Hostname: page-component-78c5997874-j824f Total loading time: 0 Render date: 2024-11-10T07:38:19.500Z Has data issue: false hasContentIssue false

Three-Dimensional Modelling of EUVE Observations of the Io Plasma Torus

Published online by Cambridge University Press:  12 April 2016

N. Thomas
Affiliation:
Max-Planck-Institut für Aeronomie, D-37191 Katlenburg-Lindau, Germany
D.E. Innes
Affiliation:
Max-Planck-Institut für Aeronomie, D-37191 Katlenburg-Lindau, Germany
R. Lieu
Affiliation:
Center for EUV Astrophysics, 2150 Kittredge St., University of California, Berkeley, CA 94720-5030, USA

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

First results from a 3-D model of EUVE observations of the Io Plasma Torus are reported. The semi-empirical model calculations follow a method previously used to describe visible and near-UV emissions. The extension to EUV wavelengths is described. Several EUV emissions have been successfully modelled although some discrepancies remain at this stage. Most EUV emissions peak at a jovicentric distance of ≈ 5.8 RJ. The observed dawn-dusk asymmetry of the torus was well fitted with a shift parameter (ϵ) of 0.03. The modelling also indicates that optical depth effects need to be considered for several EUV emission lines.

Type
X. Solar System Observations
Copyright
Copyright © Kluwer 1996

References

Bagenal, F. 1985, Plasma conditions inside Io’s orbit: Voyager measurements, J. Geophys. Res., 90, 311 Google Scholar
Bagenal, F. 1994, Empirical model of the Io plasma torus: Voyager measurements, J. Geophys. Res., 99, 11,043 Google Scholar
Bagenal, F., et al. 1992, The Abundance of O++ in the Jovian Magnetosphere, Geophys. Res. L., 19, 79 Google Scholar
Barbosa, D.D. & M.G., Kivelson 1983, Dawn-dusk electric field asymmetry of the Io plasma torus, Geophy. Res. L., 10, 210 Google Scholar
Bates, D.R. & A., Damgaard 1949, The calculation of the absolute strengths of spectral lines, Phil. Trans. Roy. Soc. London, 242, 101 Google Scholar
Broadfoot, A.L., et al. 1979, Extreme ultraviolet observations from Voyager I encounter with Jupiter, Science, 204, 979 Google Scholar
Condon, E.U. & Shortly, G.H. 1970, The theory of atomic spectra, Cambridge: Cambridge University Press Google Scholar
Hall, D.T., et al. 1994, Extreme Ultraviolet Explorer satellite observation of Jupiter’s Io plasma torus, ApJL, 426, L51 Google Scholar
Ho, Y.K. & R.J.W., Henry 1984a, Oscillator strengths for Oil ions, J. Quart. Spectrosc. Radiat. Transfer, 31, 57 CrossRefGoogle Scholar
Ho, Y.K. & R.J.W., Henry 1984b, Oscillator strengths and collision strengths for S III, ApJ, 282, 816 Google Scholar
Ip, W.H. & C.K., Goertz 1983, An interpretation of the dawn-dusk asymmetry of UV emission from the Io plasma torus, Nature, 302, 232 Google Scholar
Itikawa, Y. S.Hara, T.Kato, S.Nakazaki, Pindzola, M.S., & Crandall, D.H. 1983, Recommended data on excitation of carbon and oxygen ions by electron collisions, Institute of Plasma Physics, Nagoya University Google Scholar
Landini, M. & B.C., Monsignori, FOSSI 1990, The X-UV spectrum of thin plasmas, A&AS, Ser., 82, 229 Google Scholar
Mcgrath, M. et al. 1995, Response of the Io Plasma Torus to Comet Shoemaker-Levy 9, Science, 267, 1313 Google Scholar
Mewe, R. 1972, Interpolation Formulae for the Electron Impact Excitation of Ions in the H-, He-, Li-, and Ne-Sequences, A&A, 20, 215 Google Scholar
Morgan, J.S. 1985, Temporal and spatial variations in the Io torus, Icarus, 62, 389 Google Scholar
Nussbauer, H. & P.J., Storey 1981, O.III: Intercombination and Forbidden Lines., A&A, 99, 177 Google Scholar
Osterbrock, D.E. 1989, Astrophysics of Gaseous Nebulae and Active Galactic Nuclei, Mill Valley, Calif.: Science Books Google Scholar
Ryan, L.J., Rayburn, L.A., & Cunningham, A.J. 1989, Measurements of oscillator strengths for EUV emissions of ionized oxygen, nitrogen and sulfur, J. Quant. Spectros. Radiot. Transfer, 42, 295 Google Scholar
Sandel, B.R. & A.L., Broadfoot 1982, Io’s hot plasma torus—A synoptic view from Voyager, J. Geophys. Res., 87, 212 Google Scholar
Schneider, N.M. & Trauger, J.T. 1995, The Structure of the Io Torus, ApJ, in pressGoogle Scholar
Shemansky, D.E. 1988, Energy branching in the Io plasma torus: The failure of neutral cloud theory, J. Geophys. Res., 93, 1773 Google Scholar
Shemansky, D.E. & B.R.Sandel, 1981, The injection of energy into the Io plasma torus, J. Geophys. Res., 87, 219 Google Scholar
Shemansky, D.E. & Smith, G.R. 1981, The Voyager 1 EUV spectrum of the Io plasma torus, J. Geophys. Res., 86, 9179 Google Scholar
Sittler, E.C. & Strobel, D.F. 1987, Io plasma torus electrons: Voyager I., J. Geophys. Res., 92, 5741 Google Scholar
Smyth, W.H. & Combi, M.R. 1988, A general model for Io’s neutral gas clouds II: Application to the sodium cloud, ApJ, 328, 888 Google Scholar
Strobel, D.F. & Davis, J. 1980, Properties of the Io plasma torus inferred from Voyager EUV data., ApJL, 238, L49 Google Scholar
SultanaN., Nahar 1993, Transition Proabilities for Dipole Allowed Fine Structure Transitions in Si-like Ions: Si I, S III, Ar V and Ca VII, Physica Scripta, 48, 297 Google Scholar
Taylor, M.H. et al. 1995, A comparison of the Voyager 1 UVS and PLS measurements of the Io Plasma Torus, J. Geophys. Res., submittedGoogle Scholar
Thomas, N. 1992, Optical observations of Io’s neutral clouds and plasma torus, Surv. Geophys., 13, 91 Google Scholar
Thomas, N. 1993, Detection of [OIII]λ5007 emission from the Io plasma torus, ApJL, 414, L41 Google Scholar
Thomas, N. 1995, Ion temperatures in the Io plasma torus, J. Geophys. Res., 100, 7925 Google Scholar
Wiese, W.L., Smith, M.W., & Glennon, B. M. 1966, Atomic Transition Probabilities, 1, NSRDS-NRS 22 Google Scholar