Ion Collection Current Diagnostic for Exploring Plasma Opening Switch Performance

A study of the triggered plasma opening switch characteristics is in progress via an ion current collection diagnostic (ICCD) in addition to an offline apparatus. The ICCD will be used to explore the opening profile of the plasma opening switch. The design and fabrication of the diagnostic, as well as theoretical work to understand its functioning, and the initial measurements are presented. The ICCD utilizes 12 biased charge collectors that are positioned perpendicularly to the main switch in order to collect radially traveling ions emitted from the switch plasma. The maximum possible gap is 5 cm, and the radius of the cathode is 18 cm. As long as gap variations are small compared to the gap, it has been shown that this cylindrical geometry can be treated as a planar case of the Child-Langmuir law with only a 6% error. Additionally, electrostatic simulations with self-consistent space charge have been done using a static two-dimensional finite-element solver. It is hoped that the ICCD experimental data will provide insight into the operation of this plasma opening switch