Absolute electron density fluctuation reconstruction for two-dimensional hydrogen beam emission spectroscopy
1Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA.
The Review of Scientific Instruments
|December 1, 2023
Summary
A new method improves density fluctuation reconstruction in plasma edge turbulence. This technique enhances beam emission spectroscopy for better understanding scrape-off layer (SOL) phenomena and protecting fusion devices.
Area of Science:
- Plasma Physics
- Fusion Energy Research
- Diagnostic Techniques
Background:
- Scrape-off layer (SOL) and edge plasma turbulence drive particle and heat transport, reducing plasma confinement.
- Intermittent density filaments (blobs) in the SOL propagate outward, causing erosion and sputtering of plasma-facing components.
- Accurate characterization of SOL turbulence is crucial for fusion reactor design and operation.
Purpose of the Study:
- To introduce a novel method for accurate reconstruction of plasma density fluctuations.
- To overcome spatial smearing limitations in beam emission spectroscopy measurements.
- To improve the understanding of scrape-off layer turbulence and its impact on fusion devices.
Main Methods:
- Developed a new method involving inversion of the fluctuation response matrix on a smoothed signal.
- Applied the technique to beam emission spectroscopy data from SOL and edge plasmas.
- Compared the novel method's accuracy against direct inversion techniques.
Main Results:
- The novel method provides significantly more accurate absolute density fluctuation reconstruction.
- The technique is computationally fast, enabling real-time analysis.
- Successfully mitigated spatial smearing effects caused by atomic physics and observation misalignment.
Conclusions:
- The presented method offers a substantial improvement for beam emission spectroscopy diagnostics.
- This advancement aids in detailed characterization of SOL turbulence and filamentary structures.
- The technique is applicable to various beam emission diagnostics with sufficient spatial resolution.
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