High current regimes in RFX-mod

Valisa, M.; Bolzonella, T.; Buratti, P.; Carraro, L.; Cavazzana, R.; Bello, S. Dal; Martin, P.; Pasqualotto, R.; Sarff, J. S.; Spolaore, M.; Zanca, P.; Zanotto, L.; Agostini, M.; Alfier, A.; Antoni, V.; Apolloni, L.; Auriemma, F.; Barana, O.; Baruzzo, M.; Bettini, Paolo; Bonfiglio, D.; Bonomo, F.; Brombin, M.; Buffa, A.; Canton, A.; Cappello, S.; Cavinato, M.; Chitarin, G.; Lorenzi, A. De; Masi, G.; Escande, Dominique; Fassina, A.; Franz, P.; Gaio, E.; Gazza, E.; Giudicotti, L.; Gnesotto, F.; Gobbin, M.; Grando, L.; Guazzotto, L.; Guo, S. C.; Igochine, V.; Innocente, P.; Lorenzini, R.; Luchetta, A.; Manduchi, G.; Marchiori, G.; Marcuzzi, D.; Marrelli, L.; Martini, S.; Martines, E.; McCollam, K. J.; Milani, F.; Moresco, M.; Novello, L.; Ortolani, S.; Paccagnella, R.; Peruzzo, S.; Piovan, R.; Piron, L.; Pizzimenti, A.; Piovesan, P.; Pomaro, N.; Predebon, I.; Puiatti, M. E.; Rostagni, G.; Sattin, F.; Scarin, P.; Serianni, G.; Sonato, P.; Spada, E.; Soppelsa, A.; Spagnolo, S.; Spizzo, G.; Taliercio, C.; Terranova, D.; Toigo, V.; Vianello, N.; Yadikin, D.; Zaccaria, P.; Zaniol, B.; Zilli, E.; Zuin, M.

doi:10.1088/0741-3335/50/12/124031

Cited by 46 publications

(48 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such transition (the two stages) finds a straight similarity with the dynamics described in 3D viscoresistive nonlinear MHD [11,12]. In SHAx states, the region inside the ITB [13] spans a significantly bigger volume than in DAx states, with similar maximum electron temperature gradients at the barrier. Plasma properties such as electron temperature, soft x rays emissivity, and electron density have been found to be constant on helical magnetic surfaces [14] reconstructed with independent measurements, indicating that SHAx states are described by a MHD equilibrium characterized by almost invariant magnetic surfaces, in contrast with the low current multiple helicity states.…”

supporting

confidence: 63%

Vanishing Magnetic Shear And Electron Transport Barriers In The RFX-Mod Reversed Field Pinch

et al. 2011

View full text Add to dashboard Cite

We define the safety factor q for the helical plasmas of the experiment RFX-mod by accounting for the actual three-dimensional nature of the magnetic flux surfaces. Such a profile is not monotonic but goes through a maximum located in the vicinity of the electron transport barriers measured by a high resolution Thomson scattering diagnostic. Helical states with a single axis obtained in viscoresistive magnetohydrodynamic numerical simulations exhibit similar nonmonotonic q profiles provided that the final states are preceded by a magnetic island phase, like in the experiment.

show abstract

supporting

confidence: 63%

Vanishing Magnetic Shear And Electron Transport Barriers In The RFX-Mod Reversed Field Pinch

et al. 2011

View full text Add to dashboard Cite

show abstract

“…The secondary mode amplitude, normalized to the total magnetic field, is also found to decrease with increasing plasma current, so that experimental QSH states are progressively approaching the ideal SH condition [9,21,22]. Plasma current increase is strongly correlated to an increase of electron temperature [23].…”

Section: Introductionmentioning

confidence: 83%

Equilibrium reconstruction for single helical axis reversed field pinch plasmas

Martines

Lorenzini

Momo

et al. 2011

Plasma Phys. Control. Fusion

Self Cite

View full text Add to dashboard Cite

Abstract. Single Helical Axis (SHAx) configurations are emerging as the natural state for high current reversed field pinch (RFP) plasmas. These states feature the presence of transport barriers in the core plasma. Here we present a method for computing the equilibrium magnetic surfaces for these states in the force-free approximation, which has been implemented in the SHEq code. The method is based on the superposition of a zeroth order axisymmetric equilibrium and of a first order helical perturbation computed according to Newcomb's equation supplemented with edge magnetic field measurements. The mapping of the measured electron temperature profiles, soft X-ray emission and interferometric density measurements on the computed magnetic surfaces demonstrates the quality of the equilibrium reconstruction. The procedure for computing flux surface averages is illustrated, and applied to the evaluation of the thermal conductivity profile. The consistency of the evaluated equilibria with Ohm's law is also discussed.

show abstract

“…In particular, interest in the RFP has been revamped by the discovery of the spontaneous transition at high plasma current to a new magnetic topology, dubbed Single Helical Axis (SHAx) state [13,14,10]. In this state, which is a special instance of the more general QSH condition, the separatrix of the dominant mode magnetic island is expelled, while its X-point collapses onto the main magnetic axis of the discharge.…”

Section: Introductionmentioning

confidence: 99%

The plasma boundary in single helical axis RFP plasmas

et al. 2010

View full text Add to dashboard Cite

Single Helical Axis (SHAx) states obtained in high current reversed field pinch (RFP) plasmas display, aside from a dominant mode in the m=1 spectrum, also a dominant m=0 mode, with the same toroidal mode number as the m=1 one. The two modes have a fixed phase relationship. The island chain created by the m=0 mode across the reversal surface gives rise, at shallow reversal of the toroidal field, to an X-point structure which separates the last closed flux surface from the first wall, creating a divertor-like configuration. The plasma-wall interaction is found to be related to the connection length of the field lines intercepting the wall, which displays a pattern modulated by the dominant mode toroidal periodicity. This configuration, which occurs only for shallow toroidal field reversal, could be exploited to realize an island divertor in analogy to stellarators.PACS numbers: 52.55. Rk, 52.55.Hc, 52.25.Xz

show abstract

High current regimes in RFX-mod

Cited by 46 publications

References 28 publications

Vanishing Magnetic Shear And Electron Transport Barriers In The RFX-Mod Reversed Field Pinch

Vanishing Magnetic Shear And Electron Transport Barriers In The RFX-Mod Reversed Field Pinch

Equilibrium reconstruction for single helical axis reversed field pinch plasmas

The plasma boundary in single helical axis RFP plasmas

Contact Info

Product

Resources

About