Non-inductive plasma vertical position measurement for the 1056 s discharge on EAST

Area of Science:

• Nuclear Fusion Engineering
• Plasma Physics
• Tokamak Technology

Background:

• Vertical position stability is critical for safe, long-pulse plasma operation in fusion devices.
• Traditional inductive magnetic coils suffer from integration drift, limiting steady-state accuracy.
• A non-magnetic, non-inductive approach is needed for reliable long-pulse fusion reactor operation.

Purpose of the Study:

• To compare non-inductively determined vertical position with inductive flux loop measurements.
• To evaluate the performance of a non-magnetic measurement system for long-pulse discharges.
• To assess the feasibility of real-time vertical position control using non-inductive methods.

Main Methods:

• Utilized line-integrated interferometer and polarimeter measurements for non-inductive vertical position determination.
• Compared these measurements against inductive flux loop data during a 1056-second EAST tokamak discharge.
• Analyzed measurement robustness and drift effects over extended operational periods.

Main Results:

• Non-inductive measurements demonstrated superior robustness compared to flux loops after 300 seconds without integrator reset.
• The non-magnetic approach effectively mitigated integration drift issues inherent in inductive methods.
• Validated the potential for accurate vertical position sensing in long-duration fusion plasma scenarios.

Conclusions:

• Non-inductive vertical position measurement offers a robust, drift-free solution for long-pulse fusion devices.
• This method is essential for achieving steady-state plasma control in future fusion reactors.
• Real-time control using the non-inductive system is proposed for future EAST experiments.