Mode coupling in the solar corona

The theory of mode coupling in the radiation from solar type I storms is extended to treat coupling when the frequency! is near the plasma frequency!p. It is found that Cohen's coupling ratio Q = U/It)4, where It is the transition frequency (f'P It for strong coupling), is to be multiplied by a factor (1-!~/ J2)5/2 for QT regions, i.e. coupling is relatively suppressed close to the plasma level. The implications on the handedness of solar radio radiation are discussed. The possibility of depolarization due to mode coupling is considered briefly.