title: High-beta equilibria of drift-optimized compact stellarators.
abstract: Compact stellarator configurations have been obtained with good neoclassical confinement that are stable to both pressure- and current-driven modes for high values of beta. These configurations are drift-optimized tokamak-stellarator hybrids with a high-shear tokamak-like rotational transform profile and /B/ that is approximately poloidally symmetric. The bootstrap current is consistent with the required equilibrium current and, while larger than that in existing stellarators, is typically only a small fraction (1/3-1/5) of that in an equivalent tokamak. These configurations have strong magnetic wells and consequently high interchange stability beta limits up to beta=23%. Because of the reduced bootstrap current, these configurations are stable to low-n ideal MHD kink modes with no wall stabilization for values of beta ( approximately 7%-11%) significantly larger than in an equivalent advanced tokamak.
authors.affiliation: University of Montana-Missoula, Missoula, Montana 59812, USA.
authors.forename: A S
authors.initials: AS
authors.lastname: Ware
authors.forename: S P
authors.initials: SP
authors.lastname: Hirshman
authors.forename: D A
authors.initials: DA
authors.lastname: Spong
authors.forename: L A
authors.initials: LA
authors.lastname: Berry
authors.forename: A J
authors.initials: AJ
authors.lastname: Deisher
authors.forename: G Y
authors.initials: GY
authors.lastname: Fu
authors.forename: J F
authors.initials: JF
authors.lastname: Lyon
authors.forename: R
authors.initials: R
authors.lastname: Sanchez