The propagation of relativistic electrons in foam and solid density targets has been studied by means of K-α spectroscopy. Experimental results point out the role of self-generated electric fields in propagation and the role of heating of matter induced by the passage of fast electrons. A simple analytical formulation has been given and Spitzer conductivity has been shown to be fairly compatible with experimental results.

• Received 21 February 2001

DOI:https://doi.org/10.1103/PhysRevE.65.066409