Plasma and Fusion Research
Volume 13, 3402047 (2018)
Regular Articles
- Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
Abstract
Temporal evolution of electron density and temperature in TOKASTAR-2 tokamak plasma is obtained for the first time by He I line intensity ratio method. In the calculation of collisional radiative model, we consider the effect of radiation trapping and validity of quasi-steady-state approximation for metastable states. He I line intensities are measured using a monochromator that has a photomultiplier tube as a detector. To evaluate line intensity ratios used for analysis, their sensitivity factors for plasma parameters are newly introduced. We investigate plasma current Ip dependence of the electron density ne and temperature Te by changing the charging voltage of ohmic heating VOH. The ne depended on Ip independent of VOH. The Spitzer resistance obtained from the measured Te was consistent with the plasma resistance at Ip top phase.
Keywords
TOKASTAR-2, He I line intensity ratio method, CR model, radiation trapping, tokamak plasma
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