ON THE MHD EFFECTS ON THE FORCE-FREE MONOPOLE OUTFLOW

The stationary axisymmetric outflow from a rotating sphere with a (spl it) monopole magnetic field is considered. The stream equation describ ing the outflow is linearized in terms of the Michel magnetization par ameter sigma(-1) << 1, which allows a self-consistent analysis of the direct problem. It is shown that for a finite a the fast magnetosonic surface is located at a finite distance similar to sigma(1/3)R(L) (R-L = c/Omega(F) is the light cylinder). We have also found that the part icle energy at the fast surface is just equal to the Michel value gamm a similar to sigma(1/3). The particle acceleration and magnetic field collimation are shown to become ineffective outside the fast magnetoso nic surface.