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7 - Saturn’s Aurorae

Published online by Cambridge University Press:  13 December 2018

By
Tom Stallard ,
Sarah v. Badman ,
Ulyana Dyudina ,
Denis Grodent  and
Laurent Lamy
Edited by
Kevin H. Baines ,
F. Michael Flasar ,
Norbert Krupp  and
Tom Stallard
Kevin H. Baines
Affiliation:
University of Wisconsin, Madison
F. Michael Flasar
Affiliation:
NASA-Goddard Space Flight Center
Norbert Krupp
Affiliation:
Max-Planck-Institut für Sonnensystemforschung, Göttingen
Tom Stallard
Affiliation:
University of Leicester
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Summary

The aurorae of each planet are produced as a direct interaction between the upper atmosphere and magnetosphere of that planet. Energetic particles from the magnetosphere are driven into the top of the atmosphere, depositing energy there, and ultimately resulting in an electromagnetic emission. As a result, aurorae are related to conditions within the planetary magnetospheres so an understanding of the auroral emission provides a view of both the magnetospheric structure and how that magnetosphere is coupled with the underlying ionosphere. In the past, Saturn’s magnetosphere, and thus its aurorae, have been seen as something of a hybrid between the solar-wind-driven interaction at Earth and the rotationally dominated system at Jupiter. However, observations across a wide wavelength range by both the Cassini spacecraft and supporting Earth-based telescopes have revealed Saturn’s aurorae to be highly complex. We now recognize that Saturn’s aurorae are driven by the dynamic magnetic field interactions between the atmosphere, the solar wind and plasma trapped within the magnetosphere, all strongly affected by the rapid rotation of the planet.

In this chapter, we highlight the broad variety of auroral features observed at Saturn, and discuss how these are generated by energetic particles moving within current systems that link to solar wind interactions (Section 7.2), interactions with plasma generated within the magnetosphere (Section 7.3) and with current systems that vary periodically, including those linked to weather systems within Saturn’s upper atmosphere (Section 7.4). Finally, we conclude with a discussion of the major questions that remain about Saturn’s aurorae, and summarize the upcoming observations that will help us answer them. We begin with a discussion of how the auroral emission is generated and the characteristics of aurorae observed at Saturn. In particular, we highlight the most recent auroral research, following on from the overview of Saturn’s auroral processes presented in past reviews of the subject (for example, Kurth et al. 2009).

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Saturn in the 21st Century , pp. 166 - 195
Publisher: Cambridge University Press
Print publication year: 2018

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References

Aguilar, A., Ajello, J. M., Mangina, R. S. et al. (2008), The electron-excited mid-ultraviolet to near-infrared spectrum of H2: Cross sections and transition probabilities, Astrophys. J. Supp. Ser. 177, 388–407, DOI:10.1086/587690.Google Scholar
Andrews, D. J., Cecconi, B., Cowley, S. W. H. et al. (2011), Planetary period oscillations in Saturn’s magnetosphere: Evidence in magnetic field phase data for rotational modulation of Saturn kilometric radiation emissions, J. Geophys. Res., 116, A09206, DOI:10.1029/2011JA016636.Google Scholar
