3 research outputs found
On the origin of 140 GHz emission from the 4 July 2012 solar flare
The sub-THz event observed on the 4 July 2012 with the Bauman Moscow State
Technical University Radio Telescope RT-7.5 at 93 and 140~GHz as well as
Kislovodsk and Mets\"ahovi radio telescopes, Radio Solar Telescope Network
(RSTN), GOES, RHESSI, and SDO orbital stations is analyzed. The spectral flux
between 93 and 140 GHz has been observed increasing with frequency. On the
basis of the SDO/AIA data the differential emission measure has been
calculated. It is shown that the thermal coronal plasma with the temperature
above 0.5~MK cannot be responsible for the observed sub-THz flare emission. The
non-thermal gyrosynchrotron mechanism can be responsible for the microwave
emission near ~GHz but the observed millimeter spectral characteristics are
likely to be produced by the thermal bremsstrahlung emission from plasma with a
temperature of about 0.1~MK.Comment: 18 pages, 6 figure