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Journal ArticleDOI

Io's volcanic control of Jupiter's extended neutral clouds

01 Aug 2004-Icarus (Academic Press)-Vol. 170, Iss: 2, pp 430-442
TL;DR: In this article, dramatic changes in the brightness and shape of Jupiter's extended sodium nebula are found to be correlated with the infrared emission brightness of Io, and they conclude that silicate volcanism on Io controls both the rate and the means by which sodium escapes from Io's atmosphere.
About: This article is published in Icarus.The article was published on 2004-08-01. It has received 42 citations till now. The article focuses on the topics: Atmospheric escape & Population.
Citations
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Journal ArticleDOI
TL;DR: In this paper, an increase of supplied plasma from Io seems to be reflected in both plasma density and ion temperature, and the authors conclude that Io's volcanic enhancement with a duration time of a few days can change Jupiter's inner magnetospheric environment in aspects of both ion density and temperature.
Abstract: [1] Monitoring observations of Jupiter's sodium nebula and [SII] 673.1 nm emission from the Io plasma torus were made for 20 days in 2003. During these observations, the brightness of the sodium nebula showed a small enhancement which seemed to be caused by Io's volcanic outburst. During this enhancement, [SII] 673.1 nm brightness and the ion temperature (scale height) along Jupiter's magnetic fields did not show any significant change, but magnetic flux tube content of S+ ion was calculated from the [SII] 673.1 nm brightness and the scale height, and an increase of the ion flux tube content was clearly identified. Thus, increase of supplied plasma from Io seems to be reflected in both plasma density and ion temperature. We conclude that Io's volcanic enhancement with a duration time of a few days can change Jupiter's inner magnetospheric environment in aspects of both ion density and temperature.

24 citations

Journal ArticleDOI
TL;DR: In this article, the authors show that the increase in plasma supply from Io into Jupiter's magnetosphere weakens its field-aligned current, which generates the radio emissions and aurorae on Jupiter.
Abstract: [1] Jupiter's sodium nebula showed an enhancement in late May through the beginning of June 2007. This means Io's volcanic activity and the magnetosphere's plasma content increased during this period. On the other hand, Jupiter's radio emission called HOM became quiet after the sodium nebula enhancement. The HOM emission is considered to be related to the activity of aurorae on Jupiter. These observation results therefore suggest that the increase in plasma supply from Io into Jupiter's magnetosphere weakens its field-aligned current, which generates the radio emissions and aurorae on Jupiter. By comparing our observation results to recent model and observation results, we add supporting evidence to the possibility that Io's volcanism controls Jupiter's magnetospheric activity.

24 citations


Cites background from "Io's volcanic control of Jupiter's ..."

  • ...Several studies aimed at observing Jupiter’s sodium nebula or sulfur ion emissions from Io plasma torus have shown that Io’s volcanic supply varies [Brown and Bouchez, 1997; Mendillo et al., 2004; Nozawa et al., 2005; Yoneda et al., 2009; oneda et al., 2010]....

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Journal ArticleDOI
TL;DR: In this article, radio occultations of the Io plasma torus by the Juno spacecraft can measure plasma densities in the Io plasminar torus with uncertainties of 10% and scale heights describing the spatial variation in plasma density in each of these three regions can be measured with similar uncertainties.
Abstract: The flow of material from Io's volcanoes into the Io plasma torus, out into the magnetosphere, and along field lines into Jupiter's upper atmosphere is not adequately understood. The lack of observations of spatial and temporal variations in the Io plasma torus impedes attempts to understand the system as a whole. Here we propose that radio occultations of the Io plasma torus by the Juno spacecraft can measure plasma densities in the Io plasma torus. We find that the line-of-sight column density of plasma in each of the three regions of the Io plasma torus (cold torus, ribbon, and warm torus) can be measured with uncertainties of 10%. We also find that scale heights describing the spatial variation in plasma density in each of these three regions can be measured with similar uncertainties. Such observations will be sufficiently accurate to support system-scale studies of the flow of plasma through the magnetosphere of Jupiter.

