HR: 1340h
AN: SH23A-1162    [Abstracts]
TI: Simulated Coronal Type III Solar Radio Bursts: Source Region Dynamics and Remote Radiation Spectra
AU: Li, B
EM: boli@physics.usyd.edu.au
AF: School of Physics, University of Sydney, Sydney, NSW 2006, Australia
AU: * Cairns, I H
EM: cairns@physics.usyd.edu.au
AF: School of Physics, University of Sydney, Sydney, NSW 2006, Australia
AU: Robinson, P A
EM: robinson@physics.usyd.edu.au
AF: School of Physics, University of Sydney, Sydney, NSW 2006, Australia
AB: We have developed a 3D model for coronal type III bursts, including (1) the 3D structure of the source region, (2) a detailed simulation of the dynamics within the source of electron beams, Langmuir, ion-sound, and fundamental and second harmonic electromagnetic radiation, and (3) the propagation of the electromagnetic radiation to a remote observer. For realistic coronal conditions and beam acceleration parameters the simulated radiation dynamic spectra are consistent with the general characteristics (e.g., frequency drift rate, radiation flux and brightness temperature) of type III bursts observed at Earth. Moreover, the spectral characteristics depend quantitatively on the coronal conditions and beam acceleration parameters. We found that, in general, second harmonic emission dominates fundamental emission, since the latter is strongly damped by free-free absorption and scattering-induced damping. However, harmonic pairs may exist under some favorable conditions. A second set of simulation results imply that an interplanetary type III burst may be produced by merging of multiple coronal type III bursts as the beams propagate from the corona to the interplanetary medium.
DE: 7534 Radio emissions
DE: 7829 Kinetic waves and instabilities
DE: 7847 Radiation processes
DE: 7867 Wave/particle interactions (2483, 6984)
DE: 7868 Wave/wave interactions
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting