There is provided a microwave plasma torch system comprising: a plasma generator; a microwave generator; and at least one plasma source gas injector, wherein the microwave generator includes a waveguide, wherein the plasma generator includes a discharge tube, wherein the discharge tube passes through a waveguide in a perpendicular to the waveguide, wherein the waveguide has a width na, where n is an integer equal to or larger than 2, wherein a is defined as a width of a waveguide having a dominant mode for propagating a microwave, wherein the discharge tube is positioned relative to the waveguide such that a diameter center of the tube encounters a longitudinal null line of an electric field distribution, wherein the discharge tube is further positioned relative to the waveguide such that a diameter center of the tube encounters a transverse null line of an electric field distribution, wherein the transverse null line is perpendicular to the longitudinal null line.