Suppression of $n=1$ Tilt Instability by Magnetic Shaping Coils in Rotamak Plasmas

Suppression of $n = 1$ Tilt Instability by Magnetic Shaping Coils in Rotamak Plasmas

X. Yang, Y. Petrov, and T. S. Huang

Phys. Rev. Lett. 102, 255004 – Published 25 June 2009

Abstract

Measurements from the array of Mirnov magnetic coils provide the first evidence for $n = 1$ tilt and radial shift instabilities in a 40 ms field-reversed configuration (FRC) driven by rotating magnetic field. External plasma-shaping magnetic coils are utilized to suppress the $n = 1$ instability modes. It is demonstrated that by energizing the middle shaping coil with 250–500 A current, the tilt mode is completely suppressed when a doublet FRC with an internal figure-of-eight separatrix is formed.