A study on induced bremsstrahlung instability in a magnetized plasma

Abstract

The study of radiation problems from a turbulent plasma is important for interpretation of various astro-physical and laboratory plasma phenomena. One principle source of radiation in a hot fully ionized plasma is bremsstrahlung which is a free transition process and occurs when one particle encounters another and makes a sudden change in direction. Induced bremsstrahlung is a new kind of radiation process which originates because of electron acceleration through the modulated electric field. If a high frequency electromagnetic (EM) or electrostatic (ES) test wave is present in the plasma Containing low frequency fluctuations, coupling of EM/ES wave fields. with the latter produces modulation electric fields. These modulation fields interact nonlinearity with the resonant electrons, which causes strong acce-leration of these electrons. The energy thus acquired by the resonant electrons is emitted in the form of radiation thereby causing the high frequency test wave amplitude to grow. This radiation is known as induced bremsstrahlung which vanishes in the absence of the low frequency turbulence. Since the prediction of this new maser effect, this mode coupling process has been applied to a large number of plasma radiation observations. The most important characteristic of plasma maser effect is the energy up-conversion from a low frequency mode to a high frequency mode in a plasma. The plasma maser is a non-linear process which always coexist with the linear Landau damping. The maser effect predicts a particular phase relation between a pump field and the high frequency emission. In the first problem we study the plasma maser theory of whistler waves in the presence of ion cyclo-tron waves in magnetized plasma. We consider a homo-genous, magnetized collisionless plasma in the presence of a low frequency ion cyclotron wave propagating nearly normal to the ambient magnetic field present in the system. Because of mode coupling between the whistler mode and ion cyclotron wave, Modulation field appears. Using...