What is a magnetic field "made" of?

AI Thread Summary
The electromagnetic (EM) field is considered a fundamental entity in physics, not composed of any underlying substance. It can be described as a continuous field in classical terms or as quantized in quantum field theory, where it is associated with particles like photons. The discussion highlights confusion about whether static (DC) fields are made of photons, with clarification that photons are indeed involved in the dynamics of the EM field. The EM field serves to predict interactions between charged particles, and its properties are defined mathematically rather than through a physical composition. Ultimately, the EM field is essential for understanding electromagnetic interactions, but it does not consist of anything else.
awcrowe
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I have looked this up on several occassions and never satisfied.
It seems that either the answer keeps repeating magnetic or electromagnetic field over and over. Or the answer discuss the properties of electromagnetism.
Is the field a wave/particle like a photon ? Is it emitted like a photon?

So what is the substance or stuff that makes up an EM field?
 
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awcrowe said:
I have looked this up on several occassions and never satisfied.
It seems that either the answer keeps repeating magnetic or electromagnetic field over and over. Or the answer discuss the properties of electromagnetism.
Is the field a wave/particle like a photon ? Is it emitted like a photon?

So what is the substance or stuff that makes up an EM field?
Can you tell us a bit about your background, and what science and physics classes you have taken so far? It might help if I change the thread prefix for this thread from "I"=Intermediate/undergraduate college background to "B"=Basic background to help you get better responses. Your question is a good one at all levels, but we need to try to tune our responses to your level of understanding to give you the best answers.

Hope that makes sense. :smile:
 
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awcrowe said:
So what is the substance or stuff that makes up an EM field?
The EM field is fundamental. It isn't composed of anything else.
 
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Dale said:
The EM field is fundamental. It isn't composed of anything else.
But part of his confusion may be whether a DC magnetic field or DC electric field is also composed of photons. That seems like a good Basic question. Too bad I don't know the answer yet... :smile:

And then if not, why AC magnetic and electric / EM fields are composed of photons, and DC fields are not. I'm starting to like this B thread...:smile:
 
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awcrowe said:
Is the field a wave/particle like a photon ?

both depending which way you "look" at it

from wiki...

From a classical perspective in the history of electromagnetism, the electromagnetic field can be regarded as a smooth, continuous field, propagated in a wavelike manner; whereas from the perspective of quantum field theory, the field is seen as quantized, being composed of individual particles.
that may be enough for you, depending on how you answer Berkeman's comment on your edu. levelDave

formatting fixed
thanks mate ... my I-net is running at around 10 bytes/sec ( not really that bad, but feels like it)
and it takes forever to see a post or thread ... so didn't notice till too late
 
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The EM field is part of a particular method scientists use to predict interactions between charged particles. While this field is given various properties and rules regarding its use, there is nothing in the model or the underlying theory that describes what the EM field is made of.

A simple definition of a field is that a field is a mathematical object that assigns every point in space (and/or time) a particular value representing some property associated with that field or what it is trying to describe. For example, a classical, static electric field would give you a number at any point in space which represents the direction and magnitude of the force felt by a charged particle located at that point.

Other types of fields exist, such as the field your local weatherman uses that contains the various atmospheric properties for an area. The EM field is just regarded as a "fundamental" field, as it is required to explain one of the 4 possible types of interactions between all charged particles. The field your weatherman uses obviously doesn't do that.

The EM field, along with a few others that are regarded as being fundamental, cannot be described as being composed of anything else. That's why they're called fundamental.

You can read more at this link: https://en.wikipedia.org/wiki/Field_(physics)
 
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berkeman said:
But part of his confusion may be whether a DC magnetic field or DC electric field is also composed of photons. That seems like a good Basic question.
Photons are carriers of the EM force so must be involved with the DC magnetic field. The creation and collapse of the DC field certainly creates photons, with a very long wavelength component.
 
Try to keep it simple.

Fermions or bosons?

Even if its fundamental it had to fall into one of these categories.
 
berkeman said:
Can you tell us a bit about your background, and what science and physics classes you have taken so far? It might help if I change the thread prefix for this thread from "I"=Intermediate/undergraduate college background to "B"=Basic background to help you get better responses. Your question is a good one at all levels, but we need to try to tune our responses to your level of understanding to give you the best answers.

Hope that makes sense. :smile:

Its been a long time since i finished physics university.

Reading an watching lectures has me perusing quantum field theory recently, which I suspect may hold the answer.
 
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If you search PF, you'll find quite a few threads where essentially this same question was asked; you have to pick your way through, but here and there what look to be some helpful answers.

E.g. this is from Oct., 23, 2006; it ended up getting locked, but some comments may be helpful, e.g. see #14. Magnetic field is made of photons?

Also there is this from Feb. 19 of this year; only a one-page thread w/ what look like some good suggestions for reading. Do photons carry magnetic force?
 
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awcrowe said:
Try to keep it simple.

Fermions or bosons?

Even if its fundamental it had to fall into one of these categories.
No it doesn't. Fields are not particles.
 
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