George Mossessian, Gregory D. Fleishman
A quantitative study of the observable radio signatures of the sausage, kink,
and torsional MHD oscillation modes in flaring coronal loops is performed.
Considering first non-zero order effect of these various MHD oscillation modes
on the radio source parameters such as magnetic field, line of sight, plasma
density and temperature, electron distribution function, and the source
dimensions, we compute time dependent radio emission (spectra and light
curves). The radio light curves (of both flux density and degree of
polarization) at all considered radio frequencies are than quantified in both
time domain (via computation of the full modulation amplitude as a function of
frequency) and in Fourier domain (oscillation spectra, phases, and partial
modulation amplitude) to form the signatures specific to a particular
oscillation mode and/or source parameter regime. We found that the parameter
regime and the involved MHD mode can indeed be distinguished using the
quantitative measures derived in the modeling. We apply the developed approach
to analyze radio burst recorded by Owens Valley Solar Array and report possible
detection of the sausage mode oscillation in one (partly occulted) flare and
kink or torsional oscillations in another flare.
View original:
http://arxiv.org/abs/1112.0609
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