Ionosphere-thermosphere momentum coupling at solar maximum and solar minimum from DE-2 and AE-C data

摘要: DE-2 and AE-C satellite measurements of plasma neutral densities have been used to derive time constants for momentum transfer the neutrals from ions in high-latitude thermosphere. The solar cycle maximum (DE-2) minimum (AE-C) averaged binned according geomagnetic latitude local provide a quantitative measure tightness ion-neutral coupling altitude range 250-350 km. During conditions, respond relatively rapidly forcing ions, with e-folding time-constants order 1-3 hours. For however, are typically about an magnitude larger, implying that insensitive ion-drag winds controlled principally by large-scale, day-to-night pressure gradient. compared model calculations using Chiu (1975) MSIS-83 semi-empirical models electron (ion) density composition, respectively. Since thermospheric general circulation (TGCMs) rely on these two their parameterizations ion drag source, comparisons enable important TGCM input be critically examined. agreement between derived corresponding values obtained is reasonable maximum. At minimum, significantly smaller than experimentally-derived values. discrepancy due overestimation polar ionospheric model. which use ionosphere based therefore exaggerate importance source at significant margin.