magrid configuration brainstorming

[icarus]

Reference?

Ha, that's ironic.

I think you guys better move this discussion to "Design" or "General" or something ... it is most definitely not "Theory". As impressive as the verbiage is, let's at least have some attempt at quantification of the myriad of phenomena that are flying back and forward like daydreams here ... you know like equations, numbers, analysis ... i.e. theory.


PS: for the record, the diamagnetic inclusion to theoretically model spherical wiffle-ball was due to me (method of images), Indrek and I implemented it into his numerical calcs and others. The best non-spherical wiffle-ball model so far was by kcdodd ... but he has lost that code.

[Randy]

There are no "VIRTUAL COILS" because those rings are not complete. The "cusps" are merely places where the outgoing magnetic field lines concentrate, because of the geometry of the coils.

Physics-212 stuff, guys. Chapter 28 of my first year physics text (Giancoli, 2008). I'm sure you are only getting confused because it's a 3-dimensional structure.

The virtual poles depicted below are not produced by real ‘complete’ coils. If you can’t figure out why Kiteman called these things ‘Virtual Coils/Poles’ then I can’t help you. I know why Kiteman called these things virtual coils/poles – because they are not formed by real ‘complete’ coils – but they behave a lot like poles formed by real coils do for the most part. What would you call them? … “The other faces where the B-field has to go out through.”

Here are two simple ‘completely symmetrical’ diagrams, depicting the SAME planar magnetic fields:





I can’t think of a better name to call them other than ‘Virtual Coils/Poles’ …May just be one of the few times in science when someone named something the right ‘something’!

My vote is to call them ‘Virtual Coils/Poles’.
~Randy

[Randy]

Note: The preceding argument, relating to both inward and outward directed magnetic fields CANNOT be avoided regardless of the selected coil configuration of ANY magrid design. One must face how to best handle both the inward and outward directed magnetic fields in their chosen design.
~Randy

[Randy]

Using ‘D Tibbets’ earlier design concept:

Imagine drawing a great circle through the north and south poles of a sphere. Rotate the sphere 90 degrees about its polar axis and then draw another great circle through the north and south poles.

Using the arcs drawn one could configure a magrid consisting of only two real coils which featured only four point cusps (two at the center of each real coil and two at the center of each virtual coil) and two funny cusps (one at each pole).
…Something to think about.
~Randy

[icarus]

Problem, the regions you refer to in your above plots as "virtual poles" are actually rings, unless you've carried out some kind of stereographic mapping and not made that obvious. A pole is typically a singular point in 3-D space. Calling these regions 'poles' (virtual or whatever) is going to get as confusing as all hell.

[icarus]

The whole idea of bowing the coils to arc around a sphere is suspect in my consideration, unless I see a good simulation (or an experiment god forbid) of why it would help.

It seems at first glance to be creating the situation of having a field gradient away from the center of the device, exactly the opposite of what you want for stability of the plasma.

[WizWom]

There are no "VIRTUAL COILS" because those rings are not complete. The "cusps" are merely places where the outgoing magnetic field lines concentrate, because of the geometry of the coils.

Physics-212 stuff, guys. Chapter 28 of my first year physics text (Giancoli, 2008). I'm sure you are only getting confused because it's a 3-dimensional structure.

The virtual poles depicted below are not produced by real ‘complete’ coils.

I can’t think of a better name to call them other than ‘Virtual Coils/Poles’ …May just be one of the few times in science when someone named something the right ‘something’!

My vote is to call them ‘Virtual Coils/Poles’.

You are only proving you don't understand the software you are using.

[Randy]

Problem, the regions you refer to in your above plots as "virtual poles" are actually rings, ...

What do you call a 'ring' here? I mean - what is the definition of a (magnetic?) ring?

[KitemanSA]

Reference?

Ha, that's ironic.

In what way? Have I ever declined to provide one when asked? Have you ever asked?

[Randy]

There are no "VIRTUAL COILS" because those rings are not complete. The "cusps" are merely places where the outgoing magnetic field lines concentrate, because of the geometry of the coils.

Physics-212 stuff, guys. Chapter 28 of my first year physics text (Giancoli, 2008). I'm sure you are only getting confused because it's a 3-dimensional structure.

The virtual poles depicted below are not produced by real ‘complete’ coils.

I can’t think of a better name to call them other than ‘Virtual Coils/Poles’ …May just be one of the few times in science when someone named something the right ‘something’!

My vote is to call them ‘Virtual Coils/Poles’.

You are only proving you don't understand the software you are using.

Explain what I don't understand - Please do so - because I do want to understand.
Thanks, Randy

[WizWom]

The virtual poles depicted below are not produced by real ‘complete’ coils.

I can’t think of a better name to call them other than ‘Virtual Coils/Poles’ …May just be one of the few times in science when someone named something the right ‘something’!

My vote is to call them ‘Virtual Coils/Poles’.

You are only proving you don't understand the software you are using.

