Unanswered Questions
1,141 questions with no upvoted or accepted answers
10
votes
3
answers
515
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How to think about magnetic wells?
From classical mechanics we have the basic credo that a system chooses to minimize its energy. Since the energy is given by $$ E = T + V $$ where $T$ is the kinetic energy (usually $T=P^2$ for non-...
CommunityBot
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9
votes
0
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211
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Is the magnetic field at the centroid of a closed loop connected at two different points to a battery always zero?
Given a closed 2-dimensional conducting loop, the terminals of a battery are connected at any two points on the loop (but not the same point).
As an example, consider a circle of radius $R$; the two ...
- 186
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433
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What is actually happening when a magnetoresistive magnetometer degausses itself?
I'm trying to understand if anisotropic magnetoresistive devices themselves (not other passive ferromagnetic components) can become magnetized, and if so, how the application of a DC 1.1 gauss field ...
- 6,129
9
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2
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Boundary conditions on current carrying wire
I'm trying to simulate Maxwell equations by finite elements method for a current carrying wire. My 3d geometry consists of a cylinder and a box containing it. I will use a mixed formulation and ...
CommunityBot
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8
votes
1
answer
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Current geometry and Ampere's law
Under the right circumstances, Ampere's law $\oint \vec H\cdot d\vec \ell=I_{encl}$ can be used to deduce the field $\vec H$ at a point from the current enclosed by the circuit which produces $\vec H$....
CommunityBot
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6
votes
1
answer
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Force from solenoid
I'd like to approximate the force from a solenoid, or at the very least find a formula which is proportional to the force so that I can experimentally find the constant for my particular case. ...
CommunityBot
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5
votes
0
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91
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Location of Moebius magnet poles
If a long thin strip /ribbon permanent magnet has its ends jointed forming a loop, then where will the north and south poles be located? On the thin edges?
And if one end is turned $180^{\circ}$ ...
- 14.4k
5
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347
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Do antiferromagnets have hysteresis loops?
I am aware that ferromagnets have hysteresis loops and their shape depend on the relative size of magnetic interaction energy to thermal energy. I doubt if there is something equivalent to the ...
- 101
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How to calculate the energy transfer between working coil and working piece and dissipated energy of working piece in induction heating?
For who don't know how does induction heating work, a short description can be found here.
However, my question is about physics. Assume I have a coil inductor calculated carefully 50 uH as below:
...
- 175
5
votes
1
answer
776
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Is it possible to create arbitrary shapes of magnetic fields?
I've been reading about Transcranial Magnetic Stimulation (TMS) which can activate neurons using a magnetic field, which got me thinking... what if we can pick and choose exactly which neurons to ...
CommunityBot
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4
votes
0
answers
471
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What is the difference between a skyrmion and a magnetic vortex?
Skyrmions and magnetic vortices are spin structures occurring in magnets.
What are the differences between them? More specifically, I would like to understand their origin and how to distinguish them.
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Conservation law relating magnetic geodesics and certain Killing fields
This is going to be somewhat math-heavy, but I'd like to make physical sense of this. Consider the following setup.
$(Q, g)$ is a Riemannian manifold.
$A \in \Omega^1(Q)$ is a magnetic potential ($1$-...
- 545
4
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0
answers
1k
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Solving Laplace's Equation for magnetostatic problem in the absence of currents
I am attempting to simulate the resulting magnetic field distortion of paramagnetic nanoparticles in a static magnetic field in the absence of currents, in 3D. In my system, the static magnetic field ...
- 41
4
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0
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133
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What generates a neutron star's magnetic field?
Is the magnetic field of a neutron star generated by the minuscule amount of protons and electrons left or the spin of the neutrons?
If its because of the spin of the neutrons, how come they are all ...
- 224k
4
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0
answers
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EMF induced in a loop around a solenoid - Faraday's law
Since the magnetic field outside the solenoid is negligible, it is impossible to detect current in the solenoid from outside.
Suppose I put a conducting loop of large radius, say, $10^9 $ km around ...
- 224k