The Post-Burst Increase
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| Number: | |
| 1st Author: | Hugh Hudson |
| 2nd Author: | |
| Published: | September 30, 2013 |
| Next Nugget: | TBD |
| Previous Nugget: | Peristaltic Shocks: a model |
Introduction
This Nugget follows Negative Microwave Bursts as a source of background information into the microwave literature, which new observations make highly relevant. Here we discuss the microwave bursts classified as "Post-Burst Increase" (PBI) and "Gradual Rise and Fall" (GRF, noting that this instead means something Jovian to German astronomers). These bursts are part of the traditional classification scheme for microwave radio bursts, based on fixed-frequency observations of the whole Sun. Nowadays we have microwave imaging spectroscopy, plus of course a myriad of other wavelengths to study, and so our knowledge needs some refreshment.
These slow burst types accompany the presence of new coronal material resulting from a flare. They closely match phenomena such as GOES soft X-ray bursts, flare arcades, loop prominence systems, and others. The coronal mass cycle of a flare consists of the injection of new material from the chromosphere below up into the corona, where it finds itself to be heated to X-ray temperatures. Nowadays the presence of the GOES event that shows this is almost the defining feature of a flare. Once in the corona, and following the cessation of impulsive energy release, the mass cools slowly and loses density back to its chromospheric reservoir, and then finally collapses into coronal rain as the hydrogen recombines - that is the source of the brilliant loop prominence systems seen in Hα.
Data
Conclusions
References
[1] "Directivity of radio emission from solar flares"
[2] "Impulsive and Long-Enduring Sudden Enhancements of Solar Radio Emission at 10-cm. Wave-length" [hugh-hudsons-macbook-pro-3:nuggets/2013/grf] hughhudson%