Vector Potential: How to Find it?

In summary: This is due to the concept of gauge, where a function of position with a gradient of zero can be added to the potential. This results in a choice of gauge and more constants when finding the vector potential. It is similar to finding the scalar potential, but with more variables to integrate. In summary, the given vector can be expressed as the curl of a vector, also known as the vector potential. However, there may be more than one degree of freedom and additional constants when solving for the vector potential due to the concept of gauge.
  • #1
PrinceOfDarkness
31
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Vector V=x^2i+3xz^2j-2xzk
The divergence of this vector is zero. So it can be expressed as the curl of a vector. I have to find that vector, which is also called the vector potential.
But I don't know how to find it. When I have to find the scalar potential, then it is easier to equate components and then integrate. But in this case, if I equate components, I get two variables of integration. How can I integrate then? Is it possible to find a vector potential like this?
 
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  • #2
PrinceOfDarkness said:
But in this case, if I equate components, I get two variables of integration. How can I integrate then? Is it possible to find a vector potential like this?

It sounds like you're doing the right thing. What you're getting is what the physicists call a "choice of gauge" for the potential.

For the scalar potential, there was only one degree of freedom, and you know that that amounted to just an aribitrary offset. That is, if you add a constant to the potential, the potential still gives the same force.

For the vector potential, there are more than one degree of freedom, and this means that instead of just adding a constant, you can actually add a function of position. The function must be one that has a gradient of zero, but there are plenty of those.

And so, when you look for the vector potential, you're going to get more constants.

Carl
 

FAQ: Vector Potential: How to Find it?

1. What is vector potential?

Vector potential is a concept in vector calculus that describes the magnetic field in terms of a vector quantity. It is a mathematical tool used to simplify calculations when dealing with electromagnetic fields.

2. How is vector potential related to magnetic fields?

Vector potential is directly related to the magnetic field through the equation B = ∇ × A, where B is the magnetic field and A is the vector potential. This means that the vector potential can be used to calculate the magnetic field at any point in space.

3. How do you find the vector potential?

The vector potential can be found using the formula A = μ₀I/4πr, where μ₀ is the permeability of free space, I is the current, and r is the distance from the current-carrying wire or point source. This formula is derived from the Biot-Savart law, which describes the magnetic field created by a current-carrying wire.

4. Can the vector potential be negative?

Yes, the vector potential can be negative. This is because it is a vector quantity and can have both magnitude and direction. The direction of the vector potential is determined by the direction of the current and the distance from the current-carrying wire or point source.

5. What are some practical applications of vector potential?

Vector potential is used in many areas of science and engineering, including electromagnetism, fluid dynamics, and quantum mechanics. It is particularly useful in calculating the magnetic field in complex systems, such as electromagnets and transformers, and in understanding the behavior of particles in magnetic fields.

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