All Questions
Tagged with magnetic-fields dipole
51
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Linear approximation of the magnetic dipole field
Summary: using 3 angles to represent a magnetic dipole's orientation is redundant because the rotation around the $z$-axis of the dipole does not change the magnetic field, there are only 2 DOFs for ...
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Orientation of Magnetic Induction of a Dipole Source in MEG
I am working with source-reconstructed MEG data, and what I would like to know is that
when we obtain the magnetic induction (using the right-hand thumb rule) of a dipole source, is it only the ...
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Equation relating the current carried by a solenoid to the force experienced by a magnetic dipole?
I am trying to find an equation or a series of equations that relates the current I carried by a solenoid of length L with turns N to the force F experienced by a magnetic dipole of strength M that ...
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The force on a magnetic dipole in a non-uniform magnetic field
Let's say there is a non-uniform magnetic field $B=(0,0,z)$ (i.e. the field is parallel to $z$-axis and the amplitude is linearly changing along $z$-axis). If there is a current loop (=magnetic dipole)...
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Classical dipole-dipole interaction in iron
I've been reading about the classical magnetic dipole-dipole interaction and I'm wondering how it would work in a ferromagnet element like iron (theoretically under the assumptions I will write below)....
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Earth magnetic field, WMM/IGRF
I am studying about World Magnetic Model (WMM) and International Geomagnetic Reference Field (IGRF) models. It is well known that, to a first approximation, earth magnetic field is a field of dipole. ...
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Non-parallel magnetic dipole falling throug copper tube
What happens with magnetic dipole while falling through copper cylinder?
If it's parallel to z-axis (shown on picture below with red color) we know that it stays parallel to the z-axis all the way ...
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1
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Force components on dipole falling through copper ring
We have a magentic dipole parallel with z-axis (shown on the diagram below) falling through copper loop, because of changing magnetic flux there is induced current in cooper ring/loop and consequently ...
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Does the force between two magnetic poles ever reach zero?
If we hold two magnetic like-poles together and start to move them away, would the repelling force reach absolute zero at certain point?
In that scenario, as a layman, I think that there is something ...
user342647
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Magnetic field of dipole derivation
How can we derive the following formula:
$$\vec{B}(\vec{r})=\frac{\mu_0}{4\pi}\left[ \frac{3(\vec{m}\cdot\vec{r})\vec{r}}{r^5} - \frac{\vec{m}}{r^3}\right]\; ,$$
I want to derive it as a limit of a ...
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How to find field strength of magnetic field of an oscillating dipole without $x,y,z$ variables?
(For better viewing, visit https://lateral-bathroom-f63.notion.site/How-to-find-field-strength-of-magnetic-field-of-oscillating-dipole-without-x-y-z-variables-ea0d864f371e4649a21d6cf5d007f9ee)
I have ...
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Why is the magnetization inside a diamagnetic material antiparallel to the external field
Let's say I have a constant magnetic field and I dive into it a diamagnetic material. Griffiths says that in the presence of a magnetic field, matter becomes magnetized and it will be found to contain ...
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Formula for force on a magnetic dipole
Using the magnetic current model, the force on a magnetic dipole, commonly derived in textbooks, is found to be:
$$
\mathbf{F} = \nabla(\mathbf{m} \cdot \mathbf{B}) \tag{1}
$$
If the magnetic pole (&...
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Why magnet is always a dipole?
Why magnet is alway dipole
Even the atom of the magnetic substance is also dipole , how can small atom be dipole . Pls explain me
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Potential energy of magnetic dipole in non-uniform magnetic field
I want to understand why the potential energy of an ideal magnetic dipole with dipole moment $\boldsymbol{m}$ in a non-uniform magnetic field $\boldsymbol{B}$ (neglecting the term to keep the ...
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$H$ field formula
For a permanent bar magnet is there a formula for the magnetic field strength $H$? Just like the electric field strength $E$ can be calculated at a point in space, can we do the same for the magnetic ...
