Performance of microdischarge devices and arrays with screen electrodes

Cylindrical microdischarge devices, 50-150 mum in diameter and fabricated in Ni-polyimide-Cu or Ni foil structures, have been operated with Ni or Cu screens serving as the anode and/or cathode. As compared with annular anode (open bore) designs, the installation of at least one screen electrode has the effect of lowering the device operating voltage by as much as 30% while raising the electron temperature of the plasma. As a result, microdischarge devices 50 mum in diameter operate at voltages below 95 V at a Ne gas pressure of 700 torr, exhibit hollow cathode operation at gas pressures beyond 300 torr (or at least a factor of three higher than those observed previously), and the power output of a device with an anode screen operating at 300 torr is double that of its no-screen counterpart. Screen electrodes also stabilize the ignition characteristics of arrays and extend device lifetimes.