Why Does Current Produce a Magnetic Field But Not Vice Versa?

AI Thread Summary
Current generates a static magnetic field due to the movement of electric charge, while a static magnetic field does not induce current because it lacks motion. The relationship between electric current and magnetic fields is governed by Jefimenko’s equations, which illustrate that the cause (current) precedes the effect (magnetic field). This temporal and spatial ordering means that one cannot simply reverse the roles of current and magnetic fields. The fundamental nature of electromagnetic interactions dictates that a changing electric field is necessary to produce current, reinforcing the asymmetry in their relationship. Understanding this distinction is crucial for grasping the principles of electromagnetism.
Rav430
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Why does current produce a static magnetic field, but a static magnetic field doesn't produce current?

Specifically, why is one true, but the inverse not true? I can accept that each rule individually is just how the universe works... but it sounds so contradictory when I examine both together.

Is there some way I can think about this intuitively?
 
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Because a current is a changing electrical charge. Charge is moving. This is why it generates a magnetic field.

A magnetic field needs to be moving in a similar way for it to produce an electric field.
 
Rav430 said:
Why does current produce a static magnetic field, but a static magnetic field doesn't produce current?
Jefimenko’s equations and the retarded potentials are pretty clear about the temporal and spatial ordering. A current here now causes a magnetic field elsewhere at the retarded time. You simply cannot swap the two roles. The cause preceeds the effect and the equation cannot be reversed to get the effect preceding the cause
 
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