RESONANT 4-WAVE-MIXING OF FINITE-AMPLITUDE ALFVEN WAVES

Using the derivative nonlinear Schrodinger equation, resonant four-wav e mixing of finite-amplitude Alfven waves is explored in this paper. T he evolution equations governing the amplitudes of the interacting wav es and the conservation relations are derived from the basic equation. These evolution equations are used to study parametric amplification and oscillation of two small-amplitude Alfven waves due to two large-a mplitude pump (Alfven) waves. It is also shown that three pump waves c art mix together to generate a low-frequency Alfven wave in a dissipat ive plasma.