Jump to content

Recommended Posts

Posted

The Vector Potential, generated by an individual charge, is [math]\vec{A_{q}} \approx \frac{q}{r} \times \vec{v}[/math]. And, the Dirac expression, for the Vector Potential [math]\vec{A}[/math], of a magnetic monopole, in spherical coordinates, is:

 

[math]\vec{A_{m}} \approx \frac{1}{r} \times tan \left( \frac{\theta}{2} \right) \hat{\phi}[/math]
(Jackson.
Classical Electro-Dynamics
, p. 290)

Thus, qualitatively, a spherical distribution of charged plasma, rotating differentially, with "slowly spinning poles" and a "fast rotating equator", would have an azimuthal plasma velocity profile, comparable to [math]\vec{v} \approx tan \left( \frac{\theta}{2} \right) \hat{\phi}[/math]. And, that description sounds strikingly similar to a star, e.g. our sun, whose magnetic field is quasi-radial, according to the Parker model:

 

Parker’s model explained that the solar wind, emanating from the equator, forms a spiral in the equatorial plane... This is called the Parker spiral...

 

solarwind_twist.gif

At higher latitudes, the solar wind travels outward radially, making tighter and tighter spirals, until, ultimately, at the poles, the wind simply travels outwards in a straight vertical line.

Indeed, such a shear-inducing, differential azimuthal velocity field, sounds completely consistent, with our sun's tacho-cline:

 

The tachocline is the transition region of the Sun, between the radiative interior, and the differentially rotating outer convective zone... The convective exterior rotates as a normal fluid, with differential rotation, with the poles rotating slowly, and the equator rotating quickly. The radiative interior exhibits solid-body rotation... The rotation rate through the interior is roughly equal to the rotation rate at mid-latitudes, i.e. in-between the rate at the slow poles and the fast equator. Recent results from helioseismology indicate that the tachocline is located at a radius of [math]< 0.70 R_{\odot}[/math], with a thickness of [math]0.04 R_{\odot}[/math]. This would mean the area has a very large shear profile, which is one way that large scale magnetic fields can be formed.

Thus, solar-like differential rotation, of charged plasma:

 

DR_web.jpg

is qualitatively consistent, with quasi-radial "mono-polar" magnetic fields:

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.