THE GENERATION MECHANISM OF SOLAR METRE-WAVE MOVING TYPE IV BURSTS

In this paper a new model and radiation mechanism of type IVmAbursts are presented.Plasma clouds ejected during the exposive phase of flare move upward inside a large magnetic arch,trapped nonthermal electrons (E≈100 KeV) with forward-cone gap distribution excite Langmuir wave.Under the condition T_e>>T_i there should be ion-sound wave in the source.The electromagnetic transverse wave is produced through the nonlinear interaction between the two waves and the type IVmAburst takes place.The spectra of brightness temperature and their evolution for eight announced events are calculated and the results coincide with observations rather well.The other main characteristics of the bursts,such as polarization,life-time,the relation between the size and position of sources and frequencies etc.,are all explained more reasonably.The radiation processes under conditions T_e=T_i and T_e>>T_i are compared with one another.It is shown that the condition T_e>>T_i is more probably true,so the main contribution to the radiation doesn't come from iou scattering,but from the nonlinear process l±s(这里有图片19820101-261-1.GIF)t.This conclusion is not only true for the type IVmAbursts,but also probably for some other types of solar radio bursts.