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Magnetic Field - Science topic
Explore the latest questions and answers in Magnetic Field, and find Magnetic Field experts.
Questions related to Magnetic Field
How to calculate the magnetic field gradient of a permanent magnet in COMSOL?
Is there a gradient operator?
I have issues with the 1D ligation protocol of the MinION sequencer when handling high molecular weight DNA (>50kb). There are several cleaning steps with AmpureXP beads and the DNA is so viscous that I can't properly recover the DNA (low recovery and substantial loss of HMW over LMW DNA). Sometimes the DNA clumps when mixed with the beads and most of the times DNA get stuck on the beads (the magnetic field is not strong enough to retain the beads when pipetting the solution). Does anyone have any tip to share please? Thanks in advance.
How to calculate the Jc of MgB2 bulk materials according to MH curve? Which kind of equation should I use?
As the electromagnet is located at the head of the cylinder, the magnetic field does not reach to the magnetic piston efficiently. Therefore, need a method to obtain more magnetic field.
Terraforming Mars has captured the imagination of scientists, engineers, and space enthusiasts alike. Traditional proposals involve timescales of centuries and even millennia to revitalize Mars. In this discussion, let's explore various approaches with a special focus on methods that could accelerate the process. One such approach, explained in my latest preprint involves creating dayside magnetic reconnection events at the Mars-Sun L1 point to speed up atmospheric building and surface warming. I would love to hear your feedback and discuss other promising techniques for rapidly transforming Mars. Keep in mind that when I use the word 'terraforming,' I do not necessarily mean that we could walk around outside without suits, but rather kickstart the planet by building its atmosphere, partially melting the ice caps, heating the surface, raising water from the bedrock, etc., and initiating noticeable and significant progress. Let’s discuss diverse ideas and strategies that could make Mars a home for future generations faster than previously imagined.

Dear all,
I am doing this marine magnetic survey at a jetty/ barge, where the seabed is scattered with various dumped materials (proven from side scan sonar mosaic). After producing the QAS grid, I found the anomaly patches show a "survey line-following" trend, which means you could easily tell the survey line orientation etc by only looking at the QAS result. The result is so unreal and I couldn't figure out the main reason causing it. I have made a small assumption to trying to explain it (see picture 7 attached), and tried larger iteration number when producing residual grid.
I have attached the detail processing steps, together with illustrations to make this thing easy and clear for your understanding. If you need more information, please leave your comment and I will update you very soon. I would really appreciate if you could help me to understand this. Thank you in advance.




Dear all,
I am learning the Landau-Lifshitz-Gilbert equation for spin dynamics, which could be expressed as,
dm/dt = -(gamma/(1+alpha^2))m×B - (gamma/Ms)(alpha/(1+alpha^2))m×(m×B)
where m, B, gamma, and alpha represent the magnetic moment, magnetic field, gyromagnetic ratio, and damping coefficient.
However, when I consider the dynamics of a single spin, I feel confused that the magnetic field antiparallel to the magnetic moment could not drive the switching of the single spin! Correspondingly, if I solve the equation as an ODE (regardless of the spatial degree), the critical magnetic field to switch the magnetic moment could be infinity.
What's the problem here? Is there any mistake I made here?
Looking forward to your guidance and advice. Thanks a lot in advance!
Yours,
Ken
Hi everyone,
I want to know how the electronics/optics... properties of the material varies with the external magnetic field ? another word, Can I apply an external Magnetic field on 2D material using QE, if yes then how?
I know that there are some input keys in SCF calculation, that can force magnetic moments to be aligned along the 'z' axis. But, I ask if there is a built-in mechanism for simply applying external magnetic field along one specific direction.
Thank you in advance.
Best regards
N.Khossossi
I currently study ferrofluid magnetohydrodynamics in COMSOL by connecting "Magnetic field, no currents", "Laminar flow" and "Heat transfer in solids and fluids". So, I need to connect all these physics to get the ferrofluid motion in a channel. On the internet, I found coupling the electric, Magnetic, and flow field, but in my case, I am not required to use an electric field and required to use temperature as a function of magnetic susceptibility, so can not use those equations. Could you please suggest something or give a tutorial about the subject?

I couldn't find an analytical expression for the magnetic field of a permanent magnet in space. Mainly I interested in the Z-axis component in order to calculate the emf (and then the current and electric power produced) develops on a coil when the magnet passes through it. Rectangular or cylindrical or whatever will be the easiest to evaluate. If not an exact calculation, an approximation maybe?
Maybe also some recommended literature on this matter?
Hello.
