Observations of Solar Flares from GHz to THz Frequencies

摘要

The discovery of a new solar burst spectral component with sub-THz fluxes increasing with frequency, simultaneous but separated from the well known microwave component, brings serious constraints for interpretation. Suggested explanations are briefly reviewed. They are inconclusive indicating that further progresses on the understanding of nature of the emission mechanisms involved require the knowledge of GHz to THz continuum burst spectral shapes. New 45 and 90 GHz high sensitivity solar polarimeters arc being installed at El Leoncito high altitude observatory, where sub-THz (0.2 and 0.4 THz) solar flare flux data are being obtained regularly since several years. Solar flare THz photometry in the continuum should be carried in space or at few selected frequency windows at exceptional ground-based sites. A dual photometer system, operating at 3 and 7 THz, is being constructed to be flown in a long duration stratospheric balloon flight in Antarctica (summer 2013-2014) in cooperation with University of California, Berkeley, together with GRIPS experiment. One test flight is planned for the fall 2012 in USA. Another long duration balloon flight over Russia is considered (2015-2016), in a cooperation with Moscow Lebedev Physics Institute.