DocumentCode :
227373
Title :
Active feedback stabilization of flute instability in a mirror trap
Author :
Be´ery, Ilan ; Seemann, Omri ; Fisher, Amnon
Author_Institution :
Phys. Dept., Technion - Israel Inst. of Technol., Haifa, Israel
fYear :
2014
fDate :
25-29 May 2014
Firstpage :
1
Lastpage :
1
Abstract :
Summary form only given. 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 loss due to the violent flute instability. We demonstrates for the first time the stabilization of fast growing, slowly rotating flute instability by multi-input, multi-output active feedback system.The feedback system consists of six optical probes, digital signal processor, and six needle electrodes. Step response and MHD spectroscopy indicates a non-linear response of the plasma to the electrodes due to the sheath-limited electrodes´ current. This makes the feedback unstable at short time scales, but stable on longer times. Using local feedback algorithm, we demonstrates a large suppression of m=1 mode and significant simultaneous suppression of m=1,2 modes. Higher spatial and temporal components of the flute instability are slightly enhanced by the feedback, but are passively stable due to finite Larmor radius effect.
Keywords :
feedback; flute instability; magnetic traps; plasma diagnostics; plasma magnetohydrodynamics; plasma nonlinear processes; plasma sheaths; spatiotemporal phenomena; MHD spectroscopy; axisymmetric mirror machines; digital signal processor; finite Larmor radius effect; fusion machines; ions separation; local feedback algorithm; magnetic confinement devices; mirror trap; multiinput active feedback system; multioutput active feedback system; needle electrodes; optical probes; particle loss; plasma nonlinear response; sheath-limited electrode current; slowly rotating flute instability; spatial components; temporal components; Electrodes; Ions; Magnetic confinement; Mirrors; Optical losses; Particle beam optics; Physics;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Plasma Sciences (ICOPS) held with 2014 IEEE International Conference on High-Power Particle Beams (BEAMS), 2014 IEEE 41st International Conference on
Conference_Location :
Washington, DC
Print_ISBN :
978-1-4799-2711-1
Type :
conf
DOI :
10.1109/PLASMA.2014.7012332
Filename :
7012332
Link To Document :
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