I'd like to model a blood flow inside a vein that is affected by external magnetic field on COMSOL.
For now, I know that i will be using laminar flow and magnetic fields module.
Is there any tutorial or beneficial source to learn how to do it?
Thanks
Dear Researchers.
I have a permanent magnet that need to be inserted inside a ferromagnetic cylinder. the magnet has a cylindrical shape made with ferrite and it should be anisotropic (bought from a commercial supplier).
My intend is to study the effect of the tube on the magnetic field intensity. I tried with a magnetometer MG3002 to measure the induction of this magnet before and after it's insertion on the tube in the same point but the results where inconsistent and I could not get the same results twice.
The FEM model show show after a magneto-static test the the induction decrease after the insertion of the magnet inside the tube. yet I would like to prove that experimentally and have a near FEM results values which I believe it's hard to have.
So I would real appreciate any suggestion or feedback from you about this matter.
Thank you

If you think of electrons with spin as bar magnets, you know bar magnets of opposite polarity as long as they're not occupying the same spatial location don't cancel out each other's magnetic field.
So what's a more apt analogy/or math reason, or explanation for all electron paired atoms have no magnetic field?
In cases where the rotational of the magnetic field H is zero, we can define this field as the gradient of a scalar function defined as the magnetic scalar potential (similar to the electric potential). What is the physical meaning of this magnitude?
What if i have metal pipes or electric wires running through each other in knots ? Will i be able to defy gravity ? Will i be able to get magnetic field created ? Any idea where will i land ? We have transformers coiled around, i don't exactly remember what but its sort of a knot .
I am trying to finfd electric, magnetic field and surface current but i am getting this error. not able to find result.

When I insert the sample inside VTI, generally, it should show that the magnetic moment is zero(in emu) when the applied magnetic field is zero. But in zero magnetic field displaying magnetic moment is -0.024 emu. So, how to set this magnetic moment at zero emu?
I have seen that some lecturers claim the leakage flux of a transformer will automatically become zero in case it has an ideal iron core. I want to say NO!
This is correct for a system with a core and a single winding: referring to the magnetic equivalent circuit, there can not be any leakage flux as the leakage reluctance is in parallel with a zero reluctance, i. e. the core reluctance.
But is case we have two windings, a close look at the magnetic equivalent circuit reveals that the zero core reluctance condition just leads to the balance of the two ampere-turns, that is the current ratio for an ideal transformer will be obtained. Nevertheless, there can still be leakage fluxes in both the primary and the secondary, although the core has been assumed completely ideal.
Am I correct?
Please see the details in the attached file.
How to solve the interference of magnetic field from the energized phase on the non energized phase of a two-phase stepper motor under full step drive
Does the jet wind speed in Jupiter's atmosphere fluctuate in roughly four-year periods?
Constant velocity field and radial component of background magnetic field at 0.9 RJ. The hummock-area bump is with the central meridian at 180° in coordinate system III (highlighted in gray). The central meridian is the zero line for steady flow. The color scale for the linear background magnetic field model is specified between The current velocity is scaled with latitude to account for the polar convergence of the meridians. The peak velocity (corresponding to the equatorial jet) is 0.86 cm/s-1. Credit: Nature (2024). DOI: 10.1038/s41586-024-07046-3
A team of planetary scientists from several institutions in the United States has found a jet in Jupiter's atmosphere that oscillates in roughly four-year periods. In their paper, published in the journal Nature, the group describes how to find the jet and examine its properties using data from the Juno spacecraft.
Jupiter has a large magnetosphere, some parts of which extend to the orbit of Saturn. The planet's magnetic field is about 20 times that of Earth, making it a good target for research. Also, the fact that Jupiter is a gas giant and has no shell makes it a good target. This makes it much easier to study the dynamics that are responsible for maintaining the magnetosphere compared to the dynamics that generate the Earth's magnetic field.
NASA sent a probe specifically designed to measure and map the planet's magnetic field — the Juno probe launched in 2011 and entered Jupiter's polar orbit in 2016. Since then, it has sent back valuable information about many aspects of the planet, including Magnetic field. In this new effort, the researchers focused on data surrounding an atmospheric jet.
Wind speeds can cause atmospheric jets to create high-speed currents that sweep through the planet's atmosphere, similar in some ways to the jet stream on Earth. In this new effort, the research team focused on a jet in a circular region on Jupiter called the "Great Blue Spot." By studying data describing the jet's properties, the researchers found that it has wave-like oscillations that repeat in roughly four-year periods.
Convective currents from within the metallic hydrogen pool that forms part of the planet's inner atmosphere. Such a jet would almost certainly have periodicity in centuries, not years.
