What if there were no electrons?

[scareduck]

What if there were no electrons?

Then electrostatic repulsion would cause the atoms comprising your body to fly apart!

[apouliot]

Which begs the question- why is the magrid charged to a high positive potential? I'm guessing that if the ions are immune to effects of the pos charged grid, then it would not contribute directly to acceleration of the ions. But, would the pos charge on the grid add to the neg charge on the confined electrons to give a greater cumulative driving potential ( eg: +10,000 grid volts plus ( or would it be minus?) -10,000 volts of the contained electrons giving a difference of 20,000 driving volts)? If so, why not just drive the electrons at a higher potential. Is there engineering concers that faver this splitting the volts this way. Does it make it easier (less magnetic field strength) or more efficient to contain the electrons?
If the positive charged magrid acts as a charged hollow sphere, then it would not effect the internal electrons or ions. So, would it have no purpose in being charged, just grounded? In this case, is the pos charge soley used to aid in recirculation ( pulling back on the electrons that have escaped through the cusps so that they bounce back befor reaching the vacuum chamber walls( or orbit, if this unpopular option is real)?

Dan Tibbets

What i'm going to write is a guess. I think the magrid would be positively charge for 2 reason. Either to be at an equipotential between the electron and the outer shell or provide an additional boost for the electric field near the center. Personally I go more for the equipotential explanation that would prevent arcing between the magrid and the outer shell/electron in the middle. The other reason : being positively charged would help push the ion away from the magrid, since both would be a positive charge.

I guess that with the positive charge on the magrid and the magnetic field around the magrid both effect would help diminish the number of collision between the magrid and the ion(for fusion/result of fusion). The magnetic field providing track around the magrid and directing the ion. The electric field pushing the ion away.

[MSimon]

The other reason : being positively charged would help push the ion away from the magrid, since both would be a positive charge.

Yes.

[blaisepascal]

OK, it's been bugging me for a while that I can't answer this basic question...

What is the Magrid? Is it the 6 physical coils? Is it the surface of the whiffleball (i.e., the quasispherical edge of electron confinement)? Is it a physical anode surrounding the core?

I had believed that the Magrid was the second: a quasispherical virtual structure of magnetic fields which contained the electrons in the virtual cathode, analogous to the anode grid in a ETW fusor (in that it's the part that clumps the electrons into a virtual cathode).

However, in that interpretation, the Magrid doesn't hold a charge and interacts with the ions very weakly. This seems contrary to some of what I've seen elsewhere on this site.

What is the proper interpretation of the Magrid?

[bcglorf]

OK, it's been bugging me for a while that I can't answer this basic question...

What is the Magrid? Is it the 6 physical coils? Is it the surface of the whiffleball (i.e., the quasispherical edge of electron confinement)? Is it a physical anode surrounding the core?

I had believed that the Magrid was the second: a quasispherical virtual structure of magnetic fields which contained the electrons in the virtual cathode, analogous to the anode grid in a ETW fusor (in that it's the part that clumps the electrons into a virtual cathode).

However, in that interpretation, the Magrid doesn't hold a charge and interacts with the ions very weakly. This seems contrary to some of what I've seen elsewhere on this site.

What is the proper interpretation of the Magrid?

Finally a question I know enough to answer .

Your first guess is correct and the MaGrid is just short hand for the physical coils that make up the Magnetic-Grid(which is held at some positive charge). I'm not sure on it myself but my current understanding is that the positive charge on the MaGgrid is to attract some of the electrons that escape through the cusps back in and thus slow loses.

[chrismb]

The notion of charges attracting each other is just that - a notion.

What we are actually doing is conceptualising a change of configuration in a potential field and a change of state of that system.

In the case of electric charge, we need to find an electric field before charged particles move, and an electric field only exists between two points at a differential potential.

There is no such thing as something which is "postively charged [full-stop]", it has to be positively charged with respect to something. The influx of electrons is intended to keep the centre at a negative potential WITH RESPECT TO the magrid. That is all.

This does not necessarily imply that the magrid is at, above, below, or floating with respect to 'earth' potential. It just doesn't matter, in terms of what ions end up doing in the interviening space. All that matters is the potential difference hence why voltage is often referred to as such.

(No doubt the electrons being injected will hold some potential with respect to ground, so the magrid would have to be at the drive voltage above that potential, but this is immaterial to the actual field generated.)