Badman, S. V., Cowley, S. W. H., Gérard, J.-C. and Grodent, D. (2006), A statistical analysis of the location and width of Saturn’s southern auroras, Annales Geophysicae 24, 3533–3545, DOI:10.5194/angeo-24–3533-2006.Google Scholar
Badman, S. V., Achilleos, N., Baines, K. H. et al. (2011a), Location of Saturn’s northern infrared aurora determined from Cassini VIMS images. Geophys. Res. Lett., 38, L03102, DOI:10.1029/2010GL046193.Google Scholar
Badman, S. V., Tao, C., Grocott, A. et al. (2011b), Cassini VIMS observations of latitudinal and hemispheric variations in Saturn’s infrared auroral intensity, Icarus 216, 367–375. DOI:10.1016/j.icarus.2011.09.031.Google Scholar
Badman, S. V., Andrews, D. J., Cowley, S. W. H. et al. (2012a), Rotational modulation and local time dependence of Saturn’s infrared H3+ auroral intensity, J. Geophys. Res., 117, A09228, DOI:10.1029/2012JA017990.Google Scholar
Badman, S. V., Achilleos, N., Arridge, C. S. et al. (2012b), Cassini observations of ion and electron beams at Saturn and their relationship to infrared auroral arcs, J. Geophys. Res., 117, A01211, DOI:10.1029/2011JA017222.Google Scholar
Badman, S. V., Masters, A., Hasegawa, H. et al. (2013), Bursty magnetic reconnection at Saturn’s magnetopause, Geophys. Res. Lett., 40, 1027–1031, DOI:10.1002/grl.50199.Google Scholar
Badman, S. V., Branduardi-Raymont, G., Galand, M. et al. (2015), Auroral processes at the giant planets: energy deposition, emission mechanisms, morphology and spectra, Space Sci. Rev., 180, DOI:10.1007/s11214-014–0042-x.Google Scholar
Badman, S. V., Provan, G., Bunce, E. J. et al. (2016), Saturn’s auroral morphology and field-aligned currents during a solar wind compression, Icarus 263, 83–93, DOI:10.1016/j.icarus.2014.11.014.Google Scholar
Belenkaya, E. S., Cowley, S. W. H., Meredith, C. J. et al. (2014), Magnetospheric magnetic field modelling for the 2011 and 2012 HST Saturn aurora campaigns: Implications for auroral source regions, Annales Geophysicae 32, 689–704, DOI:10.5194/angeo-32–689-2014.Google Scholar
Branduardi-Raymont, G.,Ford, P. G., Hansen, K. C. et al. (2013), Search for Saturn’s X-ray aurorae at the arrival of a solar wind shock, J. Geophys. Res. Space Physics, 118, DOI:10.1002/jgra.50112.Google Scholar
Bunce, E. J., Arridge, C. S., Clarke, J. T. et al. (2008), Origin of Saturn’s aurora: Simultaneous observations by Cassini and the Hubble Space Telescope, J. Geophys. Res., 113, A09209, DOI:10.1029/2008JA013257.Google Scholar
Bunce, E. J., Cowley, S. W. H., Talboys, D. L. et al. (2010), Extraordinary field-aligned current signatures in Saturn’s high-latitude magnetosphere: Analysis of Cassini data during Revolution 89, J. Geophys. Res. 115, A10238, DOI:10.1029/2010JA015612.Google Scholar
Bunce, E. J. (2012), Origins of Saturn’s Auroral Emissions and Their Relationship to Large-Scale Magnetosphere Dynamics, Washington DC, American Geophysical Union, Geophysical Monograph Series 197, 397–410, DOI:10.1029/2011GM001191.Google Scholar
Bunce, E. J., Grodent, D. C., Jinks, S. L. et al. (2014), Cassini nightside observations of the oscillatory motion of Saturn’s northern auroral oval, J. Geophys. Res. Space Physics, 119, 3528–3543, DOI:10.1002/2013JA019527.Google Scholar
Carbary, J. F. (2013), Longitude dependences of Saturn’s ultraviolet aurora, Geophysical Res. Lett., 40, DOI:10.1002/grl.50430.Google Scholar
Cecconi, B., Lamy, L., Zarka, P. et al. (2009), Goniopolarimetric study of the revolution 29 perikrone using the Cassini Radio and Plasma Wave Science instrument high-frequency radio receiver, J. Geophys. Res., 114, A03215, DOI:10.1029/2008JA013830.Google Scholar
