  From radiation magnetohydrodynamic simulations of the solar atmosphere we
find a new mechanism for the excitation of longitudinal slow modes within
magnetic flux concentrations. We find that the convective downdrafts in the
immediate surroundings of magnetic elements are responsible for the excitation
of slow modes. The coupling between the external downdraft and the plasma
motion internal to the flux concentration is mediated by the inertial forces of
the downdraft that act on the magnetic flux concentration. These forces, in
conjunction with the downward movement, pump the internal atmosphere in the
downward direction, which entails a fast downdraft in the photospheric and
chromospheric layers of the magnetic element. Subsequent to the transient
pumping phase, the atmosphere rebounds, causing a slow mode traveling along the
magnetic flux concentration in the upward direction. It develops into a shock
wave in chromospheric heights, possibly capable of producing some kind of
dynamic fibril. We propose an observational detection of this process.
