A staged Z-pinch is a fusion concept where a high atomic number liner compresses a fusion fuel (deuterium–deuterium or deuterium–tritium) target. Here, we report new results from Lagrangian, Eulerian, and Arbitrary Lagrangian–Eulerian simulations, which confirm that, with proper treatment of the vacuum region outside from the pinch, fusion energy production >1 MJ can be expected without alpha heating and significantly higher if alpha heating is included. It is shown that shock waves play an important role in preheating the target plasma and in piling up liner mass at the liner/target interface. This results in higher ram pressure just before the pinch stagnation time and ultimately in higher energy density target plasma. [ABSTRACT FROM AUTHOR]