| Автор | Decker, R. B. |
| Автор | Cheng, A. F. |
| Дата выпуска | 1994 |
| dc.description | Escape of neutral hydrogen (H) and nitrogen (N) from Triton maintains a large neutral cloud, called the Triton torus, in Neptune's magnetosphere. We have developed the first detailed Monte Carlo simulation model of the Triton torus that includes the collisionality, the complex geometry, the injection of two neutral species from Triton (H and N), and the combined effects of photoionization, electron impact ionization, and charge exchange. Ionization in Neptune's plasma sheet was modeled using Voyager plasma observations. Collisions cause both the H and N neutral clouds to become more radially extended, both toward Neptune and out beyond the magnetopause, as well as more extended in latitude, when compared with collisionless models. Moreover, collisions of H with the much more massive N greatly enhance the collisional ejection of H from the system and into Neptune's atmosphere. This effect decreases the probability of H ionization within the magnetosphere relative to that for N, and furthermore causes model results for two‐species injection from Triton to differ significantly from those for H injection alone. For a hydrogen escape rate from Triton of 5 × 10<sup>25</sup> s<sup>−1</sup>, as given by photochemical models of Triton's upper atmosphere, a nitrogen escape rate of 5 × 10<sup>24</sup> s<sup>−1</sup> gives proton and N<sup>+</sup> sources of 5.6 × 10<sup>24</sup> s<sup>−1</sup> and 3.3 × 10<sup>24</sup> s<sup>−1</sup>, respectively, whose ratio is close to the observed ratio of protons to heavies. A nitrogen escape rate of 2 × 10<sup>25</sup> s<sup>−1</sup>, for the same hydrogen escape rate of 5 × 10<sup>25</sup> s<sup>−1</sup>, yields an N<sup>+</sup> source more than twice that of protons, inconsistent with the Voyager data. |
| Формат | application.pdf |
| Копирайт | Copyright 1994 by the American Geophysical Union. |
| Тема | PLANETARY SCIENCES: SOLID SURFACE PLANETS |
| Тема | Planetology: Solid Surface Planets and Satellites: Origin and evolution |
| Тема | Planetology: Solid Surface Planets and Satellites: Atmospheric composition and chemistry |
| Название | A model of Triton's role in Neptune's magnetosphere |
| Тип | article |
| DOI | 10.1029/94JE01867 |
| Electronic ISSN | 2156-2202 |
| Print ISSN | 0148-0227 |
| Журнал | Journal of Geophysical Research: Planets |
| Том | 99 |
| Первая страница | 19027 |
| Последняя страница | 19045 |
| Выпуск | E9 |
| Библиографическая ссылка | Belcher, J. W., et al., Plasma observations near Neptune: Initial results from Voyager 2, Science, 246, 1478, 1989. |
| Библиографическая ссылка | Broadfoot, A. L., et al., Ultraviolet spectrometer observations of Neptune and Triton, Science, 246, 1459, 1989. |
| Библиографическая ссылка | Cheng, A. F., Triton torus and Neptune aurora, Geophys. Res. Lett., 17, 1669, 1990. |
| Библиографическая ссылка | Fite, W. L., A. C. H.Smith, R. F.Stebbings, Charge exchange in collisions involving symmetric and asymmetric resonance, Proc. R. Astron. Soc., 268, 527, 1962. |
| Библиографическая ссылка | Hilton, D., D.Hunten, A partially collisional model of the Titan hydrogen torus, Icarus, 73, 248, 1988. |
| Библиографическая ссылка | Krimigis, S. M., et al., Hot plasma and energetic particles in Neptune's magnetosphere, Science, 246, 1483, 1989. |
| Библиографическая ссылка | Mauk, B. H., E. P.Keath, M.Kane, S. M.Krimigis, A. F.Cheng, M. H.Acuña, T. P.Armstrong, N. F.Ness, The magnetosphere of Neptune: Hot plasmas and energetic particles, J. Geophys. Res., 96, 19,061, 1991. |
| Библиографическая ссылка | Mauk, B. H., S. M.Krimigis, A. F.Cheng, andR. S.Selesnick, Energetic particles and hot plasmas of Neptune, inNeptune and Triton, edited byD.Cruikshank, University of Arizona Press,Tucson, in press,1994. |
| Библиографическая ссылка | Ness, N., M. H.Acuña, L. F.Burlaga, J. E. P.Connerney, R. P.Lepping, F. M.Neubauer, Magnetic fields at Neptune, Science, 246, 1473, 1989. |
| Библиографическая ссылка | Rapp, D., W. E.Francis, Charge exchange between gaseous ions and atoms, J. Chem. Phys., 17, 2631, 1962. |
| Библиографическая ссылка | Richardson, J. D., A.Eviatar, M.Delitsky, The Triton torus re‐visited, Geophys. Res. Lett., 17, 1673, 1990. |
| Библиографическая ссылка | Richardson, J. D., J. W.Belcher, M.Zhang, R. L.McNutt, Low‐energy ions near Neptune, J. Geophys. Res., 96, 18,993, 1991. |
| Библиографическая ссылка | Smyth, W. H., M.Marconi, The nature of the hydrogen tori of Titan and Triton, Icarus, 101, 18, 1994. |
| Библиографическая ссылка | Stebbings, R. F., W. L.Fite, D. G.Hummer, Charge exchange between atomic hydrogen and N<sup>+</sup> and O<sup>+</sup>, J. Chem. Phys., 33, 1226, 1960. |
| Библиографическая ссылка | Strobel, D., andM.Summers, Triton's upper atmosphere and ionosphere, inNeptune and Triton, edited byD.Cruikshank, University of Arizona Press,Tucson, in press,1994. |
| Библиографическая ссылка | Summers, M., D.Strobel, Triton's atmosphere: A source of N and H for Neptune's magnetosphere, Geophys. Res. Lett., 18, 2309, 1991. |
| Библиографическая ссылка | Trulsen, J., Numerical simulation of jet streams, Astrophys. Space Sci., 17, 241, 1972. |
| Библиографическая ссылка | Zhang, M., J. D.Richardson, E. C.Sittler, Voyager 2 electron observations in the magnetosphere of Neptune, J. Geophys. Res., 96, 19,085, 1991. |
