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Avoiding Tokamak Disruptions by Applying Static Magnetic Fields That Align Locked Modes with Stabilizing Wave-Driven
F A Volpe1, A Hyatt2, R J La Haye2
1Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA.
Physical Review Letters
|November 10, 2015
Summary
Locked magnetic islands causing tokamak plasma disruptions were suppressed for the first time using 3D magnetic fields and millimeter waves. This breakthrough prevents disruptions, restoring high plasma confinement and pressure.
Area of Science:
- Plasma physics
- Fusion energy research
- Tokamak confinement
Background:
- Nonrotating (locked) magnetic islands are a primary cause of major disruptions in tokamak plasmas.
- These disruptions lead to a complete loss of plasma confinement, hindering fusion energy development.
- Effective methods for suppressing locked islands are crucial for stable tokamak operation.
Purpose of the Study:
- To investigate the first-time suppression of locked magnetic islands in tokamak plasmas.
- To demonstrate the efficacy of combining applied three-dimensional magnetic fields and millimeter waves for disruption avoidance.
- To analyze the impact of this method on plasma confinement and pressure recovery.
Main Methods:
- Applied three-dimensional magnetic fields to control the phase of magnetic island locking.
- Injected millimeter waves to generate noninductive currents in a specific region.
- Aligned the magnetic island O point with the millimeter-wave-driven current region for stabilization.
Main Results:
- Successfully suppressed locked magnetic islands, preventing major disruptions.
- Achieved stabilization of the locked island through precise phase control and current alignment.
- Observed recovery of high plasma confinement and high pressure, consistent with theoretical predictions.
Conclusions:
- The combination of 3D magnetic fields and millimeter waves is a viable method for suppressing locked islands.
- This technique offers a promising pathway for disruption avoidance in tokamak reactors.
- Further research can optimize wave power and phase control for enhanced performance.
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