title: Quasi-single-helicity reversed-field-pinch plasmas
abstract: The reversed field pinch (RFP) is a configuration for plasma magnetic confinement. It has been traditionally viewed as dominated by a bath of MHD instabilities producing magnetic chaos and high energy transport. We report experimental results which go beyond this view. They show a decrease of magnetic chaos and the formation of a coherent helical structure in the plasma, whose imaging and temperature profile are provided for the first time. These quasi-single-helicity states are observed both transiently and in stationary conditions. The last case is consistent with a theoretically predicted bifurcation. Our results set a new frame for improving confinement in high current nonchaotic RFP's.
authors.affiliation: Consorzio RFX-Corso Stati Uniti, 4, 35127 Padova, Italy and CNRS-Universite de Provence, Marseille, France.
authors.initials: DF
authors.lastname: Escande
authors.initials: P
authors.lastname: Martin
authors.initials: S
authors.lastname: Ortolani
authors.initials: A
authors.lastname: Buffa
authors.initials: P
authors.lastname: Franz
authors.initials: L
authors.lastname: Marrelli
authors.initials: E
authors.lastname: Martines
authors.initials: G
authors.lastname: Spizzo
authors.initials: S
authors.lastname: Cappello
authors.initials: A
authors.lastname: Murari
authors.initials: R
authors.lastname: Pasqualotto
authors.initials: P
authors.lastname: Zanca