Can Magnetic Field Strength Decrease with Distance in Plasmas?

AI Thread Summary
Magnetic field strength decreases with distance in free space according to the inverse square law, typically expressed as source field strength divided by 4πr². For a magnetic source of 1T, the field strength at 5cm would be calculated using this formula. In plasmas, the situation is more complex due to their conductive nature, which alters the interaction with magnetic fields. The magnetic field of a moving charge decreases as 1/r², while a dipole's field strength diminishes as 1/r³. Understanding these principles is essential for grasping how magnetic fields behave in dense plasmas.
7doughnuts
Messages
5
Reaction score
0
Hi

Can anyone tell me how magnetic field strength decreases with distance in free space? If the source was effectively a point souce in a plasma, what would the field strength be at a specific distance?

Is it source field strength/4 pi r sqrd?

As an example if the source was 1T, what would the measured field be at 5cm?

I've been reading some papers claiming massive field strengths inside dense plasmas and I'm curious as to how far these fields extend.

Thanks in advance :smile:
 
Physics news on Phys.org
Well according to what I read somewhere

B=\mu H
Where H is field strength and B is flux density. But B would depend on what is being used to produce the magnetic field.
 
The magnetic field of a moving charge falls off like 1/r^2.

However, we usually see magnetic fields in the form of dipoles. A dipole has a north and a south pole--like a bar magnet. The field of a dipole falls off like 1/r^3.

That's in free space. Inside a plasma, it gets more complicated, because plasmas conduct electricity and interact with magnetic fields in complex ways.
 
Thread 'Motional EMF in Faraday disc, co-rotating magnet axial mean flux'
So here is the motional EMF formula. Now I understand the standard Faraday paradox that an axis symmetric field source (like a speaker motor ring magnet) has a magnetic field that is frame invariant under rotation around axis of symmetry. The field is static whether you rotate the magnet or not. So far so good. What puzzles me is this , there is a term average magnetic flux or "azimuthal mean" , this term describes the average magnetic field through the area swept by the rotating Faraday...

Similar threads

Back
Top