A combined millimeter wave and CO₂ interferometer on the C-2W Jet plasma

Area of Science:

• Plasma Physics
• Fusion Energy
• Interferometry

Background:

• The C-2W experiment at TAE Technologies aims to study translating field-reversed configuration (FRC) plasma.
• Accurate plasma density measurements are crucial for understanding and controlling FRC behavior.
• Existing diagnostic methods may have limitations in dynamic range or coverage.

Purpose of the Study:

• To develop and implement a novel two-wavelength interferometer for the C-2W experiment.
• To achieve full plasma coverage using both millimeter wave and CO2 laser interferometry.
• To measure line-integrated densities with a combined dynamic range exceeding 1000.

Main Methods:

• Construction of a two-wavelength, tangentially viewing multi-chord interferometer.
• Simultaneous operation of a 1 mm wavelength interferometer with a CO2 laser interferometer.
• Placement of the interferometer at the axial location of the C-2W mirror field.

Main Results:

• A novel 1 mm wavelength interferometer has been developed and is operational.
• The system is designed to provide full coverage of the Jet and FRC plasma.
• The combined system aims for a dynamic range of over 1000, though the CO2 subsystem is pending.

Conclusions:

• The developed interferometer is a key diagnostic for assessing FRC plasma before merging.
• It will play a pivotal role in evaluating divertor operation and particle outflow.
• The millimeter wave interferometer's performance and recent measurements are discussed, highlighting its contribution to fusion research.