Experimental study of XUV laser produced plasma sheet for microwave agile mirror application
- Univ. of Wisconsin, Madison, WI (United States). Dept. of Electrical and Computer Engineering
An excimer-laser ({lambda} = 193 nm, {tau} = 17 nS, E = 20 mJ) along with a cylindrical lens system is utilized to produce a sheet plasma in an organic gas (TMAE). The plasma has a peak density of 3.5 {times} 10{sup 13} cm{sup {minus}3} and a ``sheet`` like profile of 0.2--0.7 cm x 8 cm x 20 cm. The effect of the lens system on the plasma sheet thickness is examined. The triple probe measured plasma temperature agrees with the postulation of single-photon absorption-ionization process. The plasma density spatial decay along the laser beam, which is associated with TMAE photon absorption length, is measured. The absorption length is found to be a function of base pressure of the neutral working gas. The authors have obtained an optimal window of TMAE base pressure at 50--150 mTorr. Within this optimal pressure range a plasma formation can have a long absorption length, relatively high plasma density, and lifetime of 5 {micro}s. A 1-D plasma diffusion model is proposed and solved both analytically and numerically. Comparison of the modeling and the measured results yields accurate values for the plasma diffusion and recombination coefficients. The electron-ion recombination coefficient is determined to be 2.4 {times} 10{sup {minus}6} cm{sup 3} s{sup {minus}1}. This is within 30% of that previously reported measurement without a lens system. The study indicates that plasma dynamics is dominated by the recombination process except for a very short period after the laser pulse is turned off.
- OSTI ID:
- 160780
- Report Number(s):
- CONF-950612-; ISBN 0-7803-2669-5; TRN: IM9603%%362
- Resource Relation:
- Conference: 22. international conference on plasma science, Madison, WI (United States), 5-8 Jun 1995; Other Information: PBD: 1995; Related Information: Is Part Of IEEE conference record -- abstracts: 1995 IEEE international conference on plasma science; PB: 312 p.
- Country of Publication:
- United States
- Language:
- English
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