What is actally a magnetic field

[Soumen2010]

In most of the books, the magnetic field is defied circularly without the physical concept. For example, it is defied like "a magnetic field is a vecor field that can be created by a moving electric field" Some books also defined by using mathematical formula. With this type of defination, it is difficult to get the exact idea about the same. Can anybody able to help defining the magnetic field from basic physial concept? (No mathematics please)

 

[ojs]

The thing about the magnetic field is that it, unlike gravitational field and electric field, doesn't have a singular source (that is a magnetic monopole, or at least it hasn't been detected yet) so it is more difficult to define it using words like "this field comes from a source that has this and that charactaristic".
But we do know that some material produce magnetic fields even without moving electric current (look up ferromagnetism) apparently, but there is actually a moving charge that produces this field and that is the electron circuling the nucleus.

I know this doesn't explain why magnetic fields are but then again, do you know why any fields arise?

 

[Pythagorean]

In most of the books, the magnetic field is defied circularly without the physical concept. For example, it is defied like "a magnetic field is a vecor field that can be created by a moving electric field" Some books also defined by using mathematical formula. With this type of defination, it is difficult to get the exact idea about the same. Can anybody able to help defining the magnetic field from basic physial concept? (No mathematics please)

Well,the physical interaction that sparked the curiosity of magnetic fields was the force of attraction/repulsion acting between materials with magnetic properties. Like any force, it was then scrutinized and isolated and further explored (to see what kind of materials produced the effect, what was different about those materials, and what the mechanisms of the effect were). And of course, it's still being investigated today, so there's no complete answer to your question, as vague as it is. The observation came first, so it's not really circular; it's just a matter of further developing the observation.

What you say, "that it can be created by a moving electric field" was a later discovery. If you want to know about the physical mechanisms of the magnetic field, that's a necessary path to go down, which leads to electron shell geometry in atoms and domains in magnets. But this is all based on moving charges.

Here's a good qualitative description of the atomic picture:

If we were to examine Iron (atomic number 26), Cobalt (27), Nickel (28) and Gadolinium (64), all of which are considered ferromagnetic since they are strongly attracted to a magnet, it is difficult to see what makes them so different from the other elements next to them or below them in the periodic table. In other words, if Iron is so strongly magnetic, why isn't Manganese? Perhaps there are other factors we need to take into account such as the crystalline structure. But it is generally accepted that these ferromagnetic elements have large magnetic moments due to un-paired electrons in their outer orbitals. This is like having current flowing in a coil of wire, creating a magnetic field. Even the spin of the electron is thought to create a minute magnetic field. When you get a bunch of these fields together, they add up to bigger fields.

Which leads to "domains" in magnetic materials. The author further develops the physics of domains after the atomic description:

http://www.coolmagnetman.com/maghow.htm

If you're more interested in abstract aspects of magnetic fields, that could be quantum field theory or string theory. Relativity and gauge theory have interesting insights.

 

[tiny-tim]

Hi Soumen2010!

The magnetic field is not made of anything, it just is.

It is interchangeable with the electric field, in the sense that a stationary pure magnetic field is seen by a moving observer as being a mixture of electric and magnetic fields (a stationary pure electric field is also seen by a moving observer as being a mixture of electric and magnetic fields).

Btw, "moving" means at any speed … the effect is perfectly noticeable at walking speed, for example!

(Technically, btw, the electric field and the magnetic field are the ordinary and axial components of the electromagnetic field.)

So the magnetic field and the electric field are essentially the same.

Any field is coupled to one or more charges (eg electric charge, colour charge, hypercharge). The more charge something has, the more it is affected by the field.

The magnetic field and the electric field are distinguished from other types of field by being coupled only to the electric charge.

Aternatively, I suppose you could say that there is only one field, and that what we call the electric field and the magnetic field are simply the parts of that field which couple to the electric charge! ​