The development and use of a computerised data
acquisition system for the study of the temporal
variations of the plasma parameters in pulsed Helium and
Argon afterglows using a single Langmuir probe. The
controlling software and electronics were developed to a
level that enabled plasma characteristics to be analysed
and presented on a number of output devices.
A novel technique was developed to pulse the
probe which limits plasma depletion during the measurement
process. A non - Maxwellian electron energy distribution
was found at early times in the afterglow with two distinct
'temperature' or energy groups. The 'faster' or 'hotter'
electrons 'blended' with the cold group at late times in
the afterglow, giving a single group which could be
characterised by a unique temperature. This temperature
was seen to approach room temperature in the temporal
limit. The decay of bulk electron temperature and density
was modelled using the diffusion equation and reasonable
agreement was found to exist between the theoretical and
experimental data.
Metadata
Item Type:
Thesis (Master of Science)
Date of Award:
1990
Refereed:
No
Supervisor(s):
Hopkins, Michael B.
Uncontrolled Keywords:
Plasma engineering; Helium and Argon afterglows; Langmuir probes; Computerised data acquisition system