title: Efficient generation of closed magnetic flux surfaces in a large spherical tokamak using coaxial helicity injection.
abstract: A method of coaxial helicity injection has successfully produced a closed flux current without the use of the central solenoid in the NSTX device, on a size scale closer to a spherical torus reactor, for a proof-of-principle demonstration of this concept. For the first time, a remarkable 60 times current multiplication factor was achieved. Grad-Shafranov plasma equilibrium reconstructions are used to verify the existence of closed flux current. In some discharges the generated current persists for a surprisingly long time approximately 400 ms.
authors.affiliation: University of Washington, Seattle, Washington, USA.
authors.forename: R
authors.initials: R
authors.lastname: Raman
authors.forename: B A
authors.initials: BA
authors.lastname: Nelson
authors.forename: M G
authors.initials: MG
authors.lastname: Bell
authors.forename: T R
authors.initials: TR
authors.lastname: Jarboe
authors.forename: D
authors.initials: D
authors.lastname: Mueller
authors.forename: T
authors.initials: T
authors.lastname: Bigelow
authors.forename: B
authors.initials: B
authors.lastname: Leblanc
authors.forename: R
authors.initials: R
authors.lastname: Maqueda
authors.forename: J
authors.initials: J
authors.lastname: Menard
authors.forename: M
authors.initials: M
authors.lastname: Ono
authors.forename: R
authors.initials: R
authors.lastname: Wilson