Hydrogen Alpha Self-Absorption Effects in Laser-Induced Air Plasma

22nd International Conference on Spectral Line Shapes

Parigger, C.G.^1 ; Swafford, L.D.^1 ; Surmick, D.M.^1 ; Witte, M.J.^1 ; Woods, A.C.^1 ; Gautam, G.^1

University of Tennessee, Space Institute, 411 B.H. Goethert Parkway, Tullahoma

TN

37388, United States^1

关键词: Air breakdown;    Alpha self-absorption;    Laser-induced optical breakdown;    Line following;    Optical breakdown;    Self absorption;    Spectral line shape;    Time-resolved spectroscopy;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/548/1/012043/pdf
DOI  :  10.1088/1742-6596/548/1/012043

来源: IOP

【 摘 要 】

Time-resolved spectroscopy measurements of the hydrogen alpha Balmer series line following laser-induced optical breakdown in laboratory air are designed to investigate in detail the determination of electron density from Stark-broadened spectral line shapes. Comparisons of results obtained from Hβand Hγlines indicate higher electron density inferred from Hαearly in the plasma decay, suggesting self-absorption occurs. However, detailed comparisons for time delays of 300 and 400 ns after optical breakdown reveal the minute extent of self-absorption in air breakdown experiments from (i) differences of electron density determined from the N+lines and the Hαline, and/or from (ii) differences in recorded data sets with/without the mirror for the various time delays in the experiments.