Constant velocity field and radial component of background magnetic field at 0.9 RJ. The hummock-area bump is with the central meridian at 180° in coordinate system III (highlighted in gray). The central meridian is the zero line for steady flow. The color scale for the linear background magnetic field model is specified between The current velocity is scaled with latitude to account for the polar convergence of the meridians. The peak velocity (corresponding to the equatorial jet) is 0.86 cm/s-1. Credit: Nature (2024). DOI: 10.1038/s41586-024-07046-3
A team of planetary scientists from several institutions in the United States has found a jet in Jupiter's atmosphere that oscillates in roughly four-year periods. In their paper, published in the journal Nature, the group describes how to find the jet and examine its properties using data from the Juno spacecraft.
Jupiter has a large magnetosphere, some parts of which extend to the orbit of Saturn. The planet's magnetic field is about 20 times that of Earth, making it a good target for research. Also, the fact that Jupiter is a gas giant and has no shell makes it a good target. This makes it much easier to study the dynamics that are responsible for maintaining the magnetosphere compared to the dynamics that generate the Earth's magnetic field.
NASA sent a probe specifically designed to measure and map the planet's magnetic field — the Juno probe launched in 2011 and entered Jupiter's polar orbit in 2016. Since then, it has sent back valuable information about many aspects of the planet, including Magnetic field. In this new effort, the researchers focused on data surrounding an atmospheric jet.
Wind speeds can cause atmospheric jets to create high-speed currents that sweep through the planet's atmosphere, similar in some ways to the jet stream on Earth. In this new effort, the research team focused on a jet in a circular region on Jupiter called the "Great Blue Spot." By studying data describing the jet's properties, the researchers found that it has wave-like oscillations that repeat in roughly four-year periods.
Convective currents from within the metallic hydrogen pool that forms part of the planet's inner atmosphere. Such a jet would almost certainly have periodicity in centuries, not years.
James Garry added a reply
Mr Kashani,
You have seemingly copied from a number of articles to make this post:
and
This post is shown in my 'Question' feed, and I do not know what you want to know.
What is the question you ask?
Abbas Kashani added a reply
Dear James Garry
Jet in Jupiter's atmosphere found to fluctuate in roughly four-year periods.
And this issue shows that if the speed increases in Jupiter's atmosphere, it is due to what factors and the role of magnetism is effective in the wind speed in the jet. Thank you for your attention
James Garry added a reply:
Mr Kashani,
Note, the magnetosphere cannot couple to a non-current carrying fluid - and as Jupiter's atmosphere (at least, visible cloud layer) is essentially insulating, the magnetosphere cannot directly act on the atmosphere.
<just as on Earth>
In the exosphere, that's not the case. There, the 'atmosphere' is partially ionized.
But I still don't know what question you are asking.
As observed on Mercury, such large amplitude standing whistler waves cause changes in the magnetic field that are almost identical to the increase in the magnetic field in the shock ramp. However, we usually say that such sinusoidal waves are linear and shocks are non-linear. What is the essential difference between the two is an interesting question.
A discussion on relativistic effects, when electron move along a wire and carry currents. How much length contraction will it experience in it's own frame. And what is the relation between the magnetic field created by the current carrying wire in Laboratory frame?
Hi,
does anyone know a way to extract magnetic particles (magnetosomes) from marine sediments without the use of a magnetic field?
Thanks
Sergio
Hello,
I have a 3-axis magnetometer, and a small rare earth magnet. I have a structure that holds the magnetometer stationary, with the small rare earth magnet also being held stationary opposite the magnetometer (10cm away).
My aim is to use the magnetometer and rare earth magnet, and measure the change in the magnetic field caused by moving a metallic object between the magnetometer and rare earth magnet. From this, I want to somehow correlate the change in magnetic field in order to determine the position of the metallic object between the magnetometer and magnet. Would someone be able to help with this please?
Thanks.
I have plotted my VSM data in origin for a nano powder sample. I got a plot where the hysteresis behaviors' are not appropriately observed. When Magnetization is zero (y-axis is zero), both magnetic field values are negative........ similarly, when magnetic field is zero, both magnetizations are positive.
What does it indicates?? (Here, I have considered magnetic material only. - transition metal which exhibits magnetism).
What kind of magnetism is this?
Kindly help me out.
Dear COMSOL users,
I am modeling a line-to-ground fault in COMSOL Multiphysics, specifically in the MEF physics module, to study the magnetic field distribution during the fault. To achieve this, I need to incorporate a grounding resistance at the fault point to model the contact of the cable with the ground. Could someone please help me understand how to add the grounding resistance in the Magnetic and Electric Fields physics within COMSOL.
