Ultraviolet imaging of a magneto--plasmadynamic thruster

We present a project of an imaging system of a plasma produced by a magneto-plasmadynamic (MPD) thruster for space applications, in the ultraviolet range. This system consists of four detectors placed outside the thruster (5 cm from the anode surface), plus nine arrays of ultraviolet (UV)-enhanced photodiodes, viewing the plasma at three different axial positions (z =3.5, 8.0, and 12.5 cm from the cathode tip) obtained carving directly their lodgings in the cylindrical structure of the anode, in between anode and cathode. We used single UDT455 UV/LN detectors with low noise, built-in amplifiers. The system allows the imaging of m=1 helical instabilities which limit the MPD thrust efficiency. © 2004 American Institute of Physics.