The right figure shows the schematic of ion acceleration mechanism of this
thruster. The plasma is generated by microwave discharge. Electrons is
trapped in a magnetic tube, where is the area between magnetic mirrors.
Electrons gain energy from the microwaves and they collide propellant particles
and the propellant atoms are ionized. The ions are accelerated by the potential
difference between the plasma inside the thruster and the space, if the
discharge chamber is kept the potential same as the space potential. High
energetic electrons can also go out to downstream with ions against the
potential difference. These electrons and ions outside the thruster are
neutralized; it does not need a neutralizer. Therefore, this thruster is
very simple and small, and it can operate in low power consumption.
We are expecting the generation of the Double Layer. If double layer is generated, ions are accelerated by more high potential difference.
Therefore, we call this thruster TDL(Thruster with Double Layer).
Depatment of Advanced Energy Engineering Science,
Kyushu University
6-1, 816-8580, Japan, Kasuga