title: Reducing global turbulent resistivity by eliminating large eddies in a spherical liquid-sodium experiment.
abstract: Three-wave turbulent interactions and the role of eddy size on the turbulent electromotive force are studied in a spherical liquid-sodium dynamo experiment. A symmetric, equatorial baffle reduces the amplitude of the largest-scale turbulent eddies, which is inferred from the magnetic fluctuations spectrum (measured by a 2D array of surface probes). Differential rotation in the mean flow is >2 times more effective in generating mean toroidal magnetic fields from the applied poloidal field (via the Ω effect) when the largest-scale eddies are eliminated, thus demonstrating that the global turbulent resistivity (the β effect from the largest-scale eddies) is reduced by a similar amount.
authors.affiliation: Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706, USA.
authors.forename: E J
authors.initials: EJ
authors.lastname: Kaplan
authors.forename: M M
authors.initials: MM
authors.lastname: Clark
authors.forename: M D
authors.initials: MD
authors.lastname: Nornberg
authors.forename: K
authors.initials: K
authors.lastname: Rahbarnia
authors.forename: A M
authors.initials: AM
authors.lastname: Rasmus
authors.forename: N Z
authors.initials: NZ
authors.lastname: Taylor
authors.forename: C B
authors.initials: CB
authors.lastname: Forest
authors.forename: E J
authors.initials: EJ
authors.lastname: Spence