Electron thermodynamics along magnetic nozzle lines in a helicon plasma

Alfio Vinci (1) , Quentin Delavière-Delion (1) , Stéphane Mazouffre (1)

1 ICARE - Institut de Combustion, Aérothermique, Réactivité et Environnement

The electron cooling rate is experimentally investigated along the magnetic lines of a helicon plasma device operating with different magnetic nozzle shapes. Probe measurements in a 2-D region of the plasma plume outline that the polytropic index of electrons has dissimilar values along distinct streamlines ranging from gamma_e around 1.4 to gamma_e > 1.8. Accounting for ionization phenomena as an additional degree of freedom allows to predict a polytropic index smaller than the adiabatic limit. It is observed that a reduced cross-field transport can effectively reduce the electrons degrees of freedom.

Mots clés: Magnetic nozzle; Electron thermodynamics; Polytropic index; Helicon plasma

Domaines: Plasmas

Alfio Vinci, Quentin Delavière-Delion, Stéphane Mazouffre. Electron thermodynamics along magnetic nozzle lines in a helicon plasma. Journal of Electric Propulsion, 2022, 1 (1), pp.4. ⟨10.1007/s44205-022-00003-0⟩. ⟨hal-03629442⟩