Cross product of magnetic fields

In summary, the conversation discusses the physical meaning of the cross product of two magnetic fields, particularly in relation to two different current loops. While there is a geometrical interpretation of the cross product, it applies to any pair of vectors regardless of their physical interpretation. The cross product of the fields of two current loops can be used to determine the work done on a magnetic monopole moving along the other loop. However, the work is a scalar factor and can be factored out to obtain a fundamental generator of the second cohomology. The monopole does not have to move uniformly, but simply make a complete circuit of the second loop.
  • #1
wofsy
726
0
Is there any physical meaning to the cross product of two magnetic fields e.g. two fields generated in two different current loops?
 
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  • #2
I do not think so, I am at a lost as to a situation where we would take the cross of two different magnetic fields. There is of course the usual geometrical interpretation of the cross product, indicating the anti-parallelism of the vectors, a normal to the vectors, etc., but that applies to any pair of vectors independent of their physical interpretations.
 
  • #3
Two loops will interact, if that's what you mean, so that the results are more than the sum of each.
 
  • #4
Born2bwire said:
I do not think so, I am at a lost as to a situation where we would take the cross of two different magnetic fields. There is of course the usual geometrical interpretation of the cross product, indicating the anti-parallelism of the vectors, a normal to the vectors, etc., but that applies to any pair of vectors independent of their physical interpretations.

The reason I asked is that the cross product of the fields of two current loops tells you the work that one field would do on a magnetic monopole moving uniformly along the other loop.
 
  • #5
wofsy said:
The reason I asked is that the cross product of the fields of two current loops tells you the work that one field would do on a magnetic monopole moving uniformly along the other loop.

But work is a scalar quantity, not a vector.
 
  • #6
Born2bwire said:
But work is a scalar quantity, not a vector.

True. The work is a scalar factor in the cross product. If you divide out by the work you get a fundamental generator of the second cohomology of R^3 minus the two loops. For instance if the work is zero the the cross product is the curl of another vector.
 
  • #7
What do you mean by "moving uniformly along the other loop." Are these loops supposed to be electric-current loops or magnetic monopole-current loops?
 
  • #8
Phrak said:
What do you mean by "moving uniformly along the other loop." Are these loops supposed to be electric-current loops or magnetic monopole-current loops?

Sorry - the monopole doesn't need to move uniformly. It just needs to make a complete circuit of the second loop. It's just that I am used to doing the integral using the unit of arc length.
 

Related to Cross product of magnetic fields

1. What is the cross product of magnetic fields?

The cross product of magnetic fields refers to the vector product between two magnetic fields, resulting in a new vector that is perpendicular to both original fields. It is a mathematical operation used to calculate the force exerted on a charged particle moving through a magnetic field.

2. How is the cross product of magnetic fields calculated?

The cross product of magnetic fields is calculated using the vector product formula, where the resultant vector is equal to the product of the magnitude of the two original vectors multiplied by the sine of the angle between them. This can also be represented by the right-hand rule, where the direction of the resultant vector is determined by curling the fingers of the right hand in the direction of the first vector and then pointing the thumb in the direction of the second vector.

3. What is the significance of the cross product of magnetic fields?

The cross product of magnetic fields is significant in electromagnetism and plays a crucial role in understanding the behavior of charged particles in the presence of magnetic fields. It is used to calculate the force on a charged particle, the torque on a current-carrying wire, and the strength of magnetic fields in various applications.

4. Are there any real-world applications of the cross product of magnetic fields?

Yes, there are several real-world applications of the cross product of magnetic fields. These include electric motors, generators, MRI machines, particle accelerators, and magnetic levitation systems. It is also used in navigation systems, such as compasses and gyroscopes, which utilize the Earth's magnetic field.

5. How does the cross product of magnetic fields relate to other physical phenomena?

The cross product of magnetic fields is closely related to other physical phenomena, such as the Lorentz force and electromotive force. The Lorentz force, which describes the force on a charged particle in a magnetic field, is directly proportional to the cross product of the magnetic fields. Electromotive force, which is responsible for generating electrical energy, is also dependent on the cross product of magnetic fields in applications such as generators and transformers.

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