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Abstract

During geomagnetically active times near-Earth space outside the plasmapause is pervaded by a broad-spectrum of Alfvénic fluctuations. These fluctuations have scales extending into the kinetic range and appear in spacecraft measurements of magnetic and electric fields primarily at frequencies defined by advection in the fast-flowing plasmas in which they are imbedded. In this presentation it is shown how these fluctuations may be directly driven by the observed shears in these same flows. It is demonstrated how this generation mechanism combined with reflection from inhomogeneities in the plasma rapidly generates a broad-spectrum of fluctuations that replicate the spectral and morphological properties of those observed. It is shown how the characteristics of the turbulence generated via this process are particularly effective in scattering relativistic electrons. Transport coefficients are derived from numerical simulation that indicate that these fluctuations should be important in the modulation of the outer radiation belt during storm times, both by driving losses to the atmosphere and via rapid radial transport.