There have been lots of practical experiments carried out on NVIS which have developed a large collection of useful insights into how to do it. What I’m not finding so far is good references that really make understanding more than a matter of a discussion on a paper or presentation about it.

I don’t want to sound negative, but all of the explanations I’ve found run out the same information about how it works, as if they come from the same source, but I can’t find that source. That seems strange. Where is that source and why can’t I find it?

I will certainly keep looking and add my findings here as I can get my thoughts together.