  The dynamics of magnetic flux tubes (MFTs) in the accretion disk of typical
Herbig Ae/Be star with fossil large-scale magnetic field is modeled taking into
account the buoyant and drag forces, radiative heat exchange with the
surrounding gas, and the magnetic field of the disk. The structure of the disk
is simulated using our magnetohydrodynamic (MHD) model, taking into account the
heating of the surface layers of the disk with the stellar radiation. The
simulations show that MFTs periodically rise from the innermost region of the
disk with speeds up to $10-12$ km s$^{-1}$. MFTs experience decaying magnetic
oscillations under the action of the external magnetic field near the disk's
surface. The oscillation period increases with distance from the star and
initial plasma beta of the MFT, ranging from several hours at $r=0.012$ au up
to several months at $r=1$ au. The oscillations are characterized by pulsations
of the MFT's characteristics including its temperature. We argue that the
oscillations can produce observed IR-variability of Herbig Ae/Be stars, which
would be more intense than in the case of T Tauri stars, since the disks of
Herbig Ae/Be stars are hotter, denser and have stronger magnetic field.