This should explain why the idea of running the device without electrons is missing a fundamental issue - no e-field would be generated so no ions would move.

[apouliot]

The notion of charges attracting each other is just that - a notion.

Actually the notion of charges attracting or repulsing each other is electromagnetism, it based on the observed comportment of the atom. Philosophically we could say it's a notion that we created to represent a comportment of electricity and the component of the atom. But essentially it's a fact not a creation of the mind

What we are actually doing is conceptualising a change of configuration in a potential field and a change of state of that system.

In the case of electric charge, we need to find an electric field before charged particles move, and an electric field only exists between two points at a differential potential.

There is no such thing as something which is "postively charged [full-stop]", it has to be positively charged with respect to something. The influx of electrons is intended to keep the centre at a negative potential WITH RESPECT TO the magrid. That is all.

I'm not sure what you mean in that first paragraph.

A single electric charge can't move. But once you have more than one you get an electrical field unless both atom are "neutral" same amount of proton and electron.

Something can be positively charged or negatively charged you don't need a reference for comparison except it's "own" neutral state of equilibrium.

True the influx of electron is to create a negative potential with respect to the outer shell and I don't mean the vacuum chamber but the wall of the device. The magrid is probably charged to be at the same equipotential in respect between the shell and the electron trap. Also it probably help to repulse incoming ion.

This does not necessarily imply that the magrid is at, above, below, or floating with respect to 'earth' potential. It just doesn't matter, in terms of what ions end up doing in the interviening space. All that matters is the potential difference hence why voltage is often referred to as such.

(No doubt the electrons being injected will hold some potential with respect to ground, so the magrid would have to be at the drive voltage above that potential, but this is immaterial to the actual field generated.)

This should explain why the idea of running the device without electrons is missing a fundamental issue - no e-field would be generated so no ions would move.

Must agree with you here we need to have electron in the center or else no driving e-field. Just floating ion interacting with each other and the wall trying to neutralize all the different potential.

[chrismb]

The notion of charges attracting each other is just that - a notion.

Actually the notion of charges attracting or repulsing each other is electromagnetism, it based on the observed comportment of the atom. Philosophically we could say it's a notion that we created to represent a comportment of electricity and the component of the atom.

OK so far...

But essentially it's a fact not a creation of the mind

Ah! Here we find a slight problem. It is a fact that the behaviour of particles we see conforms to our theory of electromagnetism. That theory involves notions of fields and forces. The only thing we actually observe is the way things are 'configured'. i.e. where they are and their momentum, and then what happens to them next.

From this we induce the notion of 'a force' to describe why something moves.

Now let's specify an axiom and define energy; energy input or extraction into a defined closed system is what changes the configuration of that system into another state. This is a thermodynamic definition which I think should not be of any surprise or point of contention.

Now force is the derivative of energy change with respect to displacement. So what I've just done is define a force as the derivative of rate of configuration change of a closed system's material objects' positions and momenta.

That should cover your question about that part of my post, about what I mean by this.

So the next thing to then say is that we observe a charged particle accelerating only when it sits within a gradient of electrical potential between two charged bodies because if we consider a set of charged objects whose net potential does not change (i.e. neutralise in some way) then this 'configuration' has not changed and thus there is no force possible.

For example, imagine two plates charged up with respect to ground potential above a ground plane. They will repel each other. But that is not a closed system and they have organised themselves in a way which has dissipated energy in the whole system. But if you then were to put those two plates into a metal box, connect them to the metal box, then charge up the whole thing, the plates would NOT repel each other, even though we can now see that both plates HAVE been charged up to a potential above ground. The reason being that if they did move, it would require energy to do so because they will have changed their position (configuration). But if they did move, the charge of the box and the plates would still be the same so there would have been no change of energy, yet it would have required some which isn't there to be had. No energy change (for some given displacement)=no movement (configuration change).

I have avoided using the word 'force' and 'field' entirely and stuck with a basic axiom that energy must change for configuration (position and momentum) to change within a closed system, which is a fundamental thermodynamic argument. Hence, 'force' and 'field' are, as it were, second order interpretations of the dynamics of objects that make life much easier so we don't have to worry about all this double-talk, but they are interpretations and notions, and certainly not 'facts' in the strict sense. We merely choose to state that they are facts, for convenience.

