We present new results using data collected by the Poker Flat Incoherent Scatter Radar (PFISR) of energy transfer rates which include the effects from neutral winds in the high latitude E-region ionosphere-thermosphere (IT) during Fall 2015. The purpose of our investigation is to understand the magnetic local time (MLT) dependence of the peak energy transfer, which occurs asymmetrically in the morning-evening (dawn-dusk) MLT sector. The statistical characteristics of both altitude-resolved and altitude-integrated energy transfer rates in the auroral E region local to PFISR during different geomagnetic conditions are quantified. Our analysis shows that the geomagnetic activity level has a large impact on the energy transfer rates. In contrast with previous investigations, we find both the altitude integrated electromagnetic (EM) energy transfer rate and Joule heating rate are larger in the evening sector than in the morning sector during all geomagnetic activity conditions. We also observe non-negligible negative EM energy transfer rates below 110 km in the morning sector during active conditions, which is associated with neutral winds during this MLT interval. The statistical results show that the neutral winds tend to increase the Joule heating rate in a narrow altitude range in the morning sector and impact a broader region with respect to altitude and time in the evening sector in the E region under moderate and active conditions. We find that during quiet conditions that the neutral winds have a significant contribution to the Joule heating and contribute up to 75% of the Joule heating. However, during active conditions, the enhanced fields are a dominant driver of Joule heating, while the neutral wind effects can reduce the Joule heating rates by 25% or more relative to the passive heating rates.

The Anomalous Transport Experiment (ATREX) comprised seven quasi-simultaneous observations of lower thermospheric winds, horizontally separated by up to 600 km, on 27 March 2012, 0900 UT. Zonal and meridional wind profiles were obtained with five sounding rockets launched from Wallops Island (38 N, 75.5 W) releasing seven trimethyl aluminum trails which were observed from three cameral sites. The wind profiles exhibit deep coherent wave structures between 85 and 140 km, dominated by very strong diurnal and semidiurnal tides below 120 km. The total wind amplitude exceeds 100 m/s, three times the value from the Global Scale Wave Model. In addition, a large scale, vertically propagating and growing, inertia-gravity wave, most visible above 120 km, has been isolated by empirical orthogonal function analysis. The region between 100 and 110 km shows the largest mesoscale variability of winds and wind shears, often exceeding 40 m/s/km. We will present an estimation of the structure function for wind fluctuations and possible evidence for stratified mesoscale turbulence.

The Pedersen component of the Lorentz force produces an acceleration that is generally in the zonal direction in much of the dawn and dusk sectors in the auroral oval. During disturbed conditions, as the neutral flow begins to accelerate and the flow speeds increase, a balance develops in the meridional direction between the Coriolis, curvature, and pressure gradient forces, which are dominant in the lower thermosphere. The gradient wind equation that describes this balance predicts that the cyclonic flow on the dawn side is limited to the so-called regular solution, which has a maximum value of twice the geostrophic wind speed. The anticyclonic flow on the dusk side, on the other hand, can satisfy either the regular or anomalous solution with a transition at twice the geostrophic wind speed. The anomalous flow solutions have wind speeds significantly greater than the transition value, but are limited by the inertial wind value, i.e., the value that corresponds to a balance between the curvature and Coriolis forces. The analysis is carried out to show this result, which indicates that a significant quantitative asymmetry is expected between the dawn- and dusk-side flow, as is observed and has been shown in both observations and a number of numerical modeling studies. Implications for the wind distribution of perturbed pressure gradients and inertial instability are discussed.