Electron Densities in Solar Flare Loops, Chromospheric Evaporation Upflows, and Acceleration Sites

This version of CSHKP illustrates its predictions for decimeter-wave dynamic spectra. Decimeter waves ('dm') correspond to 0.3 - 3 GHz and imply a range of heights in the low corona via densities, based on inference from the plasma frequency. The really interesting observation invoked here is the occurrence of simultaneous foward-slope and reverse-slope (RS) Type III bursts, pointing possibly to the actual X point of the reconnection model as the site of the particle acceleration. This is rarely observed, perhaps because the density shown for this X point (and needed for the dm-wave emission) is extraordinarily high for such a region in the solar corona. But there are many types of decimetric solar radio bursts, and examples this clear of bidirectional flow are quite rare. In general it is a misconception to think (in the context of CSHKP) that "flare reconnection" can launch type III bursts.

      Note that an entirely distinct explanation for reverse-slope type III bursts had been described earlier by Labonte.