Multiband reflectometry system for density profile measurement with high temporal resolution on JET tokamak

Area of Science:

• Plasma physics
• Fusion energy research
• Diagnostic techniques

Background:

• Understanding plasma behavior in tokamaks is critical for achieving controlled nuclear fusion.
• Accurate measurement of plasma density profiles is essential for controlling and optimizing fusion reactions.
• Existing diagnostic methods may have limitations in speed or spatial coverage.

Purpose of the Study:

• To introduce and characterize a new fast-sweeping reflectometer system for the JET tokamak.
• To enable high-repetition-rate measurements of plasma density from the edge to the core.
• To enhance the capabilities for real-time plasma monitoring and control.

Main Methods:

• Installation of six independent fast-sweeping reflectometers operating in four frequency bands (44-150 GHz).
• Utilizing orthogonal polarizations and oversized corrugated waveguides for microwave propagation.
• Achieving a maximum repetition rate of one density profile every 15 microseconds.

Main Results:

• The system routinely produces plasma density profiles covering the entire radial extent.
• Demonstrated high-speed measurement capability with up to 100,000 profiles per pulse.
• Successful operation of the reflectometer system in the JET tokamak environment.

Conclusions:

• The new reflectometer system significantly advances the diagnostic capabilities of the JET tokamak.
• High-repetition-rate density profile measurements are now feasible, supporting advanced plasma control.
• This technology is vital for future fusion energy development and reactor operation.