Measurement of the Taylor scale in a magnetized turbulent laboratory plasma wind-tunnel

Abstract

The fluid Taylor scale is measured in the Bryn Mawr Experiment (BMX) of the Bryn Mawr Plasma Laboratory and examined as a potential dissipation scale of magnetic turbulence within the plasma. We present the first laboratory measurements of the Taylor scale of a turbulent magnetized plasma through multi-point correlations of broadband magnetic fluctuations. From spatial and temporal correlations, respectively, the measured Taylor scales are 2±1 and 3±1 cm. These measurements are on the same order of magnitude as estimated ion dissipation scales within the BMX plasma with ion inertial scales between 1 and 10 cm and ion gyroscales between 0.1 and 1.0 cm. From these measurements, a magnetic Reynolds number can be computed. Since Taylor scale values are determined using multi-point correlations and a Richardson extrapolation technique, an estimate of the magnetic Reynolds number can be found without the added complication of specifying a model of microscopic diffusivity, a parameter often difficult to obtain experimentally.