What does a magnetic field consist of?

In summary, the concept of a magnetic field is an artificial construct used to explain the phenomenon of magnetism. It is not made of anything, but rather can be described in terms of measurable properties such as energy, flux, and angular momentum. While photons can also be described in terms of a vector field, there is no evidence to suggest that the magnetic field is made of photons. Unlike matter, the focus on understanding the fundamental components of a magnetic field has not been as extensive.
  • #1
Mary Space
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4
Of what consist magnetic field?
Someone says that magnetic field consist of photon, is it true?
Thanks in advance for your answers
 
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  • #2
I don't really think that you can say that the electromagnetic field is made of anything (in layman's terms, at least...). I see it as a constitutive "thing" that can't be described as being made out of other "things" for the very reason that it is intrinsic. And I think fields are more fundamental than particles, anyways. True, photons are associated with the electromagnetic force/waves, but they do not make of the field in of themselves.

Don't know much about this at all and look forward to see some nice answers here. I'd like to know myself.
 
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  • #3
My limited understanding of this topic is pretty much identical to ProfuselyQuarky's. Fields are fundamental objects and are not made up of anything else.
 
  • #4
Yes but we know that all matter is composed of elementary particles, but because the field must also have its own construction
As for the photons I watched an interesting program "Through the wormhole with Morgan Freeman," and it said if I understood correctly that the photons strike the core and move to another, etc.
 
  • #5
Mary Space said:
Yes but we know that all matter is composed of elementary particles,

neither an electric field, nor a magnetic field is made of matter

Mary Space said:
and it said if I understood correctly that the photons strike the core and move to another, etc.

strike the core of what ?Dave
 
  • #6
davenn said:
neither an electric field, nor a magnetic field is made of matter
from what it is made?
davenn said:
strike the core of what ?
To be honest, this I did not understand, but perhaps the core of the Elements which includes a magnet.
 
  • #7
At the present time, lacking a satisfactory theory, both the magnetic and the electrostatic fields are temporary solutions in order to explain the 'action at a distance'. That was, too, the case of the gravitational field, until Einstein formulated his General relativity.
 
  • #8
NTW said:
At the present time, lacking a satisfactory theory, both the magnetic and the electrostatic fields are temporary solutions in order to explain the 'action at a distance'. That was, too, the case of the gravitational field, until Einstein formulated his General relativity.

I don't see anything unsatisfactory about fields. They are extremely useful concepts that remain the simplest, most accurate way to describe much of physics.
 
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  • #9
@Andy Resnick

can you help out here please. I have spent the last hour searching for a satisfactory answer without successDave
 
  • #10
Mary Space said:
Of what consist magnetic field?
Someone says that magnetic field consist of photon, is it true?

The question isn't really a scientific question. Magnetism is a well-defined phenomenon (materials either possesses a magnetic moment or are induced to develop a magnetic moment), but the concept 'magnetic field' is an artificial ('man-made', excuse the gender specificity) construct.

The basic entity in magnetostatics is the magnetic dipole; in the presence of magnetic materials, the dipole experiences a mechanical torque: compass needles orient themselves in response to magnets. Similarly to Coulomb's law, the magnetic field was initially defined in terms of force equations (Biot and Savart's law). Farady introduced the concept of 'fields' as a way to explain action-at-a-distance, but it wasn't appreciated until later than using the idea of a field gives independent meaning to B (and E), independent of the sources.

Rather than asking "what is the magnetic field made of", a better question is to ask "what are the measurable properties of the magnetic field?". Some of the properties include energy, flux, and angular momentum. Based on this, a reasonable object used to represent the magnetic field is a vector field. Photons can also be described in terms of a vector field, and so the magnetic field can be described in terms of photons.

There's a lot more to the foundations of electromagnetism, but hopefully this is a good start.
 
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  • #11
Andy Resnick said:
The question isn't really a scientific question. Magnetism is a well-defined phenomenon (materials either possesses a magnetic moment or are induced to develop a magnetic moment), but the concept 'magnetic field' is an artificial ('man-made', excuse the gender specificity) construct.

In my opinion, asking questions is naturally scientific. Claiming a question is "not scientific" sounds ignorant.
Andy Resnick said:
Farady introduced the concept of 'fields' as a way to explain action-at-a-distance, but it wasn't appreciated until later than using the idea of a field gives independent meaning to B (and E), independent of the sources.
Field is not a concept, it's a label, it's a name given to something to explain its effects and not itself. The "field" always depends on the source and can never be manipulated without manipulating the source because we don't know what it's made of.

Andy Resnick said:
Rather than asking "what is the magnetic field made of", a better question is to ask "what are the measurable properties of the magnetic field?". Some of the properties include energy, flux, and angular momentum. Based on this, a reasonable object used to represent the magnetic field is a vector field.
Things that you mentioned all are effects of a magnetic field. We also know the source creation of a magnetic field. But we don't know what it is exactly.
A good analogy would be, we know wind flow can turn a wind turbine, and we know wind is generated by thermal/pressure gradient in the air. We also know that wind is made out of a mixture of gas molecules exchanging thermal energy and kinetic energy between the source and the turbine.

