What is the electrical resistivity of air during breakdown?

There is a well-documented theory for breakdown voltage vs pressure in the form of Paschen's law.

But what is the trend of the electrical resistivity of air as a function of the electric field imposed on it? It is quite difficult to find such a curve.

Also, is there a minimum resistivity for arcing, i.e a breakdown is assumed to have taken place?

I understand that there are two questions in this, but I guess it will be allowed considering that the two are linked.

• look up "townsend breakdown". – niels nielsen Nov 15 '18 at 21:38