Particle in cell modelling of the quantitative evolution of a pinched electron beam across the a-k gap of a self magnetic pinch diode

Summary form only given. Particle in Cell (PiC) simulations using the Large Scale Plasma (LSP) code of a Self Magnetic Pinch (SMP) diode have been carried out to investigate the electron beam conditions present in the SMP anode-cathode (a-k) gap. The probability distributions of radial charge, macro particle energy and macro particle velocity are described as a function of emission region and position across the a-k gap. The conclusions of these investigations are that the top surface of cathode contributes around 50% of the electron flow while the lower surface accounts for only around 5% with the remaining flow coming from the tapered cathode tip. The energy of the electron beam starts as a low energy peaked distribution at the start of the a-k gap and goes through a broad distribution to one with a high energy bias, retaining a low energy tail largely independent of emission site. The angles which the electrons have across the a-k gap follow distributions which show structure for the emission sites on the top half of the cathode with the quantitative change in angle now being obtainable as a function of position. For emission sites on the lower half of the cathode, and as a position across the a-k gap, the angle distribution data has a broad shape biased to low angle with no clearly observable peaks.