The authors conduct detailed r-z two dimensional time dependent numerical simulations of a closed cycle disk MHD generator for various load conditions. The objective of this study is to compare the results of the newly performed detailed r-z two dimensional time dependent numerical simulations with those of the already performed quasi-one dimensional time dependent numerical simulations. In the calculations, the generator using cesium seeded helium plasma with 100 MW thermal input and 40 MW electrical output is assumed, and the extent from its subsonic nozzle to diffuser is considered as the analytical region. It is made clear that the two dimensional simulation results almost coincide with the quasi-one dimensional ones except for the high load resistance condition. The intermittent discharge phenomenon under high load resistance condition is simulated for the first time in the present study. This means that the quasi-one dimensional simulations are unreliable when the load resistance is high, indicating the necessity of the present simulations. (C) 2003 Elsevier Ltd. All rights reserved.