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Mechanical Electret Magnet

And a couple variations on the theme
  [vote for,

The "electromagnetic field" associated with various particles has a unique property that most folks don't hear about outside of college physics lectures.

We start with the simple electric field of a single particle, such as a negatively-charged electron. Lots of folks know that if the electron moves, it becomes associated with an overall magnetic field, too. (Even while "still" it has a magnetic field associated with its "spin", but I'm ignoring that here, and only talking about large-scale motion of the electron.)

The unique thing, that usually isn't explained, relates to the origin of that magnetic field. It is actually the SAME electric field as before! It is just that when the electron moves, its overall electromagnetic field can be PERCEIVED two different ways, partly as an electric field, and partly as a magnetic field. The magnetic field is a "relativistic effect" associated with the motion of the electron. IF the electron moved nearly at lightspeed, practically ALL of its electromagnetic field would be perceived as a magnetic field, while only a tiny fraction of it would be perceived as an electric field.

The next relevant item is an electric current moving through a wire. We know there is an associated magnetic field, and we also know that huge numbers of moving electrons are contributing to that magnetic field (something like ten-to-the-eighteenth- power electrons in one ampere of current), but most people don't think about how fast the electrons are moving in the wire. Logically, if they could move faster, then per the preceding paragraph, the magnetic field would be stronger!

Well, it turns out that in ordinary wires, the electrons move at only a couple of MILLIMETERS per second....

Now we can get to the Idea here. An "electret" is a solid object that has a permanent electric charge, similar to a permanent magnet. They can exist in any ordinary shape, so let's imagine one shaped like a piece of tubing.

Inside an electret, the electrons are "fixed" and cannot move (else they would quickly escape, since they all electrically repel each other!). However, the OVERALL electret is a thing that can move....

Let's put this tubing over part of the length of a rod, and turn the rod like an axle. All the electrons in the electret are now moving, much as if we had an ordinary electric current moving inside a "single turn coil". But we can make THESE electrons move LOTS faster than mere millimeters per second!

Alas, while we can imagine creating a super-strong magnetic field this way, There Is A Problem, which is why this Idea is Half- Baked. See that number of electrons in 1 ampere of electric current? 1,000,000,000,000,000,000 is a LOT of electrons! The electret, however, likely contains a few million electrons at most. They electrically repel each other too much, to stuff more of them into the electret!

Our spinning-electret-tube magnet is going to be far feebler than we want. Oh well.

BUT --see that subtitle, about a variation on the theme?

Let's now take a tubular piece of metal, and cool it down to become superconductive. We can now induce a LARGE flow of electrons moving around the circumference of the tube. It automatically has a strong magnetic field....

Now put THAT tubing on the length of rod, and start turning it like an axle. For maximum (theoretical) effect, we want the overall motion of the tube to be in the same direction that the electrons are moving inside the superconducting material of the tube.

ALL those already-moving electrons are now moving WAY faster than mere millimeters per second, and so we should get a super- strong magnetic field, right?

ALAS! All the POSITIVE charges (on protons) in the tubing are also moving in the same direction as the electrons, and their motion generates a CANCELLING magnetic field! The Idea is STILL Half-Baked!

But that just makes it Perfect for posting here. Enjoy!

================= Added June 4, 2015

Here is another variation of this Idea. We start with the tubular and axially-rotating electret magnet, the first invention described in this Idea. We place it in a vacuum, and install a nearby electron gun. We want to be able to "inject" an extra electron or two (or more) into the body of the electret, and we will probably have to shoot the electron at pretty high speed into the electret, to overcome the physical material's ability to lock electrons into place, inside the electret (have to get through the surface of the material).

I'm going to add a couple of links, first because of an annotation by [pashute], and second because of this variation of the initial Idea. You might want to examine that 2nd link before continuing reading here.

The relevant thing about the "pinch effect" is that as electrons move together, their mutual electric repulsion diminishes somewhat, and their magnetic fields align in a way that tends to cause the electrons to attract each other.

Now think about that in terms of our INITIAL non-rotating electret. It has some maximum number of electrons embedded in it, that can't be increased because they all repel each other (as previously stated). But when rotating, if their repulsion decreases, and magnetic attraction increases with speed, we CAN add some more electrons to it!

That is what the electron gun in the vacuum is for. Think of this as a kind of "feedback" system. The more the electret rotates, the more the magnetic attraction of the electrons tries to overcome their repulsion, and the more electrons we can add to the electret. ALSO, the more electrons we add to the electret, the stronger the magnetic field gets, even without increasing its rotational speed! And AGAIN we become able to add even more electrons to the rotating electret!

How many electrons can we add, before we reach a limit, related to the maximum possible speed that the electret can be roatated, before it breaks apart because of "centrifugal" stresses? I don't know! How strong will the magnetic field be at that point? I don't know!

But I do think it might be interesting to find out!

Vernon, May 29 2015

Electret http://en.wikipedia.org/wiki/Electret
For anyone who doesn't know about them. [Vernon, Jun 04 2015]

Pinch Effect http://en.wikipedia...ch_(plasma_physics)
As mentioned in the main text. [Vernon, Jun 04 2015]


       So can we swing around a dry charged battery, internally set with Araldite, for a nice magnetic field effect? >> more powerful electrets
wjt, May 31 2015

       Waiting for Maxwell or MechE to debunk this. But thanks for the interesting read in WP on electrets.
pashute, Jun 01 2015

       Glad to oblige. This idea completely lacks bunks.
MaxwellBuchanan, Jun 01 2015

       Folks, I've extended the main Idea, and am interested in your feedback. Thanks in advance!
Vernon, Jun 04 2015


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