Chen, Y. and Hill, T. W. (2008), Statistical analysis of injection/dispersion events in Saturn’s inner magnetosphere, J. Geophys. Res., 113, A07215, DOI:10.1029/2008JA013166.Google Scholar
Clarke, J. T., Gérard, J.-C., Grodent, D. et al. (2005), Morphological differences between Saturn’s ultraviolet aurorae and those of Earth and Jupiter, Nature 433, 717–719, DOI:10.1038/nature03331.Google Scholar
Clarke, J. T., Nichols, J. and Gérard, J.-C. (2009), Response of Jupiter’s and Saturn’s auroral activity to the solar wind, J. Geophys. Res., 114, A05210, DOI:10.1029/2008JA013694.Google Scholar
Cowley, S. W. H., Bunce, E. J., O’Rourke, J. M. (2004), A simple quantitative model of plasma flows and currents in Saturn’s polar ionosphere, J. Geophys. Res. 109, A05212, DOI:10.1029/2003JA010375.Google Scholar
Cowley, S. W. H., Badman, S. V., Bunce, E. J. et al. (2005), Reconnection in a rotation-dominated magnetosphere and its relation to Saturn’s auroral dynamics, J. Geophys. Res. 110, A02201, DOI:10.1029/2004JA010796.Google Scholar
Desch, M. D. and Kaiser, M. L. (1981), Voyager measurement of the rotation period of Saturn’s magnetic field, Geophys. Res. Lett., 8, 253–256.CrossRefGoogle Scholar
Dyudina, U. A., Ingersoll, A. P., Ewald, S. P. and Wellington, D. (2016), Saturn’s aurora observed by the Cassini camera at visible wavelengths, Icarus 263, 32–43, DOI:10.1016/j.icarus.2015.05.022Google Scholar
Farrell, W. M., Desch, M. D., Kaiser, M. L. et al. (2005), A nightside source of Saturn’s kilometric radiation: Evidence for an inner magnetosphere energy driver, Geophys. Res. Lett., 32, L18107, DOI:10.1029/ 2005GL023449.Google Scholar
Fear, R. C. and Milan, S. E. (2012), The IMF dependence of the local time of transpolar arcs: Implications for formation mechanism, J. Geophys. Res., 117, A03213, DOI:10.1029/2011JA017209.CrossRefGoogle Scholar
Galand, M., Moore, L., Mueller-Wodarg, I. et al. (2011), Response of Saturn’s auroral ionosphere to electron precipitation: Electron density, electron temperature, and electrical conductivity, J. Geophys. Res. 116, A09306, DOI:10.1029/2010JA016412.Google Scholar
Galopeau, P. H. M. and Lecacheux, A. (2000), Variations in Saturn’s radio rotation period measured at kilometer wavelengths, J. Geophys. Res., 105, 13089–13101.Google Scholar
Gérard, J.-C., Bonfond, B., Gustin, J. et al. (2009), Altitude of Saturn’s aurora and its implications for the characteristic energy of precipitated electrons, Geophys. Res. Lett., 36, L02202.Google Scholar
Gérard, J.-C., Gustin, J., Pryor, W. R. et al. (2013), Remote sensing of the energy of auroral electrons in Saturn’s atmosphere: Hubble and Cassini spectral observations, Icarus 223, 211–221, DOI:10.1016/j.icarus.2012.11.033.CrossRefGoogle Scholar
Gladstone, G. R., Waite, J. H., Grodent, D. et al. (2002), A pulsating auroral X-ray hot spot on Jupiter, Nature 415, 1000–1003.Google Scholar
Grodent, D., Gérard, J.-C., Cowley, S. W. H. et al. (2005), Variable morphology of Saturn’s southern ultraviolet aurora, Journal of Geophysical Research (Space Physics) 110, A07215, DOI:10.1029/2004JA010983.Google Scholar
Grodent, D., Radioti, A., Bonfond, B. and Gérard, J.-C. (2010), On the origin of Saturn’s outer auroral emission, J. Geophys. Res., 115, A08219, DOI:10.1029/2009JA014901.Google Scholar
Grodent, D., Gustin, J., Gérard, J.-C. et al. (2011), Small-scale structures in Saturn’s ultraviolet aurora, J. Geophys. Res., 116, A09225, DOI:10.1029/2011JA016818.CrossRefGoogle Scholar
