Magnetic perturbations in the events of broadband ELF turbulence observed by FAST

Abstract

Magnetic perturbations in the topside auroral ionosphere observed by the FAST satellite in the events of broadband extra low frequency (BB ELF) turbulence are investigated at frequencies 0.5-8 Hz (scales from 14 km down to 0.9 km). The power-law scaling and peculiar polarization patterns of the perturbations are highlighted. By comparing with the magnetic fields simulated according to the Chang et al. (2004) scenario of coarse-graining process development, we demonstrate that the magnetic perturbations observed in the events of the BB ELF turbulence can be reasonably understood in terms of non-linearly interacting multiscale field-aligned currents traversed by the spacecraft. Copyright 2011 by the American Geophysical Union.