Speaker
Mr
Matthew Reinke
(USA)
Description
In the Alcator C-Mod tokamak, strong, steady-state variations of molybdenum density within a flux surface are routinely observed in plasmas using hydrogen minority ion cyclotron resonant heating. In/out asymmetries, up to a factor of 2, occur with either inboard or outboard accumulation depending on the major radius of the minority resonance layer. Quantitative comparisons between existing parallel high-Z impurity transport theories and experimental results show good agreement when the resonance layer is on the high-field side (HFS) of the tokamak but disagree substantially for low-field side (LFS) heating. Impurity accumulation on the LFS of a flux surface can be explained by the centrifugal force, and is the first observation of intrinsic rotation generating an in/out asymmetries. The accumulation of impurity density on the HFS of a flux surface is shown to be driven by a poloidal potential variation sustained by magnetically trapped non-thermal, cyclotron heated minority ions. Parallel impurity transport theory is extended to account for these fast-ion effects and shown to agree with experimentally measured impurity density asymmetries.
Country or International Organization of Primary Author
USA
Primary author
Mr
Matthew Reinke
(USA)
Co-authors
Dr
Aaron Bader
(MIT-PSFC (now at Univ. Wisconsin))
Dr
Amanda Hubbard
(MIT-PSFC)
Prof.
Ian Hutchinson
(MIT-PSFC)
Dr
Jerry Hughes
(MIT-PSFC)
Dr
John Rice
(MIT PSFC)
Mr
Nathan Howard
(MIT-PSFC)
Dr
Pace David
(MIT-PSFC (now General Atomics))
Dr
Steve Wukitch
(MIT-PSFC)
Dr
Yijun Lin
(MIT Plasma Science and Fusion Center)
Mr
Yuri Podpaly
(MIT-PSFC)
