[Archive] Sources time steps

Message by Felicien Filleul:
I have been playing for a while now with SPIS and especially with the sources, and so far I have never acquired the feeling of understanding truly the relationships between the populationDts, the populationDurations, the plasmaDt and the plasmaDuration. How to be sure that I am setting them correctly ?
My only certitude is that each populationDt must be defined to a fraction of the plasma frequency of the specie, as in a normal PIC code.
But then what happens when I have Xenon ions and electrons sources (as particles) in my simulation ?
Shall I define the ionDt and the electronDt to two different values or shall I set both to the smallest Dt ?
Electrons will move much faster than the ions so it should no be necessary to wait the whole ionDt to actually close the electrons time loop. As said in the SPIS User Manual, in such a situation I should set plasmaDt = ionDuration. Ok, but then how to define correctly the populationDuration according the populationDt and the plasmaDuration according to the plasmaDt, and same with the simulation loop.
In short, is there a detailed explanation somewhere for me to understand the processes at work inside the SPIS black box ?
Thank you very much.