Post Author: Nathan R. Hines
The simulation was conducted by Dale Welch at Voss Scientific using the CHICAGO® Particle-In-Cell (PIC) code. 2D cylindrical coordinates are utilized with an approximated fragmentation ionization model. Particles are sourced from the desorption of 2 monolayers of surface water contaminant, with no additional particle sourcing from cold or melted electrode bulk desorption. To incorporate enhanced E-field resistive heating explosive particle emission physics, the cathode surface temperature is manually increased by 200 °C when the electric field strength initially exceeds 240 kV/cm.
Shown at small radius (image bottom) is a 1.6 mm diameter Cathode rod. Separating the Cathode and Anode electrode material is the nominal 875 µm vacuum gap, that eventually fills with low density plasma. Located between Z = -5.0 and +18.5 mm is the parallel plate region of interest, which is followed by (Z > +18.5 mm) the downstream load region.
Additional 3D and full breakdown model CHICAGO simulations are presently being conducted for comparison.