Earths Magnetic Field and solar winds

[nution]

Since the Earth's magnetic field helps to protect the Earth from a lot of the suns harsh treatments, do we also assume that in some degree light is also (possibly in very small fractions) also diverted by the magnetic field?

If no, would it even be possible to assume that a very strong magnetic field could potentially bend light? If even a very small amount?

It is just in my mind, I see a magnetic field similar to gravitational fields. Although very different and separate things, we know they both attract, both are fundamental forces and both propagate at the speed of light. Since large scale gravitational fields can bend light, wouldn't magnetism be able to bend light as well? Even possibly on a smaller scale since gravity is such a weak force compared to very intense localized magnetic fields?

 

[torquil]

The Earth's magnetic field won't have a direct measureable effect on an incoming light ray. On the other hand, the magnetic field might have an indirect effect on e.g. the opacity of the atmosphere since it changes the distribution of incoming charged particles and thereby the distribution of clouds around the globe by some (small or large?) amount.

An incredibly string magnetic field would curve spacetime and influence the motion of light via general relativity (gravitation), as you mention.

A magnetic field is made up of the same stuff as photons. Photons will interact with each other through a quantum field effect involving spontaneous production of electron/positron pairs. So in principle a magnetic field can influence a ray of light.

This could be an interesting project: study the interaction of photons with a strong magnetic background field. If it makes sense, it has probably been done a long time ago.

Perhaps it would be possible to manufacture a magnetic field background to influence a ray of light in a prescribed manner. Although I imagine the magnetic field strength would need to be pretty high...

I'm no expert on light and magnetic fields, so perhaps someone else might chime in?

 

[nution]

An incredibly string magnetic field would curve spacetime and influence the motion of light via general relativity (gravitation), as you mention.

Do you mean to say that a this strong magnetic field can create gravity from little to no mass? If by the general relativity theory you mean that gravity will be playing a role in this, I was not aware magnetism could alter or create a gravitational field. Or can magnetism curve space time by itself, without the inclusion of gravity?

 

[torquil]

The magnetic field itself contains energy that causes space to be curved through the laws of general relativity. The energy density of an electromagnetic field goes like E^2 + B^2, where E and B are the electric and magnetic fields, respectively. Such quantities would appear in the energy-momentum tensor in Einsteins law of gravity, thus themselves contributing to spacetime curvature.

Note that to create this magnetic field, a large mass would probably be needed, i.e. an enormous and incredibly powerful magnet (e.g. a spinning, charged black hole). So the magnet's mass itself would also curve spacetime, and probably much more than the contribution from only the magnetic field.

The same thing goes for electric fields. You can look up the Reissner-Nordstrøm solution for a charged black hole. The spacetime curvature depends not only on the mass of the black hole, but also its charge. I.e. differently charged black holes will have different spacetime curvatures around them, depending on the amount of electric charge in the black hole. This is due to the electric energy density E^2 around the black hole.