THE SPATIAL STRUCTURE OF THE EVERSHED EFFECT

The line asymmetry from the Evershed effect disappears beyond the boun dary of the white-light penumbra over a horizontal distance of less th an 500 km. Immediately beyond the ends of the dark penumbral continuum structures, the lines Ni I 5435.9 (g=0.5) and Fe I 5434.5 (g=0; forme d about 300 km higher) simultaneously lose their asymmetry. The spatia l distance of maximally 500 km is too short for a 'disappearence with height' as suggested by models of a penumbral 'canopy'. instead, the d ata favour a rather flat orientation of the dark structures with an ab rupt disappearence. It is suggested that this location marks the sharp threshold of the equipartition between kinetic and magnetic energy de nsity at the outer penumbral border.