Multi-propellant diamond-based hollow cathodes for space and industrial applications

The project is a national research initiative funded under the PRIN 2022 programme and coordinated by the University of Pisa, in collaboration with ISTP-CNR and Consorzio RFX. The project addresses the development of an innovative hollow cathode technology based on diamond coatings deposited on molybdenum substrates, targeting long-life, low-temperature, and multi-propellant operation. The objective is to overcome the thermal and lifetime limitations of conventional thermionic emitters, enabling hollow cathodes capable of operating over a wide current range and with alternative propellants such as xenon, iodine, argon, and hydrogen. The activity combines material development and characterization, thermionic and photoemission testing, hollow cathode design and experimental validation, and advanced modelling. Diamond-based emitters are experimentally assessed and integrated into a flexible hollow cathode prototype, which is tested under representative operating conditions with different propellants. The experimental campaign is supported by Particle-In-Cell simulations of plasma–sheath interaction and molecular dynamics simulations of surface processes. The project aims to demonstrate reduced operating temperature, improved plasma compatibility, and extended lifetime compared to state-of-the-art cathodes, enabling robust electron sources for future electric propulsion systems, satellite constellations, and plasma-based industrial applications.