I'm interest in MHD power generator, especially using salt water flow under transverse magnetic field.
In this paper, they assume that the e.m.f as f0=4w(B_0)(V_E) constant value independent of the hall current. However I think that if we connect the electrode, the ions are eliminated by reduction and oxidation on the electrode surface. So the removing charge effect will decrease the e.m.f value.
So I want to know my guess is reasonable and way how to get the maximum power produced by the device.
Dear researchers,
I would like to know if there is a hydraulic press that can press a powder and also align grains with a magnetic field (this magnetic field can be switched on or off).
Please give me some details and I will be very thankful.
Best regards.
It is easier for scientists engaged in nuclear fusion to switch careers to permanent motion, so it is recommended to switch careers.
- The three formulas in the figure are the dynamic basis of this perpetual motion machine.
- The only difficulty is charge binding: the diffusion process of charges from A to B requires a constrained electric or magnetic field. The difficulty of this constraint is relatively small compared to nuclear fusion, and it is easy for them to switch to making perpetual motion machines. Suggest transitioning to nuclear fusion and engaging in perpetual motion machines.
- Although some progress has been made in nuclear fusion, there are still many technical challenges and high costs.
- There are various ways to implement perpetual motion machines, not limited to this model.
I want to apply a field to a cluster by VASP, how can I provide a suitable INCAR for this? And if this calculation needs other point, please advise me.
I have two X-ray diffraction (XRD) patterns: one from a control sample and the other from a sample subjected to a magnetic field. I've observed that the diffraction peaks in the sample exposed to the magnetic field are more pronounced. Could you provide an interpretation for this observation?
I would like to know the possible sources of errors while measuring Hall with ac current and dc magnetic Field using lock in amplifier. If possible please suggest some literatures with experimental details
In the Cartesian Corredinate commonly the direction of the electric field is towards the Y axis and magnetic field is towards the Z axis and the propagation is towards the X axis of EMR. Here, I want to know about the polarization effect on an EMR or light wave and, if is there any situation where the electric field can directed toward the X-axis, the magnetic field toward the Y-axis, and the propagation toward the Z-axis.? Kindly explain and provide some references for understanding purpose of the students (Chapter-Remote Sensing and GIS).
Thanks & regards
How is a magnet able to do its magnetic work independently even though it is positioned within the Earth's magnetic field?
The research aims to devise an optimal copper loop antenna design specifically for testing magnetic field intensity within the frequency range of 81.39–90.00 kHz. The focus will be on selecting appropriate dimensions, materials, and configurations to ensure accurate and reliable measurement of magnetic fields, particularly relevant for wireless charging scenarios compliant with the SAE J2954 standard.
In many research I found that the method for rise low temperature fluid often excited by high voltage electrical field or magnetic field which used more energy.
How can we achieve the effect of the added magnetic field on the electrolysis process during molten salt electrolysis?
Dear colleagues,
How to perform the Reduction to the Pole for a large study area where variations in magnetic field parameters (inclination and declination) exhibit significant changes?
For example, the inclination varies from 27° to 37°.
Best regards
I have a satellite dataset from GOES-10 and I want to convert the vector magnetic field data into the mean-field aligned coordinate system. Thanks in advance.
It seems the Foucault Pendulum experiment hasn't been changed much after it was firstly introduced in 1851 as a simple proof of Earth's self-rotation.
So, I was pondering whether modern science could do something to perfect this beautiful experiment. As many Museum has electromagnetic incorporated to keep the bob swinging, I'm considering why not just let the bob statically float above that magnetic base instead of swinging around? Magnetic Levitation is a way to realize it.
The idea is pretty simple: The bob floating above the magnetic base rotating with Earth could have a relative movement with the Earth, also proving the self-rotation of Earth.
Many videos about this experiment could be found on youtube, for example, https://www.youtube.com/watch?v=g4lW7xydnH8
But I also have a concern: Would the rotating magnetic field (produced from levitation base) affect the suspended object above it if that magnetic field is inhomogeneous, which could produce force by cutting through the inhomogeneous magnetic force lines?
For BH loop study, the vibrating sample magnetometer ( VSM) is used.
In stead of using a VSM, if I pass ac current through a long coil and produce ac magnetic field inside the coil, can I get the magnetic properties such as B H loop?
Please discuss .
