A part of the performance degradation mechanism of the advanced, electrodeless, helicon plasma thruster with a magnetic nozzle, has been revealed by the research group of Dr. Kazunori Takahashi and Prof. Akira Ando at Tohoku University's Department of Electrical Engineering.
An electric propulsion device is a main engine, and a key piece of technology for space development and exploration. Charged particles are produced by electric discharge and accelerated, i.e. momentum is transferred to them via electromagnetic fields. The thrust force is equivalent to the momentum exhausted by the device, and the spacecraft can thus be propelled into space.
Mature electric propulsion devices such as ion engines, hall thrusters and magnetoplasmadynamic thrusters have electrodes exposed to the plasmas. Ion sputtering and erosion damage these exposed electrodes over time. For propulsion systems that are used over a long period, electrodeless propulsion devices have been suggested and rigorously researched as an alternative option. These are represented by the Variable Specific Impulse Magneto-plasma Rocket (VASIMR) and the helicon plasma thruster.
In the helicon plasma thruster concept, the charged particles in a high density helicon plasma source is guided to the open source exit and accelerated by the magnetic nozzle via a magnetic expansion process. Various gain and loss processes of the particle momentum occur in the thruster, significantly affecting the propulsive performance, where the thrust force is equivalent to the momentum exhausted from the system.
Getting to Mars and back in a reasonably short amount of time will require high performance propulsion systems like plasma thrusters. And as we now know, long duration space travel can apparently damage human brains. To read more, click here.