Lost alpha Faraday cup foil noise characterization during Joint European Torus plasma post-processing analysis

Area of Science:

• Plasma physics
• Fusion energy research
• Diagnostic techniques

Background:

• Capacitive plasma pickup is a significant challenge for plasma-facing edge diagnostics, complicating signal interpretation.
• Accurate measurement of fast ion losses is crucial for fusion reactor performance and safety.
• Traditional solutions involve hardware modifications, limiting adaptability and requiring new approaches.

Purpose of the Study:

• To develop and present post-processing techniques for characterizing capacitive plasma pickup noise.
• To improve the distinction between genuine fast ion signals and electromagnetic noise in diagnostic measurements.
• To evaluate these methods using data from the Joint European Torus (JET) tokamak.

Main Methods:

• Development of signal processing algorithms to identify and filter plasma pickup noise.
• Application of these techniques to Faraday cup fast ion loss detector data from JET.
• Analysis of spatial sensitivity of the detector array to understand signal origins.

Main Results:

• Successfully characterized plasma pickup noise in JET's tritium campaign discharge data.
• Demonstrated the effectiveness of post-processing techniques in separating noise from fast ion loss signals.
• Identified spatial sensitivities of the detector array, aiding physical interpretation.

Conclusions:

• Post-processing offers a versatile and robust alternative or complement to hardware modifications for managing capacitive plasma pickup.
• The developed methodology enhances the accuracy and reliability of fast ion loss measurements.
• Understanding detector spatial sensitivity improves the physical interpretation of plasma phenomena in fusion devices.