Disruption Mitigation Research

Design against off-normal events is an essential part of fusion energy research. The rapid quench of the tokamak plasma (called a 'disruption') releases a burst of energy into the reactor vessel that must be controlled. Research involves designing systems and techniques to manage this energy release in a benign manner.

Tokamak plasmas can undergo an off-normal fast quench process called a ‘disruption’. This fast quench is poses a risk to the integrity of the plasma facing components and can also drive unwanted electromagnetic stresses in the reactor structure. Using a defense in depth model, the first layer of defense is accurate disruption prediction and avoidance techniques. Disruption mitigation systems can be thought of as the final layer of defense, where actuators (like those pictured above) are rapidly deployed to mitigate the impact of the disruption on the structure and plasma-facing components. The tokamak fusion research community is committed to developing robust disruption mitigation techniques, and this will be one of the first research tasks to be executed at the ITER fusion reactor, currently being built in France.

Disruption Mitigation Research

Columbia research in this area targets one particular effect of the disruption, which is the energization of relativistic particles which can reach mega-electron volt energies, comparable to that in a modestly sized particle accelerator. These particles must be controlled, and Columbia researchers are pioneering both the experimental techniques and foundational theoretical research needed to achieve a robust control.

One particular area of focus in experimental work is the use of intrinsic and purposefully applied magnetic fields to alter the trajectories of these particles, leading them to exit the plasma in a more benign way. Theoretical research is understanding how data collected at existing facilities maps to what might be observed in the ITER fusion reactor.

DIII-D Tokamak

Disruption mitigation research at Columbia is primarily carried out at the DIII-D Tokamak. This facility is equipped with a variety of disruption mitigation actuators and has many purpose-built measurement systems to understand the disruption process.

International Tokamaks

Work at international tokamak facilities aims to demonstrate that the control solutions pioneered at DIII-D can be replicated elsewhere and under different and more stringent plasma conditions.

Fusion Technology

Columbia researchers are investigating the technology of massive material injection into plasmas. This technology initiates the disruption process in a controlled way. Columbia researchers are using on-campus technology test-bed facilities to understand the processes of cryogenic material injection and ablation under bombardment from energetic particles found in plasmas.

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