LAUSR

The electron-cyclotron maser is a process that generates the intense and coherent radio emission in the plasma. In this paper, we present a comprehensive parametric investigation on the electron-cyclotron-maser instability driven by non-thermal ring-beam electrons with intrinsic Alfven waves, which pervade the solar atmosphere and interplanetary space. It is found that both forward propagating and backward propagating waves can be excited in the fast ordinary (O) and extraordinary (X) electromagnetic modes. The growth rates of X1 mode are almost always weakened by Alfven waves. The average pitch-angle ϕ 0 of electrons is a key parameter for the effect of Alfven waves on the growth rate of modes O1, O2, and X2. For a beam-dominated electron distribution ( ϕ 0 ≲ 30 °), the growth rates of the maser instability for O1, O2, and X2 modes are enhanced with the increase of the Alfven wave energy density. In other conditions, the growth rates of O1, O2, and X2 modes weakened with the increasing Alfven wave intens...