21 citations


Cites background or methods from "Io's volcanic control of Jupiter's ..."

  • ...Moreover, line-of-sight TEC values will be greater than vertical TEC values by a factor of sec(𝜒 ), where 𝜒 is the zenith angle [Mendillo et al., 2004b]....

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  • ...Ground-based sodium cloud observations can be used to monitor the transport of material from Io’s atmosphere into the neutral clouds, since sodium can be considered as a tracer for sulfur and oxygen [Wilson et al., 2002; Mendillo et al., 2004a; Thomas et al., 2004]....

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  • ...Many ground-based surveys of spatial and temporal variability in the IPT have been conducted [e.g., Brown, 1995; Schneider and Trauger, 1995; Mendillo et al., 2004a; Nozawa et al., 2004, 2005, 2006; Yoneda et al., 2009, 2010, 2013]....

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Journal ArticleDOI
TL;DR: In this paper, the authors measured the long-term variability of the magnetodisk using Galileo magnetometer data collected from 1996 to 2003, and calculated the current sheet density parameter that gives the best fit to the data from each orbit and found that the current density parameter varies by about 15% of its average value during the Galileo era.
Abstract: Observations of Jupiter’s UV auroral emissions collected over several years show that the ionospheric positions of the main emission and the Ganymede footprint can vary by as much as 3° in latitude. One explanation for this shift is a change of Jupiter’s current sheet current density, which would alter the amount of field line stretching and displace the ionospheric mapping of field lines from a given radial distance in the magnetosphere. In this study we measure the long-term variability of Jupiter’s magnetodisk using Galileo magnetometer data collected from 1996 to 2003. Using the Connerney et al. (1981) current sheet model, we calculate the current sheet density parameter that gives the best fit to the data from each orbit and find that the current density parameter varies by about 15% of its average value during the Galileo era. We investigate possible relationships between the observed current sheet variability and quantities such as Io’s plasma torus production rate inferred from volcanic activity and external solar wind conditions extrapolated from data at 1 AU but find only a weak correlation. Finally, we trace Khurana (1997) model field lines to show that the observed changes in Jupiter’s current sheet are sufficient to shift the ionospheric footprint of Ganymede and main auroral emission by a few degrees of latitude, consistent with the magnitude of auroral variability observed by Hubble Space Telescope (HST). However, we find that the measured auroral shifts in HST images are not consistent with concurrent changes in the current density parameter measured by Galileo.

