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Huang Y.,University of New Mexico | Huang Y.,Configurable Space Microsystems Innovations and Applications Center | Wu Q.,High Altitude Observatory | Huang C.Y.,Air Force Research Lab | Su Y.-J.,Air Force Research Lab
Journal of Atmospheric and Solar-Terrestrial Physics | Year: 2016

In this study, we report observations and simulation results of heated neutrals at various altitudes inside the polar cap during two magnetic storms in January 2005. The Poynting flux measurements from the Defense Meteorological Satellite Program (DMSP) satellites show enhanced energy input in the polar cap during the storm main phase, which is underestimated in the TIE-GCM simulation. Neutral temperature measurements at 250 km from the ground-based Fabry-Perot Interferometer (FPI) at Resolute Bay are presented, along with the neutral density observations at 360 km and 470 km from Challenging Minisatellite Payload (CHAMP) and the Gravity Recovery and Climate Experiment (GRACE) satellites, respectively. These data have been analyzed to demonstrate the altitudinal dependence of neutral response to the storm energy input. By comparing the TIE-GCM simulation results and the observations, we demonstrate that Poynting fluxes as well as the thermosphere response were underestimated in the model. The simulated neutral temperature at Resolute Bay increases by approximately 260° and 280° K for the two events, respectively, much lower than the observed temperature enhancements of 750° and 900° K. Neutral density enhancements with more than 30% increase over the background density were also observed at polar latitudes, with no clear distinction between the auroral zone and polar cap. All measurements indicate enhancements at high latitudes poleward of 80° magnetic latitude (MLAT) implying that substantial heating can occur within the polar cap during storms. © 2016 Elsevier Ltd. Source


Deng Y.,University of Texas at Arlington | Huang Y.,University of New Mexico | Huang Y.,Configurable Space Microsystems Innovations and Applications Center | Wu Q.,High Altitude Observatory | And 3 more authors.
Journal of Geophysical Research: Space Physics | Year: 2014

The seasonal variation of F region neutral wind from the midlatitude conjugate Fabry-Perot interferometer observations has been studied. The meridional wind at Palmer station (64°S,64°W) has a significant local time dependence with strong equatorward wind at midnight and polarward wind at dawn and dusk. The zonal wind switches from eastward to westward in the early morning section. From the June solstice (austral winter) to equinox, the maximum meridional wind increases from 90 m/s to 130 m/s, and the zonal wind switches direction at an earlier local time. The neutral winds from Palmer have been compared with those from the geomagnetic conjugate location, Millstone Hill (MH). At equinox, the local time variation of neutral wind shows a very good conjugacy between these two locations. But at June solstice, the similarity in the zonal wind becomes less clear. This seasonal dependence can be attributed to the seasonal variation of solar and geomagnetic forcings. The annual variation of daily average neutral wind from Palmer and MH has also been compared. The meridional wind shows a clear offset of season, and the magnitude at Palmer is averagely 40 m/s more equatorward than that at MH. The zonal wind is dominantly westward at Palmer and eastward at MH. The annual variation of neutral wind, especially the zonal component, is much less symmetric between the two sites than the local time variation. The empirical horizontal wind model shows a good agreement with the observations in both local time and annual variations. Key Points F region neutral wind from the midlatitude conjugated FPI observations At equinox, the local time variation of neutral wind shows a very good conjugacy The empirical model shows a good agreement with the observations ©2014. American Geophysical Union. All Rights Reserved. Source


Huang Y.,University of New Mexico | Huang Y.,Configurable Space Microsystems Innovations and Applications Center | Huang C.Y.,Air Force Research Lab | Su Y.-J.,Air Force Research Lab | And 2 more authors.
Journal of Geophysical Research: Space Physics | Year: 2014

The parameterizations of monoenergetic particle impact ionization in Fang et al. (2010) (Fang2010) and Fang et al. (2013) (Fang2013) are applied to the complex energy spectra measured by DMSP F16 satellite to calculate the ionization rates from electron and ion precipitations for a Northern Hemisphere pass from 0030 UT to 0106 UT on 6 August 2011. Clear enhancement of electron flux is found in the polar cap. The mean electron energy in the polar cap is mostly above 100 eV, while the mean energy in the auroral zone is typically above 1 keV. At the same time, F16 captures a strong Poynting flux enhancement in the polar cap, which is comparable to those in the auroral zone. The particle impact ionization rates using Fang2010 and Fang2013 parameterizations show clear enhancement at F region altitudes mainly due to the low-energy precipitating electrons, peaking probably in the cusp but also showing enhanced levels throughout most of the polar cap region. The general circulation models (GCMs), National Center for Atmospheric Research Thermosphere-Ionosphere- Electrodynamics General Circulation Model, and Global Ionosphere-Thermosphere Model, using their default empirical formulations of particle impact ionization, do not capture the observed features shown in the total particle ionization rate applying the Fang2010 and Fang2013 parameterizations to DMSP measurements. The difference between GCM simulations and Fang2010 and Fang2013 applied to DMSP data is due to the difference of both the inputs to the models and the parameterization of the ionization rates. Key Points For a F16 pass on 6 August 2011, mean electron energy in polar cap is above 100 eV Fang 2010 and 2013 parameterizations show ionization enhancement in the polar cap Ionization enhancements in the polar cap are mainly due to low-energy electrons ©2014. American Geophysical Union. All Rights Reserved. Source


Lyke J.,U.S. Air force | Christodoulou C.G.,Configurable Space Microsystems Innovations and Applications Center | Vera A.,University of New Mexico | Edwards A.H.,University of North Carolina at Charlotte
Proceedings of the IEEE | Year: 2015

The articles in this special issue focus on reconfigurable systems. Reconfigurability is about "change," specifically soft-defined change, whereby through the manipulation of bit sequences we can customize the properties of components, and in some cases define systems themselves. One can design systems for reconfigurability (the art of engineering degrees of freedom into embedded systems), so that users expecting this reconfigurability can exploit it. This issue focuses on important reconfigurable platforms [fieldprogrammable gate arrays (FPGAs)], development tools, and applications (reconfigurable computing and software radios). As we discussed, reconfigurability can be both dynamic and adaptive, but one should not confuse the two concepts. Reconfigurability refers to specific features that can be changed (to include dynamic and partial reconfigurability), whereas adaptiveness addresses the behavioral constructs that inform how reconfigurable features might best be exploited in live use conditions. © 2015 IEEE. Source


Olivieri S.J.,Worcester Polytechnic Institute | Aarestad J.,University of New Mexico | Pollard L.H.,University of New Mexico | Wyglinski A.M.,Worcester Polytechnic Institute | And 2 more authors.
IEEE International Conference on Communications | Year: 2012

In this paper, we present an adaptive digital communication system using field programmable gate array (FPGA) technology. This system adapts the Universal Software Radio Peripheral (USRP) to better suit the space and power limitations of the CubeSat satellite form factor and the Space Plug-and-Play Avionics (SPA) protocol. The result is a highly-adaptive, plug and play software-defined radio (SDR) that is easily incorporated into any CubeSat design. © 2012 IEEE. Source

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