Grodent, D. (2014), A brief review of ultraviolet auroral emissions on giant planets, Space Sci. Rev., 187, 1-4, DOI:10.1007/s11214-014-0052-8.Google Scholar
Gurnett, D. A. et al. (2005), Radio and plasma wave observations at Saturn from Cassini’s approach and first orbit, Science, 307 no. 5713, 1255–1259, DOI:10.1126/science.1105356.Google Scholar
Gurnett, D. A., Persoon, A. M., Groene, J. B. et al. (2009), Discovery of a north-south asymmetry in Saturn’s radio rotation period, Geophys. Res. Lett., 36, L16102.Google Scholar
Gurnett, D. A., Groene, J. B., Persoon, A. M. et al. (2010), The reversal of the rotational modulation rates of the north and south components of Saturn kilometric radiation near equinox, Geophys. Res. Lett., 37, L24101.Google Scholar
Gurnett, D. A., Groene, J. B., Averkampf, T. F. et al. (2011), An SLS4 Longitude System Based on a Tracking Filter Analysis of the Rotational Modulation of Saturn Kilometric Radiation, Planetary, Solar and Heliospheric Radio Emissions (PRE VII) 51–64.Google Scholar
Gurnett, D. A. and Pryor, W. R. (2011), Auroral processes associated with Saturn’s moon Enceladus. In Relationship between Auroral Phenomenology and Magnetospheric Processes, ed. by Keiling, A., Donovan, E., Bagenal, F., Karlsson, T., Geophysical Monograph Series, American Geophysical Union, Washington, DC, pp. 305–313, DOI:10.1029/2011BK001174.Google Scholar
Gustin, J., Gérard, J.-C., Pryor, W. et al. (2009), Characteristics of Saturn’s polar atmosphere and auroral electrons derived from HST/STIS, FUSE and Cassini/UVIS spectra, Icarus 200, 176–187, DOI:10.1016/j.icarus.2008.11.013.CrossRefGoogle Scholar
Gustin, J., Bonfond, B., Grodent, D., Gérard, J.-C. (2012), Conversion from HST ACS and STIS auroral counts into brightness, precipitated power, and radiated power for H2 giant planets, J. Geophys. Res, 117, A07316. DOI:10.1029/2012JA017607.Google Scholar
Gustin, J., Gérard, J.-C., Grodent, D. et al. (2013), Effects of methane on giant planet’s UV emissions and implications for the auroral characteristics, Journal of Molecular Spectroscopy, 291, 108–117, DOI:10.1016/j.jms.2013.03.010.Google Scholar
Hui, Y., Cravens, T. E., Ozak, N. and Schultz, D. R. (2010), What can be learned from the absence of auroral X-ray emission from Saturn?, J. Geophys. Res., 115, A10239, DOI:10.1029/2010JA015639.Google Scholar
Hunt, G. J., Cowley, S. W. H., Provan, G. et al. (2014), Field-aligned currents in Saturn’s southern nightside magnetosphere: Sub-corotation and planetary period oscillation components, J. Geophys. Res., 119, 9847–9899, DOI:10.1002/2014JA020506.Google Scholar
Jackman, C. M., Achilleos, N., Cowley, S. W. H. et al. (2013), Auroral counterpart of magnetic field dipolarizations in Saturn’s tail, Planet. Space Sci., 82, 34–42, DOI:10.1016/j.pss.2013.03.010.Google Scholar
Jia, X., Kivelson, M. G. and Gombosi, T. I. (2012), Driving Saturn’s magnetospheric periodicities from the upper atmosphere/ionosphere, J. Geophys. Res., 117, A04215, DOI:10.1029/2011JA017367.Google Scholar
Kennelly, T. J., Leisner, J. S., Hospodarsky, G. B. and Gurnett, D. A. (2013), Ordering of injection events within Saturnian SLS longitude and local time, J. Geophys. Res., 118, 832–838, DOI:10.1002/jgra.50152.Google Scholar
Knight, S. (1973), Parallel electric fields, Planet. and Space Sci., 21, 741–750, DOI:10.1016/0032–0633(73)90093–7.Google Scholar
Kullen, A. and Jahnunen, P. (2004), Relation of polar auroral arcs to magnetotail twisting and IMF rotation: A systematic MHD simulation study, Ann. Geophys., 22(3), 951–970.Google Scholar
