title: Experimental study of the ion critical-gradient length and stiffness level and the impact of rotation in the JET tokamak.
abstract: Experiments were carried out in the JET tokamak to determine the critical ion temperature inverse gradient length (R/LTi=R|nablaTi|/Ti) for the onset of ion temperature gradient modes and the stiffness of Ti profiles with respect to deviations from the critical value. Threshold and stiffness have been compared with linear and nonlinear predictions of the gyrokinetic code GS2. Plasmas with higher values of toroidal rotation show a significant increase in R/LTi, which is found to be mainly due to a decrease of the stiffness level. This finding has implications on the extrapolation to future machines of present day results on the role of rotation on confinement.
authors.affiliation: Istituto di Fisica del Plasma P. Caldirola, Associazione Euratom-ENEA-CNR, Milano, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Mantica
authors.forename: D
authors.initials: D
authors.lastname: Strintzi
authors.forename: T
authors.initials: T
authors.lastname: Tala
authors.forename: C
authors.initials: C
authors.lastname: Giroud
authors.forename: T
authors.initials: T
authors.lastname: Johnson
authors.forename: H
authors.initials: H
authors.lastname: Leggate
authors.forename: E
authors.initials: E
authors.lastname: Lerche
authors.forename: T
authors.initials: T
authors.lastname: Loarer
authors.forename: A G
authors.initials: AG
authors.lastname: Peeters
authors.forename: A
authors.initials: A
authors.lastname: Salmi
authors.forename: S
authors.initials: S
authors.lastname: Sharapov
authors.forename: D
authors.initials: D
authors.lastname: Van Eester
authors.forename: P C
authors.initials: PC
authors.lastname: de Vries
authors.forename: L
authors.initials: L
authors.lastname: Zabeo
authors.forename: K-D
authors.initials: KD
authors.lastname: Zastrow