Thanks and Regards
N Das
3.2 The Three-Dimensional Nature of the Magnetic Field
It was Hermann Weyl, the philosopher of relativity as he has been called, in his beautiful book Symmetry who clearly emphasized faith in right-left equivalence as a central dogma of Western physical science, quite despite the fact that in his book he clearly shows the insurmountable difficulties in trying to frame the "asymmetry" of the behavior of the magnetic field, within an epistemological framework based on bilateral symmetry, whose real foundation is the same Aristotelian logic and whose character of faith derives from its predictive character, but which cannot account for the fact that the direction of the magnetic field is determined by the right-hand screw rule, which incidentally accounts for the formal definition of the vector product, so we can conclude that the magnetic field reflects the three-dimensional nature of space, from which its inherent capacity of energy storage could be derived.
It is significant that as soon as Weyl has stated that.
"The result is, in short, that nothing in Physics has indicated an intrinsic difference between left and right..."
that the violation of parity in weak interactions - where the invariant character of the spin direction of the magnetic field plays such a fundamental role - has indicated the opposite.
The parity-breaking experiment was performed by C.S.Wu, and for this: a sample of Co 60[2,418] was polarized in such a way that its nuclei had their magnetic fields or spins aligned:
the applied magnetic field configuration was set up as shown in Figure 3.3.a., which coincided with the polarization direction of Co 60.
"The system was inverted by rotating it 180° around the polarization line L, in such a way that the magnetic field and its spins were inverted and the experimental observation is shown in Figure 3.3.c: the result was that the direction of maximum electron emission intensity was inverted.
Actually based on the left-right equivalence it was theoretically thought to find something like the mirror image shown in Figure 3.3.b. but this was not what was observed experimentally. The experimental results are related to the fulfillment of the right-hand thread rule for the magnetic field and the indivisible unity of the magnetic poles.
All this we can interpret then, giving the magnetic field an ontological priority in relation to the electric field or the electric charge, and as an experimental proof of what Hermann Weyl did not want to recognize: that the physical structure of space contains a right-hand screw; that there is a fundamental asymmetry that leads us precisely to another type of symmetry whose starting point is not a line, but an ontological center that contains in itself a fundamental polarity, i.e., the same magnetic field.

I am working in Barium ruthenate triple perovskites. I have been observing proper downward peaks at about 30 K, with the minima shifting to higher temperature for higher frequencies. The magnitude of the dips is also higher for higher frequencies. An exactly opposite trend is seen in the imaginary part of ac susceptibility data at the same temperature. There is no transition visible at 30 K in the DC magnetization or heat capacity data. The measurement was carried out in the Quantum Design SVSM MPMS3 multiple times and from multiple instruments at a magnetic field of 3 oe. I have observed this in two different Barium ruthenate triple perovskite compounds of mine. I had also carried out the ac susceptiility measurement in ACMS option of QD PPMS with 13 Oe magnetic field and this anomaly at 30 K is absent. Figures are given for reference.
When there is no magnetic field in the simulation, emittances given by the postprocessing and my own code are same. But when there is magnetc field in the simulation, no matter how small of the field, emittances parallel to magnetic induction are different.
The simulation software is CST Studio Suite 2020 Particle Tracking Solver. For the same structure of RF negative hydrogen ion source, the H- beam is extracted from plasma electrode and accelerated by the extracted electrode and accelerated electrode. There are two pairs of rod filter magnet in this structure.
It is commonly believed that the concept of electron spin was first introduced by A.H. Compton (1920) when he studied magnetism. "May I then conclude that the electron itself, spinning like a tiny gyroscope, is probably the ultimate magnetic particle?"[1][2]; Uhlenbeck and Goudsmit (1926) thought so too [4], but did not know it at the time of their first paper (1925) [3]. However, Thomas (1927) considered Abraham (1903) as the first to propose the concept of spinning electron [5]. Compton did not mention Abraham in his paper "The magnetic electron" [2], probably because Abraham did not talk about the relationship between spin and magnetism [0]. In fact, it is Abraham's spin calculations that Uhlenbeck cites in his paper [4].
Gerlach, W. and O. Stern (1921-1922) did the famous experiment* on the existence of spin magnetic moments of electrons (even though this was not realized at the time [6]) and published several articles on it [7].
Pauli (1925) proposed the existence of a possible " two-valuedness " property of the electron [8], implying the spin property; Kronig (1925) proposed the concept of the spin of the electron to explain the magnetic moment before Uhlenbeck, G. E. and S. Goudsmit, which was strongly rejected by Pauli [9]. Uhlenbeck, G. E. and S. Goudsmit (1925) formally proposed the concept of spin[3], and after the English version was published[4], Kronig (1926), under the same title and in the same journals, questioned whether the speed of rotation of an electron with internal structure is superluminal**[10]. Later came the Thomas paper giving a beautiful explanation of the factor of 2 for spin-orbit coupling[11]. Since then, physics has considered spin as an intrinsic property that can be used to explain the anomalous Seeman effect.
