Reasoning for circuit solver failure


I have just begun work on simulation of spacecraft charging at relatively high electron density ~E11. To do this I am using a blunt-cone re-entry body and simulating a 2-ion species 1-electron species plasma flow around the spacecraft.

I am looking for details on the circuit solver used by SPIS. I seem to be having an issue where the time step will get very small at a certain point in the run, at which point the circuit solver will then say it has failed. To solve this issue I have attempted to change the spacecraft material and capacitance, as well as the simulationDt, so that it would be on one lesser order than the last failed time step.

Does anybody have any tips on how I may go about resolving a circuit solver failure and/or where I can find more detailed documentation on the circuit solver.

Tyler G