A particle-in-cell simulation is conducted to investigate the plasma acceleration process in a micro-cathode vacuum arc thruster.A coaxial electrode structure thruster with an applied magnetic field configuration is u...A particle-in-cell simulation is conducted to investigate the plasma acceleration process in a micro-cathode vacuum arc thruster.A coaxial electrode structure thruster with an applied magnetic field configuration is used to investigate the effects of the distribution of the magnetic field on the acceleration process and the mechanism of electrons and ions.The modeling results show that due to the small Larmor radius of electrons,they are magnetized and bound by the magnetic field lines to form a narrow electron channel.Heavy ions with a large Larmor radius take a long time to keep up with the electron movement.The presence of a magnetic field strengthens the charge separation phenomenon.The electric field caused by the charge separation is mainly responsible for the ion acceleration downstream of the computation.The impact of variations in the distribution of the magnetic field on the acceleration of the plasma is also investigated in this study,and it is found that the position of the magnetic coil relative to the thruster exit has an important impact on the acceleration of ions.In order to increase the axial velocity of heavy ions,the design should be considered to reduce the confinement of the magnetic field on the electrons in the downstream divergent part of the applied magnetic field.展开更多
The structure, fabrication and emission characteristics of a silicon cold micro-cathode using ultra-shallow PN+ junction are presented. Implantation of As+ with a energy around 12 kev, rapid thermal annealing combined...The structure, fabrication and emission characteristics of a silicon cold micro-cathode using ultra-shallow PN+ junction are presented. Implantation of As+ with a energy around 12 kev, rapid thermal annealing combined with argon sputtering are used for forming ultra-shallow pn+ junction, whose depth is lower than 30nm. In a vacuum system Ⅰ-Ⅴcharacteristics were measured. The stability problem which was found in the devices testing is also discussed in this paper.展开更多
基金supported by National Natural Science Foundation of China(Nos.11735004,11575019,and 11702021)National Postdoctoral Program for Innovative Talents(BX20180029)Defense Industrial Technology Development Program(JCKY2018203B029)。
文摘A particle-in-cell simulation is conducted to investigate the plasma acceleration process in a micro-cathode vacuum arc thruster.A coaxial electrode structure thruster with an applied magnetic field configuration is used to investigate the effects of the distribution of the magnetic field on the acceleration process and the mechanism of electrons and ions.The modeling results show that due to the small Larmor radius of electrons,they are magnetized and bound by the magnetic field lines to form a narrow electron channel.Heavy ions with a large Larmor radius take a long time to keep up with the electron movement.The presence of a magnetic field strengthens the charge separation phenomenon.The electric field caused by the charge separation is mainly responsible for the ion acceleration downstream of the computation.The impact of variations in the distribution of the magnetic field on the acceleration of the plasma is also investigated in this study,and it is found that the position of the magnetic coil relative to the thruster exit has an important impact on the acceleration of ions.In order to increase the axial velocity of heavy ions,the design should be considered to reduce the confinement of the magnetic field on the electrons in the downstream divergent part of the applied magnetic field.
文摘The structure, fabrication and emission characteristics of a silicon cold micro-cathode using ultra-shallow PN+ junction are presented. Implantation of As+ with a energy around 12 kev, rapid thermal annealing combined with argon sputtering are used for forming ultra-shallow pn+ junction, whose depth is lower than 30nm. In a vacuum system Ⅰ-Ⅴcharacteristics were measured. The stability problem which was found in the devices testing is also discussed in this paper.
