Universität zu Köln

Bloecker, Aljona, Saur, Joachim ORCID: 0000-0003-1413-1231 and Roth, Lorenz ORCID: 0000-0003-0554-4691 (2016). Europa's plasma interaction with an inhomogeneous atmosphere: Development of Alfven winglets within the Alfven wings. J. Geophys. Res-Space Phys., 121 (10). S. 9794 - 9829. WASHINGTON: AMER GEOPHYSICAL UNION. ISSN 2169-9402

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Abstract

We apply a three-dimensional magnetohydrodynamic (MHD) model to study the influence of inhomogeneities in Europa's atmosphere, as, for example, water vapor plumes, on Europa's plasma interaction with the Jovian magnetosphere. In our model we have included electromagnetic induction in a subsurface water ocean, collisions between ions and neutrals, plasma production and loss due to electron impact ionization, and dissociative recombination. We present a systematic study of the plasma interaction when a local inhomogeneity in the neutral density is present within a global sputtering generated atmosphere. We show that an inhomogeneity near the north or south pole affects the plasma interaction in a way that a pronounced north-south asymmetry is generated. We find that an Alfven winglet develops within Europa's main Alfven wing on that side where the inhomogeneity is located. In addition to the MHD model we apply an analytic model based on the model of Saur et al. (2007) to understand the role of steep gradients and discontinuities in the interaction. We compare our model results with the measured magnetic field data from three flybys of the Galileo spacecraft at Europa which included Alfven wing crossings. Our analysis suggests that the magnetic field might be influenced by atmospheric inhomogeneities during the E26 flyby. The findings of this work will aid in the search for plumes at Europa in future plasma and field observations.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Bloecker, Aljona UNSPECIFIED UNSPECIFIED UNSPECIFIED Saur, Joachim UNSPECIFIED orcid.org/0000-0003-1413-1231 UNSPECIFIED Roth, Lorenz UNSPECIFIED orcid.org/0000-0003-0554-4691 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-259221
DOI:	10.1002/2016JA022479
Journal or Publication Title:	J. Geophys. Res-Space Phys.
Volume:	121
Number:	10
Page Range:	S. 9794 - 9829
Date:	2016
Publisher:	AMER GEOPHYSICAL UNION
Place of Publication:	WASHINGTON
ISSN:	2169-9402
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language JUPITERS MAGNETOSPHERE; JOVIAN MAGNETOSPHERE; IOS INTERACTION; MAGNETIC-FIELD; SUBSURFACE OCEANS; MHD SIMULATION; WATER-VAPOR; GAS TORUS; CONSTRAINTS; CALLISTO Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/25922