Kurth, W. S., Gurnett, D. A., Clarke, J. T. et al. (2005), An Earth-like correspondence between Saturn’s auroral features and radio emission, Nature, 433, 722–725, DOI:10.1038/nature03334.Google Scholar
Kurth, W. S., Lecacheux, A., Averkamp, T. F. et al. (2007), A Saturnian longitude system based on a variable kilometric radiation period, Geophys. Res. Lett., 34, L02201.Google Scholar
Kurth, W. S., Averkamp, T. F., Gurnett, D. A. et al. (2008), An update to a Saturnian longitude system based on kilometric radio emissions, J. Geophys. Res., 113, A05222.Google Scholar
Kurth, W. S., Bunce, E. J., Clarke, J. T. et al. (2009), Auroral Processes, Saturn from Cassini-Huygens. 333, DOI:10.1007/978–1-4020–9217-6_12.Google Scholar
Lamy, L., Zarka, P., Cecconi, B. et al. (2008), Saturn kilometric radiation: Average and statistical properties, J. Geophysical Research 113, A07201, DOI:10.1029/2007JA012900.CrossRefGoogle Scholar
Lamy, L., Cecconi, B., Prangé, R. et al. (2009), An auroral oval at the footprint of Saturn’s kilometric radio sources, co-located with the UV aurorae, J. Geophys. Res., 114, A10212, DOI:10.1029/2009JA014401.Google Scholar
Lamy, L., Schippers, P., Zarka, P. et al. (2010), Properties of Saturn kilometric radiation measured within its source region, Geophysical Research Letters, 37, L12104, DOI:10.1029/2010GL043415.Google Scholar
Lamy, L. (2011), Variability of southern and northern SKR periodicities, in Planetary Radio Emissions VII, edited by Rucker, H. O. et al., pp. 39–50, Austrian Acad. Sci. Press, Vienna, Austria.Google Scholar
Lamy, L., Prangé, R., Pryor, W. et al. (2013), Multispectral simultaneous diagnosis of Saturn’s aurorae throughout a planetary rotation, J. Geophys. Res., 118, 4817–4843, DOI:10.1002/jgra.50404.Google Scholar
Masters, A., Achilleos, N., Bertucci, D. et al. (2009), Surface waves on Saturn’s dawn flank magnetopause driven by the Kelvin–Helmholtz instability, Planetary and Space Science, 57, 1769–1778, DOI:10.1016/j.pss.2009.02.010.CrossRefGoogle Scholar
Masters, A., Achilleos, N., Kivelson, M. G. et al. (2010), Cassini observations of a Kelvin–Helmholtz vortex in Saturn’s outer magnetosphere, J. Geophys. Res. 115, A07225, DOI:10.1029/2010JA015351.Google Scholar
Mauk, B. H., Saur, J., Mitchell, D. G. et al. (2005), Energetic particle injections in Saturn’s magnetosphere, Geophysical Research Letters 32, L14S05, DOI:10.1029/2005GL022485.Google Scholar
McAndrews, H. J., Thomsen, M. F., Arridge, C. S. et al. (2009), Plasma in Saturn’s nightside magnetosphere and the implications for global circulation, Planet. Space Sci., 57, 1714–1722, DOI:10.1016/j.pss.2009.03.003.Google Scholar
Melin, H., Stallard, T., Miller, S. et al. (2011), Simultaneous Cassini VIMS and UVIS observations of Saturn’s southern aurora: Comparing emissions from H, H2 and H3+ at a high spatial resolution, Geophysical Research Letters 38, L15203, DOI:10.1029/2011GL048457.Google Scholar
Melin, H., Badman, S. V., Stallard, T. S. et al. (2016), Simultaneous multi-scale and multi-instrument observations of Saturn’s aurorae during the 2013 observing campaign, Icarus 263, 56–74, DOI:10.1016/j.icarus.2015.08.021.Google Scholar
Menietti, J. D., Mutel, R. L., Schippers, P., Ye, S.-Y., Gurnett, D. A., and Lamy, L. (2011), Analysis of Saturn kilometric radiation near a source center, J. Geophys. Res. 116, A12222, DOI:10.1029/2011JA017056.Google Scholar
Meredith, C. J., Cowley, S. W. H., Hansen, K. C. et al. (2013), Simultaneous conjugate observations of small-scale structures in Saturn’s dayside ultraviolet auroras: Implications for physical origins, J. Geophys. Res. 118, 2244–2266, DOI:10.1002/jgra.50270.Google Scholar
