Study on the strong cyclotron interaction of an electromagnetic wave with a plasma

Results of experimental and theoretical investigation of the interaction between UHF wave and nonuniform plasma in the electron cyclotron resonance mode are described. One-particle approximation is shown to be valid for low electron densities, when ωsub(pe)sup(2)/ωsub(0)sup(2)<=2Δωsub(Hec)/ωsub(0) (Δωsub(Hec) is the halfwidth of resonance line), cyclotron in,.eraction being accompanied by production of 30-40 keV electrons. According to experimental data, the width of the resonance line in conditions of described experiments is mostly determined by relativistic change in the electron cyclotron frequency. The reasons for a transformation of a strong cyclotron absorption into a weak one when plasma density rises are related to changes in polarization and propagation angle of the wave