Scintillator-based fast ion loss measurements in the EAST

Area of Science:

• Fusion energy research
• Plasma physics
• Diagnostic instrumentation

Background:

• Understanding fast ion behavior is crucial for achieving stable, high-performance plasmas in fusion devices.
• Experimental Advanced Superconducting Tokamak (EAST) requires advanced diagnostics to study energetic particle dynamics.
• Neutral Beam Injection (NBI) and Ion Cyclotron Resonance Heating (ICRH) are key heating methods that generate fast ions.

Purpose of the Study:

• To introduce and detail the newly installed scintillator-based Fast Ion Loss Detector (FILD) on the EAST tokamak.
• To investigate the behavior and loss pathways of fast ions generated by NBI and ICRH in high-performance EAST plasmas.
• To establish a new diagnostic capability for measuring fast ion pitch angle and gyroradius distributions.

Main Methods:

• Installation of a 2D scintillator plate (40 mm × 40 mm, ZnS:Ag coated stainless steel) at the detector's front.
• Imaging of photons emitted from the scintillator using a Phantom V2010 CCD camera.
• Measurement of lost fast ions within a pitch angle range of 60°–120° and gyroradius range of 10–180 mm.

Main Results:

• Successful deployment and initial characterization of the FILD diagnostic on EAST.
• Preliminary data acquisition demonstrating the capability to detect and analyze fast ion losses.
• Observation of fast ion loss patterns correlated with NBI and ICRH operational phases (details to be presented).

Conclusions:

• The FILD diagnostic is a valuable new tool for studying fast ion physics on EAST.
• The detector provides essential measurements for understanding fast ion confinement and loss mechanisms.
• Future work will focus on detailed analysis of fast ion loss during various plasma scenarios.