Stabilization of the Microwave Plasma Facility (MPF) by a microwave isolator

Summary form only given. A microwave isolator and a new tuner have been added to the UTK Microwave Plasma Facility (MPF), an approximately 200-liter steady-state, uniform plasma generated by 2 kW of 2.45 GHz microwave power. The uniform steady state plasma, before the addition of the microwave isolator, had an electron number density of about 6 /spl times/ 10/sup 16// electrons/m/sup 3/ and an electron kinetic temperature of 16 eV. The plasma was difficult to stabilize since the reflected power reacted with the magnetron source, changing its characteristics. The microwave isolator has successfully decoupled the reflected power from the load, thus facilitating the process of tuning the plasma. Additional tuning stubs in the microwave circuit have further enhanced the ease of tuning the plasma and minimizing the amount of reflected power.