Description du sujet de thèse

The iodine molecule I2 is now emerging as a credible alternative to the standard electric propulsion propellants xenon and krypton. Although a great deal of work has been carried out in recent years on iodine discharges and propellants, there are still many grey areas, particularly concerning discharge physics, system lifetimes and the development of sub-systems such as cathodes and neutralizers.
This thesis has two major objectives: to develop diagnostic tools for low-pressure iodine discharges, and to study a cathode based on radio-frequency (RF) plasma.
The PhD student will work at ICARE on the development of a laser-induced fluorescence spectroscopy diagnostic to probe the singly-charged atomic iodine ion I+ in the infrared. The diagnostic will be based on a tunable laser diode. A series of electrostatic tools will also be developed: compensated Langmuir probe, current probe, energy analyzer. The instruments will be developed and validated using a miniature magnetic nozzle RF thruster operating at low power. The PhD student will also be responsible for developing the thruster and iodine supply system, with the vacuum chamber and pumping system available.
Secondly, the PhD student will carry out measurements using the tools he has built and characterized in the plasma discharge and jet of an iodine RF cathode. The experiments will be carried out at DLR in Germany. The results obtained will be compared with numerical simulations. The aim is to optimize cathode operation (power, efficiency, size, etc.).

The work proposed to the PhD student is mainly experimental in nature. It will involve applying electrical and optical diagnostic techniques to measure ion flux, ion energy and plasma electronic properties in an electrodeless RF thruster and in an RF cathode. The experiments will be coupled with theoretical investigations based on work already carried out at ICARE, and with numerical simulations conducted at the Universities of Padua and Bologna.

Contexte de travail

The ICARE laboratory at CNRS Orléans is a CNRS unit in its own right. It has around 80 members, including 33 researchers and lecturers, whose main research topics are combustion, energy conversion, environmental chemistry and space propulsion. The candidate will work in the laboratory's Electric Propulsion team, and more specifically in the HE BOOST European project, coordinated by the University of Bologna in Italy. This project concerns the study and characterization of iodine magnetic nozzle thrusters and associated subsystems.
This position is financed as part of the European HE BOOST project. Work is scheduled to start in December 2023, for a period of 3 years. The PhD student will be based mainly in Orléans at the ICARE laboratory (UPR 3021, CNRS)

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.

Contraintes et risques

The candidate will work mainly in Orléans with vacuum chambers, DC and RF power supplies, iodine plasma discharges and magnetic fields. He/she will use optical diagnostics such as laser-induced fluorescence spectroscopy and electrical diagnostics such as Langmuir probes, Faraday cups and energy analyzers to carry out his/her research.
The candidate will be required to travel to Germany and Italy as part of collaborations with our colleagues in the BOOST consortium.

Informations complémentaires

Applicants should send a detailed CV and covering letter via the CNRS job portal.
Selected candidates will be interviewed in October either at the ICARE laboratory or by videoconference.