Solar Cycle Effects on the Dynamics of Jupiter’s and Saturn’s Magnetospheres
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The giant planetary magnetospheres surrounding Jupiter and Saturn respond in quite different ways, compared to Earth, to changes in upstream solar wind conditions. Spacecraft have visited Jupiter and Saturn during both solar cycle minima and maxima. In this paper we explore the large-scale structure of the interplanetary magnetic field (IMF) upstream of Saturn and Jupiter as a function of solar cycle, deduced from solar wind observations by spacecraft and from models. We show the distributions of solar wind dynamic pressure and IMF azimuthal and meridional angles over the changing solar cycle conditions, detailing how they compare to Parker predictions and to our general understanding of expected heliospheric structure at 5 and 9 AU. We explore how Jupiter’s and Saturn’s magnetospheric dynamics respond to varying solar wind driving over a solar cycle under varying Mach number regimes, and consider how changing dayside coupling can have a direct effect on the nightside magnetospheric response. We also address how solar UV flux variability over a solar cycle influences the plasma and neutral tori in the inner magnetospheres of Jupiter and Saturn, and estimate the solar cycle effects on internally driven magnetospheric dynamics. We conclude by commenting on the effects of the solar cycle in the release of heavy ion plasma into the heliosphere, ultimately derived from the moons of Jupiter and Saturn.
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- Badman, S.V., Bunce, E.J., Clarke, J.T., Cowley, S.W.H., Gérard, J.-C., Grodent, D., Milan, S.E.: 2005, Open flux estimates in Saturn’s magnetosphere during the January 2004 Cassini-HST campaign, and implications for reconnection rates. J. Geophys. Res. 110, A11216. doi:10.1029/2005JA011240. CrossRefADSGoogle Scholar
- Bunce, E.J., Arridge, C.S., Clarke, J.T., Coates, A.J., Cowley, S.W.H., Dougherty, M.K., Gérard, J.-C., Grodent, D., Hansen, K.C., Nichols, J.D., Southwood, D.J., Talboys, D.L.: 2008, Origin of Saturn’s aurora: simultaneous observations by Cassini and the Hubble Space Telescope. J. Geophys. Res. 113, A09209. doi:10.1029/2008JA013257. CrossRefGoogle Scholar
- Cowley, S.W.H., Arridge, C.S., Bunce, E.J., Clarke, J.T., Coates, A.J., Dougherty, M.K., Gérard, J.-C., Grodent, D., Nichols, J.D., Talboys, D.L.: 2008b, Auroral current systems in Saturn’s magnetosphere: comparison of theoretical models with Cassini and HST observations. Ann. Geophys. 26, 2613 – 2630. CrossRefADSGoogle Scholar
- Jackman, C.M., Achilleos, N., Bunce, E.J., Cowley, S.W.H., Dougherty, M.K., Jones, G.H., Milan, S.E., Smith, E.J.: 2004, Interplanetary magnetic field at ∼ 9 AU during the declining phase of the solar cycle and its implications for Saturn’s magnetospheric dynamics. J. Geophys. Res. 109, A11203. doi:10.1029/2004JA010614. CrossRefADSGoogle Scholar
- Phan, T.D., Gosling, J.T., Paschmann, G., Pasma, C., Drake, J.F., Øieroset, M., Larson, D., Lin, R.P., Davis, M.S.: 2010, The dependence of magnetic reconnection on plasma ß and magnetic shear: evidence from solar wind observations. Astrophys. J. 719(2), L199. doi:10.1088/2041-8205/719/2/L199. CrossRefADSGoogle Scholar
- Thomas, N., Bagenal, F., Hill, T.W., Wilson, J.K.: 2004, The Io neutral clouds and plasma torus. In: Jupiter: The Planet, Satellites and Magnetosphere, Cambridge University Press, Cambridge, 561 – 591. Google Scholar