| タイトル | Heliospheric hydrogen beyond 15 AU - Evidence for a termination shock |
| 著者（英） | Judge, D. L.; Gruntman, M. A.; Hall, D. T.; Shemansky, D. E.; Gangopadhyay, P. |
| 著者所属（英） | NASA Headquarters |
| 発行日 | 1993-09-01 |
| 言語 | eng |
| 内容記述 | The Voyager and Pioneer 10 spacecraft are moving upstream and downstream into the local interstellar flow, monitoring H Lyman alpha radiation resonantly scattered from heliospheric hydrogen. Voyager Cruise Maneuver observations obtained between 15 and 35 AU reveal that H Lyman alpha intensities in the upstream direction fall as r exp -0.75+/-0.05. Beyond 15 AU downstream, Pioneer 10 intensities fall as r exp -1.07+/-0.1. These trends cannot be simultaneously reproduced using a hot H distribution model that does not include termination shock structure. The Voyager H Lyman alpha intensities also show a distinctive trend to decrease less rapidly with increasing heliocentric distance. Between 15 and 20 AU, Voyager intensities fall as r exp -1, whereas between 30 and 35 AU they fall as r exp -0.35. This flattening trend implies that the upstream H density is increasing rapidly with heliocentric distance beyond about 25 AU. This steepening trend is significant because similar H density gradients are predicted in models which include the effects of the termination shock. Taken together, the Voyager and Pioneer 10 H Lyman alpha observations beyond 15 AU imply the existence of a solar wind termination shock, suggesting that it lies between 70 and 105 AU in the upstream direction. |
| NASA分類 | ASTROPHYSICS |
| レポートNO | 94A10159 |
| 権利 | Copyright |
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