Practical selection of emission lines of He I to determine the photon absorption rate
- EcoTopia Science Institute, Nagoya University, Nagoya 464-8603 (Japan)
- Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan)
A combination of helium line intensities and a collisional radiative model has been used to measure electron density and temperature. However, radiation trapping of resonance lines may disturb the measurements due to disturbances in the population distribution of helium atoms. In this study, we show that the principal contribution of radiation trapping in helium plasma can be evaluated by additionally measuring one or two specific line intensities from the singlet state. The inclusion of the effects of radiation trapping sufficiently compensates for anomalous increases in the electron density and temperature, and consequently yields proper values. An experiment was performed in the divertor simulator NAGDIS-II, and the method's validity was confirmed by comparing the spectroscopically obtained results and the values from the electrostatic probe method.
- OSTI ID:
- 22063629
- Journal Information:
- Review of Scientific Instruments, Vol. 82, Issue 2; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
Similar Records
Helium I line intensity ratios in a plasma for the diagnostics of fusion edge plasmas
Evaluation of emission contributions from charge-exchange between the excited states of deuterium with He+ during diagnostic of thermal helium gas beam injection and laser-induced fluorescence