The pick-up of cometary protons by the solar wind

Neugebauer, M.; Lazarus, A. J.; Altwegg, Kathrin; Balsiger, H.; Goldstein, B. E.; Goldstein, R.; Neubauer, F. M.; Rosenbauer, H.; Schwenn, R.; Shelley, E. G.; Ungstrup, E.

doi:10.1007/978-3-642-82971-0_3

Cited by 16 publications

(23 citation statements)

References 4 publications

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“…The pickup ions described above appear to have a distribution that is random in time. We have not seen an expected ring‐like distribution [ Neugebauer et al ., ] and the reason may be that these ions are created locally and have only sufficient time to accelerate to several hundred eV/e and are still on a relatively linear trajectory. These observations are thus very different from those measured previously during relatively fast flybys of very active comets such as the case for the Giotto mission to comet Halley and represent a view of the beginning of plasma processes at a comet.…”

Section: Discussionmentioning

confidence: 99%

The Rosetta Ion and Electron Sensor (IES) measurement of the development of pickup ions from comet 67P/Churyumov‐Gerasimenko

Goldstein

Burch

Mokashi

et al. 2015

Geophysical Research Letters

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The Rosetta Ion and Electron Sensor (IES) has been measuring solar wind ions intermittently since exiting from hibernation in May 2014. On 19 August, when Rosetta was ~80 km from the comet 67P/Churyumov‐Gerasimenko, which was ~3.5 AU from the Sun, IES began to see ions at its lowest energy range, ~4–10 eV. We identify these as ions created from neutral species emitted by the comet nucleus, photoionized by solar UV radiation in the neighborhood of the Rosetta spacecraft (S/C), and attracted by the small negative potential of the S/C resulting from the population of thermal electrons. Later, IES began to see higher‐energy ions that we identify as having been picked up and accelerated by the solar wind. IES continues to measure changes in the solar wind and the development of the pickup ion structure.

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Section: Discussionmentioning

confidence: 99%

The Rosetta Ion and Electron Sensor (IES) measurement of the development of pickup ions from comet 67P/Churyumov‐Gerasimenko

Goldstein

Burch

Mokashi

et al. 2015

Geophysical Research Letters

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“…comets, Jupiter) decrease with distance from the source (cf. Neugebauer et aL, 1987;Geiss et aL, 1994b;Ogilvie et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

Origin of C+ ions in the heliosphere

1996

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C + pickup ions were investigated with the SWICS instrument along the trajectory of Ulysses, covering a broad range of solar latitude and distance. Whereas nearly all the observed H +, He +, N +, O + and Ne + pickup ions are created from the interstellar gas penetrating deep into the heliosphere, C + comes primarily from an "inner source" which is located at a solar distance below a few AU and extends over all heliospheric latitudes investigated up to now. We present evidence that the C + originates from carbon compounds evaporating from interstellar grains. This inner source also produces some O + and N + with estimated relative abundances of C+/O + ,v 1 and N+/O + -,~ 0.2. However, the total amount of O + and N + produced by this inner source is only of the order of 10 -3 as compared to the total production of O + and N + from the interstellar gas in the heliosphere, respectively. Thus the inner source does not significantly contribute to oxygen or nitrogen in the anomalous cosmic rays (ACR) but its contribution to ACR-carbon may not be negligible.

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“…We assume that the pick-up ion velocity distribution is shell-like due to rapid pitch-angle scattering-this is supported observationally [Neugebauer et al, 1987b] and ensures that •he plasma flow is essentially hydrodynamic. Conservation of mass then becomes where q m average volume production rate of comet dry ions, m• m cometdry ion mass, d =-observed shock thickness, p the fluid density and u•0 the normal upstream fluid velocity.…”

Section: Equations and Analysismentioning

confidence: 95%

Mass‐loading and parallel magnetized shocks

Zank¹,

Oughton²,

Neubauer³

et al. 1991

Geophysical Research Letters

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Abstract. Recent observations at comets Giacobini-ginnet and Halley suggest that simple non-reacting gas dynamics or MHD is an inappropriate description for the bow shock. The thickness of the observed (sub)shock implies that mass-loading is an important dynamical process within the shock itself, thereby requiring that the RankineHugoniot conditions possess source terms. This leads to shocks with properties similar to those of combustion shocks We consider parallel magnetized shocks subjected to massloading, describe some properties which distinguish them from classical MHD parallel shocks, and establish the existence of a new kind of MHD compound shock. These results will be of importance both to observations and numerical simulations of the comet-solar wind interaction.

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The pick-up of cometary protons by the solar wind

Cited by 16 publications

References 4 publications

The Rosetta Ion and Electron Sensor (IES) measurement of the development of pickup ions from comet 67P/Churyumov‐Gerasimenko

The Rosetta Ion and Electron Sensor (IES) measurement of the development of pickup ions from comet 67P/Churyumov‐Gerasimenko

Origin of C+ ions in the heliosphere

Mass‐loading and parallel magnetized shocks

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