  In this work we study time-dependent precipitation of an electron beam
injected into a flaring atmosphere with a converging magnetic field by
considering collisional and Ohmic losses with anisotropic scattering and pitch
angle diffusion. Two injection regimes are investigated: short impulse and
stationary injection. The effects of converging magnetic fields with different
spatial profiles are compared and the energy deposition produced by the
precipitating electrons at different depths and regimes is calculated. The time
dependent Fokker-Planck equation for electron distribution in depth, energy and
pitch angle was solved numerically by using the summary approximation method.
It was found that steady state injection is established for beam electrons at
0.07-0.2 seconds after the injection onset depending on the initial beam
parameters. Energy deposition by a stationary beam is strongly dependent on a
self-induced electric field but less on a magnetic field convergence. Energy
depositions by short electron impulses are found to be insensitive to the
self-induced electric field but are strongly affected by a magnetic
convergence. Short beam impulses are shown to produce sharp asymmetric hard
X-ray bursts within a millisecond timescale often observed in solar flares.