The current state of physics is in many ways the situation: "When we do something in physics, after a while, there is a tendency to forget the overall meaning of what we are working on. The long range perspective fades into the background, and we may become blind to important a priori questions."[11]. With this in mind, C. N. Yang briefly reviewed how spin became a part of physics. For spin, he summarized several important issues: The concept of spin is both an intriguing and extremely difficult one. Fundamentally it is related to three aspects of physics. The first is the classical concept of rotation; the second is the quantization of angular momentum; the third is special relativity. All of these played essential roles in the early understanding of the concept of spin, but that was not so clearly appreciated at the time [11].
Speaking about the understanding of spin, Thomas said [5]: "I think we must look towards the general relativity theory for an adequate solution of the problem of the "structure of the electron" ; if indeed this phrase has any meaning at all and if it can be possible to do more than to say how an electron behaves in an external field. Yang said too: "And most important, we do not yet have a general relativistic theory of the spinning electron. I for one suspect that the spin and general relativity are deeply entangled in a subtle way that we do not now understand [11]. I believe that all unified theories must take this into account.
What exactly is spin, F. J. Belinfante argued that it is a circular energy flow [12][15] and that spin is related to the structure of the internal wave field of the electron. A comparison between calculations of angular momentum in the Dirac and electromagnetic fields shows that the spin of the electron is entirely analogous to the angular momentum carried by a classical circularly polarized wave [13]. The electron is a photon with toroidal topology [16]. At the earliest, A. Lorentz also used to think so based on experimental analysis. etc.
Our questions are:
1) Is the spin of an electron really spin? If spin has classical meaning, what should be rotating and obeying the Special Relativity?
2) What should be the structure of the electron that can cause spin quantization and can be not proportional to charge and mass?
3) If spin must be associated with General Relativity, must we consider the relationship between the energy flow of the spin and the gravitational field energy?
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* It is an unexpectedly interesting story about how their experimental results were found. See the literature [17].
** Such a situation occurs many times in the history of physics, where the questioned and doubted papers are published in the same journal under the same title. For example, the debate between Einstein and Bohr, the EPR papers [18] and [19], the debate between Wilson and Saha on magnetic monopoles [20] and [21], etc.
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Reference:
[0] Abraham, M. (1902). "Principles of the Dynamics of the Electron (Translated by D. H. Delphenich)." Physikalische Zeitschrift 4(1b): 57-62.
[1] Compton, A. H. and O. Rognley (1920). "Is the Atom the Ultimate Magnetic Particle?" Physical Review 16(5): 464-476.
[2] Compton, A. H. (1921). "The magnetic electron." Journal of the Franklin Institute 192(2): 145-155.
[3] Uhlenbeck, G. E., and Samuel Goudsmit. (1925). "Ersetzung der Hypothese vom unmechanischen Zwang durch eine Forderung bezüglich des inneren Verhaltens jedes einzelnen Elektrons." Die Naturwissenschaften 13.47 (1925): 953-954.
[4] Uhlenbeck, G. E. and S. Goudsmit (1926). "Spinning Electrons and the Structure of Spectra." Nature 117(2938): 264-265.
[5] Thomas, L. H. (1927). "The kinematics of an electron with an axis." The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science 3(13): 1-22.
[6] Schmidt-Böcking, H., L. Schmidt, H. J. Lüdde, W. Trageser, A. Templeton and T. Sauer (2016). "The Stern-Gerlach experiment revisited." The European Physical Journal H 41(4): 327-364.
[7] Gerlach, W. and O. Stern. (1922). "Der experimentelle Nachweis der Richtungsquantelung im Magnetfeld. " Zeitschrift f¨ur Physik 9: 349-352.
[8] Pauli, W. (1925). "Über den Einfluß der Geschwindigkeitsabhängigkeit der Elektronenmasse auf den Zeemaneffekt." Zeitschrift für Physik 31(1): 373-385.
[9] Stöhr, J. and H. C. Siegmann (2006). "Magnetism"(磁学), 高等教育出版社.
[10] Kronig, R. D. L. (1926). "Spinning Electrons and the Structure of Spectra." Nature 117(2946): 550-550.
[11] Yang, C. N. (1983). "The spin". AIP Conference Proceedings, American Institute of Physics.
