problems about dsmcfoam+ simulation

[JefferyX00]

Hello everyone, I'm a newbee to dsmc simulation. I met a problem in my case with dsmcfoam+ solver.
I set up a case like the picture below. It's near vacuum about 1 Pa in the torus , and I just used 1/8 of the full torus to do the simulation. The boundary setting up is the same as the picture.

The problem is the simulation only running for 0.005s, then stopped, and won't continue to run even after tens of hours.



where is the problem? Thanks a lot!!!