Radiation mechanisms of the plasma near point L1 affected by CMEs and associated microwave bursts

When coronal mass ejections (CMEs) interact with the solar corona and the interplanetary medium, emissions at different wavelengths occur. On the basis of study of the various radiation mechanisms of space plasma in the case of absence of CMEs, the radio radiation mechanisms of the plasma close to the Lagrange point L1 and affected by large CMEs from February to August 1999 are statistically analyzed. As shown by the results, the main radiation mechanisms are the Bremsstrahlung, a small amount of cyclotron radiation and a still weaker recombination radiation. Also, solar microwave bursts which are associated with CMEs in the same period are investigated. The results show that the microwave bursts are of the gradual type as well as spike bursts, and that the chief radiation mechanisms are the Bremsstrahlung, cyclotron resonance radiation, plasma radiation and electronic cyclotron maser radiation.