Remote sensing of cometary bow shocks: Modelled asymmetric outgassing and pickup ion observations
| Autor: | Cyril Simon Wedlund, Riku Jarvinen, Tuija Pulkkinen, Markku Alho, Hans Nilsson, Esa Kallio |
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| Přispěvatelé: | Department of Electronics and Nanoengineering, Esa Kallio Group, Austrian Academy of Sciences, Swedish Institute of Space Physics, Aalto-yliopisto, Aalto University, Doctoral Programme in Particle Physics and Universe Sciences, Space Physics Research Group, Particle Physics and Astrophysics, Department of Physics |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Shock wave
010504 meteorology & atmospheric sciences IMPACT FLOW Flow (psychology) 114 Physical sciences 01 natural sciences miscellaneous [techniques] methods: numerical comets: individual: 67P individual: 67P [comets] NEUTRAL COMPOUNDS Ionization 0103 physical sciences 010303 astronomy & astrophysics 0105 earth and related environmental sciences DENSITY DISTRIBUTION Physics PLASMA 67P/CHURYUMOV-GERASIMENKO Astronomy and Astrophysics numerical [methods] Plasma shock waves plasmas Computational physics Pickup Ion Solar wind Outgassing techniques: miscellaneous GAS 13. Climate action Space and Planetary Science Remote sensing (archaeology) SOLAR-WIND IONIZATION ATMOSPHERES |
| Popis: | Despite the long escort by the ESA Rosetta mission, direct observations of a fully developed bow shock around 67P/Churyumov–Gerasimenko have not been reported. Expanding on our previous work on indirect observations of a shock, we model the large-scale features in cometary pickup ions, and compare the results with the ESA Rosetta Plasma Consortium Ion Composition Analyser ion spectrometer measurements over the pre-perihelion portion of the escort phase. Using our hybrid plasma simulation, an empirical, asymmetric outgassing model for 67P, and varied interplanetary magnetic field (IMF) clock angles, we model the evolution of the large-scale plasma environment. We find that the subsolar bow shock standoff distance is enhanced by asymmetric outgassing with a factor of 2 to 3, reaching up to $18\,000\, \rm {km}$ approaching perihelion. We find that distinct spectral features in simulated pickup ion distributions are present for simulations with shock-like structures, with the details of the spectral features depending on shock standoff distance, heliocentric distance, and IMF configuration. Asymmetric outgassing along with IMF clock angle is found to have a strong effect on the location of the spectral features, while the IMF clock angle causes no significant effect on the bow shock standoff distance. These dependences further complicate the interpretation of the ion observations made by Rosetta. Our data-model comparison shows that the large-scale cometary plasma environment can be probed by remote sensing the pickup ions, at least when the comet’s activity is comparable to that of 67P, and the solar wind parameters are known. |
| Databáze: | OpenAIRE |
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