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Annales Geophysicae An interactive open-access journal of the European Geosciences Union
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Volume 33, issue 1
Ann. Geophys., 33, 47–53, 2015
https://doi.org/10.5194/angeo-33-47-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue: Observation, analysis and modelling of solar and heliospheric...

Ann. Geophys., 33, 47–53, 2015
https://doi.org/10.5194/angeo-33-47-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Regular paper 12 Jan 2015

Regular paper | 12 Jan 2015

Three-dimensional multi-fluid model of a coronal streamer belt with a tilted magnetic dipole

L. Ofman1,2,3, E. Provornikova1,2, L. Abbo4, and S. Giordano4 L. Ofman et al.
  • 1Department of Physics, Catholic University of America, Washington, DC 20064, USA
  • 2NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771, USA
  • 3Visiting Associate Professor, Department of Geosciences, Tel Aviv University, Tel Aviv, Israel
  • 4INAF-Astrophysical Observatory of Torino, via Osservatorio 20, 10025 Pino Torinese, Italy

Abstract. Observations of streamers in extreme ultraviolet (EUV) emission with SOHO/UVCS show dramatic differences in line profiles and latitudinal variations in heavy ion emission compared to hydrogen Ly-α emission. In order to use ion emission observations of streamers as the diagnostics of the slow solar wind properties, an adequate model of a streamer including heavy ions is required. We extended a previous 2.5-D multi-species magnetohydrodynamics (MHD) model of a coronal streamer to 3-D spherical geometry, and in the first approach we consider a tilted dipole configuration of the solar magnetic field. The aim of the present study is to test the 3-D results by comparing to previous 2.5-D model result for a 3-D case with moderate departure from azimuthal symmetry. The model includes O5+ ions with preferential empirical heating and allows for calculation of their density, velocity and temperature in coronal streamers. We present the first results of our 3-D multi-fluid model showing the parameters of protons, electrons and heavy ions (O5+) at the steady-state solar corona with a tilted steamer belt. We find that the 3-D results are in qualitative agreement with our previous 2.5-D model, and show longitudinal variation in the variables in accordance with the tilted streamer belt structure. Properties of heavy coronal ions obtained from the 3-D model together with EUV spectroscopic observations of streamers will help understanding the 3-D structures of streamers reducing line-of-sight integration ambiguities and identifying the sources of the slow solar wind in the lower corona. This leads to improved understanding of the physics of the slow solar wind.

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First results from the three-fluid 3D model of the solar corona are reported. The model extends previous 2.5D three-fluid studies, and includes electron, protons, and oxygen ions (O5+) as coupled fluids in a tilted dipole solar magnetic field configuration. The model demonstrates the variation in abundances of the oxygen ions relative to protons in a coronal streamer belt, thus identifying the sources of the slow solar wind and helping in the interpretation of past spectroscopic observations.
First results from the three-fluid 3D model of the solar corona are reported. The model extends...
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