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Force on a magnetic dipole
How to deduce the force on a magnetic dipole given by $F = \nabla(m \cdot B)$ from the Lorentz force?
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Magnetic field around a magnetic dipole and circular current loop
Qualitatively, how does the magnetic field around an ideal dipole compare with the magnetic field around a circular current loop?
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Field of an infinitely wide magnetic dipole
Students commonly wonder about the near-analogies between electricity & magnetism. One such:
The field of an electric dipole in the limit of an infinitely wide plane tends to 0 outside the plane (...
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Uniform electric field formation in motional emf induction
Why is the electric field $E$ across the ends of a conducting rod, when it's moved with a uniform velocity $v$ in a magnetic field $B$, uniform? Wouldn't it vary non-linearly, since there are opposite ...
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Magnetic dipole in gradient magnetic field
I know that a magnetic dipole in a uniform magnetic field will precess.
What happens qualitatively (or quantitatively) to a magnetic dipole in a gradient magnetic field? According to Wikipedia, "...
user243050
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Measuring neodymium magnet strength with magnetometer sensor in phone
I try to measure neodymium magnet magnetic field strength, exactly - how it depends on distance to magnet, by using integrated magnetometer sensor in Huawei phone. My setup is like :
Then I move ...
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Is it possible to align a magnetic dipole completely in the direction of field?
considering $L$ is always greater than $L_z$ i.e angle between angular momentum/magnetic moment and magnetic field/z direction cannot be zero. Means $B$ and magnetic moment cannot be in same ...
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A Classical model for diamagnetism
I'm trying to derive a classical model to describe diamagnetism, and I'd like to understand if it is possible to understand the basic properties of diamagnetic materials with it i.e.:
''A diamagnetic ...
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Source of magnetic dipole potential energy
One of the basic expression that goes without much thinking is the potential energy expression of a magnetic dipole in a magnetic field, $$ U = -\mu\cdot B $$
In the case of electric and gravitational ...
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Can there be a torque-less net force on a dipole in a magnetic field?
I realise that a magnetic dipole moment is essentially defined on the basis of torque, which also seems to imply that a magnetic field imposed on a current-carrying closed loop can only induce a ...
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Why are domains formed as separate units?
I was reading about exchange coupling and domain formation in ferromagnetic materials. As far as I can understand, some of the dipoles in the ferromagnetic material align themselves in a group called ...
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Can we understand a moving charge as a dipole?
I work as a physics teacher at a high school and I have to explain these days the magnetic field of a curreny carrying wire. Of course I may just give the formulae and describe how the field $\vec{B}$ ...
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Is the vector potential component $A_\phi$ for a dipole necessarily 0 due to symmetry about the $z$-axis?
Consider an electric dipole (+$q(t)$, -$q(t)$) [where say $q(t)=q_0\cos\omega t$] is placed along the $\hat z$ axis. In the spherical polar coordinates, its vector potential $$\vec{A} = A_r \hat r + ...
user199113
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How to determine the best-fit magnetic dipole Gauss coefficient in a shifted coordinate system?
Introduction
A planetary magnetic field $\vec{B}$ can be described outside of the planet using Gauss coefficients $g_n^m$ and $h_n^m$ and a spherical harmonic expansion:
$$\vec{B} \;=\; -\vec{\...
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Can I replace a multipole expansion by a combination of separate dipoles?
If I want to be able to model a magnetic field flux density $\mathbf{B}$ from a magnetic source located at the origin at a position $\mathbf{r}$, it is my understanding that I can represent $\mathbf{B}...
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Isn't magnetism governed by the inverse square law? [duplicate]
Why does magnetism appear to decay much faster than gravity with distance?
A clear indication of this is the fact that a magnet that in short distance able to overcome gravity and pick up some object,...
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Point particle with a magnetic dipole?
I have read these questions:
Are contravariant basis vectors and basis 1-forms identical?
Where John Rennie's answer says that electrons do have an electric dipole moment and we imagine that in math ...
