ABSTRACT

If the electrons are warm they can change the frequency of the incident waves, damp the waves, amplify the waves, create plasma instabilities and plasma heating and generate many kinds of internal plasma waves. Arguments about wave propagations in plasma look inextricable for non-experts because plasma physicists base their reasonings on miscellaneous wave/plasma parameters. Waves are stopped or reflected in the so-called cut-off zones inside the plasma which also are deduced from the dispersion relations and occur when the index of refraction N˜ goes to zero. The problem of wave accessibility to the resonances becomes very involved, when propagation occurs at an angle to the magnetic field. The best known type of interaction is Landau damping when a wave can be damped as it propagates in the plasma, even though there are no binary or collective collisions in the medium. Electron cyclotron resonance heating is a very impressive method to heat selectively the electrons in the plasma.