What is Vector potential: Definition and 183 Discussions

In vector calculus, a vector potential is a vector field whose curl is a given vector field. This is analogous to a scalar potential, which is a scalar field whose gradient is a given vector field.
Formally, given a vector field v, a vector potential is a vector field A such that





v

=

×

A

.


{\displaystyle \mathbf {v} =\nabla \times \mathbf {A} .}

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  1. B

    Magnetic Vector Potential Drawing

    Why is it that I can't find a drawing on the internet of what the magnetic vector potential looks like around a current carrying wire?
  2. Peeter

    Electrodynamic vector potential wave equations in free space.

    In David Bohm's "Quantum Theory" (an intro topic building up to the Rayleigh-Jeans law), he states: "We now show that in empty space the choice div a = 0 also leads to \phi = 0 ... But since div a = 0, we obtain \nabla^2\phi = 0 This is, however, simply Laplace's equation. It is...
  3. S

    E/M Vector Potential of finite Wire

    Homework Statement Consider a finite wire which lies on the z-axis and extends from the point z=-Λ to the point z=+Λ. The vector potential in the xy plane a distance s from the wire is: Λ->∞ A=(µₒI/2π) ln (2Λ/s) k̂ An equally good vector potential is given by A'=A+∆λ, where λ is any...
  4. L

    How Does the Magnetic Vector Potential Change with Infinite Wire Length?

    Homework Statement A finite wire lies on the z axis and extends from the point z=-V to z=+V. the equation from griffiths introduction to electrodynamics (equation 5.62) can be used to determine the vector potential at a point in the xy plane a distance s from the wire to be A=mu(naught)I/4pi...
  5. L

    What is the Surface Current and Magnetic Field for a Rotating Charged Disc?

    Homework Statement There is a disc with radius R which has a uniformly-distributed total charge Q, rotating with a constant angular velocity w. (a) in a coordinate system arranged so that the disc lies in the xy plane with its center at the origin, and so that the angular momentum point in...
  6. J

    Integral formula for vector potential

    http://en.wikipedia.org/wiki/Vector_potential The Wikipedia article is mentioning an interesting formula for defining vector potentials. Isn't that the same thing as a formula \nabla\times\int d^3y\;(V(y)\times\nabla)\frac{1}{\|x-y\|} = -4\pi V(x), where V:\mathbb{R}^3\to\mathbb{R}^3 is...
  7. G

    Vector Potential: Finding the Vector Potential of a Long Wire

    Hello all. I am hoping someone could lend a hand. I need to determine the vector potential of a long wire. I am given the B-field = (\muI)/(2\pir) and I know at some point I will need to use \nabla X A. Thanks in advance.
  8. L

    Prove that 4 vector potential is really a 4 vector?

    Prove that 4 vector potential does really a 4 vector? Most of the textbooks I found only mention that divergence of 4 vector potential equals to zero and the d'Alembertian of it is a four vector current and therefore it 'should be' a four vector. However I do not see there is any tensor theorem...
  9. N

    FInd a simple expression for the vector potential which will yield this field

    em Homework Statement In a certain region, the magnetic field as a linear function of time is given by B = Bo \frac{t}{/tau} z hat Bo and tau constants. A)FInd a simple expression for the vector potential which will yield this field. B)Assuming the scalar potential is a constant, find E...
  10. N

    Deriving Jeans' Result from Magnetic Vector Potential

    I'm trying to get from the magnetic vector potential \vec{A}(\vec{x},t) = \frac{1}{\sqrt{\mathcal{V}}}\sum_{\vec{k},\alpha=1,2}(c_{\vec{k}\alpha}(t) \vec{u}_{\vec{k}\alpha}(\vec{x}) + c.c.) where c_{\vec{k}\alpha}(t) = c_{\vec{k}\alpha}(0) e^{-i\omega_{\vec{k}\alpha}t}...
  11. E

    Compute Vector Potentials for Two-Dimensional Fields | Homework Question

    Homework Statement Compute the vector potentials for the following two-dimensional fields: \vec{F} = \frac{xy\vec{i}}{1} - \frac{y^{2}\vec{j}}{2} Homework Equations (1)\int^{1}_{0} t \vec{F}\times \frac{d\vec{r}}{dt} dt The Attempt at a Solution I solved this problem a...
  12. E

    Vector potential of a 2 dimensional field

    Homework Statement Compute vector potential for the following field: \vec{F} = <xy, y^2/2 > Homework Equations ^{0}_{1}\int t\vec{F} x \frac{d\vec{r}}{dt}dt The Attempt at a Solution I set r = tR, where R = <x,y,z>. Taking the crossproduct F x R, I get <0,0,xy^{2} +...
  13. P

    Is the Magnetic Vector Potential Dependent on a Constant Vector?

    Homework Statement It's problem 2.b) on this page: http://www.phys.washington.edu/users/schick/322A/322-08ps3.pdf The Attempt at a Solution So, what it looks like to me, since the only terms in the actual vector potential are all multiplied, Lambda would have to be a constant, so...
  14. S

    How to Calculate Vector Potential and Magnetic Induction for a Square Loop?

    Homework Statement A current I flows counter-clockwise in a thin wire bent around a square form of side 2a. Calculate the vector potential A and the magnetic induction B along an axis passing through the center of the square parallel to one of the sides. for definiteness, assume the loop...
  15. P

    Why Is the Magnetic Vector Potential Azimuthal Inside an Infinite Solenoid?