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How can the magnetic field of a dipole be exceedingly large close to its singularity?
I am trying to figure out the magnetic field close to a micrometer sized bar magnet in my experiment. The field gets detected 1 micrometer away from the north of the bar magnet. For now, I just take ...
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Function of dipoles in particle accelerators
I know now that quadrupoles are used to focus the beam in a particle accelerator, but what about dipoles? Are they used to center or accelerate the beam?
The number for the LHC magnets I think it is ...
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How do I graph a magnetic field?
For a school project, I'm trying to graph a magnetic field. I found this page on the NASA website with spherical coordinate equations for a dipole field, but I'm having trouble interpreting the page.
...
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Determining North and South pole of magnet
If I have an irregularly shaped magnetic material and want to find which way is the north and south. How do I do it?
And more importantly, why are the north and south poles of a magnet situated where ...
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Electromagnetic field energy "paradox"
The starting point is the energy density in electromagnetic fields:
$$ u = \frac{1}{2} \left( \epsilon_0 |\mathbf{E}|^2 + \frac{1}{\mu_0} |\mathbf{B}|^2 \right) \tag{1}$$
The "paradox" is if we use ...
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How are the magnetic field lines in a electric dipole formed (step by step and graphically)?
The following picture shows how an oscillating electric dipole generates closed electric field lines step by step (it is common to find those picture in textbooks).
But how are the magnetic field ...
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How to derive the inclination angle evolution of a dipolar pulsar?
The spin-down evolution of a simple vacuum pulsar model is well known. Using the power output of radiation emission of a rotating magnetic dipole, we get the following equation (assuming that the ...
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What happens when an electric dipole is placed in a uniform magnetic field?
I am currently trying to understand the classical consequences of more than one charged particles in a magnetic field. So a thought experiment which came to mind was an electric dipole being placed in ...
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What is the strength of magnetic flux density inside a magnet?
I am trying to simulate the magnetic flux density in 3D space. I can get B by following model which is a dipole's contribution to the magnetic field at a point.
However, the strength of B is wrong ...
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Why does magnetic force vary in proportion to the cube of the distance instead of the square?
Magnetic forces vary from gravity and electromagnetic radiation (such as light) in that gravity and radiation diminish by the square of the distance from the source, but magnetism diminishes by the ...
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Knowing the force of attraction of two bar magnets what is the force between two surfaces made of the same material?
Two bar magnets with area $a$, in axis, at a distance of $d$ ($d$ is much biffer than $a$) attract each other with a force of $F$.
What is the force between two infinite surfaces made of the same ...
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Relationship between exp(1/z) and the magnetic field
I will preface this by saying that I'm a math student, so I know a fair bit of math but almost no physics beyond what is learned in a first year undergraduate course.
I was recently looking at this ...
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Is my definition of a dipole and its dipole moment correct?
Assume that we have a dipole affected only by an applied magnetic field where only 2 possible orientations for its dipole moment are possible: "up" and down".
A dipole is simply an object with a ...
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The Strength of the Tangential and Radial Components of a Dipole Magnetic Field
I am following along well several textbooks (Geophysics) that helps me understand the in-depth physics behind the magnetic field of a dipole magnet. I understand that the basic magnetic potential (...
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Entropy reversal in magnets
Entropy is an irreversible phenomenon without any energy supplied to reverse it.
I was reading about paramagnetic substances and how dipoles align inside them on application of magnetic field.
My ...
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How does one calculate or even approximate the force observed by a magnet as its dropped inside of a diamagnetic cylinder?
How does one calculate or even approximate the force observed by a magnet as its dropped inside of a diamagnetic cylinder?
Wikipedia and Google does not provide much information on this topic. ...
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Calculation of Magnetic Field Lines
I am doing some research on how to calculate magnetic field lines for a bar magnet.
So far I have found the following equations:
\begin{align}
\frac{B_r}{B_\theta} &= \frac{d_r}{rd_\theta}\\
B_r&...
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