Study of a perturbation in a glow discharge

The perturbation in a glow discharge in hydrogen is studied theoretically and experimentally. In an ordinary glow discharge a perturbation has been produced by applying a small sinusoidal high frequency electric field. This modulates the electron energy and hence the number density of atoms in excited states; The relative phase and amplitude of light emitted in the first four lines of the Balmer series have been measured. A theory based on the work of Bates et al, is developed in this thesis and the results predicted give better agreement with the experimental values than do alternative theories which have been published recently. These if absorption of line radiation by the discharge is shown to have a critical effect on the behaviour of the plasma. The limitations and validity of assumptions are discussed and a modified experiment is suggested.Science, Faculty ofPhysics and Astronomy, Department ofGraduat