The amplification mechanism of extra-ordinary mode radiation in the presence of kinetic Alfvén wave turbulence driven by an electron beam is studied. It is shown that plasma maser process may be responsible for the amplification of the extra-ordinary mode through up-conversion of turbulent energy via nonlinear wave particle interaction. The relevance of this investigation to space plasmas is discussed.

This paper contains the plasma maser interaction between high frequency nonresonant whistler R-mode and low frequency resonant ion acoustic mode in a relativistic plasma. It shows that the whistler R-mode grows through the plasma maser interaction between the relativistic electrons and the ion acoustic fluctuation.