Disruption halo current rotation scaling on Alcator C-Mod and HBT-EP
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22ja052_full.pdf
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Author(s)
Saperstein, Alex R.
Tinguely, R. Alex
Granetz, R.S.
Levesque, J.P.
Maue, M.E.
Navrati, G.A.
Date Issued
December 2022
Journal
Physics of Plasmas
Publisher
AIP
Abstract
Asymmetric halo currents (HCs) can exert large net forces on the vacuum vessel and other components during disruptions on tokamaks. The displacements caused by these forces can then be amplified if these asymmetric forces rotate at frequencies resonant with the vessel. This paper reports on the investigation of a recently proposed scaling law for the disruption HC rotation frequency that combines measurements on Alcator C-Mod with those on HBT-EP. We find that a new non-circular version of the scaling law ( *m/ \propto 1 B*T*(S/pi) ) takes into consideration the dependence of f_rot on the poloidal structure of the MHD instability (m) driving the asymmetry and describes the disruption-averaged rotation frequency on C-Mod. Disruption rotation is also found to be insensitive to the vertical position and impurity content of the plasma at the onset of the disruption.However, a stagnation in the time-evolution of f_rot is occasionally observed. Observations are consistent with the dominance of poloidal rotation during the disruption, which is motivated by the poloidal drift nature of the scaling law.
Description
Submitted for publication in Physics of Plasmas
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1063/5.0140867
