One-dimensional Models of Stationary Plasma Thruster

A stationary plasma thruster (SPT, or Hall Thruster) is an electromagnetic thruster whose properties make it especially suitable for applications such as satellite station-keeping. Fig. 1 represents schematically the geometry of the SPT. Xenon is injected from the anode (rate on the order of 5mg/s), at the end of the dielectric cylinders and on the cathode side, outside the cylinders. We are mainly interested here in the plasma column which is located between the coaxial cylinders (internal radius: 3 cm, external radius: 5 cm). Since the device must work under conditions of relatively low gas density (the xenon density is on the order of a few 10 cm close to the anode), and the length of the column is on the order of a few cm (typically 4 cm), the electrons undergo very few collisions from the cylinder entrance, on the cathode side, to the anode and it would not be possible to sustain a plasma in the column without enhancing the confinement of the electrons. This confinement is provided by a magnetic field created by coils which are located on the external surface of the cylinder. The magnetic field is radial in the exhaust region (cathode side of the cylinders), and on the order of 200 G at the exhaust and ten times less at the anode). The potential drop in the plasma column can be as large as 200 to 300 V in standard conditions.