J Geophys Res Space Phys
December 2024
Simultaneous observations of and in Jupiter's northern infrared aurora were conducted on 02 June 2017 using Keck-NIRSPEC to produce polar projection maps of radiance, rotational temperature, column density, and radiance. The temperature variations within the auroral region are K, generally consistent with previous studies, albeit with some structural differences. Known auroral heating sources including particle precipitation, Joule heating, and ion drag have been examined by studying the correlations between each derived quantity, yet no single dominant mechanism can be identified as the main driver for the energetics in Jupiter's northern auroral region.
View Article and Find Full Text PDFThis review provides a critical, multi-faceted assessment of the practical contribution tidal stream energy can make to the UK and British Channel Islands future energy mix. Evidence is presented that broadly supports the latest national-scale practical resource estimate, of 34 TWh/year, equivalent to 11% of the UK's current annual electricity demand. The size of the practical resource depends in part on the economic competitiveness of projects.
View Article and Find Full Text PDFJupiter's upper atmosphere is considerably hotter than expected from the amount of sunlight that it receives. Processes that couple the magnetosphere to the atmosphere give rise to intense auroral emissions and enormous deposition of energy in the magnetic polar regions, so it has been presumed that redistribution of this energy could heat the rest of the planet. Instead, most thermospheric global circulation models demonstrate that auroral energy is trapped at high latitudes by the strong winds on this rapidly rotating planet.
View Article and Find Full Text PDFPhilos Trans A Math Phys Eng Sci
December 2020
H has been detected at all of the solar system giant planets aside from Neptune. Current observational upper limits imply that there is far less H emission at Neptune than rudimentary modelling would suggest. Here, we explore via modelling a range of atmospheric conditions in order to find some that could be consistent with observational constraints.
View Article and Find Full Text PDFPhilos Trans A Math Phys Eng Sci
September 2019
The upper atmosphere of Uranus has been observed to be slowly cooling between 1993 and 2011. New analysis of near-infrared observations of emission from H obtained between 2012 and 2018 reveals that this cooling trend has continued, showing that the upper atmosphere has cooled for 27 years, longer than the length of a nominal season of 21 years. The new observations have offered greater spatial resolution and higher sensitivity than previous ones, enabling the characterization of the H intensity as a function of local time.
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