Radio burst emission mechanisms - General review

Mechanisms for the emission of metric-wave solar radio bursts are reviewed. The standard theory of fundamental plasma emission is presented in terms of an analogy between the scattering of Langmuir waves into transverse waves by nonlinear coupling with the shielding electric fields associated with thermal ions and Thomson and induced scattering. Consideration is then given to the alternative conversion mechanisms of the coalescence of Langmuir waves with low-frequency waves to produce a transverse wave and the direct conversion of Langmuir waves into o-mode waves by inhomogeneities in the plasma. The generation of second harmonic plasma emission is described in a manner analogous to standard fundamental emission, and burst polarization and the role of gyro-synchrotron emission and absorption are considered.