Temporal Evolution of an Energetic Electron Population in an Inhomogeneous Medium. Application to X-ray Bursts.

The interpretation of spatially resolved hard X-ray data implies the use of models where the spectral, spatial and temporal evolution of the X-ray flux can be studied. As a first step to construct detailed hard X-ray source models, we present here time-dependent solutions of the electron continuity equation in an inhomogeneous medium and we illustrate the evolution of the electron population and of the X-ray flux for simple situations. Applications of the results to stereoscopic X-ray observations is briefly discussed.