Novel Trigger Mechanism High-Power Switch: The Electrostatic Plasma Injection Switch

High-power gas switches like the Pseudospark have been developed for decades, and past research has focused on the trigger mechanism of Pseudospark. This paper presents a new type of switch called the electrostatic plasma injection switch (EPIS), which uses transmission-line reflections of incoming trigger pulse to generate voltage gradients on a vertical multisection trigger structure that extends from a hollow cathode into a symmetrical hollow anode. Low-current preionization glow discharge at the bottom of the cathode region provides seed electrons for fast turn on. The trigger voltage injects plasma into the trigger structure and then accelerates plasma vertically into the gap between anode and cathode. Similar to Pseudospark, a superdense-glow-discharge plasma is responsible for the high current. The trigger electron density is measured by optical spectroscopy to be 3times10
¹⁵
/cm
³
inside the hollow cathode and 8times10
¹⁴
/cm
³
at the anode-cathode gap. plasma injection speed is 1-4times10
⁷
cm/s between 0.1and 0.4-torr pressure and is proportional to pressure and trigger voltage. Delay time decreases when the pressure increases. The EPIS has been operated at 16.6-kV hold-off voltage and 4.96 kA with 95 mtorr of hydrogen. This switch operates in the left-hand branch of the Paschen curve, as do Thyratron and Pseudospark, but it should provide better trigger reliability and higher current capability. Hold-off voltage is limited by local field emission. This device is operational, and waveforms of anode voltage, anode current, trigger voltage, and plasma emissions are recorded. Future applications are discussed