Browsing by Subject "Plasma electrodynamics"
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Item An electron cyclotron resonance toroidal plasma system for thin film deposition(Texas Tech University, 1995-05) Greig, Wendy EllenA toroidal electron cyclotron resonance (TECR) plasma deposition system has been built and tested with an argon plasma. Design considerations for the TECR system will be discussed and improvements for future designs will be presented. Diagnostic techniques were used in the system for comparison with existing ECR and other plasma deposition systems. These diagnostics included a magnetic filed profile of the main deposition chamber and determination of plasma parameters, such as electron temperature, through the use of a Langmuir probe. The results of these diagnostics will be presented, as well as a discussion of the accuracy of a Langmuir probe in an ECR plasma. Finally, the plasma parameters will be linked to the TECR system's suitability for thin film growth.Item Item Velocity space diffusion in ion acoustic turbulence(Texas Tech University, 1989-08) Yuen, Kin-mingThe nonresonant nature of charged particle motion in the ion acoustic turbulence is studied numerically and analytically. We set the teat particles in prescribed turbulent electric fields of which the second order correlation functions are characterized by a sinusoidal structure with the exponential damping in real apace, described as E(x,t)= Σ f(kj)cos[w(kj)t-kjX +βj) where f(kj) is a shaping factor with a Gauasian form, βj is a random phase and CO(kj)= kjC^. The numerical experiments are carried out with particles placed randomly in the system, or alternatively they are followed with the same initial position for different realization of electric fields. Number of test particles ranging from 20 to 500 and mode number 16 to 200 are used, respectively, for the trajectory calculations. The diffusion coefficient is measured in velocity space by taking mean square variation as a function of time and then it is compared with the analytic predictions evaluated by The numerical results show good agreement with the theoretical prediction provided that δ is not greater than 0.01.