[en] Abstract Hubble Space Telescope images of Jupiter's UV aurora show that the main emission occasionally contracts or expands, shifting toward or away from the magnetic pole by several degrees in response to changes in the solar wind dynamic pressure and Io's volcanic activity. When the auroral footprints of the Galilean satellites move with the main emission this indicates a change in the stretched field line configuration that shifts the ionospheric mapping of a given radial distance at the equator. However, in some cases, the main emission shifts independently from the satellite footprints, indicating that the variability stems from some other part of the corotation enforcement current system that produces Jupiter's main auroral emissions. Here, we analyze HST images from the Galileo era (1996–2003) and compare latitudinal shifts of the Ganymede footprint and the main auroral emission. We focus on images with overlapping Galileo measurements because concurrent measurements are available of the current sheet strength, which indicates the amount of field line stretching and can influence both the main emission and satellite footprints. We show that the Ganymede footprint and main auroral emission typically, but do not always, move together. Additionally, we find that the auroral shifts are only weakly linked to changes in the current sheet strength measured by Galileo. We discuss implications of the observed auroral shifts in terms of the magnetospheric mapping. Finally, we establish how the statistical reference main emission contours vary with central meridian longitude and show that the dependence results from magnetospheric local time asymmetries.
Research Center/Unit :
STAR - Space sciences, Technologies and Astrophysics Research - ULiège
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Vogt, Marissa F.
Rutala, Matthew
Bonfond, Bertrand ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP)
Clarke, John T.
Moore, Luke
Nichols, Jonathan D.
Language :
English
Title :
Variability of Jupiter's Main Auroral Emission and Satellite Footprints Observed With HST During the Galileo Era
Bonfond, B., Grodent, D., Gérard, J.-C., Stallard, T., Clarke, J. T., Yoneda, M., et al. (2012). Auroral evidence of Io's control over the magnetosphere of Jupiter. Geophysical Research Letters, 39, L01105. https://doi.org/10.1029/2011GL050253
Bonfond, B., Saur, J., Grodent, D., Badman, S. V., Bisikalo, D., Shematovich, V., et al. (2017). The tails of the satellite auroral footprints at Jupiter. Journal of Geophysical Research: Space Physics, 122, 7985–7996. https://doi.org/10.1002/2017JA024370
Bonfond, B., Yao, Z., & Grodent, D. (2020). Six pieces of evidence against the corotation enforcement theory to explain the main aurora at Jupiter. Journal of Geophysical Research: Space Physics, 125, e2020JA028152. https://doi.org/10.1029/2020JA028152
Caldwell, J., Turgeon, B., & Hua, X.-M. (1992). Hubble Space Telescope imaging of the North Polar aurora on Jupiter. Science, 257, 1512–1515. https://doi.org/10.1126/science.257.5076.1512
Clarke, J. T., Ajello, J., Ballester, G., Jaffel, L. B., Connerney, J., Gérard, J.-C., et al. (2002). Ultraviolet emissions from the magnetic footprints of Io, Ganymede, and Europa on Jupiter. Nature, 415, 997–1000. https://doi.org/10.1038/415997a
Clarke, J. T., Nichols, J., Gérard, J.-C., Grodent, D., Hansen, K. C., Kurth, W., et al. (2009). Response of Jupiter's and Saturn's auroral activity to the solar wind. Journal of Geophysical Research, 114, A05210. https://doi.org/10.1029/2008JA013694
Connerney, J. E. P., Acuña, M., & Ness, N. (1981). Modeling the Jovian current sheet and inner magnetosphere. Journal of Geophysical Research, 86(A10), 8370–8384. https://doi.org/10.1029/ja086ia10p08370
Connerney, J. E. P., Acuña, M. H., Ness, N. F., & Satoh, T. (1998). New models of Jupiter’s magnetic field constrained by the Io flux tube footprint. Journal of Geophysical Research, 103, 11929–11939. https://doi.org/10.1029/97ja03726
