  With the gauge-invariant perturbation theory, we study the effects of the
stellar magnetic fields on the polar gravitational waves emitted during the
homogeneous dust collapse. We found that the emitted energy in gravitational
waves depends strongly not only on the initial stellar radius but also on the
rasio between the poloidal and toroidal magnetic components. The polar
gravitational wave output of such a collapse can be easily up to a few order of
magnitude larger than what we get from the nonmagnetized collapse. The changes
due to the existence of magnetic field could be helpful to extract some
information of inner magnetic profiles of progenitor from the detection of the
gravitational waves radiated during the black hole formation, which results
from the stellar collapse.
