  We study processes occurring after a sudden heating of the chromosphere at
the flare arcade footpoints which is assumed to be caused by particle beams.
For the numerical simulations we adopt a 2-D magnetohydrodynamic (MHD) model,
in which we solve a full set of the time-dependent MHD equations by means of
the FLASH code, using the Adaptive Mesh Refinement (AMR) method. In the initial
state we consider a model of the solar atmosphere with densities according to
the VAL-C model and the magnetic field arcade having the X-point structure
above, where the magnetic reconnection is assumed. We found that the sudden
pulse-beam heating of the chromosphere at the flare arcade footpoints generates
magnetohydrodynamic shocks, one propagating upwards and the second one
propagating downwards in the solar atmosphere. The downward moving shock is
reflected at deep and dense atmospheric layers and triggers oscillations of
these layers. These oscillations generate the upwards moving
magnetohydrodynamic waves that can influence the above located magnetic
reconnection in a quasi-periodic way. Because these processes require a sudden
heating in very localized regions in the chromosphere therefore they can be
also associated with seismic waves.
