The influence of magnetic circuit and operating parameters on the plasma property of 2 cm ECRIT ion source

The ion source of 2 cm electron cyclotron resonance ion thruster (ECRIT) extracts ion beam to generate thrust. The magnetic circuit of the source has important influence on plasma distribution associated with beam extracting. It is necessary to diagnose the plasma field of the ion source through the straight and bent Langmuir probe. The diagnosing results showed that at the same power and gas flow rate, the magnetic circuits affected the peak values of plasma parameters and their distribution. For different magnetic circuit, the ion density and electron temperature were positively and negatively correlated with the gas flow rate relatively; the ion density and electron temperature were all positively correlated with microwave power. At the high flow rate, microwave power and magnetic circuit affected slightly the plasma distribution. However, at the high power, gas flow rate and magnetic circuit had obviously impact on plasma distribution. In addition, the suitable gas flow rate range of the ion source with different magnetic circuits was different. •The probe with axis almost vertical to magnetic flux lines can reduce the influence of magnetic field on probe current.•As ECR layer formed near screen grid, ion density near screen grid is high, which will provide appropriate condition for ion extraction.•When ECR layer formed in a narrow gap between antenna and conductor wall, the plasma generation is easy.