal Hard and Soft X-Ray Source Observed by RHESSI: Evidence for Magnetic Reconnection and Particle Acceleration in Solar Flares

This could be the first attempt to integrate the turbulent acceleration theory into some sort of geometry defined by the images, rather than confining it into a meaningless (but homogeneous) simple sphere.. Whatever, the little bubbles make a nice colorful cartoon. The paper is an excellent piece of data analysis - RHESSI's high resolution is apparent in an estimate of source separations of 4.6+-0.3 arc sec! The interpretation follows that for earlier RHESSI observations described by Sui and Holman in terms of coronal reconnection site and current sheet, but with turbulence grafted on (as the cartoon shows).. Some of the analysis seems plausible but not too compelling. For example, we know that the footpoint regions are where the flare energy appears. How do we know that these interesting sources are connected properly? The same question could be asked of the hasty (over)-interpretation usually given to the celebrated Masuda flare.

The label "Mach 2 jet" is not incorrect, although of course it has never been observed. For subtle reasons this is how the theory works out.