(February 4, 2022 at 12:48 pm)HappySkeptic Wrote:(February 3, 2022 at 8:50 pm)Ferrocyanide Wrote: But besides that magnetic moment caused by spin, I think a stationary electron or an electron that is moving at the same velocity as a detector is said to NOT have a magnetic field.
So, a magnetic field is a relative thing.
If we have a stationary detector and a current is going through a wire (or vacuum), then we can detect a magnetic field that is circular around the wire (perpendicular to the wire direction).
The magnetic field becomes detectable since the detector and electrons are NOT moving at the same velocity.
The magnetic moment remains, regardless of velocity (because you can't stop an electron from spinning), but yes magnetic fields caused by moving charges are proportional to the rate of flow of charge.
Electric and magnetic forces have been unified. You can write a transformation that will transform any electric and magnetic field when the reference frame changes.
As a physicist, I think of the magnetic field as a fictitious thing - a result of the Lorentz Transformations (Special Relativity) acting on an electric field. There is no such thing (barring the discovery of a magnetic monopole) of a magnetic field being primal. It is always a result of moving (or spinning) charges relative to the measurement frame.
Yes, in reality there is the magnetic moment of the electron like you said, so this contributes to a magnetic field.
so, this means that the original Lorentz force equation might need an adjustment
F = qE + qv cross B
F = force
q = charge (the electric field of the particle. This is used as a sign value and also a quantized value)
E = electric field (external electric field)
q = charge (This is used as a sign value and also a quantized value)
v = velocity of the particle
B = external magnetic field.
so, I think that equation needs to be adjusted to take into account that some particles have a magnetic dipole moment.
From the discussion about neutrons with polymath, it looks like a non-uniform magnetic field can be used to change the direction of neutrons, so the same applies to electrons/protons.
If we just stick q = 0 into the Lorentz force equation, it gives
F = 0
which isn’t right. So, the Lorentz force equation is just a simplified equation.