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Time evolution of Lyman-alpha fine-structure components for Al XIII
J M A Ashbourn1, I M Melnick, N J Peacock
1Clare Hall, University of Cambridge, Cambridge CB3 9AL, England. J.M.A.Ashbourn@damtp.cam.ac.uk
Summary
We compared modeled and measured Lyman-alpha intensity ratios for aluminum ions in tokamak plasma. Modeled values matched experimental data in L-mode, but H-mode showed discrepancies due to iron emission interference.
Area of Science:
- Plasma Physics
- Atomic Physics
- Spectroscopy
Background:
- Accurate modeling of impurity ion behavior is crucial for understanding tokamak plasma.
- Lyman-alpha emission is a key diagnostic for plasma properties.
Purpose of the Study:
- To compare measured and theoretically modeled Lyman-alpha intensity ratios of hydrogenlike Al XIII ions.
- To validate collisional-radiative models using experimental tokamak data.
Main Methods:
- Utilized a collisional-radiative model to compute time evolution of intensity ratios.
- Employed a high-resolution crystal spectrometer to measure line-of-sight integral values.
- Compared modeled ratios with experimental data from COMPASS-D tokamak plasma.
Main Results:
- Modeled intensity ratios closely followed experimental data for L-mode plasma, accounting for electron parameter variations.
- Discrepancies in H-mode plasma were observed and attributed to line blending from nearby iron (Fe) emission satellites.
- The study highlights the importance of considering line blending in spectral analysis.
Conclusions:
- The collisional-radiative model is effective for predicting Al XIII Lyman-alpha ratios in L-mode tokamak plasmas.
- Iron emission line blending presents a challenge for accurate spectral analysis in H-mode plasmas.
- Further refinement of models is needed to account for complex spectral features in fusion plasmas.