In the uphill battle to bring electric fields and currents to a *causal* status in astrophysics, one sometimes finds very clear evidence and analysis. A recent article by Stutz & Gould is just such an example
http://arxiv.org/pdf/1512.04944v3.pdf
To set the stage, the only story of star formation publishable or teachable for the past 70 years has been what we can call the gravity model. This model states that large clouds of gas & dust randomly condense under the force of gravity to make stars.
Recently the Hershel telescope has shown that most all star formation takes place along filaments. This is impossible from a "gravity only" view.
The EU community has for decades predicted that we would see star formation along filaments. One would hope that a scientific paradigm could gain some street cred by predicting what one would see. I certainly was taught this is one of the true measures of a useful scientific model.
In examining the Orion nebula, Stutz & Gould point out, about the observed filamentary nature of star formation:
"However, given that circular (or more generally, helical) magnetic fields, which would be generated primarily by currents moving along the filaments, are the form that is necessary to confine filaments of approximately uniform thickness, the Heiles (1997) observations constituted a “smoking gun”.
And
"Such high field strengths are naturally explained by magnetic compression of gas due to currents. That is, the material gets to its current position not by crossing field lines but by compressing them. It may be objected that this process would lead to pinching instabilities. Our answer: yes, pinching instabilities are expected and this is exactly what leads to cluster formation."
I have read Heiles (1997) and, notably, in 44 pages describing the magnetic fields, there is NO mention of currents. So Stutz & Gould are doing us a great favor in pointing out the smoking gun.
Why do all the hallowed halls of astrophysics fight tooth and nail against electric fields and currents? I no longer know. Probably it is all because of mortgages and professional prestige. I am not immune to such motivations.