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Fast-ion orbit sensitivity of neutron emission spectroscopy diagnostics
H Järleblad1, L Stagner2, M Salewski1
1Department of Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
The Review of Scientific Instruments
|July 10, 2021
Summary
Fast ion behavior in fusion plasmas is revealed by neutron emission diagnostics. Orbit weight functions for TOFOR and NE213 show sensitivity to specific fast ion orbits, aiding plasma analysis.
Area of Science:
- Nuclear Fusion Science
- Plasma Physics
- Diagnostic Techniques
Background:
- Fast ions in fusion plasmas create unique neutron emission signatures.
- Diagnostic measurements of neutron emission depend on phase-space sensitivity.
- Weight functions can map this diagnostic sensitivity.
Purpose of the Study:
- To present orbit weight functions for TOFOR and NE213 neutron diagnostics.
- To map the phase-space sensitivity of these diagnostics in 3D orbit space.
- To understand how diagnostics detect fast ions.
Main Methods:
- Development and application of orbit weight functions.
- 3D orbit space mapping of diagnostic sensitivity.
- Analysis of fast ion orbit types (potato, passing, trapped, stagnation).
Main Results:
- Both TOFOR and NE213 are sensitive to fast ions spending significant time within their viewing cones.
- TOFOR shows sensitivity to potato orbits, localized counter-passing orbits, and trapped orbits with "banana tips" in view.
- NE213-scintillator exhibits high sensitivity to stagnation orbits.
Conclusions:
- Orbit weight functions effectively map the phase-space sensitivity of neutron diagnostics.
- Understanding diagnostic sensitivity is crucial for interpreting fast ion behavior in fusion plasmas.
- Specific orbit types are preferentially detected by TOFOR and NE213, informing experimental analysis.
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