Radiation diagnostics for plasma current ramp-up and ramp-down research

Area of Science:

• Nuclear Fusion Engineering
• Plasma Physics
• Diagnostic Instrumentation

Background:

• Tokamak operation relies on controlled plasma current ramp-up and ramp-down.
• Understanding these processes is crucial for efficient tokamak performance.
• The Sino-UNIted Spherical Tokamak (SUNIST) requires advanced diagnostics for research.

Purpose of the Study:

• To develop and implement novel diagnostic systems for SUNIST.
• To investigate plasma radiation across a wide spectrum (X-ray to visible light).
• To analyze plasma behavior, energy loss, and MHD activities during current transitions.

Main Methods:

• Utilized CdZnTe and silicon drift detectors for hard and soft X-ray spectroscopy.
• Employed a pinhole camera with UV photodiodes for high-resolution imaging of radiation power loss and MHD activity.
• Implemented CCD cameras and photomultiplier tubes for vacuum ultraviolet spectroscopy.
• Applied filter scopes for rapid visible light spectrum acquisition (3 ms) and specific line intensity measurements (Hα, Hγ).
• Developed a Doppler broadening system to measure edge plasma ion temperature.

Main Results:

• Successfully deployed multiple diagnostic systems on SUNIST.
• Enabled measurement of hard X-ray and soft X-ray energy spectra.
• Provided high temporal and spatial resolution data on radiation power loss and MHD activities.
• Acquired detailed spectral information in UV and visible ranges, including specific Balmer lines.
• Established capability for in-situ edge plasma ion temperature measurement.

Conclusions:

• The developed diagnostic suite provides comprehensive monitoring of plasma radiation during current ramp-up/down on SUNIST.
• These diagnostics are essential for understanding fundamental tokamak processes and optimizing operational scenarios.
• The systems offer high performance in terms of spectral range, temporal resolution, and spatial imaging.