Connerney, J. E. P., Kotsiaros, S., Oliversen, R. J., Espley, J. R., Joergensen, J. L., Joergensen, P. S., et al. (2018). A new model of Jupiter's magnetic field from Juno's first nine orbits. Geophysical Research Letters, 45, 2590–2596. https://doi.org/10.1002/2018GL077312
Connerney, J. E. P., Timmins, S., Herceg, M., & Joergensen, J. L. (2020). A Jovian magnetodisc model for the Juno era. Journal of Geophysical Research: Space Physics, 125, e2020JA028138. https://doi.org/10.1029/2020JA028138
Cowley, S. W. H., & Bunce, E. J. (2001). Origin of the main auroral oval in Jupiter’s coupled magnetosphere-ionosphere system. Planetary and Space Science, 49, 1067–1088. https://doi.org/10.1016/s0032-0633(00)00167-7
Elliott, S. S., Gurnett, D. A., Kurth, W. S., Clark, G., Mauk, B. H., Bolton, S. J., et al. (2018). Pitch angle scattering of upgoing electron beams in Jupiter's polar regions by whistler-mode waves. Geophysical Research Letters, 45, 1246–1252. https://doi.org/10.1002/2017GL076878
Gershman, D. J., Connerney, J. E. P., Kotsiaros, S., DiBraccio, G. A., Martos, Y. M., F.-Viñas, A., et al. (2019). Alfvénic fluctuations associated with Jupiter's auroral emissions. Geophysical Research Letters, 46, 7157–7165. https://doi.org/10.1029/2019GL082951
Grodent, D., Bonfond, B., Gérard, J.-C., Radioti, A., Gustin, J., Clarke, J. T., et al. (2008). Auroral evidence of a localized magnetic anomaly in Jupiter’s northern hemisphere. Journal of Geophysical Research, 113, A09201. https://doi.org/10.1029/2008JA013185
Grodent, D., Clarke, J. T., Kim, J., Waite, J. H., & Cowley, S. W. H. (2003). Jupiter's main auroral oval observed with HST-STIS. Journal of Geophysical Research, 108(A11), 1389. https://doi.org/10.1029/2003JA009921
Grodent, D., Gérard, J.-C., Radioti, A., Bonfond, B., & Saglam, A. (2008). Jupiter’s changing auroral location. Journal of Geophysical Research, 113, A01206. https://doi.org/10.1029/2007JA012601
Hill, T. W. (2001). The Jovian auroral oval. Journal of Geophysical Research, 106, 8101–8107. https://doi.org/10.1029/2000ja000302
Joy, S. P., Kivelson, M. G., Walker, R. J., Khurana, K. K., Russell, C. T., & Ogino, T. (2002). Probabilistic models of the Jovian magnetopause and bow shock locations. Journal of Geophysical Research, 107, 1309. https://doi.org/10.1029/2001JA009146
Kronberg, E. A., Glassmeier, K.-H., Woch, J., Krupp, N., Lagg, A., & Dougherty, M. K. (2007). A possible intrinsic mechanism for the quasi-periodic dynamics of the Jovian magnetosphere. Journal of Geophysical Research, 112, A05203. https://doi.org/10.1029/2006ja011994
Kronberg, E. A., Woch, J., Krupp, N., Lagg, A., Khurana, K. K., & Glassmeier, K.-H. (2005). Mass release at Jupiter: Substorm-like processes in the Jovian magnetotail. Journal of Geophysical Research, 110, A03211. https://doi.org/10.1029/2004JA010777
Krüger, H., Geissler, P., Horányi, M., Graps, A. L., Kempf, S., Srama, R., et al. (2003). Jovian dust streams: A monitor of Io's volcanic plume activity. Geophysical Research Letters, 30, 2101. https://doi.org/10.1029/2003GL017827
Louarn, P., Paranicas, C. P., & Kurth, W. S. (2014). Global magnetodisk disturbances and energetic particle injections at Jupiter. Journal of Geophysical Research: Space Physics, 119, 4495–4511. https://doi.org/10.1002/2014JA019846
Lysak, R. L., & Song, Y. (2020). Field line resonances in Jupiter's magnetosphere. Geophysical Research Letters, 47, e2020GL089473. https://doi.org/10.1029/2020GL089473
Mauk, B. H., Williams, D. J., McEntire, R. W., Khurana, K. K., & Roederer, J. G. (1999). Storm-like dynamics of Jupiter's inner magnetosphere. Journal of Geophysical Research, 104(22), 759. https://doi.org/10.1029/1999ja900097
Nichols, J. D. (2011). Magnetosphere-ionosphere coupling in Jupiter's middle magnetosphere: Computations including a self-consistent current sheet magnetic field model. Journal of Geophysical Research, 116, A10232. https://doi.org/10.1029/2011JA016922
Nichols, J. D., Achilleos, N., & Cowley, S. W. H. (2015). A model of force balance in Jupiter’s magnetodisc including hot plasma pressure anisotropy. Journal of Geophysical Research: Space Physics, 120, 10185–10206. https://doi.org/10.1002/2015JA021807
