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Topic: Magnetic monopole

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  Magnetic monopole - Wikipedia, the free encyclopedia
The magnetic force is actually due to the finite speed of a disturbance of the electric field, the speed of light, which gives rise to forces that appear to be acting along a line at right angles to the charges.
Since all known forms of magnetic phenomena involve the motion of electrically charged particles, and since no theory suggests that "pole" is, in that context, a thing rather than a convenient fiction, it may well be that nothing that could be called a magnetic monopole exists or ever did or could.
The hypothetical existence of a magnetic monopole would imply that the electric charge must be quantized in certain units; also, the existence of the electric charges implies that the magnetic charges of the hypothetical magnetic monopoles, if they exist, must be quantized in units inverse to the elementary electric charge.
en.wikipedia.org /wiki/Magnetic_monopole   (2480 words)

 Magnetism - Wikipedia, the free encyclopedia
Normally, magnetic fields are seen as dipoles, having a "South pole" and a "North pole"; terms dating back to the use of magnets as compasses, interacting with the Earth's magnetic field to indicate North and South on the globe.
Alnico magnets are made by casting or sintering a combination of aluminium, nickel and cobalt with iron and small amounts of other elements added to enhance the properties of the magnet.
Flexible magnets are similar to injection molded magnets, using a flexible resin or binder such as vinyl, and produced in flat strips or sheets.
en.wikipedia.org /wiki/Magnetic   (2344 words)

 Magnetic monopole - Biocrawler   (Site not responding. Last check: 2007-10-05)
In physics, magnetic monopole is a term describing a hypothetical particle that could be quickly clarified to a person familiar with magnets but not electromagnetic theory as "a magnet with only one pole".
A hypothetical isolated magnetic pole is called a magnetic monopole; it has been theorized that such things might exist in the form of tiny particles similar to electrons or protons, forming from topological defects in a similar manner to cosmic strings, but no such particles have ever been found.
So, classically, the question is "Why does the magnetic charge always seem to be zero?" This has been a curiosity for a long time, but it has become more of a problem in recent years, when new theories of physics seem to predict the existence of magnetic monopoles.
www.biocrawler.com /encyclopedia/Magnetic_monopole   (884 words)

 monopole - Search Results - MSN Encarta
Another common antenna shape is the half-dipole or monopole antenna, which uses a single quarter-wavelength piece of metal connected to one of the...
What may prove to be one of the most momentous discoveries in the history of physics was announced this summer by a group of cosmic ray physicists from the University of California at Berkeley and the University of Houston.
It is the discovery of a magnetic monopole, and although it confirms a...
ca.encarta.msn.com /monopole.html   (146 words)

 Magnetic field - definition of Magnetic field - Labor Law Talk Dictionary (via CobWeb/3.1 vn1.cs.wustl.edu)   (Site not responding. Last check: 2007-10-05)
The second equation is a statement of the observed non-existence of magnetic monopoles.
Thus, using special relativity, magnetic forces are a manifestation of electrostatic forces of charges in motion and may be predicted from knowledge of the electrostatic forces and the movement (relative to some observer) of the charges.
Technically, the magnetic field isn't a vector according to the formal definition, it is a pseudovector: it gains an extra sign flip under improper rotations of the coordinate system.
encyclopedia.laborlawtalk.com.cob-web.org:8888 /Magnetic_field   (715 words)

 Magnetic monopole
Magnets exert forces on one another; similarly to electric charges, like poles will repel each other and unlike poles will attract.
An isolated magnetic pole is called a magnetic monopole; it has been theorized that such things might exist in the form of tiny particles similar to electrons or protons, forming from topological defects[?] in a similar manner to cosmic strings, but no such particles have ever been found.
The existence of a magnetic monopole automatically leads to the conclusion that electric charge must be quantized (a result due to Paul Dirac).
www.ebroadcast.com.au /lookup/encyclopedia/ma/Magnetic_monopole.html   (161 words)

