A&A 475, 1093-1100 (2007)
Plasma flows around magnetic obstacles in the solar windE. Romashets1, 2, 3 and S. Poedts1
1 Centre for Plasma Astrophysics and Leuven Mathematical Modelling and Computational Science Centre, K.U. Leuven, 3001, Belgium
2 Institute of Terrestrial, Magnetism, Ionosphere, and Radio Wave Propagation of Russian Academy of Sciences, Troitsk, 142092, Russia
3 Solar Observatory of Prairie View A& M University, Prairie View, 77446, USA
(Received 20 June 2006 / Accepted 13 September 2007 )
Context.Recent numerical simulations and data analysis have shown that the area in front of magnetic clouds is very important from the point of view of its geo-efficiency. This area has very complicated magnetic and plasma structures. It is necessary to describe the plasma parameter distributions in the vicinity of magnetic clouds and other stable structures in the solar wind. Assuming that the magnetic field around the object is determined or measured, the velocity field is calculated from the frozen-in equation, while the density and pressure are given by explicit formulas expressing P and as functions of only and . An alternative method is to solve the full system of MHD equations numerically, but even in this case the analytical estimates determined here are also useful when formulating initial and boundary conditions.
Aims.The aim is to treat the region in front of interplanetary magnetic clouds in terms of analytical functions for a detailed consideration of general phenomena and also for particular phenomena of specific clouds.
Methods.First, the velocity and magnetic field distributions satisfying the boundary conditions and the frozen-in condition are determined. Next, the plasma density and pressure are calculated.
Results.The three-dimensional plasma parameter distributions are found for the general case of an inclined cylindrical cloud.
Key words: solar wind -- Sun: magnetic fields -- solar-terrestrial relations -- Sun: coronal mass ejections (CMEs)
© ESO 2007