RANDOM MAGNETIC-IMPURITIES AND THE LANDAU PROBLEM

The 2-dimensional density of states of an electron is studied for a po issonian random distribution of point vortices carrying a Aux in units of the quantum of flux. It is shown that, for any given density of im purities, there is a transition, when alpha similar or equal to 0.3-0. 4, from an ''almost free'' density of state - with only a depletion of states at the bottom of the spectrum characterized by a Lifschitz tai l - to a Landau density of state with sharp Landau level oscillations. Several evidences and arguments for this transition - numerical and a nalytical - are presented.