A discussion of probe measurement of the magnetic field in a plasma is presented with particular reference to the perturbation of the magnetic field caused by the probe. A correction procedure is developed to compensate for this perturbation. Using magnetic probes, radial variation of the current density distributions are obtained for an argon plasma in a z-pinch discharge. Initial argon pressures of 100, 250, and 500 μHg are investigated. The current density distributions are determined for 1 μsec intervals between the initiation of the discharge and the occurrence of the first pinch. These current density distributions are compared with photographic observations. The experimental results are discussed in terms of the snowplow model and the shock wave model. Mathematically, the non-linear snowplow equation is solved using an approximation technique which results in analytic solutions. The shock wave equation is solved by a graphical technique. An extension of the shock wave model is proposed for a better understanding of the experimental results. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The suppression of radial hydromagnetic oscillations of a theta pinch plasmoid produced in air has been investigated with magnetic probes and a framing camera. In the presence of essentially static and uniform magnetic bias fields (produced by Helmholtz coils) it was found that the oscillations are suppressed by a flip instability of the plasmoid and the direction of flip is controlled by the transverse magnetic field. Using the suppression of radial hydromagnetic oscillation as the criterion for flip, it is found experimentally that if [formula omitted] is greater than a critical value, then the plasma ring flips. [formula omitted] is the strength of the bias field perpendicular to the axis of the theta coil, 'a' the radius of the discharge vessel and 'p' is the gas pressure. The experimental results are interpreted in terms of a snowplough model for the discharge, in which the plasma current forms two concentric cylinders. The predictions of the theory agree with the experimental observations. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The temperature of a Helium plasma produced in a shock tube has been determined from absolute intensity measurements. The plasma was considered to be homogeneous, transparent and in local thermodynamic equilibrium. The emissivity of the plasma has been measured by comparing the plasma radiation to the radiation from a carbon arc through a simple optical system. The influence of errors in measured parameters and the presence of impurities is discussed. Temperatures which depend on large exponential terms are relatively insensitive to both errors in measurement and the impurity content of the plasma. The accuracy of absolute intensity measurements is at best comparable to relative intensity measurements. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Improvements to the laser excited interferometer previously constructed in this laboratory are described. The use of a rotating retro-reflector in the interferometer cavity, and electronic circuitry, permit direct recording of electron densities. The sensitivity of the interferometer is 5 x 1015 cm-2, and the temporal resolution is 0.1 usee. Pyrex tubes, terminated by windows, enclosing the laser beam, have been used to improve spatial resolution. The effects of the tubes, and of all other sources of error associated with interferometric measurements of electron densities, have been carefully assessed. A Z-pinch discharge in 4 torr helium has been studied with this instrument, and with spectroscopic determinations of electron temperature. Under the conditions chosen, the pinching plasma does not reach the axis of the discharge tube, but stops at a radius of 2.7 cm. The shock front caused by the pinching action has been shown to be weak. Longitudinal structure, due to heat flux, characteristic cathode behaviour, and variations in timing of the pinching action, has been found. The discharge has been assessed as a spectroscopic source and as a medium for laser scattering experiments. The characteristics of two suitable regions are presented. These are the axial region and the hollow cylinder of plasma formed by the arrest of the pinching plasma. Both are free of instabilities. At the appropriate time the latter is also current free, and shows longitudinal electron density variations of less than 2%. The length of time that the current spends near the wall of the vessel is determined by the balance between kinetic and magnetic pressures. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Thesis (M.App.Sc.) - Carleton University, 2005. / Includes bibliographical references (p. 188-190). Also available in electronic format on the Internet.

Thesis (M.S.)--U.S. Naval Postgraduate School, 1960. / "Controlled Thermonuclear Processes, UC-20" -t.p. "TID-4500 (15th Ed.)" -t.p. Includes bibliographical references (p. 26-27).

by Tsui Chi Wa. / Chinese title: / Bibliography: leaf 51 / Thesis (M.Phil.) -- Chinese University of Hong Kong, 1983

by Chan Pui-King. / Bibliography: leaf 45 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1984

Thesis (doctoral)--University of Tartu,, 2006. / Thesis based on four papers.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 186-203). Also available via the Internet