A plasma torch comprising: - a plasma generator having: - a cathode extending along an axis X and an anode, the cathode and the anode being provided so as to be able to generate, in a chamber, an electric arc between the anode and the cathode when voltage is applied; and - an injection device for injecting a plasmagen gas comprising an injection duct opening, along an injection axis (Ii), via an injection orifice into the chamber, - means for injecting a material to be sprayed into a plasma flux generated by said plasma generator; the plasma torch being characterized in that - the ratio R" between: - the radial distance (y i) of said injection orifice, defined as a minimum distance between the axis X and a center of said injection orifice; and - the largest transverse dimension (D C) of the cathode in a region of the chamber downstream of an axial position p AC, p AC denoting the axial position of minimum radial distance between the anode and cathode, is smaller than 2.5, and - a projection of the injection axis (I i) in a transverse plane passing through the center of the injection orifice of said injection duct defines an angle β smaller than 45° and greater than 5° with a radius extending in said transverse plane and passing through the axis X and through the center of said injection orifice, the chamber comprising successively, from upstream to downstream, an expansion chamber extending axially from the back of the chamber as far as the position p AC, then an arc chamber (26") extending axially from the position p AC as far as the position p A of an outlet aperture, bounded by the downstream end of the anode and through which the plasma exits from the plasma generator, the axial position designating a position along the axis X. - a plasma generator having: - a cathode extending along an axis X and an anode, the cathode and the anode being provided so as to be able to generate, in a chamber, an electric arc between the anode and the cathode when voltage is applied; and - an injection device for injecting a plasmagen gas comprising an injection duct opening, along an injection axis (Ii), via an injection orifice into the chamber, - a cathode extending along an axis X and an anode, the cathode and the anode being provided so as to be able to generate, in a chamber, an electric arc between the anode and the cathode when voltage is applied; and - an injection device for injecting a plasmagen gas comprising an injection duct opening, along an injection axis (Ii), via an injection orifice into the chamber, - means for injecting a material to be sprayed into a plasma flux generated by said plasma generator; - the ratio R" between: - the radial distance (y i) of said injection orifice, defined as a minimum distance between the axis X and a center of said injection orifice; and - the largest transverse dimension (D C) of the cathode in a region of the chamber downstream of an axial position p AC, p AC denoting the axial position of minimum radial distance between the anode and cathode, is smaller than 2.5, and - the radial distance (y i) of said injection orifice, defined as a minimum distance between the axis X and a center of said injection orifice; and - the largest transverse dimension (D C) of the cathode in a region of the chamber downstream of an axial position p AC, p AC denoting the axial position of minimum radial distance between the anode and cathode, - a projection of the injection axis (I i) in a transverse plane passing through the center of the injection orifice of said injection duct defines an angle β smaller than 45° and greater than 5° with a radius extending in said transverse plane and passing through the axis X and through the center of said injection orifice,