 The Magnetic Monopole
Another magnetic problem which has attracted a surprising amount of interest is the problem of the motion of a charged particle in the field of an isolated magnetic monopole, first analyzed by Poincare (74) in 1896.
The particle spirals in from infinity, is reflected, and recedes to infinity on a path asymptotic to an element of the cone.
One of their immediate conclusions was that if the monopole were to exist as an isolated particle, its magnetic charge would have to be quantized, and as an indirect conclusion one could deduce the necessity of quantizing electric charge as well.
delta.cs.cinvestav.mx /~mcintosh/comun/symm/node8.html   (1518 words)

 Monopole problem
A magnetic monopole would be a magnet with only one pole.
When a magnet with a north and south pole is cut in half, it becomes two magnets, each with its own north and south poles.
This creates a problem, because it predicts that the monopole density today should be 1011 times the critical density of our Universe, according to the Big Bang model.
www.ebroadcast.com.au /lookup/encyclopedia/mo/Monopole_problem.html   (229 words)

Magnetic monopoles are elementary particles that carry units of magnetic charge.
Due to their topological nature, monopoles are naturally produced in great numbers at the beginning of the Universe via the Kibble mechanism.** Because of their unique properties, as will be seen later, monopole production rate must be constrained significantly by other factors, such as inflation of the Universe.
The ability of monopoles to catalyze energy release sets limits upon the primordial monopole flux, F. For example, only 10E28 monopoles in the center of the sun are required to produce the entire solar luminosity of 4E33 ergs/second.
www.orionsarm.com /tech/monopoles.html   (1577 words)

 Magnetic monopole - tScholars.com   (Site not responding. Last check: 2007-10-05)
In more accurate terms, it would have net "magnetic charge." Interest in the concept stems from particle theories, notably Grand Unified Theories and superstring theories that predict either the existence or the possibility of magnetic monopoles.
In the toy model of an atom the electrons orbit the nucleus, and thus have a charge in motion giving rise to a magnetic field.
Although there have been tantalizing events recorded, in particular the event recorded by Blas Cabrera on the night of February 14, 1982, there has never been reproducible evidence for the existence of magnetic monopoles.
www.tscholars.com /encyclopedia/Magnetic_monopole   (1815 words)

 magnetic monopole concept from the Astronomy knowledge base   (Site not responding. Last check: 2007-10-05)
Magnetic monopoles have never been observed, but they are predicted to exist by grand unified theories.
Magnetic monopoles are predicted by grand unified theories of physics.
Normally, magnetic poles, the sources of a magnetic field, occur in pairs as north and south poles.
www.site.uottawa.ca:4321 /astronomy/magneticmonopole.html   (238 words)

 Monopole FAQ   (Site not responding. Last check: 2007-10-05)
You may have heard about magnetic harges too, probably something like "magnetic sources don't exist," or "if magnetic sources exist, we haven't seen them yet." So magnetic monopoles are usually left out of the pictures.
Their mass means that magnetic monopoles are also going to be pretty slow (makes sense, right?).
Magnetic fields in the solar system and in the galaxy will tend to accelerate monopoles to speeds of 0.0001 to 0.01 times the speed of light.
budoe.bu.edu /~corth/monopole_faq.html   (1112 words)

 Magnetic Monopoles: Their Construction and Use
Magnetic monopoles, objects bearing a magnetic charge without an corresponding opposite charge, has been postulated by established science, but so far never observed.
This requires that the fields are strong enough to overcome the magnetic momentum of the object, which depends mainly on the material, its size and symmetry.
Possible future directions of research are: increasing the magnetisation strength by building a more powerful charging unit (possibly using several layers of coils arranged in a series of polyhedrons and current from homopolar generators or the Russian implosion technique), building a double monopolar chamber and the search for a magnetic tripole.
members.tripod.com /~CyberMax/Monopol.htm   (1624 words)

