Self-reversal in Lyman-α line profile for diagnosis of fusion plasma

23rd International Conference on Spectral Line Shapes

Goto, M.^1,2 ; Sawada, K.^3 ; Oishi, T.^1,2 ; Morita, S.^1,2

National Institute for Fusion Science, Toki

509-5292, Japan^1

SOKENDAI (The Graduate University of Advanced Study), Toki

509-5292, Japan^2

Department of Applied Physics, Faculty of Engineering, Shinshu University, Nagano

380-8553, Japan^3

关键词: Absorption co-efficient;    Fusion plasmas;    Laplace inversions;    Line measurements;    Line profile analysis;    Neutral densities;    Plasma boundary;    Radiation transport equations;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/810/1/012016/pdf
DOI  :  10.1088/1742-6596/810/1/012016

来源: IOP

【 摘 要 】

We have observed Lyman-α line profile which exhibits the so-called "self reversal" at the line center. A one-dimensional radiation transport equation is numerically solved for simulating the Lyman-α line profile, where the emission and absorption coefficient distributions over the line-of-sight are evaluated based on the Laplace inversion analysis of the Balmer-α line measured simultaneously with the Lyman-α line. While the synthetic profile of the Lyman-α line shows a good agreement with the measured data in the line profile tail, the central part shows a significant discrepancy between the synthetic and measured profiles. It has been known that the neutral density profile in the plasma boundary region derived from the Balmer-α line profile analysis has a relatively large error and the present results shows that the Lyman-α line measurement would play a complementary role to determine an entire neutral density profile from the core to the edge.