How to create an electron source


Could anyone tell me how to create an electron source from a surface? I do not see any option in the Group Editor for sources aside from thrusters, which is not what I want. I am looking to inject an additional electron species from only one point in my domain, while all external boundaries inject a quasi-neutral plasma.

The documentation seems to indicate that there is some ability to define a surface with a “SourceID” but I see no option, and do not have any mention of sources in my global paramaters. Am I missing something or should I move to a previous version of SPIS? (I am using 6.1.0)

Help is much appreciated, thanks,