Plasma Pressures in the Heliosheath From Cassini ENA and Voyager 2 Measurements: Validation by the Voyager 2 Heliopause Crossing
Abstract We report “ground truth,” 28‐ to 3,500‐keV in situ ion and 5.2‐ to 55‐keV remotely sensed ENA measurements from Voyager 2/Low Energy Charged Particle detector and Cassini/Ion and Neutral Camera, respectively, that assess the components of the ion pressure in the heliosheath. In this process...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2019-07-01
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| Series: | Geophysical Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2019GL083924 |
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| Summary: | Abstract We report “ground truth,” 28‐ to 3,500‐keV in situ ion and 5.2‐ to 55‐keV remotely sensed ENA measurements from Voyager 2/Low Energy Charged Particle detector and Cassini/Ion and Neutral Camera, respectively, that assess the components of the ion pressure in the heliosheath. In this process, we predict an interstellar neutral hydrogen density of ∼0.12 cm−3 and an interstellar magnetic field strength of ∼0.5‐nT upstream of the heliopause in the direction of V2, that is, consistent with the measured magnetic field and neutral density measurements at Voyager 1 from August 2012, when the spacecraft entered interstellar space, to date. Further, this analysis results in an estimated heliopause crossing by V2 of ∼119 AU, as observed, suggesting that the parameters deduced from the pressure analysis are valid. The shape of the >5.2‐keV ion energy spectra play a critical role toward determining the pressure balance and acceleration mechanisms inside the heliosheath. |
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| ISSN: | 0094-8276 1944-8007 |