OK, if you haven't yet read this IEEE paper, do so now, before proceeding:http://www.combinationafci.com/resources/doc_ieee_combination_afci.pdf
Now, for the point of this thread:
The author refers to a 'law of physics' which, he asserts, proves that a series arc cannot form between copper electrodes (think: broken wire) at household voltages.
(See page 7 of the paper)
The graph included in the paper as "Figure 5" does not support this. It is a graph of voltage vs. air pressure, with the electrodes kept 1" apart at all times. He posted the wrong graph.
I am looking for links, or other DATA, that directly address his assertion.