Milan, S. E., Hubert, B. and Grocott, A. (2005), Formation and motion of a transpolar arc in response to dayside and nightside reconnection, J. Geophys. Res., 110, A01212, DOI:10.1029/2004JA010835.Google Scholar
Mitchell, D. G., Kurth, W. S., Hospodarsky, G. B. et al. (2009), Ion conics and electron beams associated with auroral processes on Saturn. Journal Geophysical Research 114, 2212.Google Scholar
Mitchell, D. G., Carbary, J. F., Bunce, E. J. et al. (2016), Recurrent pulsations in Saturn’s high latitude magnetosphere, Icarus 263, 94–100, DOI:10.1016/j.icarus.2014.10.028.Google Scholar
Moore, L., Mueller-Wodarg, I., Galand, M., Kliore, A. and Mendillo, M. (2010), Latitudinal variations in Saturn’s ionosphere: Cassini measurements and model comparisons, Journal of Geophysical Research 115, A11317, DOI:10.1029/2010JA015692.Google Scholar
Müller-Wodarg, I. C. F., Moore, L. and Mendillo, G. M. (2012), Magnetosphere-atmosphere coupling at Saturn: 1. Response of thermosphere and ionosphere to steady state polar forcing, Icarus 221(2) DOI:10.1016/j.icarus.2012.08.034.Google Scholar
Mutel, R. L., Menietti, J. D., Gurnett, D. A. et al. (2010), CMI growth rates for Saturnian kilometric radiation, Geophys. Res. Lett., 37, L19105, DOI:10.1029/2010GL044940.Google Scholar
Nichols, J. D., Clarke, J. T., Cowley, S. W. H. et al. (2008), Oscillation of Saturn’s southern auroral oval, J. Geophys. Res., 113, A11205, DOI:10.1029/2008JA013444.Google Scholar
Nichols, J. D., Badman, S. V., Bunce, E. J. (2009), Saturn’s equinoctial auroras, Geophys. Res. Lett. 36, L24102- DOI:10.1029/2009GL041491.Google Scholar
Nichols, J. D., Cowley, S. W. H. and Lamy, L. (2010), Dawn‐dusk oscillation of Saturn’s conjugate auroral ovals, Geophys. Res. Lett., 37, L24102, DOI:10.1029/ 2010GL045818.Google Scholar
Nichols, J. D., Badman, S. V., Baines, K. H. et al. (2014), Dynamic auroral storms on Saturn as observed by the Hubble Space Telescope, Geophys. Res. Lett., 41, 3323–3330, DOI:10.1002/2014GL060186.Google Scholar
Nichols, J. D., Badman, S. V., Bunce, E. J. et al. (2016), Saturn’s northern auroras as observed using the Hubble Space Telescope, Icarus 263, 17–31, DOI:10.1016/j.icarus.2015.09.008.Google Scholar
O’Donoghue, J., Stallard, T. S., Melin, H. et al. (2013), The domination of Saturn’s low-latitude ionosphere by ring “rain,” Nature 496, 193–195, DOI:10.1038/nature12049.Google Scholar
Provan, G., Cowley, S. W. H. and Nichols, J. D. (2009), Phase relation of oscillations near the planetary period of Saturn’s auroral oval and the equatorial magnetospheric magnetic field, J. Geophys. Res., 114, A04205, DOI:10.1029/2008JA013988.Google Scholar
Pryor, W. R., Rymer, A. M., Mitchell, D. G. et al. (2011), The auroral footprint of Enceladus on Saturn, Nature, 472, 331–333, DOI:10.1038/nature09928.Google Scholar
Radioti, A., Grodent, D., Jia, X. et al. (2016), A multi-scale magnetotail reconnection event at Saturn and associated flows: Cassini/UVIS observations, Icarus, DOI:10.1016/j.icarus.2014.12.016.Google Scholar
Radioti, A., Grodent, D., Gérard, J.-C. et al. (2015), Auroral spirals at Saturn, J. Geophys. Res., 120, DOI:10.1002/2015JA021442.Google Scholar
Radioti, A., Grodent, D., Gérard, J.-C. et al. (2014), Saturn’s elusive nightside polar arc, Geophys. Res. Lett., 41, 6321–6328, DOI:10.1002/2014GL061081.Google Scholar
