An actual physical experiment that will perhaps be able to measure the different values of Birkeland currents and plasma double layers, may be one of the possible bonuses for Phase 2 of the SAFIRE Project.
Montgomery Childs, during an update on the SAFIRE Project at EU 2016 convention, mentioned that the latest version of the SAFIRE chamber needed over 40,000 new components that had to be sourced by one person.
The updated SAFIRE system, with its enhanced accuracy of 0.03mm, should allow instruments to measure the differences in plasma, especially important for double layers of plasma that help to form Birkeland currents.
SAFIRE Phase 2 news video
You can see some of the latest news and implications of this continuing plasma experiment in the Thunderbolts youtube video from the Electric Universe 2016 conference. Monty's talk is a more technical review of what has been happening, not a presentation on all of its results and conclusions.