Abstract: The invention relates to a device generating a plasma flow comprising an electrically conductive housing, tubular in shape, forming a central channel traversed by a vortex gas, a central electrode arranged coaxially in said channel and an electric power source intended to apply an electric voltage V between the electrode and the housing, characterized in that the mean diameter of the channel formed by the housing decreases progressively from an area situated substantially at the level of the free end of the electrode as far as an end area of said housing, said end area being configured in such a way that the minimum electric voltage Vcmin(0) to be applied in order to develop an electric arc between said electrode and said end area is strictly greater than said voltage V.