[12] Belinfante, F. J. (1940). "On the current and the density of the electric charge, the energy, the linear momentum and the angular momentum of arbitrary fields." Physica 7(5): 449-474.
[13] Ohanian, H. C. (1986). "What is spin?" American Journal of Physics 54(6): 500-505. 电子的自旋与内部波场结构有关。
[14] Parson, A. L. (1915). Smithsonian Misc. Collections.
[15] Pavšič, M., E. Recami, W. A. Rodrigues, G. D. Maccarrone, F. Raciti and G. Salesi (1993). "Spin and electron structure." Physics Letters B 318(3): 481-488.
[16] Williamson, J. and M. Van der Mark (1997). Is the electron a photon with toroidal topology. Annales de la Fondation Louis de Broglie, Fondation Louis de Broglie.
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[17] Friedrich, B. and D. Herschbach (2003). "Stern and Gerlach: How a bad cigar helped reorient atomic physics." Physics Today 56(12): 53-59.
[18] Bohr, N. (1935). "Can quantum-mechanical description of physical reality be considered complete?" Physical review 48(8): 696.
[19] Einstein, A., B. Podolsky and N. Rosen (1935). "Can quantum-mechanical description of physical reality be considered complete?" Physical review 47(10): 777.
[20] Wilson, H. (1949). "Note on Dirac's theory of magnetic poles." Physical Review 75(2): 309.
[21] Saha, M. (1949). "Note on Dirac's theory of magnetic poles." Physical Review 75(12): 1968.
What is the (maximum) magnetic field outside a superconductive disk located in a uniform magnetic field B and very close to the edges? (Consider the London penetration depth to be zero and let the magnetic field be perpendicular to the disk if it was a perfect conductor.) According to the article attached below, the maximum field can be four times the external field (4B), though I am not sure.
Hey there, I am using CST Microwave Studios for Power Source (Magnetron) analysis. I need help in Particle in Cell simulations to analyze the E field (V/m) value at specified distances (0.5-2 Kms) from the power source. But i am unable to set the parameters correctly i.e Mesh Settings, Far field Probes and field monitors. Also need help with excitation of cathode and the ports and magnetic field settings.
During the VSM measurement, the data I measured shows hysteresis curve appearing only on the positive side of magnetic field what could be the possible reasons for that ?

Fermions have four properties: charge, spin moment, mass and gravitational field.
1) Why don't we consider the spin moment as an effect of "magnetic charge", so that we don't need to look for magnetic monopoles [1][2][3].
2) If this is correct, we can divide the four properties into two pairs, charge e, magnetic charge g [4]; mass m and gravitational field G.
3) We will find that e and g are inseparable (except, it seems, for neutrinos) and m and G are definitively inseparable. e satisfies Gauss's theorem for the electric field and g can likewise satisfy Gauss's law for the magnetic field, as long as it appears in bipolar form.
4) So, why four properties instead of one or more? In what way and in what relationship would these four properties be set in one?
[1] Dirac, P. A. M. (1931). "Quantised singularities in the electromagnetic field." Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character 133(821): 60-72.
[2] Acharya, B., J. Alexandre, P. Benes, K. S. Babu and etl. (2021). "First Search for Dyons with the Full MoEDAL Trapping Detector in 13 TeV p p Collisions." Physical Review Letters 126(7): 071801.
[3] Preskill, J. (1984). "Magnetic monopoles." Annual Review of Nuclear and Particle Science 34(1): 461-530.
[4] Dirac, P. A. M. (1948). "The theory of magnetic poles." Physical Review 74(7): 817.
Keywords: Fermion, Charge, Monopole, magnetic charge, Spin moment, Gauss's law, Maxwell equation, MoEDAL, Standard Model.
I wanna to asked that if I have a cylindrical permanent magnet and I can measure the Three-dimensional magnetic vector(Bx,By,Bz) of every point, how can I calculate the space position(x,y,z) from the magnetic field(Bx,By,Bz)? Thank you!
Hello,
My name is Radu Jubleanu, I am PhD student at the Politehnica University of Bucharest. I work in the field of magnetic storage in superconductors, I studied some works related with superconductors , and I have a confusion related to the magnetic anisotropy of them.
More precisely, I would like a clarification, related to parallel and perpendicular magnetic fields. I saw that there are Jc curves as a function of B. But it is not clear to me who is B. Who produces this external magnetic field?
Thank you!
I have received as a comment expressing recent research that: Of course this is 100% correct because energy is the universal electric field and every quantum of energy generates a corresponding vector within the magnetic field (and visa versa). Moreover, vectors act instantaneous because vectors are 1 dimensional (vectors are not bound to the speed of light).
