Experimental Studies On Low-pressure Discharge Plasma Sources And Their Performances

There are two major low-pressure discharge forms: one is gas discharge,another is vacuum metal arc discharge.In this thesis,studies on the performances of the lowpressure gas discharge and vacuum metal arc discharge are conducted based on IEX-2015 system in our lab.The main work of this thesis includes:1)A set of DC metal arc generator is designed on the small platform driven by the WS-315 C argon arc welding machine.The plasma generator can produce a stable plasma jet with a length of more than 15 cm at the arc current I=20~40 A.Due to the relatively high chamber pressure(10~103Pa)on this small platform,the discharge is actually a combination of the metal vapor discharge and air discharge.2)With modifications on the structure of the preceding plasma generator,the experiments on the breakdown performances and the discharge features of the arcs driven by the Topcon DC power supply are conducted on IEX-2015.It can be found that the discharges of the metal arc at 10-1 Pa is obviously different from those at the pressure levels between 10 and 103 Pa.3)The effect of external magnetic field on the ion extraction process under a radio frequency(RF)electric field is analyzed theoretically.It is found that the magnetic field with a certain intensity has a great effect on the RF ion extraction process.The ion extraction efficiency with different sizes of aluminum plates is higher than that with the same size parallel plates.When the frequency of the RF electric field is constant,the current increases first and then decreases with the increase of the magnetic field.