Images of the phase space diagrams during the unfurling of the electrons when a plasma expands into a plasma

Using a 1-D1v (one dimension for space, one for velocity) electrostatic particle-in-cell (PIC) code, we simulate the dynamics of the expansion of a plasma into a limited plasma, between two polarized electrodes. We show the phase space diagrams for the two electron families, on which we observe the electron unfurling. The unfurling branches are observed to fold up on the others. The velocity distribution is broadened: the electron population is heated.