One may have a long re-bar (roughened metal bar used to reinforce concrete) and would find that a hammer tap on the end results in a propagating wave that eventually reaches the other end. A strong blow with a sledge hammer would produce that result plus a longitudinal motion of the entire bar that would affect anything in contact with the far end much sooner, almost instantaneously because the bar would move as a whole.
Are electric field vectors stiff in the latter sense of the re-bar's motion as is implied by "instantaneous" in the above comment?
Cited research as well as opinion might get an old guy up to speed on this since he'll never get it all read. Note, this is not about an EM wave propagating in accord with theories treating that phenomenon. The speed of light must not be allowed to confuse this new awareness of recent research. lfh 3-13-23
In Hall effect, when a magnetic field is applied to a sample, electrons are deflected and accumlate sideways. Can one determine this angle? I have a formula and want to check it.
Kindly share the link of any video tutorial or data.
Some people believe that it is the end of physics laws. this question has taken around a century to be solved. But what are the problems? please inform them.
Hi everyone,
I'm using COMSOL Multiphysics Magnetic field interface to modeling 3 phase power reactor. According to COMSOL Manual reference the best preconditioner for iterative solver in magnetic field is geometric multigrid (GMG) where in coarse solver configured with Auxiliary-Space Maxwell (AMS). Whereas, AMS is not support complex number and each phase has 120 degrees phase difference with each other (for ex. current in phase B= Irms*exp(j*2*pi/3)). Also, I have tried direct solver instead of AMS and solution not converged. Does any one know how to configure the GMG preconditioner or any solution for get true results?
Thanks
Best regards,
AhmadReza



I'm confused! In 13CNMR spectroscopy, is 13C nucleus used in the device? What exactly is the nature of the magnetic field produced by the device? From carbon 12 or 13? And does it only stimulate the 13C in the sample or does it also stimulate the 12C in our sample? (Of course, the abundance of 13C is much less than 12C)
Stern-Gerlach experiment is often seen as idealization of measurement. Using strong magnetic field, it makes magnetic dipoles (of e.g. atoms) align in parallel or anti-parallel way. Additionally, gradient of magnetic field bends trajectories depending on this choice.
Magnetic dipoles in magnetic field undergo e.g. Larmor precession ( https://en.wikipedia.org/wiki/Larmor_precession ) due to τ=μ×B torque, unless μ×B=0 what means parallel or anti-parallel alignment.
Precession means magnetic dipole becomes kind of antenna, should radiate this additional kinetic energy. Thanks to duality between electric and magnetic field ( https://en.wikipedia.org/wiki/Duality_(electricity_and_magnetism) ), we can use the attached formula for precessing electric dipole, e.g. from http://www.phys.boun.edu.tr/%7Esevgena/p202/docs/Electric%20dipole%20radiation.pdf .
Using which I get power like 10^−3W, suggesting radiation of atomic scale energies (∼10^−18J) in e.g. femtoseconds (to μ×B=0 parallel or anti-parallel).
So can we see spin alignment in Stern-Gerlach as a result of EM radiation of precessing magnetic dipole?
Beside photons, can we interpret other spin measurement experiments this way?

Hi,
I want to simulate a solenoid magnetic field in Comsol. Where should I start?
Apropos the Meissner Effect : how is a totally still magnetic field expelled from the interior of a superconducting body, when it is cooled below the transition temperature? From whence do the supercurrent elements obtain their impulse ; how can they suddenly become screening currents, without a cause?
Conversely, it is quite understandable that bringing a superconducting body into a magnetic field-- in this case the supercurrent elements obtain their impulse from a changing magnetic field, via the Lenz-Faraday Law. But in the above case, the magnetic field is absolutely still, and so cannot possibly provide the mechanism to set up surface screening currents.
I was just wondering if hall effect sensor would measure magnetic field inside a pipeline when being placed inside. As I am currently doing a project to identify corrosion in a pipeline, i was hoping to use it to find the magnetic fields to detect corrosion in the pipe.
Hi everyone
Considering a magnetized plasma with non-isothermal electrons ( free and trapped electrons ) what is the influence of the magnetic field on the electron capture (trapping)?
and what processes are used to determine the proportion of captured electrons?
Thanks
I am trying to build a setup to cure magnetic powders in a polymer matrix in a uniform magnetic field to align the particles in certain orientations. What would be the a setup to do this? In literature I do see some researchers use electromagnets and some use electromagnets. What would be the proffered method in terms of having control over the field being applied?