Analytic magnetic field

You can manually define the magnetic field to what ever shape you like. To get a gaussian peak in y-direction for example, you can do the following:

bool fout[3] = { true, true, true };
MeshVectorField bfield( geom, fout );
for( int32_t i = 0; i < bfield.size(0); i++ ) {
    //double x = bfield.origo(0)+i*bfield.h();
    for( int32_t j = 0; j < bfield.size(1); j++ ) {
        //double y = bfield.origo(1)+j*bfield.h();
        for ( int32_t k = 0; k < bfield.size(2); k++ ) {
            double z = bfield.origo(2)+k*bfield.h();

            const double z_ave = 2.0e-3;
            const double s = 2.5e-3;
            double t = z-z_ave;
            double By0 = -100.0e-3;
            double By = By0*exp(-t*t/(2.0*s*s));

            bfield.set( i, j, k, Vec3D( 0, By, 0 ) );
        }
    }
}