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Radiation transport of heliospheric Lyman-alpha from combined Cassini and Voyager data setsстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
- Авторы: Pryor W., Gangopadhyay P., Sandel B., Forrester T., Quemerais E., Moebius E., Esposito L., Stewart I., McClintock W., Jouchoux A., Colwell J., Izmodenov V., Malama Y., Tobiska K., Shemansky D., Ajello J., Hansen C., Bzowski M.
- Журнал: Astronomy and Astrophysics
- Том: 491
- Номер: 1
- Год издания: 2008
- Издательство: Springer Verlag
- Местоположение издательства: Germany
- Первая страница: 21
- Последняя страница: 28
- DOI: 10.1051/0004-6361:20078862
- Аннотация: Aims. Heliospheric neutral hydrogen scatters solar Lyman-alpha radiation from the Sun with "27-day" intensity modulations observed near Earth due to the Sun's rotation combined with Earth's orbital motion. These modulations are increasingly damped in amplitude at larger distances from the Sun due to multiple scattering in the heliosphere, providing a diagnostic of the interplanetary neutral hydrogen density independent of instrument calibration. Methods. This paper presents Cassini data from 2003-2004 obtained downwind near Saturn at similar to 10 AU that at times show undamped "27-day" waves in good agreement with the single-scattering models of Pryor et al. ( 1992, ApJ, 394, 363). Simultaneous Voyager 1 data from 2003- 2004 obtained upwind at a distance of 88.8-92.6 AU from the Sun show waves damped by a factor of similar to 0.21. The observed degree of damping is interpreted in terms of Monte Carlo multiple-scattering calculations ( e. g., Keller et al. 1981, A& A, 102, 415) applied to two heliospheric hydrogen two-shock density distributions ( discussed in Gangopadhyay et al. 2006, ApJ, 637, 786) calculated in the frame of the Baranov-Malama model of the solar wind interaction with the two-component ( neutral hydrogen and plasma) interstellar wind (Baranov & Malama 1993, J. Geophys. Res., 98, 15157; Izmodenov et al. 2001, J. Geophys. Res., 106, 10681; Baranov & Izmodenov 2006, Fluid Dyn., 41, 689). Results. We conclude that multiple scattering is definitely occurring in the outer heliosphere. Both models compare favorably to the data, using heliospheric neutral H densities at the termination shock of 0.085 cm(-3) and 0.095 cm(-3). This work generally agrees with earlier discussions of Voyager data in Quemerais et al. ( 1996, ApJ, 463, 349) showing the importance of multiple scattering but is based on Voyager data obtained at larger distances from the Sun ( with larger damping) simultaneously with Cassini data obtained closer to the Sun. Key words. ISM: atoms
- Добавил в систему: Измоденов Владислав Валерьевич