Effects of imposed electric fields on turbulence-induced fluxes associated with strong interchange instabilities

The Texas Helimak, an experimental approximation of the infinite cylindrical slab with dimensionless parameters similar to those of a tokamak scrape-off layer [Gentle and Huang, Plasma Sci. Technol. 10, 284, (2008)], is dominated by strong interchange turbulence. Magnetically-insulated baffled-probe compact-cluster enables real-time measurement of the fields, flows, and fluctuations associated with equilibrium discharges in the Helimak [Rev. Sci. Instrum., in prep.] and the relative phases between the oscillations. Measurement confirms that thermal and particle transport rates are reduced when external bias is applied to introduce a radially varying radial electric field and, thus, enhance plasma poloidal flow. We present results from recent experiments that were designed to compare transport-related measurements from the probes within the compact-cluster as the cluster is radially translated from the low-field-side of the plasma density peak to the high-field-side.