21 citations

References
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Book
01 Jan 2004
TL;DR: In this paper, the authors present a model for the formation and evolution of the inner and outer clouds of the Jovian satellite system, including the formation of the outer clouds.
Abstract: Preface 1. Introduction F. Bagenal, T. E. Dowling and W. B. McKinnon 2. The origin of Jupiter J. I. Lunine, A. Corandini, D. Gautier, T. C. Owen and G. Wuchterl 3. The interior of Jupiter T. Guillot, D. J. Stevenson, W. B. Hubbard and D. Saumon 4. The composition of the atmosphere of Jupiter F. W. Taylor, S. K. Atreya, Th. Encrenaz, D. M. Hunten, P. G. J. Irwin and T. C. Owen 5. Jovian clouds and haze R. A. West, K. H. Baines, A. J. Friedson, D. Banfield, B. Ragent and F. W. Taylor 6. Dynamics of Jupiter's atmosphere A. P. Ingersoll, T. E. Dowling, P. J. Gierasch, G. S. Orton, P. L. Read, A. Sanchez-Lavega, A. P. Showman, A. A. Simon-Miller and A. R. Vasavada 7. The stratosphere of Jupiter J. I. Moses, T. Fouchet, R. V. Yelle, A. J. Friedson, G. S. Orton, B. Bezard, P. Drossart, G. R. Gladstone, T. Kostiuk and T. A. Livengood 8. Lessons from Shoemaker-Levy 9 about Jupiter and planetary impacts J. Harrington, I. de Pater, S. H. Brecht, D. Deming, V. Meadows, K. Zahnle and P. D. Nicholson 9. Jupiter's thermosphere and ionosphere R. V. Yelle and S. Miller 10. Jovian dust: streams, clouds and rings H. Kruger, M. Horanyi, A. V. Krivov and A. L. Graps 11. Jupiter's ring-moon system J. A. Burns, D. P. Simonelli, M. R. Showalter, D. P. Hamilton, C. C. Porco, H. Throop and L. W. Esposito 12. Jupiter's outer satellites and trojans D. C. Jewitt, S. Sheppard and C. Porco 13. Interior composition, structure and dynamics of the Galilean satellites G. Schubert, J. D. Anderson, T. Spohn and W. B. McKinnon 14. The lithosphere and surface of Io A. S. McEwen, L. P. Keszthelyi, R. Lopes, P. M. Schenk and J. R. Spencer 15. Geology of Europa R. Greeley, C. F. Chyba, J. W. Head III, T. B. McCord, W. B. McKinnon, R. T. Pappalardo and P. Figueredo 16. Geology of Ganymede R. T. Pappalardo, G. C. Collins, J. W. Head III, P. Helfenstein, T. B. McCord, J. M. Moore, L. M. Procktor, P. M. Shenk and J. R. Spencer 17. Callisto J. M. Moore, C. R. Chapman. E. B. Bierhaus, R. Greeley, F. C. Chuang, J. Klemaszewski, R. N. Clark, J. B. Dalton, C. A. Hibbitts, P. M. Schenk, J. R. Spencer and R. Wagner 18. Ages and interiors: the cratering record of the Galilean satellites P. M. Schenk, C. R. Chapman, K. Zahnle and J. M. Moore 19. Satellite atmospheres M. A. McGrath, E. Lellouch, D. F. Strobel, P. D. Feldman and R. E. Johnson 20. Radiation effects on the surfaces of the Galilean satellites R. E. Johnson, R. W. Carlson, J. F. Cooper, C. Paranicas, M. H. Moore and M. C. Wong 21. Magnetospheric interactions with satellites M. G. Kivelson, F. Bagenal, W. S. Kurth, F. M. Neubauer, C. Paranicas and J. Saur 22. Plasma interactions of Io with its plasma torus J. Saur, F. M. Neubauer, J. E. P. Connerney, P. Zarka and M. G. Kivelson 23. The Io neutral clouds and plasma torus N. Thomas, F. Bagenal, T. W. Hill and J. K. Wilson 24. The configuration of Jupiter's magnetosphere K. K. Khurana, M. G. Kivelson, V. M. Vasyliunas, N. Krupp, J. Woch, A. Lagg, B. H. Mauk and W. S. Kurth 25. Dynamics of the Jovian magnetosphere N. Krupp, V. M. Vasyliunas, J. Woch, A. Lagg, K. K. Khurana, M. G. Kivelson, B. H. Mauk, E. C. Roelof, D. J. Williams, S. M. Krimigis, W. S. Kurth, L. A. Frank and W. R. Paterson 26. Jupiter's Aurora J. T. Clarke, D. Grodent, S. W. H. Cowley, E. J. Bunce, P. Zarka, J. E. P. Connerney and T. Satoh 27. Jupiter's inner radiation belts S. J. Bolton, R. M. Thorne, S. Bourdarie, I. de Pater and B. Mauk Appendix 1. Maps and spectra of Jupiter and the Galilean satellites J. R. Spencer, R. W. Carlson, T. L. Becker and J. S. Blue Appendix 2. Planetary parameters J. W. Weiss Index.

486 citations


"Io's volcanic control of Jupiter's ..." refers background in this paper

  • ...While a consensus model is far from complete, its potential elements have been described in several review articles (Schneider et al., 1989; Spencer and Schneider, 1996; Thomas, 1997; Bagenal, 2004)....

