Double Plasma Resonance for Decimetric dot-Emissions

The mechanism of the double plasma resonance has been applied to the dot-like emission structures observed in the decimetric band. In particular, the existence of dot-emissions on definite trajectories in the dynamic spectra offers a rare opportunity to delineate the details of the double resonance mechanism as well as the diagnostics of the radio source and the ambient corona. The modeling of the chains of dots points to the excitation of the electron Bernstein modes predominantly at the second cyclotron harmonic and their subsequent coalescence to produce the observed dot-emissions. The coalescence process doubles the cyclotron harmonic number and thereby reduces the cyclotron absorption significantly. The discrete nature of the emissions results from the finite extent of the resonant region due to the presence of inhomogeneities. The determination of the relative scales of spatial variation of the magnetic field and the electron density in the region of the decimetric emission is particularly desirable as it has important consequences for the energy release, acceleration processes and the configuration of the participating plasma structures.