Date of Graduation


Document Type


Degree Type



Eberly College of Arts and Sciences


Physics and Astronomy

Committee Chair

Earl E. Scime.


Laser Induced Fluorescence (LIF) measurements of ion velocity distribution functions (ivdf) in a compact, expanding helicon plasma were limited by optical access and laser power. LIF measurements in the Compact HElicon Waves and Instabilities Experiment (CHEWIE) determined the ivdf of a compact helicon argon plasma as a function of fill pressure, magnetic field, and partial pressure of argon. The LIF scheme used the ring dye laser to 611.662 nm (vacuum wavelength) to pump the Ar II 3d2G9/2 metastable state to the 4p2F7/2 state. The ion decayed to the 4s 2D5/2 level and the fluorescent emission at 460.96 nm was recorded as a function of laser frequency. RF power up to 450 Watts created steady state plasma in a 60 cm long, 7.5 cm diameter Pyrex tube source chamber. A 30 cm long, 15 cm diameter stainless steel expansion chamber was connected to one end of the source chamber. The magnetic field strength ranged from 0--550 Gauss. Argon ivdfs indicate the presence of an accelerated ion population for fill pressure less than 1.5 mTorr.