COSMIC-RAYS .2. EVIDENCE FOR A MAGNETIC ROTATOR WOLF-RAYET STAR ORIGIN

Based on 1) a conjecture about the mean free path for particle scatter ing in perpendicular shock geometries, and 2) a model for Wolf-Rayet s tar winds, we argue that explosions of Wolf-Rayet stars can lead throu gh diffusive particle acceleration to particle energies up to 3 10(9) GeV. As a test we first demonstrate that the magnetic fields implied b y this argument are compatible with the dynamo limit applied to the co nvective interior of the main sequence stars which are predecessors of Wolf-Rayet stars; second we show that this implies the same strength of the magnetic fields as is suggested by the magnetically driven wind theory. Third, we use data from radio supernovae to check the spectru m, luminosity and time dependence which suggest that the magnetic fiel ds again have to be as high as suggested by the magnetically driven wi nd theory. This constitutes evidence for the magnetic field strengths required to accelerate particles to 3 10(9) GeV. Fourth, we demonstrat e that within our picture the nonthermal radio emission from OB and Wo lf-Rayet stars can reproduce the proper radio spectra, time variabilit y and radio luminosities. Fifth, the comparison of Wolf-Rayet stars an d radio supernovae suggests that electron injection into the accelerat ion process is a step function of efficiency with the shock speed as t he independent parameter; the critical speed appears to be that speed at which the thermal downstream electrons become relativistic. We make detailed predictions on the temporal and spectral behaviour of the no nthermal radio emission of OB and Wolf-Rayet stars that will allow fur ther checks our model.