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Journal ArticleDOI
TL;DR: In this paper, the authors report the following results from a decade of infrared radiometry of Io: (1) the average global heat flow is more than approx. 2.5 W/sq.m, large warm (less than or equal to 200 K) volcanic regions dominate the global heat flows, smal high-temperature (greater than or = 300 K) 'hotspots' contribute little to the average heat flow, thermal anomalies on the leading hemisphere contribute about half of the heat flow and a substantial amount of heat is radiated during Io's night, high
Abstract: We report the following results from a decade of infrared radiometry of Io: (1) The average global heat flow is more than approx. 2.5 W/sq.m, (2) large warm (less than or equal to 200 K) volcanic regions dominate the global heat flow, (3) smal high-temperature (greater than or = 300 K) 'hotspots' contribute little to the average heat flow, (4) thermal anomalies on the leading hemisphere contribute about half of the heat flow, (5) a substantial amount of heat is radiated during Io's night, (6) high-temperature (greater than or = 600 K) 'outbursts' occurred during approx. 4% of the nights we observed, (7) 'Loki' is the brightest, persistent, infrared emission feature, and (8) some excess emission is always present at the longitude of Loki, but its intensity and other characteristics change between apparitions. Observations of Io at M(4.8 micrometer), 8.7 micrometer, N(10 micrometer), and Q(20 micrometer) with the Infrared Telescope Facility presented here were collected during nine apparitions between 1983 and 1993. These measurements provide full longitudinal coveraged as well as an eclipse observation and the detection of two outbursts. Reflected sunlight, passive thermal emission, and radiation from thermal anomalies all contribute to the observed flux densities. We find that a new thermophysical model is required to match all the data. Two key elements of this model are (1) a 'thermal reservoir' unit which lowers daytime temperatures, and (2) the 'thermal pedestal effect' which shifts to shorter wavelengths the spectral emission due to the reradiation of solar energy absorbed by the thermal anomalies. The thermal anomalies are modeled with a total of 10 source components at five locations. Io's heat flow is the sum of the power from these components.

217 citations


"Io's volcanic control of Jupiter's ..." refers background in this paper

  • ...Hence, w there is continuity of nebula observations from year to y shorter time resolution issues cannot be addressed with a dataset....

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Journal ArticleDOI
TL;DR: Io, the innermost of Jupiter's large moons, is one of the most unusual objects in the Solar System as discussed by the authors, which produces a global heat flux 40 times the terrestrial value, producing intense volcanic activity and a global resurfacing rate averaging perhaps 1 cm yr−1.
Abstract: ▪ Abstract Io, innermost of Jupiter's large moons, is one of the most unusual objects in the Solar System. Tidal heating of the interior produces a global heat flux 40 times the terrestrial value, producing intense volcanic activity and a global resurfacing rate averaging perhaps 1 cm yr−1. The volcanoes may erupt mostly silicate lavas, but the uppermost surface is dominated by sulfur compounds including SO2 frost. The volcanoes and frost support a thin, patchy SO2 atmosphere with peak pressure near 10−8 bars. Self-sustaining bombardment of the surface and atmosphere by Io-derived plasma trapped in Jupiter's magnetosphere causes escape of material from Io (predominantly sulfur, oxygen, and sodium atoms, ions, and molecules) at a rate of about 103 kg s−1. The resulting Jupiter-encircling torus of ionized sulfur and oxygen dominates the Jovian magnetosphere and, together with an extended cloud of neutral sodium, is readily observable from Earth.

184 citations


"Io's volcanic control of Jupiter's ..." refers background in this paper

  • ...Keywords: Io; Jupiter, magnetosphere; Satellites, atmospheres; Volcanism nds phe and the ter’s and surd Io niza ally on, ter’s r in ave ronto a eres, ear iled the ecraft ervabit. n vol- proain e in a onents 997; d with...

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  • ...They are estimated to occur 3% o time globally(Spencer and Schneider, 1996)....

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  • ...In 1995, Tiermes Patera and Ukko Patera erupted a tectable levels for 60–80 days and 30–70 days, respecti Together, these represent 14 of the 23 non-Loki erup measurements in the total dataset of 120 nights....

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  • ...While a c sensus model is far from complete, its potential elem have been described in several review articles(Schneider et al., 1989; Spencer and Schneider, 1996; Thomas, 1 Bagenal, 2004)....

