Magnetic field of an electron and general relativity

[potatocar]

This is from an older thread:

The electric field lines of an electron traveling close to the speed of light will be squeezed in the direction of motion (by length contraction). So much so, the electric field strength in front of and behind the electron (in the direction of motion call it x) will be much less than in y-z plane. The y-z plane will be a circular disc containing the strongest electric field lines that is perpendicular to the direction of motion.
by what

If that's true, how does the electron's spin cause it to behave like a small bar magnet? Why does relativity demand an electron have a magnetic field?

Thanks!

 

[Dale]

Why does relativity demand an electron have a magnetic field?

I am not sure what you mean. It is Maxwell's equations which demand that a moving electron has a magnetic field.

Relativity just provides a transformation that preserves Maxwell's equations in different reference frames. Before relativity was developed it was believed that Maxwell's equations only held exactly in one reference frame, but in that frame (without relativity) a moving electron would still have a magnetic field.

 

[zn5252]

This is from an older thread:

If that's true, how does the electron's spin cause it to behave like a small bar magnet? Why does relativity demand an electron have a magnetic field?

Thanks!

Perhaps this important paper will shed some light on the subject :

https://docs.google.com/viewer?a=v&q=cache:vuufvQCj-bcJ:houchmandzadeh.net/cours/Relativite/Biblio/messner_wheeler_1957.pdf+&hl=en&pid=bl&srcid=ADGEEShUytAxuSDGA71OKZ38QcnQwbmujHOfBuY_snupR8l2D2qVxJlSWj1yG2FDQATp-updXoOLWySewTXSGpp63eSI1KJ_v2Lop97ABm8St4WQNEgVkqd4w5hci7L6qygrY1u1LxTP&sig=AHIEtbQo8N0ZggLcjVzj0xHF4hYiHMMuLA