Abstract: The present invention relates to an ionized gas generator with supersonic homogeneous flow. This generator comprises unitary modules comprising:two coaxial electrodes of cylindrical form, the downstream electrode being open and having the flow passing therethrough;means for injecting as vortical gas along planes perpendicular to the axis common to said electrodes, the gas thus injected passing through an electric arc which consequently takes an elongated form;means for striking the arc between the two coaxial electrodes;means for cooling the electrodes, the gas injection devices and the coupling chamber;coils creating around the first upstream electrode a magnetic field ensuring the displacement of the base of the arc around the inner surface of said upstream electrode.The invention is applicable to testing of heat-protection materials.