THE VERTICAL STRUCTURE OF THE GALACTIC GASEOUS DISK AND ITS RELATION TO THE DYNAMO PROBLEM

Galaxy-wide lower limits for the alpha- and eta-coefficients of the tu rbulent EMF have been obtained combining the empirically found global density distribution of interstellar matter with that minimal turbulen t pressure necessary to prevent onset of Parker instability (cf. Bloem en 1987). The criterion used is that delineated by Lachieze-Rey et al. (1980). Upper limits for alpha and eta result from identifying the to tal internal pressure, following the assumption of hydrostatical equil ibrium. The correlation time, tau(corr), scale like the local hydrosta tic time-scale.