ACTIVE FEEDBACK STABILIZATION OF FLUTE INSTABILITY IN A MIRROR TRAP

TYPEPlasma Physics
Speaker:Ilan Be'ery
Affiliation:Physics Department, Technion
Date:18.03.2014
Time:11:30
Location:Lidow Asher Peres (502)
Remark:Ph.D. seminar
Abstract:ACTIVE FEEDBACK STABILIZATION OF FLUTE INSTABILITY IN A MIRROR TRAP
Ilan Be’ery
Under the supervision of Prof. Amiram Ron, Prof. Amnon Fruchtman and Prof. Amnon Fisher

Axi-symmetric mirror machines are the simplest magnetic confinement devices, and as such could be attractive for fusion machines, ions separation, and more. However, mirror machines suffer from particle and energy loss due to the violent flute instability. I will demonstrate for the first time the stabilization of fast growing, slowly rotating flute instability by multi-input, multi-output active feedback system. Step response and MHD spectroscopy indicates a non-linear response of the plasma to the electrodes due to sheath-limited current. This makes the feedback unstable at short time scales, but stable on longer times. Using local feedback algorithm, I will show the suppression of m=1 mode and significant simultaneous suppression of m=1,2 modes. I will show that these results are scalable to fusion-scale plasma traps and discuss the implications in terms of the required feedback power, temporal response and number of sensing elements.