J. D. Nichols, S. V. Badman, F. Bagenal, S. J. Bolton, B. Bonfond, E. J. Bunce, J. T. Clarke, J. E. P. Connerney, S. W. H. Cowley, R. W. Ebert, M. Fujimoto, J. -C. Gerard, G. R. Gladstone, D. Grodent, T. Kimura, W. S. Kurth, B. H. Mauk, G. Murakami, D. J. McComas, G. S. Orton, A. Radioti, T. S. Stallard, C. Tao, P. W. Valek, R. J. Wilson, A. Yamazaki, I. Yoshikawa
GEOPHYSICAL RESEARCH LETTERS, 44(15) 7643-7652, Aug, 2017 Peer-reviewed
We present the first comparison of Jupiter's auroral morphology with an extended, continuous, and complete set of near-Jupiter interplanetary data, revealing the response of Jupiter's auroras to the interplanetary conditions. We show that for similar to 1 - 3 days following compression region onset, the planet's main emission brightened. A duskside poleward region also brightened during compressions, as well as during shallow rarefaction conditions at the start of the program. The power emitted from the noon active region did not exhibit dependence on any interplanetary parameter, though the morphology typically differed between rarefactions and compressions. The auroras equatorward of the main emission brightened over similar to 10 days following an interval of increased volcanic activity on Io. These results show that the dependence of Jupiter's magnetosphere and auroras on the interplanetary conditions are more diverse than previously thought.
Plain Language Summary Jupiter's auroras (northern lights) are the brightest in the solar system, over a hundred times brighter than the Earth's. Auroras on Earth are driven by the solar wind, a million mile-per-hour stream of charged particles flowing away from the Sun, hitting the Earth's magnetic field, and stirring it around, but it is not known whether the solar wind causes any significant auroras on Jupiter. The main reason for this uncertainty is a lack of observations of the planet's auroras obtained while spacecraft have been near Jupiter and able to supply a full and continuous set of measurements of the solar wind and its accompanying magnetic field. In early mid-2016 Juno approached Jupiter, providing such an interplanetary data set, and we obtained over a month's worth of observations of Jupiter's auroras using the Hubble Space Telescope. We saw several solar wind storms, each causing auroral fireworks on Jupiter. We captured the most powerful auroras observed by Hubble to date, brightened main oval emissions, and flashing high-latitude patches of auroras during the solar wind storms. These results indicate that Jupiter's auroral response to the solar wind is more diverse than we previously have thought.