Nichols, J. D., Allegrini, F., Bagenal, F., Bunce, E. J., Cowley, S. W. H., Ebert, R. W., et al. (2020). An enhancement of Jupiter's main auroral emission and magnetospheric currents. Journal of Geophysical Research: Space Physics, 125, e2020JA027904. https://doi.org/10.1029/2020JA027904
Nichols, J. D., Clarke, J. T., Gérard, J. C., & Grodent, D. (2009). Observations of Jovian polar auroral filaments. Geophysical Research Letters, 36, L08101. https://doi.org/10.1029/2009GL037578
Nichols, J. D., & Cowley, S. W. H. (2004). Magnetosphere-ionosphere coupling currents in Jupiter's middle magnetosphere: Effect of precipitation-induced enhancement of the ionospheric Pedersen conductivity. Annales Geophysicae, 22, 1799–1827. https://doi.org/10.5194/angeo-22-1799-2004
Nozawa, H., Misawa, H., Takahashi, S., Morioka, A., Okano, S., & Sood, R. (2004). Long-term variability of [SII] emissions from the Io plasma torus between 1997 and 2000. Journal of Geophysical Research, 109, A07209. https://doi.org/10.1029/2003JA010241
Nozawa, H., Misawa, H., Takahashi, S., Morioka, A., Okano, S., & Sood, R. (2005). Relationship between the Jovian magnetospheric plasma density and Io torus emission. Geophysical Research Letters, 32, L11101. https://doi.org/10.1029/2005GL022759
Pan, D.-X., Yao, Z.-H., Manners, H., Dunn, W., Bonfond, B., Grodent, D., et al. (2021). Ultralow-frequency waves in driving Jovian aurorae revealed by observations from HST and Juno. Geophysical Research Letters, 48, e2020GL091579. https://doi.org/10.1029/2020GL091579
Radioti, A., Gérard, J.-C., Grodent, D., Bonfond, B., Krupp, N., & Woch, J. (2008). Discontinuity in Jupiter’s main auroral oval. Journal of Geophysical Research, 113, A01215. https://doi.org/10.1029/2007JA012610
Saur, J., Janser, S., Schreiner, A., Clark, G., Mauk, B. H., Kollmann, P., et al. (2018). Wave-particle interaction of Alfvén waves in Jupiter's magnetosphere: Auroral and magnetospheric particle acceleration. Journal of Geophysical Research: Space Physics, 123, 9560–9573. https://doi.org/10.1029/2018JA025948
Thomas, N., Bagenal, F., Hill, T. W., & Wilson, J. K. (2004). In F. Bagenal, T. E. Dowling, & W. B. McKinnon (Eds.), Jupiter: The planet, satellites, and magnetosphere. New York: Cambridge University Press.
Vogt, M. F., Bunce, E. J., Kivelson, M. G., Khurana, K. K., Walker, R. J., Radioti, A., et al. (2015). Magnetosphere-ionosphere mapping at Jupiter: Quantifying the effects of using different internal field models. Journal of Geophysical Research: Space Physics, 120, 2584–2599. https://doi.org/10.1002/2014JA020729
Vogt, M. F., Bunce, E. J., Nichols, J. D., Clarke, J. T., & Kurth, W. S. (2017). Long-term variability of Jupiter’s magnetodisk and implications for the aurora. Journal of Geophysical Research: Space Physics, 122, 12090–12110. https://doi.org/10.1002/2017JA024066
Vogt, M. F., Gyalay, S., Kronberg, E. A., Bunce, E. J., Kurth, W. S., Zieger, B., & Tao, C. (2019). Solar wind interaction with Jupiter's magnetosphere: A statistical study of Galileo in situ data and modeled upstream solar wind conditions. Journal of Geophysical Research: Space Physics, 124, 10170–10199. https://doi.org/10.1029/2019JA026950
Vogt, M. F., Kivelson, M. G., Khurana, K. K., Walker, R. J., Bonfond, B., Grodent, D., & Radioti, A. (2011). Improved mapping of Jupiter’s auroral features to magnetospheric sources. Journal of Geophysical Research, 116, A03220. https://doi.org/10.1029/2010JA016148
Yao, Z. H., Dunn, W. R., Woodfield, E. E., Clark, G., Mauk, B. H., Ebert, R. W., et al. (2021). Revealing the source of Jupiter’s X-ray auroral flares. Science Advances, 7(28). eabf0851. https://doi.org/10.1126/sciadv.abf0851
Yao, Z. H., Grodent, D., Kurth, W. S., Clark, G., Mauk, B. H., Kimura, T., et al. (2019). On the relation between Jovian aurorae and the loading/unloading of the magnetic flux: Simultaneous measurements from Juno, HST and Hisaki. Geophysical Research Letters, 46(21), 11632–11641. https://doi.org/10.1029/2019GL084201