The possibility of an instantaneous determination of the Balmer alpha (Hα) line profile of hydrogen atoms in large plasma devices by rapid-frequency-scan (RAFS) laser spectroscopy is discussed. A detailed analysis of the SN ratio shows that, although the SN ratio in Hαline profile measurements by RAFS is smaller than those in neutral hydrogen density measurements, a remarkable improvement can be obtained by the choice of the optimum saturation parameter and the long-pulse operation. Based on the experiment of the Hαprofile measurement in a hydrogen DC glow discharge plasma by RAFS, the profile distortion in saturated excitation is evaluated. The SN ratio in the profile measurement by RAFS for Heliotron E plasma is estimated from the data on the neutral density measurement.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)