HAO PROFILES IN SCIENCE: Dr. Astrid Maute
Dr. Astrid Maute has research interests in the modeling of the ionospheric electrodynamics, ionospheric current systems and their associated magnetic perturbations. She studies the upper atmosphere response due to metrological and geospace forcing, and is interested in the high-latitude magnetosphere-ionosphere energgy transfer.
Figure: Average upward ExB drift [m/s] between +/- 30 deg magnetic latitude due to neutral wind for 5-6 LT (blue/ long dashed), 13-14 LT (brown/dotted), 18-19 LT (red/dasheddotted), and 23-24 LT (green/solid) with migrating and nonmigrating tidal components (thick lines) and with migrating components (thin lines).
(1)Sources of low-latitude ionospheric ExB drifts and their variability
Maute, A., A. D. Richmond, and R. G. Roble (2012), Sources of low-latitude ionospheric E×B drifts and their variability, J. Geophys. Res., 117, A06312, doi:10.1029/2011JA017502.
Abstract: The complete mechanism of how upward propagating tropospheric tides connect to the upper atmosphere is not yet fully understood. One proposed mechanism is via ionospheric wind dynamo. However, other sources can potentially alter the vertical ExB drift: gravity and plasma pressure gradient driven current, the geomagnetic main field, and longitudinal variation in the conductivities. In this study we examine the contribution to the vertical drift from these sources, and compare them. We use March equinox results from the Thermosphere Ionosphere Mesosphere Electrody namics General Circulation Model. We found that the gravity and plasma pressure gradient driven current and the longitudinal variation of the conductivities excluding the variation due to the geomagnetic main field do not change the longitudinal variation of the vertical drift significantly. Modifying the geomagnetic main field will change the vertical drift at 5-6 LT, 18-19 LT and 23-24 LT at almost all longitudes. In general the influence of the geomagnetic main field on the vertical drift is larger, with respect to the maximum difference, at 18-19 LT and 23-24 LT, equal at 5-6 LT, and smaller at 14-15 LT than the influence due to nonmigrating tidal components in the neutral winds. Examination of the contribution from E- and F-region neutral winds to the vertical drift shows that their importance depends on the local time and the solar activity. This implies that the vertical drift has to be analyzed at specific local times to examine the relation between the wavenumber in the vertical drift and in the neutral winds.