Halo current rotation scaling in post-disruption plasmas

Halo current (HC) rotation during disruptions can be potentially dangerous if resonant with the structures surrounding a tokamak plasma. We propose a drift-frequency-based scaling law for the rotation frequency of the asymmetric component of the HC as a function of toroidal field strength and plasma minor radius (f (rot) proportional to 1/B (T) a (2)). This scaling law is consistent with results reported for many tokamaks and is motivated by the faster HC rotation observed in the HBT-EP tokamak. Projection of the rotation frequency to ITER and SPARC parameters suggest the asymmetric HC rotation will be on the order of 10 Hz and 60 Hz, respectively.

Automated summary

Halo current (HC) rotation during disruptions can be potentially dangerous if resonant with surrounding structures. A scaling law based on drift frequency is proposed to describe the rotation frequency of the asymmetric component of HC. This scaling law is consistent with results from many tokamaks and is motivated by observations in the HBT-EP tokamak. The projected rotation frequency in ITER and SPARC parameters is estimated to be around 10 Hz and 60 Hz, respectively.