Plasma flows around magnetic obstacles in the solar wind

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 e-mail: eromashets@pvamu.edu

Received: 20 June 2006
Accepted: 13 September 2007

Abstract

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 ρ 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.