 The Hairpin Monopole Antenna
A hairpin monopole is simply one half of a folded dipole, therefore, a good starting point for our discussion is to briefly describe the electrical properties of the folded dipole antenna.
The noted difference between a basic folded monopole antenna and a hairpin is that the hairpin is considerably shorter.
The article on the Hairpin Monopole is representative of a magnetic antenna, of the same type as the DDRR.
www.antennex.com /preview/monopole.htm   (1359 words)

 Re: How will scientists recognize a magnetic monopole if they ever find one?
Magnetic monopoles, as you probably already know, are basically theorized particles that no one has found yet.
It has been suggested that magnetic monopoles must have been produced in great amounts in the start of the universe but inflation seems to have whittled them down to the level of one per particle horizon.
The two most widely used methods are induction (which measures the monopole's magnetic charge) and ionization (which depends on a magnetic charge producing greater ionization than electrical charges with the same velocity).
www.madsci.org /posts/archives/may98/895430221.Ph.r.html   (411 words)

 Magnetic Water Treatment-Study Results   (Site not responding. Last check: 2007-10-05)
It has long been observed in practice that the magnetic effect lasted for a period after treatment, after which the water returned to the condition prior to treatment.
However, the Polish report shows that the observed "magnetic memory" is simply the post treatment activity of activated silica that apparently continues to adsorb minerals for a period of time after magnetic influence.
The difference in magnetic flux density between the two processes (in a gap) is significant with the bi-pole equipment producing double and sometimes tripple the strength of monopole.
magneticwatertreatment.com /whyimp.html   (766 words)

 Magnetic Fields, Magnetic Forces, and Electromagnetic Induction   (Site not responding. Last check: 2007-10-05)
The magnetic field near a long straight wire is directly proportional to the current I in the wire and inversely proportional to the distance r from the wire.
At the center of the loop, the magnetic field is perpendicular to the plane of the loop.
The direction of the magnetic field at the center of the loop can be determined using a RHR (the thumb is pointed in the direction of the current and the curled fingers are placed at the center of the loop, then the palm pushes in the direction of the magnetic field.)
www.pschweigerphysics.com /magnetism.html   (2455 words)

 CERN Courier - MACRO delivers its final wor - IOP Publishing - article
The magnetic monopole is a hypothetical particle with a single magnetic charge.
During the 1970s, monopoles appeared on the scene again, when theorists found that electric charge is naturally quantized in gauge theories that unify the strong and the electroweak interactions (GUTs).
Because of the smallness of the monopole's core this should be a very rare phenomenon, but if there are baryon number violating terms in the four-fermion virtual condensate around a GUT monopole of up to 1 fm radius, the cross-section could be large and the phenomenon could be observed.
www.cerncourier.com /main/article/43/4/11   (836 words)

 Lectures on Electrodynamics - A Book of professor Pavel M. Mednis   (Site not responding. Last check: 2007-10-05)
From the classical point of view the properties of a substance and an electromagnetic field are substantially determined by the √Ćaxwell's-Lorentz's electrodynamics equations including the equations of a field which sources are microscopic density of an electric charge and a current, and the mechanical equations of movement of the charged particles in this field.
In our case magnetic density of a charge and a current of the separate charged particles carry magnetic dipole character that leads to equality to zero of a full magnetic charge of a particle in all space.
In particular, from them follows, that if the density of a magnetic charge is equal motionless system of readout to zero in the system of readout moving concerning motionless, density of a magnetic charge, generally speaking, can be not equal to zero.
www.magneticcurrents.com   (999 words)