Explain what I don't understand - Please do so - because I do want to understand.

What you are graphing is exactly the graph of a 4-wire system - such a system has NO poles.

Technically, in an electromagnet, there are never any physical poles - all the field is built up by additions of the circular field generated around a wire.
When you arrange a wire in a loop, though, the addition makes one side of the loop a north pole and the other side of the loop a south pole - the whole area outside is not a pole at all. The "virtual poles" of a solenoid or wire loop are where the exits of the loop or solenoid are; if you wanted a similar field from a physical magnet, you would orient it and place it that way - with it's South pole where the current enters the solenoid, and its North pole where the current leaves the solenoid. But, just as there are no "poles" outside the magnet, there are no poles outside the solenoid.

[Randy]

You are only proving you don't understand the software you are using.

Explain what I don't understand - Please do so - because I do want to understand.

What you are graphing is exactly the graph of a 4-wire system - such a system has NO poles.

Technically, in an electromagnet, there are never any physical poles - all the field is built up by additions of the circular field generated around a wire.
When you arrange a wire in a loop, though, the addition makes one side of the loop a north pole and the other side of the loop a south pole - the whole area outside is not a pole at all. The "virtual poles" of a solenoid or wire loop are where the exits of the loop or solenoid are; if you wanted a similar field from a physical magnet, you would orient it and place it that way - with it's South pole where the current enters the solenoid, and its North pole where the current leaves the solenoid. But, just as there are no "poles" outside the magnet, there are no poles outside the solenoid.

I think I understand what you’re saying.

But in my model I defined the depth to be one inch (not that it matters for the shape of the field produced – it definitely matters for the magnitude of the field produced). ‘Depth’ for the software I’m using means: How deep into the picture the wire goes before it loops around to the other side of the coil. The graphic thus rendered shows only a slice (of the magnetic field produced) through the middle of said loop (coil). Maybe you can understand what I’m saying?

[WizWom]

What you are graphing is exactly the graph of a 4-wire system - such a system has NO poles.

Technically, in an electromagnet, there are never any physical poles - all the field is built up by additions of the circular field generated around a wire.
When you arrange a wire in a loop, though, the addition makes one side of the loop a north pole and the other side of the loop a south pole - the whole area outside is not a pole at all. The "virtual poles" of a solenoid or wire loop are where the exits of the loop or solenoid are; if you wanted a similar field from a physical magnet, you would orient it and place it that way - with it's South pole where the current enters the solenoid, and its North pole where the current leaves the solenoid. But, just as there are no "poles" outside the magnet, there are no poles outside the solenoid.

I think I understand what you’re saying.

But in my model I defined the depth to be one inch (not that it matters for the shape of the field produced – it definitely matters for the magnitude of the field produced). ‘Depth’ for the software I’m using means: How deep into the picture the wire goes before it loops around to the other side of the coil. The graphic thus rendered shows only a slice (of the magnetic field produced) through the middle of said loop (coil). Maybe you can understand what I’m saying?

First: magnetic field of a loop (of which a solenoid is a special case) is just
F1) {number of turns} * current * mu-nought
inside the loop, outside it is reduced by 2 * pi * d^2. If there are multiple loops, you just vector sum the effect of all of them at any point you choose. The formula acquires a binormal vector from the position vector to the loop and the plane of the loop exit (I hope you have had vector calculus and understand that).

Now, any charge moving in this field, at each point, will be subject to a force:
F2) {charge} * ( {magnetic field} x {velocity} )
each are vectors, and the resultant will be binormal to that.

Now, magnetic field works because the electrons are attracted to the surface outside the coil. The electric field will turn them toward the charged surface. The magnetic field will accelerate them perpendicular to it. So, if you had a charged rod with a high current inside it, at a balance of charge and current you could get any charged particle to "orbit" like a planet orbits the sun, by having enough transverse momentum to keep missing the sun as it falls toward it. The magrid supplies the transverse momentum. The direction it will orbit will depend on its charge, because of the charge being positive or negative in the formula F2 above.

What this means is that electrons orbit from North pole to South pole. Now, if you design so that the north poles all point in, they get a sort of sargasso sea, a little extra velocity, a little chaos, and the go into the low magnetic field area in the center - plaus, since all your magrids have the same charge, they cancel out in there, too. So the electrons get lower and lower forces on them as they approach the center.

If you have alternating north and south coils, then that cancellation does not happen, and you have the electrons in the center being accelerated by the magnetic fields in the center, which is not what you want.

Now, as the charge builds up in the center, you get a coulomb repulsion to the charge, and if the electrons are going fairly slow, they won't generate much magnetic field.

