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Author: Chau, Jorge L. × Start date: 2018 × DDC: 620 × Type: Article × WGL Institute: IAP ×

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Now showing 1 - 3 of 3
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    The future of auroral E-region plasma turbulence research
    (Lausanne : Frontiers Media, 2022) Huyghebaert, Devin; Billett, Daniel; Chartier, Alex; Chau, Jorge L.; Hussey, Glenn C.; Hysell, David L.; Ivarsen, Magnus F.; Mesquita, Rafael L. A.; Rojas, Enrique; Vierinen, Juha; Young, Matthew
    The heating caused by ionospheric E-region plasma turbulence has documented global implications for the energy transfer from space into the terrestrial atmosphere. Traveling atmospheric disturbances, neutral wind motion, energy deposition rates, and ionospheric conductance have all been shown to be potentially affected by turbulent plasma heating. Therefore it is proposed to enhance and expand existing ionospheric radar capabilities and fund research into E-region plasma turbulence so that it is possible to more accurately quantify the solar-terrestrial energy budget and study phenomena related to E-region plasma turbulence. The proposed research funding includes the development of models to accurately predict and model the E-region plasma turbulence using particle-in-cell analysis, fluid-based analysis, and hybrid combinations of the two. This review provides an expanded and more detailed description of the past, present, and future of auroral E-region plasma turbulence research compared to the summary report submitted to the National Academy of Sciences Decadal Survey for Solar and Space Physics (Heliophysics) 2024–2033 (Huyghebaert et al., 2022a).
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    Improving ionospheric predictability requires accurate simulation of the mesospheric polar vortex
    (Lausanne : Frontiers Media, 2022) Harvey, V. Lynn; Randall, Cora E.; Bailey, Scott M.; Becker, Erich; Chau, Jorge L.; Cullens, Chihoko Y.; Goncharenko, Larisa P.; Gordley, Larry L.; Hindley, Neil P.; Lieberman, Ruth S.; Liu, Han-Li; Megner, Linda; Palo, Scott E.; Pedatella, Nicholas M.; Siskind, David E.; Sassi, Fabrizio; Smith, Anne K.; Stober, Gunter; Stolle, Claudia; Yue, Jia
    The mesospheric polar vortex (MPV) plays a critical role in coupling the atmosphere-ionosphere system, so its accurate simulation is imperative for robust predictions of the thermosphere and ionosphere. While the stratospheric polar vortex is widely understood and characterized, the mesospheric polar vortex is much less well-known and observed, a short-coming that must be addressed to improve predictability of the ionosphere. The winter MPV facilitates top-down coupling via the communication of high energy particle precipitation effects from the thermosphere down to the stratosphere, though the details of this mechanism are poorly understood. Coupling from the bottom-up involves gravity waves (GWs), planetary waves (PWs), and tidal interactions that are distinctly different and important during weak vs. strong vortex states, and yet remain poorly understood as well. Moreover, generation and modulation of GWs by the large wind shears at the vortex edge contribute to the generation of traveling atmospheric disturbances and traveling ionospheric disturbances. Unfortunately, representation of the MPV is generally not accurate in state-of-the-art general circulation models, even when compared to the limited observational data available. Models substantially underestimate eastward momentum at the top of the MPV, which limits the ability to predict upward effects in the thermosphere. The zonal wind bias responsible for this missing momentum in models has been attributed to deficiencies in the treatment of GWs and to an inaccurate representation of the high-latitude dynamics. In the coming decade, simulations of the MPV must be improved.
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    Determination of the Azimuthal Extent of Coherent E‐Region Scatter Using the ICEBEAR Linear Receiver Array
    (Hoboken, NJ : Wiley, 2021) Huyghebaert, Devin; McWilliams, Kathryn; Hussey, Glenn; Galeschuk, Draven; Chau, Jorge L.; Vierinen, Juha
    The Ionospheric Continuous-wave E-region Bistatic Experimental Auroral Radar (ICEBEAR) is a VHF coherent scatter radar that operates with a field-of-view centered on 58°N, 106°W and measures characteristics of ionospheric E-region plasma density irregularities. The initial operations of ICEBEAR utilized a wavelength-spaced linear receiving array to determine the angle of arrival of the ionospheric scatter at the receiver site. Initially only the shortest baselines were used to determine the angle of arrival of the scatter. This publication uses this linear antenna array configuration and expands on the initial angle of arrival determination by including all the cross-spectra available from the antenna array to determine both the azimuthal angle of arrival and the azimuthal extent of the incoming ionospheric scatter. This is accomplished by fitting Gaussian distributions to the complex coherence of the signal between different antennas and deriving the azimuthal angle and extent based on the best fit. Fourteen hours of data during an active ionospheric period (March 10, 2018, 0–14 UT) were analyzed to investigate the Gaussian fitting procedure and determine its feasibility for implementation with ICEBEAR. A comparison between mapped scatter, both neglecting azimuthal extent and including azimuthal extent is presented. It demonstrates that the azimuthal extent of the ionospheric E-region scatter is very important for accurately portraying and analyzing the ICEBEAR measurements.