Radioti, A., Roussos, E., Grodent, D. et al. (2013a), Signatures of magnetospheric injections in Saturn’s aurora, J. Geophys. Res. 118, 1922–1933, DOI:10.1002/jgra.50161.Google Scholar
Radioti, A., Grodent, D., Gérard, J.-C., Bonfond, B., Gustin, J., Pryor, W., Jasinski, J. M. and Arridge, C. S. (2013b), Auroral signatures of multiple magnetopause reconnection at Saturn, Geophys. Res. Lett., 40, 4498–4502, DOI:10.1002/grl.50889.Google Scholar
Radioti, A., Grodent, D., Gérard, J.-C. et al. (2011), Bifurcations of the main auroral ring at Saturn: ionospheric signatures of consecutive reconnection events at the magnetopause, J. Geophys. Res. 116, 11209.Google Scholar
Radioti, A., Grodent, D., Gérard, J.-C., Roussos, E., Paranicas, C., Bonfond, B., Mitchell, D. G., Krupp, N., Krimigis, S. and Clarke, J. T. (2009), Transient auroral features at Saturn: Signatures of energetic particle injections in the magnetosphere, J. Geophys. Res., 114, A03210, DOI:10.1029/2008JA013632.Google Scholar
Ray, L. C., Galand, M., Moore, L. E.. and Fleshman, B. L. (2012), Characterizing the limitations to the coupling between Saturn’s ionosphere and middle magnetosphere, J. Geophys. Res 117, A07210, DOI:10.1029/2012JA017735.Google Scholar
Ray, L. C., Galand, M., Delamere, P. A. and Fleshman, B. L. (2013) Current-voltage relation for the Saturnian system, J. Geophys. Res 118, 3214–3222, DOI:10.1002/jgra.50330.Google Scholar
Sandel, B. R., Shemansky, D. E., Broadfoot, A. L. et al. (1982), Extreme ultraviolet observations from the Voyager 2 encounter with Saturn, Science, 215, 548–553, DOI:10.1126/science.215. 4532.548.Google Scholar
Schippers, P., Blanc, M., André, N. et al. (2008), Multi-instrument analysis of electron populations in Saturn’s magnetosphere, J. Geophys. Res. 113, A07208, DOI:10.1029/2008JA013098.Google Scholar
Schippers, P., Arridge, C. S., Menietti, J. D. et al. (2011), Auroral electron distributions within and close to the Saturn kilometric radiation source region, J. Geophys. Res. 116, A05203, DOI:10.1029/2011JA016461.Google Scholar
Schippers, P., André, N., Gurnett, D. A. et al. (2012), Identification of electron field-aligned current systems in Saturn’s magnetosphere, J. Geophys. Res. 117, A05204, DOI:10.1029/2011JA017352.Google Scholar
Smith, C. G. A. (2014), On the nature and location of the proposed twin vortex systems in Saturn’s polar upper atmosphere, J. Geophys. Res. 119, 5964–5977, DOI:10.1002/2014JA019934.Google Scholar
Stallard, T. S., Miller, S., Trafton, L. M. et al. (2004), Ion winds in Saturn’s southern auroral/polar region, Icarus 167, 204–211. DOI:10.1016/j.icarus.2003.09.006.Google Scholar
Stallard, T., Miller, S., Melin, H. et al. (2007a), Saturn’s auroral/polar H3+ infrared emission. I. General morphology and ion velocity structure, Icarus 189, 1–13, DOI:10.1016/j.icarus.2006.12.027.Google Scholar
Stallard, T., Smith, C., Miller, S. et al. (2007b), Saturn’s auroral/polar H3+ infrared emission. II. A comparison with plasma flow models, Icarus 191, 678–690, DOI:10.1016/j.icarus.2007.05.016.Google Scholar
Stallard, T., Miller, S., Melin, H. et al. (2008c), Jovian-like aurorae on Saturn, Nature 453, 1083–1085, DOI:10.1038/nature07077.Google Scholar
Stallard, T., Miller, S., Lystrup, M. et al. (2008d), Complex structure within Saturn’s infrared aurora, Nature 456, 214–217, DOI:10.1038/nature07440.Google Scholar
Stallard, T., Melin, H., Cowley, S. W. H. et al. (2010), Location and magnetospheric mapping of Saturn’s mid-latitude infrared auroral oval, Astrophysical Journal Letters 722, L85–L89, DOI:10.1088/2041–8205/722/1/L85.Google Scholar
