Investigations on characteristics of TE11 mode encountering plasma in a circular waveguide

Summary form only given. The subject of electromagnetic waves and plasma interaction has diverse applications in particle acceleration, frequency up shifting, resonance absorption, controlled fusion investigations related to ITER (International Thermonuclear Experimental Reactor) etc. For the purpose of particle acceleration, researchers all over the world have mainly focused on lasers due to their ultrahigh intensities. In such schemes of particle acceleration, it is required that the laser pulses propagate without diffraction or changing their shapes in the plasma. It is also needed that this interaction remains for longer distances. However, the propagation characteristics of electromagnetic waves have been found to change during their propagation in the plasma. In view of possible application of electromagnetic waves to ITER, we investigate in the present article the interaction of TE₁₁ mode with plasma. For this type of interaction, we consider two waveguides of identical size, out of which one is evacuated and another one is filled with plasma. The TE₁₁ mode propagating in evacuated waveguide encounters the plasma in second waveguide. During this process, the propagation characteristics of the mode and the distribution of plasma density in the waveguide are found to change self consistently. As mentioned, we consider the propagation of TE₁₁ mode in a circular waveguide, which continues to propagate through another waveguide filled with plasma. In order to study this interaction, we obtain the field components of this mode in evacuated waveguide and consider the plasma effect through the permittivity epsiv. Here we consider a balance between the effects of ponderomotive force and the electron pressure. Then we obtain differential equations in terms of the electric field component of TE₁₁ mode in the plasma filled waveguide. These equations are solved numerically and we obtain the electric field structure in the waveg- ide and observe the corresponding density perturbations. The amplitude of the electric field and wavelength of the mode are investigated under the effects of microwave frequency, plasma density and waveguide radius. By increasing electron temperature enormously, we also investigate the mode propagation in highly nonlinear conditions.