Plasma column development in the CO/sub 2/ laser-heated solenoid
Axial and radial plasma dynamics in the CO/sub 2/ laser-heated solenoid have been studied experimentally and numerically. The axial behavior is found to be well described by a self-regulated bleaching wave model. The radial expansion is found to be strongly dependent on the focusing ratio of the input laser beam. With a fast focus ( f/5), the early radial expansion rate is twice that found with a slower focusing arrangement ( f/15). The faster focusing ratio also results in a significantly wider plasma column. On the other hand, no significant dependence of f/number on the axial propagation was found. A finite ionization time and the rapid formation of a density minimum on axis are observed and verify earlier experimental results. Detailed comparisons are made with a 2-D magnetohydrodynamic (MHD) and laser propagation code. The axial and radial plasma behavior and, in particular, the dependence of the radial behavior on the focal ratio of the laser are reasonably well supported by the simulation results. Computational results are also in good agreement with experimental measurements of temperature and density using stimulated scattering (Brillouin, Raman) and interferometry diagnostic techniques.
- Research Organization:
- Department of Electrical Engineering, University of Alberta, Edmonton, Alberta, T6G 2G7, Canada
- OSTI ID:
- 6460112
- Journal Information:
- Phys. Fluids; (United States), Vol. 30:8
- Country of Publication:
- United States
- Language:
- English
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