title: Observation of a free-Shercliff-layer instability in cylindrical geometry.
abstract: We report on observations of a free-Shercliff-layer instability in a Taylor-Couette experiment using a liquid metal over a wide range of Reynolds numbers, Re∼10(3)-10(6). The free Shercliff layer is formed by imposing a sufficiently strong axial magnetic field across a pair of differentially rotating axial end cap rings. This layer is destabilized by a hydrodynamic Kelvin-Helmholtz-type instability, characterized by velocity fluctuations in the r-θ plane. The instability appears with an Elsasser number above unity, and saturates with an azimuthal mode number m which increases with the Elsasser number. Measurements of the structure agree well with 2D global linear mode analyses and 3D global nonlinear simulations. These observations have implications for a range of rotating MHD systems in which similar shear layers may be produced.
authors.affiliation: Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas and Princeton Plasma Physics Laboratory, P.O. Box 451 Princeton, New Jersey 08543, USA. aroach@pppl.gov
authors.forename: Austin H
authors.initials: AH
authors.lastname: Roach
authors.forename: Erik J
authors.initials: EJ
authors.lastname: Spence
authors.forename: Christophe
authors.initials: C
authors.lastname: Gissinger
authors.forename: Eric M
authors.initials: EM
authors.lastname: Edlund
authors.forename: Peter
authors.initials: P
authors.lastname: Sloboda
authors.forename: Jeremy
authors.initials: J
authors.lastname: Goodman
authors.forename: Hantao
authors.initials: H
authors.lastname: Ji