Global plasma-parameter simulation of Comet 67P/Churyumov-Gerasimenko approaching the Sun

Gortsas, Nikolaos; Motschmann, U.; Kührt, Ekkehard; Glaßmeier, Karl‐Heinz; Hansen, K. C.; Müller, Jakob; Schmidt, Albrecht

doi:10.1051/0004-6361/201014761

Cited by 12 publications

(4 citation statements)

References 21 publications

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“…Hybrid simulations consider fluid electrons and kinetic ions and they solve the standard set of kinetic equations [cf. Szegő et al, 2000;Bagdonat and Motschmann, 2002;Lipatov et al, 2002;Katoh et al, 2003;Bagdonat et al, 2004;Delamere, 2006;Hansen et al, 2007;Gortsas et al, 2009Gortsas et al, , 2010Wiehle et al, 2011]. Magnetofluid simulations, on the other hand, incorporate quite a bit of cometary physics into the governing equations.…”

Section: Mathematical Descriptionmentioning

confidence: 99%

Physics of Cometary Magnetospheres

Gombosi

2015

Magnetotails in the Solar System

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This tutorial summarizes our present, pre-Rosetta understanding of the basic physical processes operating in cometary environments with particular attention to cometary magnetotails. Ionization of cometary gases is responsible for most plasma processes in the magnetospheres of active comets. The interaction between the superalfvénic, magnetized solar wind and cometary ions forms a number of plasma boundaries starting with the weak bow shock and continuing with the contact surface (diamagnetic cavity boundary), the recombination layer and the inner shock. The plasma tail is sensitive to changes in the solar wind and to varying cometary activity. These processes will be explored in detail.

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Section: Mathematical Descriptionmentioning

confidence: 99%

Physics of Cometary Magnetospheres

Gombosi

2015

Magnetotails in the Solar System

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“… Benna and Mahaffy [2006] extrapolated results from their model of comet 26P/Grigg‐Skjellerup to comet 67P/Churyumov‐Gerasimenko to derive the expected plasma environment at perihelion. Model predictions for the comet's plasma environment in the whole range of heliocentric distances relevant for Rosetta have been presented by Gortsas et al [2010], Motschmann and Kührt [2006], and Hansen et al [2007].…”

Section: Introductionmentioning

confidence: 99%

Kelvin‐Helmholtz instabilities at the magnetic cavity boundary of comet 67P/Churyumov‐Gerasimenko

Rubin¹,

Hansen²,

Combi³

et al. 2012

J. Geophys. Res.

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[1] We investigate the plasma environment of comet 67P/Churyumov-Gerasimenko, the target of the European Space Agency's Rosetta mission. Rosetta will rendezvous with the comet in 2014 at almost 3.5 AU and follow it all the way to and past perihelion at 1.3 AU. During its journey towards the inner solar system the comet's environment will significantly change. The interaction of the solar wind with a well developed neutral coma leads to the formation of an upstream bow shock and, closer to the comet, the inner shock separating the solar wind, with cometary pick-up ions mass-loaded, from the inner cometary ions which are dragged outward through abundant collisions and charge exchange with the expanding neutral gas. As a consequence the interplanetary magnetic field is prevented from penetrating the innermost region of the comet, the so-called magnetic cavity. We use our magnetohydrodynamics model BATSRUS (Block-Adaptive-Tree-Solarwind-Roe-Upwind-Scheme) to simulate the solar wind -comet interaction. The model includes photoionization, ion-electron recombination, and charge exchange. Under certain conditions our model predicts an unstable plasma flow at the inner shock. We show that the plasma shear flow around the magnetic cavity can lead to Kelvin-Helmholtz instabilities. We investigate the onset of this phenomenon with change of heliocentric distance and furthermore show that a previously stable magnetic cavity boundary can become unstable when the neutral gas is predominately released from the dayside of the comet.

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“…The concept of an ion composition boundary (ICB) has been introduced in some recent papers (see, e.g., Gortsas et al 2010). It is defined as the locus of points in the shock layer where the density of solar wind protons becomes equal to the density of cometary ions.…”

Section: Discussionmentioning

confidence: 99%

Density distribution of solar wind protons and “loaded” ions in the shock layer ahead of a cometary ionosphere

Баранов

Lebedev

2014

Astron. Lett.

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We propose a simple method that allows the density fields of solar wind protons and heavy ions of cometary origin ("loaded" ions) in the solar wind-cometary ionosphere interaction region to be separated from the general density field calculated within the framework of a single-fluid model. The method is based on the assumption that the velocities of both components are identical. We analyze the density fields in the solar wind obtained in this way before and after the passage of the bow shock ahead of the cometary ionosphere and make a comparison with the distributions measured with various instruments onboard the Giotto spacecraft when it flew past Comet Halley and calculated on the basis of more complex multi-fluid models.

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Global plasma-parameter simulation of Comet 67P/Churyumov-Gerasimenko approaching the Sun

Cited by 12 publications

References 21 publications

Physics of Cometary Magnetospheres

Physics of Cometary Magnetospheres

Kelvin‐Helmholtz instabilities at the magnetic cavity boundary of comet 67P/Churyumov‐Gerasimenko

Density distribution of solar wind protons and “loaded” ions in the shock layer ahead of a cometary ionosphere

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