Installation of spectrally selective imaging system in RF negative ion source

Area of Science:

• Plasma Physics
• Fusion Energy Research
• Optical Diagnostics

Background:

• The International Thermonuclear Experimental Reactor (ITER) requires efficient negative ion beams for plasma heating.
• Understanding the hydrogen negative ion production mechanism is crucial for optimizing beam performance.
• Diagnostic tools are needed to probe the plasma close to the ion source surface.

Purpose of the Study:

• To investigate the spatial distribution of hydrogen Balmer-α (Hα) emission near the negative ion production surface.
• To validate the performance of a newly installed spectrally selective imaging system.
• To compare Hα emission data with optical emission spectroscopy measurements.

Main Methods:

• Installation of a spectrally selective imaging system using a GigE vision camera and an optical band-path filter.
• Remote control of the camera system via a high-speed network connection.
• Measurement of Hα emission close to the bias plate in the ELISE negative ion beam test facility.

Main Results:

• Clear observation of the Hα emission distribution near the bias plate.
• Confirmation of a consistent time trend between Hα intensities measured by the imaging diagnostic and optical emission spectroscopy.
• Successful remote operation and data acquisition from the imaging system.

Conclusions:

• The developed imaging system effectively visualizes Hα emission in the negative ion source.
• The results provide valuable insights into the hydrogen negative ion production process.
• The imaging diagnostic complements existing methods for plasma characterization in fusion devices.