Stallard, T. S., Masters, A., Miller, S. et al. (2012d), Saturn’s auroral/polar H3+ infrared emission: The effect of solar wind compression, J. Geophys. Res, A12302.Google Scholar
Stallard, T., Miller, S. and Melin, H. (2012c), Clues on Ionospheric Electrodynamics from IR Aurora at Jupiter and Saturn. Auroral Phenomenology and Magnetospheric Processes: Earth and Other Planets, Geophysical Monograph Series 197, 215–224, DOI:10.1029/2011GM001168.Google Scholar
Stallard, T. S., Melin, H., Miller, S. et al. (2012b), Temperature changes and energy inputs in Giant Planet atmospheres: What we are learning from H3+, Phil. Trans. R. Soc. A 370, 5213–5224, DOI:10.1098/rsta.2012.0028.Google Scholar
Stallard, T. S., Melin, H., Miller, S. et al. (2012a), Peak emission altitude of Saturn’s H3+ aurora, Geophysical Research Letters 39, L15103, DOI:10.1029/2012GL052806.CrossRefGoogle Scholar
Tao, C., Badman, S. V. and Fujimoto, M. (2011), UV and IR auroral emission model for the outer planets: Jupiter and Saturn comparison, Icarus 213, 581–592, DOI:10.1016/j.icarus.2011.04.001.Google Scholar
Tao, C., Lamy, L., Prangé, R. (2014), The brightness ratio of H Lyman-alpha H2 bands in FUV auroral emissions: A diagnosis for the energy of precipitating electrons and associated magnetospheric acceleration processes applied to Saturn, Geophysical Research Letters 41, 6644–6651, DOI:10.1002/2014GL061329.CrossRefGoogle Scholar
Talboys, D. L., Arridge, C. S., Bunce, E. J. et al. (2009), Characterization of auroral current systems in Saturn’s magnetosphere: High-latitude Cassini observations, J. Geophys. Res. 114, A06220, DOI:10.1029/2008JA013846.Google Scholar
Talboys, D. L., Bunce, E. J., Cowley, S. W. H. et al. (2011), Statistical characteristics of field-aligned currents in Saturn’s nightside magnetosphere, J. Geophys. Res. 116, A04213, DOI:10.1029/2010JA016102.CrossRefGoogle Scholar
Thomsen, M. F. (2013), Saturn’s magnetospheric dynamics, Geophysical Research Letters 40, 5337–5344, DOI:10.1002/2013GL057967.Google Scholar
Trafton, L., Carr, J., Lester, D. and Harvey, P. (1988), A possible detection of Jupiter’s northern auroral S1(1) H2 quadrupole line emission, Icarus 74, 351–356, DOI:10.1016/0019–1035(88)90047–4.Google Scholar
Trafton, L. M., Miller, S., Geballe, T. R. et al. (1999), H2 quadrupole and H3+ emission from Uranus: The Uranian thermosphere, ionosphere, and aurora, Ap. J. 524, 1059–1083, DOI:10.1086/307838.Google Scholar
Walker, R. J., Fukazawa, K., Ogino, T. and Morozoff, D. (2011), A simulation study of Kelvin–Helmholtz waves at Saturn’s magnetopause, J. Geophys. Res., 116, A03203, DOI:10.1029/2010JA015905.Google Scholar
Waite, J. H., Combi, M. R., Ip, W.-H. et al. (2006), Cassini ion and neutral mass spectrometer: Enceladus plume composition and structure, Science 311, 1419–1422, DOI:10.1126/science.1121290.Google Scholar
Warwick, J. W., Pearce, J. B., Evans, D. R. et al. (1981), Planetary radio astronomy observations from Voyager 1 near Saturn, Science, 212, 239–242.Google Scholar
Young, D. T., Berthelier, J.-J., Blanc, M. et al. (2005), Composition and dynamics of plasma in Saturn’s magnetosphere, Science 307, 1262–1266, DOI:10.1126/science.1106151.Google Scholar
Zarka, P. (1998), Auroral radio emissions at the outer planets: Observations and theories, Journal of Geophysical Research 103, 20159–20194, DOI:10.1029/98JE01323.Google Scholar
Zarka, P., Lamy, L., Cecconi, B. et al. (2007), Modulation of Saturn’s radio clock by solar wind, Nature, 450, 265–267.Google Scholar

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