gas is injected through the swirl gas injection ports 32 the swirl gas enters the discharge tube sideways creating a vortex inside the discharge tube 12 stabilizing the torch flame and protecting the discharge tube wall the discharge tube 12 is fixed by the quartz holder 40 which is made of stainless steel the swirl gas is introduced through single inlet port or through multiple e g two or four inlet ports circumferentially arranged the microwave 22 a radiated from the magnetron 22 propagates through a tapered waveguide section 10 the numerical reference 60 denotes the plasma torch flame generated by the breakdown of gas injected as a swirl gas in the strong electric field with the help of an ignition device 44 the ignitor 44 is retractable and consists of the tungsten electrode 45 which is insulated by an alumina tube a carbon containing gas 34 and a transition metal catalyst precursor 36 are introduced to the center of plasma torch flame 60 through introduction lines 34 a and 36 a respectively the transition metal catalyst precursor 36 is vaporized by an ultrasonication system 38 and is carried by an inert gas for example argon moreover the carbon containing gas 34 and vaporized transition metal catalyst precursor 36 is mixed and diluted by a swirl gas in the region of plasma flame 60 the diluent gas as a swirl gas plays no direct role in the carbon nanotube forming reaction but plays a contributory.