    Why is the magnetic vector potential of a point inside a infinite soleniod azimuthal assuming the axis of solenoid is the z axis. Problem is the formulae A(\vec r)=\int_{v} \frac {\vec J(\vec r^{'})}{r} d\tau doesn't hold any more due to the infinite extent of the current
  16. W

    Mechanics, charge in vector potential

    Homework Statement A particle of charge q in a vector potential \vec{A} = (B/2) (-y\vec{i} + x\vec{j} ) show that a classical particle in this potential will move in circles at an angular frequency \omega_0 = qB/ \mu c, \mu is the mass of the particle. Homework Equations The Attempt...
  17. C

    Understand Vector Potential A Physically: Proof of E = ∂A/∂t - ∇φ

    i am having trouble visualiszing what vector potential A means physically. I understand that if you take the curl of it it give you the magnetic field B. I was wondering if anybody could also direct me to a website or show me a proof of how the electric field E is equal to the partial derivative...
  18. C

    Vector Potential: Proving Partial Derivative of A = E

    can anyone show me how to prove that the partial derivaive of vector potential A with respect t is equal to the electric field E?
  19. S

    Vector Potential of Magnetized Cylinder

    Homework Statement Find the vector potential and magnetic field everyehere of a cylinder of radius R and length L which carries a magnetization \vec{M} = ks^2 \hat{\phi} where k is a constant and s is the distance from the axis of the cylinder. Homework Equations A(r) =...
  20. S

    Vector potential in cylindrical coordinates

    Homework Statement What current density would produce the vector potential, A = k \hat{\phi} where k is a constant, in cylindrical coordinates? Homework Equations \nabla^2 A = -\mu_{0} J In cylindrical coordinates for radial and z symmetry \nabla^2 t = \frac{1}{s^2}...
  21. K

    Is It Justified to Prove divA=0 for Vector Potential?

    Is it at all ethical to prove divA=0 here A is the magnetic vector potential? That is, curlA=B? Griffiths goes through a systematic development to show that we may make sure that div A=0 to make life easy.But in our exam the question appeared assuming the vector potential's form:[1/4 pi]int{J...
  22. K

    Why Does Vector Potential Align with Current in Infinite Distributions?

    We know in all ordinary cases the direction of vector potential will be mimic to the direction of current.As it is evident from the expression of A=(mu/4*pi) int{J /(r-r')}dV which is valid only for finite current distributions. But in example 5.12 and in exercise 5.25 Griffiths has given...
  23. K

    Vector potential in a coaxial cable

    Homework Statement I have to find the magnetic vector potential in a round coaxial cable. The internal conductor has a finite (known) conductivity. The external conductor is a perfect electrical conductor. Both the radius of the internal and the external conductors are known. I have to assume...
  24. siddharth

    Magnetic vector potential of infinite wire

    I don't know if this thread belongs in Introductory Physics or here, so please feel free to move it if you wish. The question is Find the vector potential a distance r from an infinite straight wire carrying a current I I know that the vector potential can be given by \frac{\mu_0}{4 \pi}...
  25. pinestone

    How would one measure magnetic vector potential?

    How would one measure magnetic vector potential? I know there is a formula, but is there an experiment that proves it?
  26. P

    Vector Potential: How to Find it?

    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...
  27. T

    Understanding the Vector Potential for a Given Function

    \mathbf{F}(x,y,z)=(x^2+yz,y^2+zx,-2z(x+y)) Find the vector potential. A vector potential \mathbf{V} would have to satisfy \mathbf{V}_x=x^2+yz \mathbf{V}_y=y^2+zx \mathbf{V}_z=-2z(x+y) So, \mathbf{V}=\frac{x^3}{3}+xyz+M(y)+N(z) \Rightarrow \mathbf{V}_y=zx+M_y(y) \Rightarrow M_y(y)=y^2...
  28. H

    Finding Vector Potential of Infinite Solenoid

    How to find the Vector Potential of an infinite solenoid with n turns per unit length,radius R and current I. since here current extends to infinty.. How will it be done Pls Help
  29. Reshma

    Vector Potential: Analyzing the Lines of Force & B Direction

    The vector potential (A) in a certain region is given by A = xj-yi where i and j are unit vectors. How will the lines of force look like? What is the direction of magnetic induction B in the given region of space?
  30. S

    Vector Potential of Magnetic Field: Why Set Divergence to 0?

    vector potential of magnetic field Hi everyone. I have a question about the vector potential of magnetic field, A: we just set the divergance(A)=0 inorder to define the potential. I just wanted to know why we are allowed to do this. Thanks a lot. Somy :smile:
  31. S

    Can the B field be obtained from the magnetic potential using matrix inversion?

    How do you get the B field from the magnetic potential? I tried converting the curl into matrix format, but the corresponding matrix can't be inverted.
  32. S

    Vector Potential in Schrodinger eqn

    How do you get the B field from the magnetic potential? I tried converting the curl into matrix format, but the corresponding matrix can't be inverted.
  33. G

    Vector Potential Between Parallel Wires: Calculating & Differences

    Hi All, I've just looked at an example for calculating the vector potential for a point in the vicinity of a long straight wire. I've now got to calculate the vector potential for a point between 2 parallel straight wires carrying currents in opposite directions. How does the vector...
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