Modulational Instability and Electromagnetic Wave Scattering of Plasma Flute Modes

Abstract

The modulation instability of the plasma electromagnetic flute modes has been derived and investigated for two different cases. In the first case, the modulational instability of the flute modes for finite beta plasmas, where the plasma pressure is comparable to that of the external magnetic field one, has been derived. While in the second case, the modulational instability of the flute modes for low beta plasmas, where the plasma dynamics are dominated by the external magnetic field, with the effects of the ion temperature gradient has been derived. It is shown through numerical code, called FLUTE which was developed by Dr. Leboeuf for the NTF, that these flute modes are responsible for the generation of large scale structures in the plasma (the zonal flows), which in turn are responsible for transferring the energy to higher values of the wave vectors through the four wave interaction which has been shown through the modulational instability. In the second part of this dissertation, the scattering of electromagnetic waves by plasma flute vortices has been studied. The scattering cross section has been calculated for the incident S-wave, using MATHEMATICA in order to obtain the angle distribution of scattering cross section and the total scattering cross section numerically. It is found that the scattering cross-section decreases as the incident wave frequency increases and the scattering cross-section increases as the vortex radius increases.