But what can we say about the magnetic field. What are the carriers of the magnetic field?

Andy Resnick said:
Photons can also be described in terms of a vector field, and so the magnetic field can be described in terms of photons.
Can you cite a reference for your statement, that the magnetic field is made out of photons, or the magnetic field interaction with a charged particle is through photon interaction with the charged particle?

The thing is unlike matter, where we deeply focused on its constituents and we have formulated different theories down to quarks, we stopped thinking about the magnetic field or fields in general because the current theories work and we haven't had a need to study their nature further but rather focused on their effects on other things.
 
  • #12
AN electric charge in motion creates a magnetic field... if you change the coordinate system so the particle is at rest there is no magnetic field.
 
  • #13
To give some added emphasis to how difficult the question is try googling "Richard Feynman Magnets". It seems to me that Feynman is being a bit evasive at the beginning but then starts to get some thoughts together. Personally I like to think of the field as a mathematical construct which is informed by the observations and which enables us to carry out certain calculations such as calculating the force on a moving charged particle.
 
  • #14
wimax32 said:
In my opinion, asking questions is naturally scientific. Claiming a question is "not scientific" sounds ignorant.
The scientific method is a technique for answering a certain class of questions, and it is quite appropriate to describe questions that cannot be answered using the scientific method as "not scientific" - indeed, that's close to a tautology.

It's worth comparing with what the first and greatest field theory does and doesn't do. Newton's ##F=Gm_1m_2/r^2## tells us how a gravitational field behaves, but doesn't try to answer the question of what it is "made of". Einstein's General Relativity doesn't provide an answer either; it replaces one methematical description of the interaction of nearby masses with another (more accurate and more beautiful) one, but it's still a description of how gravity behaves, not what it's made of. As with electromagnetism, we're answering questions about how the fields behave and what laws they obey, but not why or what they are made of.
But what can we say about the magnetic field. What are the carriers of the [electro]magnetic field?
...
Can you cite a reference for your statement, that the [electro]magnetic field is made out of photons, or the [electro]magnetic field interaction with a charged particle is through photon interaction with the charged particle?
(I have taken the liberty of replacing all references to the "magnetic" field with "electromagnetic", as it makes no sense to talk of a magnetic field in isolation).
Any standard text on quantum electrodynamics will cover this in great detail. It is stuff that has been well understood for better than a half-century and is a staple of any graduate-level physics program. The field is not "made of" photons, but as Andy Resnick says, it is described in terms in terms of photons.
(A very mathematical gentle introduction is http://www.physics.usu.edu/torre/3700_Spring_2015/What_is_a_photon.pdf)
 
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  • #15
I hesitated before responding, let's see if my initial impulse was correct:

wimax32 said:
In my opinion, asking questions is naturally scientific. Claiming a question is "not scientific" sounds ignorant.

Lots of questions (and opinions) are nonscientific. The act of asking a question is not a privileged activity.

wimax32 said:
Field is not a concept, it's a label, it's a name given to something to explain its effects and not itself. The "field" always depends on the source and can never be manipulated without manipulating the source because we don't know what it's made of.

The term "field" is a label for a specific mathematical object. Electric and magnetic fields can be source-free.
wimax32 said:
Can you cite a reference for your statement, that the magnetic field is made out of photons, or the magnetic field interaction with a charged particle is through photon interaction with the charged particle?

The use of virtual photons to describe electrostatic and magnetostatic phenomena is well established in QED. Here's an explanation from someone with a lot more patience than I:

https://van.physics.illinois.edu/qa/listing.php?id=414
 
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  • #16
Andy Resnick said:
Faraday introduced the concept of 'fields' as a way to explain action-at-a-distance,
Lord Kelvin conceptualized a force field as a network of Faraday lines of force that surround a field-generating body.
Fields in this sense would be imaginary objects.
 
  • #17
  • #18
Is the angular momentum part the idea that a charged particle will swerve around a magnetic line? Or tend to swerve, perhaps going in circles around the field line if the particle is close enough?
 
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1. What is a magnetic field made of?

A magnetic field is made up of invisible lines of force that are created by moving electric charges. These lines of force are what enable magnets to attract or repel each other and can also affect the motion of charged particles.

2. How is a magnetic field generated?

A magnetic field is generated by either moving electric charges or by the intrinsic magnetic dipole moment of elementary particles such as electrons. In most cases, it is generated by the movement of electrons in an electric current.

3. What materials can produce a magnetic field?

Any material that contains moving electric charges, such as electrons, can produce a magnetic field. This includes metals like iron, nickel, and cobalt, as well as certain types of alloys and compounds.

4. Can a magnetic field exist without a magnet?

Yes, a magnetic field can exist without a magnet. As mentioned earlier, any material with moving electric charges can produce a magnetic field, so even without a permanent magnet, there can still be a magnetic field present.

5. How does the strength of a magnetic field change with distance?

The strength of a magnetic field decreases as the distance from the source increases. This decrease follows an inverse-square law, meaning that the strength of the field is inversely proportional to the square of the distance from the source. So the further away from the source, the weaker the magnetic field becomes.

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