This discussion on 'no electrons' would not have even been possible if you only had 'energy' and 'configuration' as tools of discussion, so clearly talking about 'forces' and 'fields' can intuitively give you the wrong impression of things on occasions.

Yes, yes, I realise you can argue the thing with forces and fields. Of course you can. If you couldn't then something would be amiss and there isn't - forces and fields are just fine concepts. But I can't see a force or a fields, can you? We can only observe them second order, what they do. Whereas I CAN see things in a position, then in another position in the next moment. Notwithstanding the nature of my consciousness of the world around me, seeing something move is as close as I can come to knowing something as a fact - the point is, I don't NEED to look any further than seeing objects with position and momentum because, along with the one simple axiom above, it describes ALL dynamics! So interpreting these things as forces and fields is therefore just a notion of practical convenience because you can get into some ugly arithmetic if you stick with the thermodynamic argument I've presented here.

I've tried to make this terse (as best as I can) else it would be pages long if I made it an easier read. I hope you can follow the argument.

best regards,

Chris MB.

[apouliot]

You can see a field. Maybe not a low frequency field but if you can see light then you see a electromagnetic field since the electromagnetic field carrier is a photon. Light is only a high frequency photon that posses a electric and magnetic field.

For your example it's true if you have 2 charged plane inside of a sphere you will see no reaction if they all have the same charge. Because the photon movement of each element cancel each other. But if you observe the system over a long period if we suppose a perfectly closed system the energy in the system will diminish because of entropy.

Regards,

[MSimon]

Iron filings and a magnet.

Now what is a field? Strictly it is a mathematical construct that describes observations.

"As far as the laws of mathematics refer to reality, they are not certain, as far as they are certain, they do not refer to reality." Einstein

Fortunately it works well enough to make things.

[bcglorf]

But if you observe the system over a long period if we suppose a perfectly closed system the energy in the system will diminish because of entropy.


Um, not unless mass is changing. If the system is perfectly closed then energy can not diminish, it can only be converted to mass.

[apouliot]

Sorry you are right. Energy will be the same. Entropy will increase with time but energy/mass should remain equal all thing considered.

I mixed the thermodynamic concept a little bit, been a long time since I had to used them.

MSimon you are right a field is a mathematical construct that explain some observations. Those construction are grounded in reality and on our own observations. We could go in philosophical argument that because something is an observations is not real. But eventually we will continue the very old debate about the world existence or is nothing but a dream. Debate still going on from the antic Greece.

In summary:
A field is still more practical for understanding and explaining how a shell with a charge comport itself. Than talking about photon creating a dragging effect on ion. Since you have photon arriving from everywhere in a sphere they cancel each other effect on the ion.

[93143]

chrismb, I think you may have confused charge and potential.

Saying something is positively charged is not the same thing as saying it has a positive potential. Potential is relative, yes. But charge is absolute.

Take your example of two plates at a positive potential. If they're just in free air with their surroundings at ground, then they will accumulate positive charge, and will repel each other. But if they're in a conducting box at the same potential, they won't repel one another. Why not?

Forget the energy method; the answer is simple. The plates aren't charged. The positive charges (holes in this case, I suppose) want to get as far away from one another as possible, and that means the outer surface of the box. Despite the high positive potential on the plates, the number of protons in each plate matches the number of electrons; ie: the plates are neutral. This is because there is no potential difference between them and their surroundings (here's where your energy argument comes in).

Take the case of the direct-conversion Polywell. Outer shell at high positive potential for alpha capture. Problem: Gauss' Law -> this doesn't affect the alphas. Solution: ground the magrid. Result: magrid acquires a negative charge, which is what actually hauls back on the alphas and decelerates them.

Now, in a real system you'd want a trap grid outside the magrid and at a small (slightly larger than drive) negative potential with respect to it, in order to allow for primary system operation (the magrid has to be positively charged). The alpha capture system would also probably be more complicated than a simple spherical shell. But the basic principle is the same.

Regarding running a Polywell without electrons, a while back I thought of using a negatively-charged magrid with VERY heavy magnetic shielding, to do with ions what Bussard's configuration does with electrons. No electrons anywhere in the system, hence no bremsstrahlung. There are two really obvious problems with this - 1) anemic plasma density due to no charge buffering, and 2) alpha spallation and thermionic emission would flood the system with electrons rapidly. So that's a non-starter.

