Alfvén contended that some of the properties of the Sun can be explained by a 3.00 × 10⁹ amp electric current.^1:54

 

Figure 1. Alfvén's Heliospheric Circuit

A: the rotation of the Sun generates a unipolar inductor, which is the primary electromotive force. Charge build-up at the poles expels the charge in an axial current, with half of it going in each direction.

 

B₁: the inductor draws in current at the equator, but since currents tend to follow magnetic field lines, they actually arrive at auroral latitudes.

 

B₂: the current is driven by repulsion from the e.m.f.

 

B₃: repulsion at B₂ and attraction at B₁ form a closing current.

 

C: the primary supply flows in on the equatorial plane.

 

D: the charge stream will surely induce a balancing double-layer, outside of which there will be no electric field.

 

I₀: the current was estimated at 3.00 × 10⁹ amps.

 

 

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Criticisms

 

It would be a stretch to say that the predictions of this model have been met. First, the 3.00 × 10⁹ A current is relatively trivial, and could not reasonably be thought to exert the force, through electrical resistance, to explain differential rotation as Alfvén suggested. Second, the equatorial streamers show a diffuse current that is consolidated in the "helmet" regions, contrary to the auroral expections, which would have the interior of the streamers devoid of current.