Ecliptic North-South Symmetry of Hydrogen Geocorona
| Autor: | Masaki Sato, Shota Ikezawa, Go Murakami, Makoto Taguchi, Masaki Kuwabara, Yoshizumi Miyoshi, Seiji Sugita, Naoya Osada, Ichiro Yoshikawa, Shingo Kameda, Ryu Funase, Masaki Fujimoto, Kazuo Yoshioka |
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| Rok vydání: | 2017 |
| Předmět: |
Physics
010504 meteorology & atmospheric sciences Atmospheric escape Hydrogen Ecliptic Astronomy chemistry.chemical_element Plasmasphere 01 natural sciences Earth radius Geophysics chemistry Radiation pressure Physics::Space Physics 0103 physical sciences General Earth and Planetary Sciences Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics 0105 earth and related environmental sciences Exosphere Geocorona |
| Zdroj: | Geophysical Research Letters. 44:11-11,712 |
| ISSN: | 0094-8276 |
| DOI: | 10.1002/2017gl075915 |
| Popis: | The hydrogen exosphere constitutes the uppermost atmospheric layer of the Earth, and its shape may reflect the last stage of the atmospheric escape process. The distribution of hydrogen in the outer exosphere remains unobserved because outer geocoronal emissions are difficult to observe from within the exosphere. In this study, we used the Lyman Alpha Imaging Camera (LAICA) onboard the Proximate Object Close Flyby with Optical Navigation (PROCYON) spacecraft, located outside the exosphere, to obtain the first image of the entire geocorona that extends to more than 38 Earth radii. The observed emission intensity distribution can be reproduced using our analytical model that has three parameters: exobase temperature, exobase density, and solar radiation pressure, which implies that hot hydrogen production in the magnetized plasmasphere is not the dominant process shaping the outer hydrogen exosphere. However, the role of the magnetic effect in determining the total escape flux cannot be ruled out |
| Databáze: | OpenAIRE |
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