Note something else. Positively charges ions will be turned the opposite way, and orbit south to north. These particles will be forced by the positively charged grid toward the center of the charged coils. They will then rapidly exit along the most extenuated magnetic line, from the center of the coils, if they are all North facing in. In such a system, the "cusps" spew electrons, the ions go out the face centers. Ions will have a lifetime in the core, being repulsed by the grid and pulled to the electron cloud in the center. As they enter the electron cloud, it will lose its force, but since they have gained energy while getting there, they will enter a situation of racing through the center, with their speed being highest when exactly in the center (and feeling the least force). Near the edge, their speed hits zero and reverses. As the electron cloud increases in charge the ions will be at higher velocity in the center.

[D Tibbets]

A couple of points. You mention magnetic fields created by moving charged particles, certainly as they slow the induced magnetic field lessens, but I believe the dominate effect of the small or absent magnetic field is due to the opposing forces canceling out. The charged particles move in and out, canceling out each others effect. Added to that is some bias in the numbers and or directions which also serves to exclude the magnetic fields created by the magrids. Keep in mind that there is ~ 40 amps of electron current out of the magrid in WB6 during while at the Beta=1, and neutron producing stage (net ion current is zero, or close to it).

The pole orientation is significant if you are talking about a single pass, but with thousands, if not millions of passes/ bounces, divergent and chaotic magnetic field entry vectors, I think the N-S orientation is meaningless (so long as they are the same for all of the magnets).

Concerning field polarity in the real vs virtual coils in the corners of WB6, etc. truncated cubes. When I trace the current path with arrows, if the current is clockwise in the real coils, it is counter clockwise in the virtual corner coil. I have never resolved how this seems to work, considering that the real coils must be consistently oriented. It does apparently allow these areas to act like a poor point cusp (Bussard, etel mentioned that they were ~ 5-7 times a leaky as true point cusps (but this is much better than line/equatorial type cusps)). This real / virtual magrid field orientation effects on Wiffleball mechanics is what I cannot figure out. If I just consider the virtual magnet description as a convenient dodge to serve as the reasoning for the cusp morphology, but ignore them otherwise, the confusion is resolved- they are not real after all.

Dan Tibbets

[KitemanSA]

Now, magnetic field works because the electrons are attracted to the surface outside the coil.

Is this intended to be a general statement about magnetic field or a specific statement about how the MaGrid behaves?

The electric field will turn them toward the charged surface. The magnetic field will accelerate them perpendicular to it. So, if you had a charged rod with a high current inside it, at a balance of charge and current you could get any charged particle to "orbit" like a planet orbits the sun, by having enough transverse momentum to keep missing the sun as it falls toward it.

If you are talking about a solid rod, charged, with a current running axially along the length of the rod, this would seem incorrect. In such a case, the B field would run around the rod and the electron (if it could be balanced) would move in, along the length, and away again. It would cork-screw (gyrate) around the field lines as it moved around the rod if it had any transverse momentum. And the direction it would move around the rod would depend on its initial momentun, not the "direction" (N to S) of the lines.
If the rod were actually a long solenoid, and the B field ran along the length of the rod, it should be possible to have the electron orbit the rod. In which case, any motion along the length of the rod would be simply a matter of initial momenton, not the direction toward "north".

The magrid supplies the transverse momentum. The direction it will orbit will depend on its charge, because of the charge being positive or negative in the formula F2 above.

From the description so far, I am still not sure what is orbiting what. It seems you are saying that the electrons are somehow orbiting the case of the toruses. If so, you need to rethink your field.

What this means is that electrons orbit from North pole to South pole.

Not so. The electrons gyrate around the field lines and drift north or south depending on the residual velocity they had along the line when they got trapped.

Now, if you design so that the north poles all point in,

As Randy's analysis shows, if you have some north in, you must also have some south in. It matters not whether they are both real magnets or some are real and some virtual.

they get a sort of sargasso sea, a little extra velocity, a little chaos, and the go into the low magnetic field area in the center - plaus, since all your magrids have the same charge, they cancel out in there, too. So the electrons get lower and lower forces on them as they approach the center.

"They"... the electrons?

If you have alternating north and south coils, then that cancellation does not happen,

As Randy's analysis showed, the field still cancels in the middle, even when he uses alternating polarities.

and you have the electrons in the center being accelerated by the magnetic fields in the center, which is not what you want.

Doesn't happen.

Now, as the charge builds up in the center, you get a coulomb repulsion to the charge, and if the electrons are going fairly slow, they won't generate much magnetic field.

Note something else. Positively charges ions will be turned the opposite way, and orbit south to north.

Again, the charges don't orbit north OR south. The gyrate around the field lines and drift north or south depending on their initial velocity.

These particles will be forced by the positively charged grid toward the center of the charged coils.

?? What happened to Gauss?

They will then rapidly exit along the most extenuated magnetic line, from the center of the coils, if they are all North facing in. In such a system, the "cusps" spew electrons, the ions go out the face centers.

Nonsense. This just ain't so. To the degree the ion energy has upscattered and overcomes the potential well created by the electrons, they will exit whatever cusp they are pointed at, north or south. Same with the electrons. If they hit a cusp directly enough, they exit, north cusp or south cusp.