Abstract
It is well known that at the microwaves there is an enhanced brightness
temperature of the Sun in
the plage-associated active regions. It is generally agreed that this is
due to a slightly enhanced
electron density in the solar corona above plages. Here we present the
results of the observations
of a plage region with a filament. These observations were carried out
in September-October,
1996, at 2-20cm wavelengths with the radio telescope RATAN-600 and at
1.7cm with the
Nobeyama Radio Heliograph.
At the shortest wavelengths it was observed
the filament only as a
dark formation. On the longer wavelengths on the both sides of the
filament two sources with the
enhanced radio brightness appear with the increase of the brightness
temperature as lambda^3
suggesting that the character of this emission is non-thermal. The
observed radio brightness
distributions were modelled as a combined action of bremsstrahlung and
non-thermal
gyrosynchrotron radio emission of a large coronal magnetic loop.
Considerable stability of the
phenomenon (more then two solar rotations) indicate that there are the
non-thermal processes
continuously acting in the solar corona in the period of deep minimum of
solar activity.