Optimization of machine operation, including plasma position control, density control and especially feedback control on multiple magnetohydrodynamic modes, has led RFX-mod to operate reliably at 1.5 MA, the highest current ever achieved on a reversed field pinch (RFP). At high current and low density the magnetic topology spontaneously self-organizes in an Ohmical helical symmetry, with the new magnetic axis helically twisting around the geometrical axis of the torus. The separatrix of the island disappears leaving a wide and symmetric thermal structure with large gradients in the electron temperature profile. The new topology still displays an intermittent nature but its overall presence has reached 85% of the current flat-top period. The large gradients in the electron temperature profile appear to be marginal for the destabilization of ion temperature gradient modes on the assumption that ions and electrons have the same gradients. There are indications that higher currents could provide the conditions under which to prove the existence of a true helical equilibrium as the standard RFP configuration. © 2008 IOP Publishing Ltd.

Valisa, M., Bolzonella, T., Buratti, P., Carraro, L., Cavazzana, R., Dal Bello, S., et al. (2008). High current regimes in RFX-mod. PLASMA PHYSICS AND CONTROLLED FUSION, 50(12) [10.1088/0741-3335/50/12/124031].

High current regimes in RFX-mod

Martines E;
2008

Abstract

Optimization of machine operation, including plasma position control, density control and especially feedback control on multiple magnetohydrodynamic modes, has led RFX-mod to operate reliably at 1.5 MA, the highest current ever achieved on a reversed field pinch (RFP). At high current and low density the magnetic topology spontaneously self-organizes in an Ohmical helical symmetry, with the new magnetic axis helically twisting around the geometrical axis of the torus. The separatrix of the island disappears leaving a wide and symmetric thermal structure with large gradients in the electron temperature profile. The new topology still displays an intermittent nature but its overall presence has reached 85% of the current flat-top period. The large gradients in the electron temperature profile appear to be marginal for the destabilization of ion temperature gradient modes on the assumption that ions and electrons have the same gradients. There are indications that higher currents could provide the conditions under which to prove the existence of a true helical equilibrium as the standard RFP configuration. © 2008 IOP Publishing Ltd.
Articolo in rivista - Articolo scientifico
reversed field pinch; RFP; RFX-mod; quasi-single helicity; QSH;
English
2008
50
12
124031
reserved
Valisa, M., Bolzonella, T., Buratti, P., Carraro, L., Cavazzana, R., Dal Bello, S., et al. (2008). High current regimes in RFX-mod. PLASMA PHYSICS AND CONTROLLED FUSION, 50(12) [10.1088/0741-3335/50/12/124031].
File in questo prodotto:
File Dimensione Formato  
088 - PPCF 08 high current.pdf

Solo gestori archivio

Dimensione 664.54 kB
Formato Adobe PDF
664.54 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/355911
Citazioni
  • Scopus 47
  • ???jsp.display-item.citation.isi??? 44
Social impact