title: Dynamic modeling of stepwise internal transport barrier formation in DIII-D negative-central-shear discharges.
abstract: The GLF23 transport model is used to dynamically follow bifurcations in the energy and toroidal momentum confinement in DIII-D discharges with an internal transport barrier. The temperatures and toroidal velocity profiles are evolved while self-consistently computing the effects of E x B shear stabilization during the formation and expansion of internal transport barriers. The barrier is predicted to form in a stepwise fashion through a series of sudden jumps in the core-electron and ion temperatures and toroidal rotation velocity. These results are consistent with experimental observations. In the simulations, the step transitions are a direct result of local E x B driven transport bifurcations.
authors.affiliation: Lehigh University, Bethlehem, Pennsylvania 18015, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Kinsey
authors.forename: G M
authors.initials: GM
authors.lastname: Staebler
authors.forename: K H
authors.initials: KH
authors.lastname: Burrell
authors.forename: M E
authors.initials: ME
authors.lastname: Austin
authors.forename: R E
authors.initials: RE
authors.lastname: Waltz