Control of magnetic islands by pellet injection in tokamaks

Journal Article · Mon Jan 01 04:00:00 EST 2007 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2743516· OSTI ID:1081816

Shaing, K. C. ^[1]; Rome, James A ^[2]; Peng, Yueng Kay Martin ^[2]

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1. University of Wisconsin
2. ORNL

The appearance of magnetic islands in tokamaks degrades plasma confinement. It is therefore important to control or eliminate the growth of the islands to improve the performance of a tokamak. A theory is developed to control magnetic islands using the localized pressure gradient driven bootstrap current by injecting pellets at the O-point of the island to create a peaked plasma pressure profile inside the island. This localized bootstrap current replenishes the missing equilibrium bootstrap current density that causes the island to grow in the first place. It is shown that the effect of the localized bootstrap current tends to reduce or eliminate the original drive for the growth of the island in the island evolution equation. The theory is also valid for the localized bootstrap current created by localized heating, but with much less effectiveness. A possibility of eliminating the island by controlling the equilibrium profiles is also discussed. (c) 2007 American Institute of Physics.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1081816
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 7 Vol. 14; ISSN 1070-664X
• Country of Publication: United States
• Language: English