A Novel Diamond-Based Plasma Neutraliser

The work presented in this paper addresses specific issues of plasma cathodes operated on alternative propellants aiming at improving the current extraction of the technology using a novel DC plasma neutraliser developed by a partnership between the Surrey Space Centre and the Institute for Plasma Science and Technology of the Italian Research Council. This neutraliser uses thin diamond films on metallic disks (the cathode). The experimental development of the diamond-based plasma neutraliser (DBC) is described along with the preliminary characterisation and the resulting operating envelope. The highest achieved performance by the DBC was 0.215 A at 125 W and 10 sccm (0.67 mg/s) mass flow rate of krypton. Efficiency metrics (such as electron extraction power efficiency, and gas utilisation factor) for the neutraliser were compared for different diamond cathodes with unique film properties and operating conditions.