Compound double coaxial line atmospheric pressure low-temperature microwave plasma jet source

A compound double coaxial line atmospheric pressure low-temperature microwave plasma jet source, comprising an outer coaxial line and an inner coaxial line;

• wherein
• the inner coaxial line is arranged inside the outer coaxial line, and a top of the inner coaxial line is flush with a top of the outer coaxial line;
• the outer coaxial line comprises a tube body;
• a metal tube is arranged in the tube body;
• a short-circuit plunger is movably arranged at a bottom of the metal tube;
• the inner coaxial line comprises a needle electrode;
• the needle electrode is arranged in the metal tube, and a top of the needle electrode protrudes out of the metal tube;
• a first gas inlet is arranged on the tube body, and the first gas inlet is connected between the tube body and the metal tube;
• a second gas inlet is arranged at the bottom of the metal tube, and the second gas inlet is connected between the metal tube and the needle electrode;
• the tube body is provided with a microwave input port, and the microwave input port is connected to the metal tube.