[chrismb]

Forget the energy method; the answer is simple. The plates aren't charged. The positive charges (holes in this case, I suppose) want to get as far away from one another as possible, and that means the outer surface of the box. Despite the high positive potential on the plates, the number of protons in each plate matches the number of electrons; ie: the plates are neutral. This is because there is no potential difference between them and their surroundings (here's where your energy argument comes in).

Well......... OK but so what? It's just fiddling with the mind-experiement.

OK, I'll fix that by placing the whole metal box and internal plates in a dielectric box with the inner and outer faces holding a potential gradient and where the inner face has the same potential as the positive charge on the box. That way there will be no preference for the 'holes of electrons' to go anywhere throughout the metal structure.

Bigdealsowhat?

chrismb, I think you may have confused charge and potential.
Saying something is positively charged is not the same thing as saying it has a positive potential. Potential is relative, yes. But charge is absolute.

charge and potential are proportional: charge = capacitance * potential. Providing the capacitance doesn't change so the potential won't change.

Not sure what you are referring to that needs correcting? happy to retract any errors or correct omissions if you make it specific....

But that is a relevant point if you start talking about point charges in a metal box, because if you charged up some 'theoretical' box that only contains two deuterons, would they fuse without any Coulomb repulsion? I think the answer is 'no', though it is a very contrived example for me to be prepared to be 'sure' about it! You can simply say that the mutual capacitance of the two charges is altered on a small scale (two small spheres will have a different combined capacitance to a dumb-bell pair of spheres) so their potential changes as a mutual pair. So energy would be required to get two protons together because the energy of the system goes up as (1/2)(CV^2), whereas V is actually only going up proportional to C, not to V^2, hence more energy would be required.

You can see how it begins to get awkward talking about configuration and energy, but we still don't have to resort to declaring a belief in the existence of fields and forces.

In fact - how would fields and forces handle this problem? As far as fields are concerned, the capacitance of each proton would stay the same because each is the 'agent' of its own repulsive field and thus wouldn't change. I think you would have to rely on the energy/configuration method to properly handle this problem.

All that being said, I would never suggest anyone backs away from using fields and forces, it is what should be used even though it is just a representation of reality. The quote from Einstein is spot on, in this regard.

[chrismb]

Back of the envelope calculation - reams and reams of caveats may apply:

(This is worth exactly what you've paid for it!!! - I like that saying!)

Capacitance of a remote sphere of radius a = 4.pi.e.a (e=permittivity)

for a proton, charge radius a=0.875fm, capacitance of equivalent sphere = 4.pi.(8.85E-12).(0.875E-15) = 9.73E-26 F

'free-space potential' of a proton = 1.6E-19 / 9.73E-26 = 1.6 MV

capacitance for a sphere radius 0.1m = 11pF

charge on a spherical surface to displace potential by 1.6MV = 1.6E6 * 11E-12 = 1.8E-5C

So, enclose a thin walled neutral (net zero charge) perfectly evacuated metallic sphere of radius 0.1 in a dielectric box whose inner face is charged to 1.6MV **(with respect to??). Remove 3.6E-5 Coulombs of charge from the thin walled sphere (to cover the charge required on each face to take it to 1.6MV - **make sure the dielectric box is charged in a way that keeps both faces of the sphere at the same potential) and insert just two protons into this sphere.

All parts will be 'at 1.6MV' (whatever than means!!). By 'the theory of' fields and forces, there would be zero repulsion between the protons.

However, by the energy and configuration discussion above, and knowing that the capacitance of two touching spheres of radius a is 8.pi.e.a.(ln(2)):

for two protons to come up and touch, their potential would become Q/C where C is now 1.35E-25F = 2.4E6 volts. Their capacitive energy would therefore become 0.5(C.V^2) = 3.8E-13J, whereas the energy of two protons alone would be 2.4E-13J.

The energy required for two protons to come to touch by this calculation with my 'theory' of energy and configuration is therefore 1.4E-13J or 870keV. (note: Gamow energy for p+p is 492keV), whereas the repulsive forces with the 'theory' of fields and forces would be zero!

This is a very rough and ready calculation, but comes up with a modest answer of useable accuracy using my proposal of energy and configuration. There is no electrostatic nor strong-nuclear force in sight!

best regards,

Chris MB.