Tailoring tokamak error fields to control plasma instabilities and transport

Area of Science:

• Nuclear Fusion Engineering
• Plasma Physics
• Magnetic Confinement Fusion

Background:

• Tokamaks use magnetic fields for plasma confinement, aiming for clean energy.
• Construction errors create magnetic field asymmetries, known as error fields (EFs).
• EFs can trigger plasma disruptions, a major challenge in fusion energy research.

Purpose of the Study:

• To optimize error fields (EFs) for controlled edge 3D plasma response.
• To minimize core 3D response to prevent plasma disruptions and confinement degradation.
• To demonstrate a method for favorably controlling tokamak EFs for enhanced stability and confinement.

Main Methods:

• Designing tailored magnetic field configurations to create specific EFs.
• Utilizing the KSTAR facility's flexible 3D coil system for experimental validation.
• Optimizing the balance between edge and core 3D plasma responses.

Main Results:

• Successfully demonstrated an edge-localized 3D plasma response for ELM control.
• Minimized the core 3D response, reducing the risk of plasma disruptions.
• Showcased the potential of tailored EFs to improve tokamak performance.

Conclusions:

• Optimized error fields offer a promising approach for controlling plasma instabilities like ELMs.
• This method advances the design of intrinsically 3D tokamaks for future fusion reactors.
• Favorable EF control is key to enhancing stability and confinement in next-step fusion devices.