Lower hybrid drift waves: space observations
Publication date: 03 Aug 2012
Authors: C. Norgren, et al.
Journal: Physical Review Letters
Copyright: American Physical SocietyLower hybrid drift waves (LHDW) are commonly observed at plasma boundaries in space and laboratory, often having the strongest measured electric fields within these regions. We use data from two of the Cluster satellites (C3 and C4) located in the Earth's magnetotail and separated by a distance of the order of the electron gyroscale. These conditions allow us, for the first time, to make cross-spacecraft correlations of the LHDW and to determine the phase velocity and wavelength of the LHDW. Our results are in good agreement with the theoretical prediction. We show that the electrostatic potential of LHDW is linearly related to fluctuations in the magnetic field magnitude, which allows us to determine the velocity vector through the relation: Integral_of delta_E dt v = phi_delta_B_par . The electrostatic potential fluctuations corresponds to ~10 per cent of the electron temperature, which suggests that the waves can strongly affect the electron dynamics. Published online on 31 July 2012.