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Journal ArticleDOI
TL;DR: In this paper, a three-dimensional, stationary, two-fluid plasma model for electrons and one ion species was developed to understand the local interaction of Io's atmosphere with the Io plasma torus and the formation of Io ionosphere.
Abstract: A three-dimensional, stationary, two-fluid plasma model for electrons and one ion species was developed to understand the local interaction of Io's atmosphere with the Io plasma torus and the formation of Io's ionosphere. Our model calculates, self-consistently, the plasma density, the velocity and the temperatures of the ions and electrons, and the electric field for a given neutral atmosphere and imposed Io plasma torus conditions but assumes for the magnetic field the constant homogeneous Jovian field. With only photoionization in a pure SO2 atmosphere it is impossible to correctly model the plasma measurements by the Galileo spacecraft. With collisional ionization and photoionization the observations can be successfully modeled when the neutral atmospheric column density is Ncol = 6 × 1020 m−2 and the atmospheric scale height is H = 100 km. The energy reservoir of the Io plasma torus provides via electron heat conduction the necessary thermal energy for the maintenance of the collisional ionization process and thus the formation of Io's ionosphere. Anisotropic conductivity is shown numerically as well as analytically to be essential to understand the convection patterns and current systems across Io. The electric field is very greatly reduced, because the ionospheric conductances far exceed the Alfven conductance ΣA, and also strongly twisted owing to the Hall effect. We find that the electric field is twisted by an analytic angle tan Θtwist = Σ2/(Σ1 + 2ΣA) from the anti-Jupiter direction toward the direction of corotation for constant values of the Pedersen and Hall conductances Σ1 and Σ2 within a circle encompassing Io's ionosphere. Because the electron velocity is approximately equal to the E × B drift velocity, the electron flow trajectories are twisted by the same angle toward Jupiter, with E and B the electric and magnetic fields, respectively. Since Σ1 ∼ Σ2, the electron flow is strongly asymmetric during convection across Io, and the magnitude of this effect is directly due to the Hall conductivity. In contrast, the ions are diverted slightly away from Jupiter when passing Io. Large electric currents flow in Io's ionosphere owing to these substantially different flow patterns for electrons and ions, and our calculations predict that a total electric current of 5 million A was carried in each Alfven wing during the Galileo flyby. We also find a total Joule heating rate dissipated in Io's ionosphere of P = 4.2 × 1011 W.

144 citations

Journal ArticleDOI
02 Jan 2003-Nature
TL;DR: The detection of NaCl in Io's atmosphere is reported; it constitutes only ∼0.3% when averaged over the entire disk, but is probably restricted to smaller regions than SO2 because of its rapid photolysis and surface condensation.
Abstract: The atmosphere of Jupiter's satellite Io is extremely tenuous, time variable and spatially heterogeneous. Only a few molecules—SO2, SO and S2—have previously been identified as constituents of this atmosphere, and possible sources1,2,3,4 include frost sublimation, surface sputtering and active volcanism. Io has been known5,6 for almost 30 years to be surrounded by a cloud of Na, which requires an as yet unidentified atmospheric source of sodium. Sodium chloride has been recently proposed as an important atmospheric constituent, based on the detection of chlorine in Io's plasma torus7,8 and models of Io's volcanic gases9 . Here we report the detection of NaCl in Io's atmosphere; it constitutes only ∼0.3% when averaged over the entire disk, but is probably restricted to smaller regions than SO2 because of its rapid photolysis and surface condensation10. Although the inferred abundance of NaCl in volcanic gases is lower than predicted9, those volcanic emissions provide an important source of Na and Cl in Io's neutral clouds and plasma torus.

100 citations


"Io's volcanic control of Jupiter's ..." refers background in this paper

  • ...%)...

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  • ...…erable evidence for calling it NaCl+. Observations of Cl+ in the plasma torus(Kuppers and Schneider, 2000), direct detection of NaCl in Io’s atmosphere(Lellouch et al., 2003), and a recent set of atmospheric models for volcanic co tions offer ample evidence to base further discussions u NaCl being…...

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