THE ELECTROSTATIC PLASMA INJECTION SWITCH (EPIS) Max Chung Department of Electvonics Engineering, Southem Taiwan University of Technology Tainan, Taiwan, 71 0, R. 0. C. Erich Kunhardt Department of Physics, Steven Institute of Technology, Hobokn, New Jersey, NJ07030, USA Abstract A new type of switch called Electrostatic Plasma Injection Switch (EPIS) is developed which uses transmission line reflections of incoming trigger pulse to generate voltage gradients on a multi-section hollow trigger pin that extends f" cathode into a hollow anode. Low current pre-ionization at the bottom of cathode region provides free electrons for fast turn on. The voltage gradient on the trigger pin injects triggering plasma into the region between anode and cathode, thus initiates a high current hollow cathode discharge. This switch operates in the left hand side of Pachen curve as thyratron and pseudospark, but should provide better trigger reliability and higher current capability. The EPIS has been operated at 16.6 KV hold off voltage and 4.96 KA with 0.095 Torr of hydrogen. Hold off voltage is limited by local field emission, and a pseudospark like plasma is responsible for the high current capability. This device is operational and waveforms of anode voltage, anode current, trigger voltage, and spectral emission are recorded. I. INTRODUCTION Gas discharge closing switch has applications in high power laser, radar, and various pulse power applications. Despite the recent development in high pressure switch [1][2], Pseudospark [3][4][5] and Back Light T h p t r o n (BLT)[S], traditional Thyratron [6] still occupied a large market share of small to medium power applications, and some high power high repetition rate one. The main advantage of Thyratron is its low jitter, which is a result of its heated dispenser cathode that provides abundant trigger electrons. Unfortunately, the dispenser cathode also carries the role of mail discharge current supply, which is a target difficult for it to fulfill in today's high power long life scenario. Also the heating power supply of dispenser cathode is a big burden in weight. Thus come Pseudospark and BLT. Pseudospark uses long path high voltage trigger to initiate a super dense grow discharge to conduct current. BLT uses flash lamp or laser to provide initial electrons for a similar conduction mode. In principle, they both initiates the mail discharge by starting a new discharge, in pseudospark is the long path high voltage triggered discharge, while BLT is the discharge in the flash lamp. Due to the uncertain nature of gas breakdown, trigger jitter may be introduced Here we introduce another switch concept, the Electrostatic Plasma Injection Switch (EPIS). The switch prototype (Fig.1) is built of stainless steel inside a glass cross. n 0 w'wmmcn I Figure 1. Drawing of EPIS The anode has a hollow center in order for the trigger pin to extend into it in order to confme anode field in the 0-7803-7915-2/03617.00 BZ0031EEE. 583 Authorized licensed use limited to: Southern Taiwan University. Downloaded on June 18,2010 at 03:37:28 UTC from IEEE Xplore. Restrictions apply.