2. Potential magnetic field configurations
The coronal magnetic field structure is treated in Cartesian coordinates with the z-axis in the vertical direction. All physical quantities are assumed stationary and y-invariant, so they depend on the variables x and z only.
Potential magnetic fields are characterised by
and, in what follows, we shall assume , i.e. we consider a y-invariant, potential magnetic field contained in the x, z plane. Then,
To determine the flux function in the corona () one must integrate this partial differential equation, imposing some boundary conditions. We prescribe the value of the flux function at the photospheric level, , and assume that A does not diverge as .
© European Southern Observatory (ESO) 1999
Online publication: November 3, 1999