A Magic Simulation on the Effect of Plasma Density to the Performance of PEOS

Summary form only given. We present a PIC code MAGIC simulation of charge density evolution in time in a 20-100 ns class plasma erosion opening switch, which is intended for use in a TW high power microwave system. The conclusions are: (a) the higher the plasma density, the higher the stored magnetic energy, however, higher plasma density usually means larger volume, which changes the impedance matching in transmission line and thus efficiency loss occurs. (b) In ns class PEOS, the conduction is mainly carried by electrons, ions hardly move during the entire conduction and opening process, therefore replacing carbon plasma with hydrogen plasma should present no significant macroscopic difference. (c) The energy required to break a C-C bond is 144 kcal/mole, much more than ionizing the hydrogen. The saving in trigger energy is obvious and vital to deliverable system. Hydrogen plasma also does not contaminate the transmission line. Replacing carbon flashboard with hydrogen gun is recommended. (d) The sheath does not play an important role in sustaining the conduction as in previous theoretical model. The PEOS does not erode because the sheath can no longer supply electron through secondary effect, it is even questionable the sheath has time to form in fast switches. (e) Magnetic insulation initiates almost immediately after conduction, however starting with a small area affected. Magnetic insulation initiates from the cathode where the magnetic field is stronger than the anode. (f) Plasma injection velocity is not important in single shot system, but it is important in repetitive system. (g) Microsecond PEOS is not practical. The required charge density is too high to produce in a practical system. Multiple ns PEOS fired consecutively is more feasible.