A method for generating a propulsion thrust by means of a plasma thruster comprising the following steps:
- injection, into a discharge chamber comprising an internal cavity and an outlet opening, using at least one injection means comprising an outlet end called the injection nozzle, of a propellant gas along a predefined axis;
- generation, using a magnetic field generator, of a magnetic field of setting electrons of the propellant gas present in the discharge chamber in gyromagnetic rotation;
- emission into the propellant gas present in the discharge chamber, using an electromagnetic wave generator, of at least one electromagnetic wave the electric field of which has a right-hand circular polarization and a frequency equal to the gyromagnetic resonance frequency, fECR, of the electrons of the propellant gas magnetized by said magnetic field generator;
- ignition of the plasma by ionization of the propellant gas;
- and
- sustaining of the plasma by cyclotron resonance of the electrons;
- wherein:
- the ignition of the plasma is realized by microhollow cathode discharge using the injection means which is made of magnetic material and comprises, at the downstream end of its injection nozzle, an injection channel with an external diameter of less than a few millimeters;
- the injection of the propellant gas and the emission of the electromagnetic wave are carried out by one and the same injection means and at the same location in the discharge chamber, said injection means being produced from an electrically conductive material and electrically connected to the electromagnetic wave generator in order to emit the electromagnetic wave into the propellant gas at the outlet of the gas from said injection nozzle, so as to maximize the level of ionization of the propellant gas on exiting;
- said magnetic field generation is such that:
- on the one hand, the magnetic field has:
- a first local maximum of intensity situated inside the injection nozzle and at the outlet end of the injection nozzle;
- field lines which determine an iso-field surface, known as the ECR surface, with an intensity equal to that allowing a cyclotron resonance of the electrons under the effect of said electromagnetic wave, said ECR surface enveloping the outlet end of said injection nozzle;
- a second local maximum of the intensity of the magnetic field inside the injection nozzle, separated from the first local maximum by a local minimum of the intensity of the magnetic field inside said injection nozzle;
- on the other hand, the magnetic field gives said field lines the shape of a nozzle, so as to generate a diamagnetic force;
- the sustaining of the plasma by cyclotron resonance of the electrons being realized by resonance of the electromagnetic wave in the volume delimited by the ECR surface.