title: Observation of weak impact of a stochastic magnetic field on fast-ion confinement.
abstract: Fast ions are observed to be very well confined in the Madison Symmetric Torus reversed field pinch despite the presence of stochastic magnetic field. The fast-ion energy loss is consistent with the classical slowing down rate, and their confinement time is longer than expected by stochastic estimates. Fast-ion confinement is measured from the decay of d-d neutrons following a short pulse of a 20 keV atomic deuterium beam. Ion confinement agrees with computation of particle trajectories in the stochastic magnetic field, and is understood through consideration of ion guiding center islands.
authors.affiliation: Department of Physics, University of Wisconsin--Madison and Center for Magnetic Self Organization in Laboratory and Astrophysical Plasmas, Madison, Wisconsin 53706, USA.
authors.forename: G
authors.initials: G
authors.lastname: Fiksel
authors.forename: B
authors.initials: B
authors.lastname: Hudson
authors.forename: D J
authors.initials: DJ
authors.lastname: Den Hartog
authors.forename: R M
authors.initials: RM
authors.lastname: Magee
authors.forename: R
authors.initials: R
authors.lastname: O'Connell
authors.forename: S C
authors.initials: SC
authors.lastname: Prager
authors.forename: A D
authors.initials: AD
authors.lastname: Beklemishev
authors.forename: V I
authors.initials: VI
authors.lastname: Davydenko
authors.forename: A A
authors.initials: AA
authors.lastname: Ivanov
authors.forename: Yu A
authors.initials: YA
authors.lastname: Tsidulko