Feedback stabilization of resistive wall modes in a reversed-field pinch
2005 (English)In: Physics of Plasmas, ISSN 1070-664X, Vol. 12, no 9, 092508- p.Article in journal (Refereed) Published
An array of saddle coils having Nc =16 equally spaced positions along the toroidal direction has been installed for feedback control of resistive wall modes (RWMs) on the EXTRAP T2R reversed-field pinch [P. R. Brunsell, H. Bergsaker, M. Cecconello, Plasma Phys. Controlled Fusion 43, 1457 (2001)]. Using feedback, multiple nonresonant RWMs are simultaneously suppressed for three to four wall times. Feedback stabilization of RWMs results in a significant prolongation of the discharge duration. This is linked to a better sustainment of the plasma and tearing mode toroidal rotation with feedback. Due to the limited number of coils in the toroidal direction, pairs of modes with toroidal mode numbers n, n′ that fulfill the condition ∫n- n′ ∫ = Nc are coupled by the feedback action from the discrete coil array. With only one unstable mode in a pair of coupled modes, the suppression of the unstable mode is successful. If two modes are unstable in a coupled pair, two possibilities exist: partial suppression of both modes or, alternatively, complete stabilization of one target mode while the other is left unstable.
Place, publisher, year, edition, pages
2005. Vol. 12, no 9, 092508- p.
Feedback, Feedback control, Plasmas, Resonance, Stability
Other Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-5427DOI: 10.1063/1.2048168ISI: 000232109000038ScopusID: 2-s2.0-27444433256OAI: oai:DiVA.org:kth-5427DiVA: diva2:9789
QC 201009152006-03-082006-03-082012-03-22Bibliographically approved