Étude des plasmas micro-ondes pour la fixation de l'azote par des diagnostics laser avancés // Microwave plasma investigations for nitrogen fixation by advanced laser diagnostics

For continuous plasma generation, a very promising approach recently developed at the EM2C laboratory consists of generating a microwave (MW) discharge in jets or capillaries (see Figures a and b) in attachment [1]. Even at very low power levels (e.g., a few watts), microwave plasmas can be generated over lengths ranging from a few millimeters to a few centimeters. The main advantage of capillary or jet microwave discharges over standard pulsed electrode discharges lies in their continuous nature (continuous production of reactive species), non-invasive character (absence of electrodes), extended transport of radicals and efficient energy transfer.
The MW plasma generated in capillaries is a high-potential candidate for improving the efficiency of the Birkeland-Eyde (BE) process. Controlling species density, temperature, and their gradients should be advantageous in capillary plasmas, where fine tuning of plasma parameters and significant production of nitric oxide (NO) radicals through heat transfer have recently been demonstrated [2]. The efficiency of the discharge in producing NO has been significantly improved (i.e., by an order of magnitude), offering an original means of reducing the high cost of the BE process.
To achieve the necessary technological innovations, there are a wide variety of complex phenomena that need be studied in these MW plasmas. To date, the physical properties, the reactivity and transport, the energy coupling and power budget are poorly known. The understanding of these plasmas is limited by the lack of fine discharge diagnostics.
The objective of this thesis is to characterize microwave plasmas using high-end spectroscopic laser diagnostics in order to understand the key mechanisms of plasma nitrogen fixation and to optimize the efficiency of these plasmas.
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For continuous plasma generation, a very promising approach recently developed at the EM2C laboratory consists of generating a microwave (MW) discharge in jets or capillaries (see Figures a and b) in attachment [1]. Even at very low power levels (e.g., a few watts), microwave plasmas can be generated over lengths ranging from a few millimeters to a few centimeters. The main advantage of capillary or jet microwave discharges over standard pulsed electrode discharges lies in their continuous nature (continuous production of reactive species), non-invasive character (absence of electrodes), extended transport of radicals and efficient energy transfer.
The MW plasma generated in capillaries is a high-potential candidate for improving the efficiency of the Birkeland-Eyde (BE) process. Controlling species density, temperature, and their gradients should be advantageous in capillary plasmas, where fine tuning of plasma parameters and significant production of nitric oxide (NO) radicals through heat transfer have recently been demonstrated [2]. The efficiency of the discharge in producing NO has been significantly improved (i.e., by an order of magnitude), offering an original means of reducing the high cost of the BE process.
To achieve the necessary technological innovations, there are a wide variety of complex phenomena that need be studied in these MW plasmas. To date, the physical properties, the reactivity and transport, the energy coupling and power budget are poorly known. The understanding of these plasmas is limited by the lack of fine discharge diagnostics.
The objective of this thesis is to characterize microwave plasmas using high-end spectroscopic laser diagnostics in order to understand the key mechanisms of plasma nitrogen fixation and to optimize the efficiency of these plasmas.
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Début de la thèse : 01/10/2026

Contrats ED : Programme blanc GS-SIS

Université Paris-Saclay GS Sciences de l'ingénierie et des systèmes

579 Sciences Mécaniques et Energétiques, Matériaux et Géosciences

This thesis project is intended for engineer/M2 graduates in fields of engineering sciences or physics. Knowledge of plasmas, lasers, spectroscopy or transport phenomena is appreciated. If you are highly motivated by challenging experiments, passionate about research in applied physics and engineering, and interested in a greener planet, then you're the one we're looking for!
This thesis project is intended for engineer/M2 graduates in fields of engineering sciences or physics. Knowledge of plasmas, lasers, spectroscopy or transport phenomena is appreciated. If you are highly motivated by challenging experiments, passionate about research in applied physics and engineering, and interested in a greener planet, then you're the one we're looking for!