On the modelling of fundamental ion cyclotron absorption by finite Larmor radius wave equations

Modified sixth order wave equations from a finite temperature expansion of the linearized Vlasov-Maxwell equations in the ion cyclotron range of frequencies are constructed for modelling the power deposition of the fast magnetosonic wave whenever a majority or high concentration minority fundamental cyclotron resonance resides in a plasma. The negative absorption sometimes observed around the cyclotron resonance in the solutions of the equations obtained by a rigorous perturbation expansion to second order in ion Larmor radius is avoided.