  A Magnetic Rotator Wind-Disk(MRWD) model is considered for the formation of
Keplerian disks around Be stars. Material from low latitudes of the stellar
surface flows along magnetic flux tubes and passes through a shock surface to
form a pre-Keplerian disk region. Initially, the density in this region is
small. After a fill-up time, the density of the disk is significantly larger
and the magnetic force becomes negligible compared with the centrifugal force.
The material then expands to form a Keplerian disk. During disk fill-up, the
meridional component B-star of the magnetic field at the stellar surface must
be larger than a minimum value B-star-min. The radial extent of the Keplerian
region will be larger when B-star is larger or when viscosity plays a role. In
B-type stars, B-star-min must be of order 1 G to 10 G. In faster rotating
stars, the wind speed must be correspondingly larger for the formation of
shock-compressed disk regions.
