[Archive] Source particles

Message by Alessandro Colovini:
Hello,I’m simulating a thruster+cathode configuration to check the neutralization of the plume and I’ve been playing a lot with timesteps lately. I’ve noticed that when i increase the sourcedt/simulationDt and sourceDuration, the number of particles emitted by the cathode increases by several powers of 10.
I would like to understand what should i set up to make my source emit less particles if I want to increase the simulation Dt. Can somebody explain the relation between SimulationDt, sourceDt and sourceDuration?

Message by Sébastien Hess:
this one is a tough one to answer!
To keep it simple:
During each simulationDt you make plasmaDt/plasmaDuration cycles on the plasma.
During each PlasmaDt you make sourceDt/sourceDuration cycles on the source particle motion.
During each sourceDt you inject a given number of particle, that is controled by the value of sourceFlag
The time of residence (in simulation cycle) of each particle in the domain is then ~ Domain_size/V_part/sourceDuration*plasmaDuration/plasmaDt
The number of particle in the simulation domain is then about Domain_size/V_part/sourceDt*plasmaDuration/plasmaDt*sourceFlag
Then there is a hierarchy that is enforced between time steps: SimulationDT>PlasmaDuration>PlasmaDt>SourceDuration>SourceDt…
I hope you get the idea…
Best Regards,