Energies at t = 0.003 s for 10 000 electrons which have been moving in a plasma of density n_e = 5 × 10¹⁰ cm^-3, for a variety of electric fields. All electrons start with an energy of 1.3 keV. The initial positions of the particles were randomly distributed within the region r < 1, and the initial particle pitch angles were randomly chosen to be between 0 and 2π. For this simulation, .