Cyclotron Radiation Model of Type III Bursts

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Solar radio burst phenomena have been traditionally classified into Types I to V. Of these, Type II bursts are associated with interplanetary shock waves (also known as coronal mass ejections or CMEs) while Type III bursts are closely related to flares. Many in the solar radio community feel that Type III bursts are the most well-studied and well-understood solar radio emission phenomenon. In spite of such a pervasive view, there is observational evidence suggesting that the customary theories may not be applicable in some situations. This proposal specifically aims to address some of these difficulties, particularly those associated with Type III bursts.The standard interpretation of radio bursts involves electron beam-generated Langmuir waves that are nonlinearly converted to electromagnetic radiation. While some (or majority) of the observations of coronal and interplanetary Type III bursts can be explained in light of such a scenario (known as the plasma emission model), a shortcoming of this approach is that it ignores the effects of the solar magnetic field. Observational evidence shows that some Type III and other solar radio bursts are closely associated with active regions (sunspots) where the magnetic field is very intense. As an alternative model to the standard theory of Type III bursts, the PI proposes to investigate the effects of these strong magnetic fields on the radiation generation process. In particular, the PI will study the role of the electromagnetic cyclotron maser instability as a source of Type III radio bursts. Over the past few years, the PI and Co-PI have been working very closely with colleagues in China. The proposed project will involve a number of scientists from China, many of whom are junior personnel. The proposed project will obviously encourage international collaboration and promote the education and training of young scientists.