Accretion disk structure of adiabatic and magnetised CTTS-systems

The role of a large-scale magnetic field in a classical TTS star-disk syste m is studied. The central object yields a magnetic dipolar field which is m odified and amplified by the accretion disk. The entropy in the equatorial plane is assumed as unchanged by the magnetic field. The disk halo is consi dered as a plasma with the same conductivity as the disk and corotating wit h the star. The induced toroidal fields are confirming a former estimate by Campbell (1992); their (vertical) angular momentum transport strictly chan ges the accretion disk structure. For rather weak magnetic fields there is no disk inside the corotation radius, but outside the corotation radius the disk becomes much warmer, thicker and more massive than the corresponding non-magnetic solutions. For stellar magnetic field exceeding 2000 Gauss we find the maximal magnetic torque starting to saturate.