Experimental analysis of an MPD closed-cycle generator with quasi-equilibrium plasma

The first series of MPD experiments performed with the closed-cycle facility of the Comitato Nazionale per l'Energia Nucleare (CNEN) are described. The entire facility, a blowdown loop capable of producing a high-purity noble gas, alkali-seeded plasma of 2 MW thermal power, has been thoroughly tested and has performed satisfactorily. The performance of a small-scale MPD generator with quasi-equilibrium plasma is shown to be influenced by ceramic leakage and plasma insulation from ground. Operating at Hall parameters up to three, the open-circuit Faraday field (29 V/cm) remains over 80 percent of its ideal value and the Hall field (28 V/cm) over 50 percent of its theoretical value, it which electrode voltage drop and segmentation effects are taken into account. The deviations of measured values from theoretical ones for both electric fields and conductivity are explained, at least qualitatively, by a simplified analytical model of wall and ground-loop leakages.