  Young low-mass stars are characterized by ejection of collimated outflows and
by circumstellar disks which they interact with through accretion of mass. The
accretion builds up the star to its final mass and is also believed to power
the mass outflows, which may in turn remove the excess angular momentum from
the star-disk system. However, although the process of mass accretion is a
critical aspect of star formation, some of its mechanisms are still to be fully
understood. A point not considered to date and relevant for the accretion
process is the evidence of very energetic and frequent flaring events in these
stars. Flares may easily perturb the stability of the disks, thus influencing
the transport of mass and angular momentum. Here we report on three-dimensional
magnetohydrodynamic modeling of the evolution of a flare with an idealized
non--equilibrium initial condition occurring near the disk around a rotating
magnetized star. The model takes into account the stellar magnetic field, the
gravitational force, the viscosity of the disk, the magnetic-field-oriented
thermal conduction (including the effects of heat flux saturation), the
radiative losses from optically thin plasma, and the coronal heating. We show
that, during its first stage of evolution, the flare gives rise to a hot
magnetic loop linking the disk to the star. The disk is strongly perturbed by
the flare: disk material evaporates under the effect of the thermal conduction
and an overpressure wave propagates through the disk. When the overpressure
reaches the opposite side of the disk, a funnel flow starts to develop there,
accreting substantial disk material onto the young star from the side of the
disk opposite to the flare.
