Accession Number : ADP001436

Title :   Magnetohydrodynamic (MHD) Description of Solar Radio Bursts,


Personal Author(s) : Wu,S. T.

Report Date : 27 DEC 1982

Pagination or Media Count : 18

Abstract : The nature of solar radio bursts and their dynamic spectra usually are discussed in terms of a static, semi-quiet corona. In particular, the value of the electron density and the general topological nature of the magnetic field, necessary for a proper description of the radio bursts, are deduced from undisturbed coronal models. We know, however, that Type II and moving Type IV bursts are related to flare-generated disturbances in the corona; as the disturbances pass through the atmosphere, all plasma properties are changed. In order to take these disturbed coronal conditions into consideration we have used a two-dimensional MHD model to compute the properties of the disturbed corona. Given these spatial and temporal properties, we have then deduced the resulting dynamic spectra of Type II and moving Type IV radio bursts. Three different initial magnetic field topologies were considered: closed-field, open-field, and coronal streamer configurations. While the model is unable to specify the particular form of radiation mechanism present in any given observation, the results strongly suggest that temporal collective MHD behavior must be considered regardless of the mechanism (plasma oscillations or gyrosynchrotron emission).

Descriptors :   *Solar disturbances, *Radio signals, *Magnetohydrodynamics, Burst transmission, Solar corona, Mathematical models, Solar flares, Two dimensional, Time dependence, Solar radiation, Magnetic fields, Topology, Plasmas(Physics)

Distribution Statement : APPROVED FOR PUBLIC RELEASE