Portable microwave plasma systems including supply lines for providing microwaves and gas flow are disclosed. The supply line includes at least one gas line or conduit and a microwave coaxial cable. A portable microwave plasma system includes a microwave source, a waveguide-to-coax adapter and a waveguide that interconnects the microwave source with the waveguide-to-coax adapter, a portable discharge unit and the supply line. The portable discharge unit includes a gas flow tube coupled to the supply line to receive gas flow and a rod-shaped conductor that is axially disposed in the gas flow tube and has an end configured to receive microwaves from the microwave coaxial cable and a tapered tip positioned adjacent the outlet portion of the gas flow tube. The tapered tip is configured to focus microwave traveling through the rod-shaped conductor and generate plasma from the gas flow.