Radiometry for the vertical electron cyclotron emission from the runaway electrons at the COMPASS tokamak

Area of Science:

• Plasma Physics
• Fusion Energy Research
• Diagnostic Techniques

Background:

• Runaway electron (RE) phenomena are of increasing interest in tokamak research.
• Accurate diagnostics are needed to understand RE populations in plasma.
• Nonthermal electron cyclotron emission (ECE) offers a potential diagnostic method.

Purpose of the Study:

• To design and implement a novel diagnostic system for runaway electrons.
• To utilize a heterodyne radiometer for measuring nonthermal ECE.
• To assess the feasibility of diagnosing REs up to 1 MeV.

Main Methods:

• Installation of a vertical ECE (V-ECE) system at the COMPASS tokamak.
• Utilizing a 16-channel heterodyne radiometer with an E2-band horn antenna (76.5-90 GHz).
• Employing the SPECE code for ray-tracing simulations to determine measurement feasibility.

Main Results:

• The V-ECE system is feasible for measuring runaway electrons up to 1 MeV.
• Reflected waves from the tokamak wall were detected due to low plasma optical depth.
• Initial results demonstrate a strong correlation with other RE diagnostics at COMPASS.

Conclusions:

• The V-ECE system is a viable diagnostic tool for runaway electron research.
• The system can provide valuable insights into RE population dynamics and generation mechanisms.
• This diagnostic contributes to advancing the understanding of RE phenomena in tokamaks.