 Physics - Wikipedia, the free encyclopedia (via CobWeb/3.1 vn1.cs.wustl.edu)   (Site not responding. Last check: 2007-10-05)
Condensed matter physics, by most estimates the largest single field of physics, is concerned with how the properties of bulk matter, such as the ordinary solids and liquids we encounter in everyday life, arise from the properties and mutual interactions of the constituent atoms.
A magnet levitating above a high-temperature superconductor (with boiling liquid nitrogen underneath), demonstrating the Meissner effect, is a phenomenon of importance to the field of condensed matter physics.
This was done by demonstrating that a moving magnet induced an electric current in a conductor.
en.wikipedia.org.cob-web.org:8888 /wiki/Physics   (5065 words)

 Magnetic Monopole
The fact is that no magnetic monopoles have been ever found (like a point particle being the source of a magnetic field).
The magnetic phenomena, with respect to it's detailed origin and expression, is one of the most least understood aspects of physics.
Magnetic fields can be treated completely as relativistic corrections to the fields of moving electric charges.
www.physicsforums.com /showthread.php?p=288646   (720 words)

 Felix Ehrenhaft: Magnetic Current --- 9 articles
Conventional wisdom has it that magnetic poles always occur in pairs of opposites and that it is not possible for a magnetized object to have a north pole without an attached south pole.
The movement of magnetic ions in a homogenous magnetic field is a ‘magnetic currnet’.
Magnetic poles (charges) were induced in various non-magnetic and annealed pieces of iron (paperclips, nails,little iron rods), which were placed perpendicularly to the geomagnetic field, by irradiation for periods varying from minutes to several hours.
www.rexresearch.com /ehrenhaf/ehrenhaf.htm   (8419 words)

 Mr. Fusion: Magnetic Monopole
The only choices you'd have would be a system that is constrained by an attractive force - gravity or electrostatics (as there are no magnetic monopoles) - or a compressive force, like the surface of a balloon pressing in upon the gas, keeping it spherically confined.
The generation of a "local" monopole field does not violate Maxwell's first law, since "globally" the net integral does not result in a monopole.
Certainly the use of five fold symmetry in these magnetic configurations have caught my eye, as well as the possibility of producing a system local magnetic monopole.
mr-fusion.hellblazer.com /000021.html   (850 words)

 Magnetic fields and how to make them
The magnetic field is a vector, the same way the electric field is. The electric field at a particular point is in the direction of the force a positive charge would experience if it were placed at that point.
The magnetic field at a point is in the direction of the force a north pole of a magnet would experience if it were placed there.
The direction of the force exerted by a magnetic field on a moving charge is perpendicular to the field, and perpendicular to the velocity (i.e., perpendicular to the direction the charge is moving).
physics.bu.edu /~duffy/PY106/MagField.html   (1399 words)

 Alternate View Column AV-01
Only if one monopole were to encounter another monopole of the opposite magnetic charge, north monopole meeting south monopole, could their burdens of magnetic flux be released so that the monopole pair could annihilate in a burst of energy and disappear.
Thus the monopole is the analog of a chemical catalyst.
The hemi-bottle magnetic nozzle then provides the dual function of guiding the charged nuclear fragments from the exploded nuclei out the exhaust port of the engine and at the same time collecting the monopoles at the pinch point for re-use in the next engine cycle.
www.npl.washington.edu /AV/altvw01.html   (2793 words)

 David Guarrera's Worldsheet: Magnetic Monopoles
In fact, things are actually much nicer with magnetic charge, as Maxwell's equations are perfectly symmetric between E and B fields (I would write them out if I knew how to do equations in my blog, anybody know?), so the physics is much more beautiful if magnetic charge exists.
Well, you might ask: what about the vector potential A? We know that B= \del X A, and that if magnetic charges exist \del (dot) B=m \delta^3 (r) (up to a constant for a monopole at the origin, where m is the "magnetic charge", and the delta is the Dirac delta function).
So, we can put back the monopole if we just get rid of the vector potential (which, for classical electrodynamics, is not necessary), and just use E and B in our calculations.
web.mit.edu /guarrera/www/2005/02/magnetic-monopoles.html   (1092 words)

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