I wanna do a simulation of a ground-based simulation experiment, and I started with a cube in vacuum chamber like the example “SPIS-EP_ChamberTestCases.spis5”, The walls of the vacuum chamber are set to node 0 and the groundPotFlag is set to 1 so as to let the other node floating relative to the node 0. One thing bothering me is how does Csat work in this case? Csat connects plasma at infinity and floating elements. But when groundPotFlag is set to 1 to simulate a vacuum chamber, Csat seems to have lost its meaning. However, I found that Csat still affects the simulation. How to explain?