The character of cyclotron instability of hydromagnetic waves

The method of energy balance is used for calculating the growth rate of hydromagnetic waves ( _H in the regime of a cyclotron resonance. The HM waves are propagated at an angle to the external magnetic field. A tenuous beam of charged particles with a finite Larmor radius penetrating through a cold plasma is assumed to be responsible for the cyclotron instability process.The author is grateful to Assoc. Prof. Dr. A. Hruka CSc. for helpful discussions and remarks concerning the problem. He is also indebted to Mrs. E. Lomecká for the graphical work.