Posted: Sat Jan 19, 2008 9:54 am Post subject: Magnetism: Form, Structure, & Dynamics Reply with quote
http://www.scribd.com/doc/34317/Spintro ... rd-Johnson
A few excerpted pictures w/captions below from the beginning of the book.
(refer also: Two electric stories in the same week?! thread)
Caption: The over simplification of magnetic field,
showing its movement from the north pole
of the magnet to the south pole.
Caption: This is what the direction of the lines of force really looks like, demonstrated with a cubical magnet having the top face for the north pole and the bottom face for the south pole (top) as opposed to (bottom)
Caption: This actual graphic mapping of a magnet shows its lines of force by measuring the intensity of the magnetic field every 1/16" at each point on a grid, covering the entire magnet, as well as some of the field in the area around the magnet. (Sec page # 29 for description of method.) This measurement of the strength of the magnetic field is rated in gauss.
Caption: The preceding process uses the two particle principle, laying down lines going in opposite directions around a current carrying wire.This is made possible in keepingwith the principle that, around the wire conducting current, these two opposing particles orbit in opposite directions.
Caption: Computer color illustration. In the permanent magnet, we have the same two spins in opposite directions. We do not knowwhat makes them behave that way, but we do believe therecord of our excellent monitoring and recording equipment.
Caption: Lines of Force are Spins forming Vortices: One of the most most amazingly illustrative and thoroughly innovative concepts in the area of magnetic field structure has been the discovery of vortices caused by the path of the particles which make up the lines of force. Notice the previously used illustration
Caption: Noticing the last illustration, it is evident that the "whirlwind" or "tornado" effect is present and that there are two vortices present at each "pole". An interesting and important piece of information, though, is that these vortices are not all the same, as is shown in previous illustration for clarity. Notice the distribution of the spins
Caption: THE DOUBLE VORTEX WITH THE SPINS ALONGSIDE
Here is a picture which recorded the discovery of the Double Vortex
Caption: The Double-Vortex is highly significant in many ways, but the point to be reckoned with here is that both particles exist at both poles. Therefore, there is an element of both the "north" and the "south" in each pole. The north element (vortex) is dominant, and has proven to be the stronger vortex with higher gauss ratings.
Caption: Since the stronger north element (vortex) exists in both poles, you are sure to ask what the deciding factor is that distinguishes the north pole from the south pole. The same illustration just used shows that the north pole is the one with the weakest south element (vortex). This means the other pole must be south.
Caption: This is a topographical map of the fields at the end of a square ceramic bar magnet magnitized through its thickness.
ATTRACTION AND REPULSION
To this point, the discussions and descriptions have dealt with single magnets, or single magnet arrangements and their fields. Now, we will present interactions between magnets, and show what really happens in attraction and repulsion.
Taking a ceramic magnet magnetized through the thickness we mount a curved metallic magnet over it and monitor the reacting fields in a one-half inch air gap. Study itcarefully - the result may not be what you were expecting.
Notice first what happens in attraction; We are all familiar with the pull of one magnet toward another. But, the mechanism is not visible, even if we use iron filings. What wc need to see is the activity of atomic particles that constitute the magnetic fields.
Our mapping operation shows these particles pairing off as the unlike fields merge. Examine the illustration: (illustration here)
Then, our topographical program snows that the gauss count (the strength of the lines of force) at the attracting end has been reduced, because the pairing of a large part of the particle populations. The repulsion of like poles represents particle activity which is quite different from attraction.
The particles react with each other as they form two vortices that spin in the same direction. There is no reduction in the gauss count, which registers about three times as high as it does at the attracting end.