Quasi-single-helicity reversed-field-pinch plasmas
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.
Escande
DF
Consorzio RFX-Corso Stati Uniti, 4, 35127 Padova, Italy and CNRS-Universite de Provence, Marseille, France.
Martin
P
Ortolani
S
Buffa
A
Franz
P
Marrelli
L
Martines
E
Spizzo
G
Cappello
S
Murari
A
Pasqualotto
R
Zanca
P