How fast does an electon move?

[John Heath]

One ampere is approximately equivalent to 6.2415093×10^18 elementary charges moving past a boundary in one second according to Wikipedia.

I have a current meter that will measure the strength of a magnetic field only and from that information can predict current in amps as magnetic field equals current of electrons moving past a boundary as stated in wiki quote. I will put 1 m amp , 6.2415 x 10^15 electrons , through a copper wire . Electrons are moving on average 1 inch per second , ball park number. The magnetic field is X therefore current must be 1 m amp. I will now adjust the CRT current of a small black and white TV to 1 m amp , 6.2415 x 10^15 electrons. I will place the same current meter around the CRT neck and it will measure the magnetic field as X therefore the current is 1 m amp. The velocity of the CRT electrons at the neck is 10 to 20 percent c not 1 inch per second. You see the problem. The magnetic field is independent of the electron velocity for the same number of electrons 6.2415 x 10^15. However if the electrons always move at c in either random direction or somewhat averaged in one direction then the problem goes away.  Does this mean that the electron is always moving at c regardless. If there something wrong with the logic I am using. I would like to know what others think. How fast does an electron move?

[Nerull]

As a particle with mass, it is not possible for an electron to move at c.

[David Hess]

You are looking for drift velocity.  In common situations with copper wire it is incredibly slow.

[John Heath]

Thank you for taking the time for a long answer evb149 and Nerull I hear you , can not go c if you have mass.

I am going to have some more fun with this. I am now in space with 2 magnetic probes and 1 electron. The electron wizes past the first magnetic probe and measures a magnetic field around the electron. The second magnetic probe is moving with the electron and measures no magnetic field around the electron. Two identical magnetic probes yet one says magnetic field around the electron and the other says no magnetic field around the same electron. The only difference between the probes is one is moving with the electron and the other not.  How can magnetism be real if the magnetic field magically disappears when you catch up to the electron ? The electric negative field , Coulomb force , of the electron is real as my movement relative to that field can not make it disappear. This is not true of a magnetic field as I can make it disappear by catching up the the electron. A magnetic or electric field in a vacuum is either real or not real in that vacuum. . In the case of a magnetic field does not seem to be real if it is only there when I move relative to a charge. I am open to counter arguments on this as I am not entirely sure I have it right.

[Paul Moir]

Analogy:  I'm holding a flaming torch, therefore I'm warm.  I walk past someone stationary, who warms up from the torch then cools off as I leave.  Yet I'm warm all the time.  Is heat real?   For whom is work being done?

Put it another way; when I went and picked up the flaming torch, I warmed up.  Eventually when I set it down, I'll cool off.

[David Hess]

I like this analogy: if I have a tube full of marbles and I add a marble to one end forcing another marble out the other end, how fast are the marbles moving?

The most sensitive circuits I have regularly worked with had a bias current of 2 femptoamps which is about 6000 electrons per second.

[Marco]

I'm curious, how fast does an electron move in ye average through air static spark?

[DTJ]

I'm curious, how fast does an electron move in ye average through air static spark?

...and how far?

[IanB]

I have a current meter that will measure the strength of a magnetic field only and from that information can predict current in amps as magnetic field equals current of electrons moving past a boundary as stated in wiki quote. I will put 1 m amp , 6.2415 x 10^15 electrons , through a copper wire . Electrons are moving on average 1 inch per second , ball park number. The magnetic field is X therefore current must be 1 m amp. I will now adjust the CRT current of a small black and white TV to 1 m amp , 6.2415 x 10^15 electrons. I will place the same current meter around the CRT neck and it will measure the magnetic field as X therefore the current is 1 m amp. The velocity of the CRT electrons at the neck is 10 to 20 percent c not 1 inch per second. You see the problem.

So far, I don't see a problem. What problem do you see?

Try a simple thought experiment.

Let's measure the rate of traffic flow on a road by counting the number of cars that pass a boundary every second. Let's call this the traffic current.

Road A is a suburban road, and on this road we count one car per second passing the boundary. So the traffic current is one car per second, or 60 cars per minute. On this road the cars are moving at an average speed of 20 mph.

Road B is a major highway, and on this road we also count one car second passing the boundary. So the the traffic current here is also 60 cars per minute. However, on this road the cars are moving at an average speed of 70 mph.

Does our intuition here also have a problem? I suggest not. We are very familiar with roads, and therefore everything seems fine.

The explanation, if we look for it, is that on road A the individual cars are bunched up close together with small gaps between them. We could say the traffic density is higher. Whereas on road B the cars are much more spaced out with larger gaps between them. Here the traffic density is lower.

[salbayeng]

My recollection is that a human can outrun the drift velocity of electrons in copper even at current densities sufficient to melt the wire.

The other puzzle is interesting, it might be tied into the "Faraday Paradox" , the fault with this paradox relies on the way humans draw a magnetic field on paper with lines, and then infer that moving these flux lines will push on a wire. In actual fact a magnetic field can't move, its like gravity, the gravity field doesn't rotate with the Earth. You can make all sorts of homopolar motors that display the paradox, they are great for confounding high school physics teachers.

[John Heath]

Analogy:  I'm holding a flaming torch, therefore I'm warm.  I walk past someone stationary, who warms up from the torch then cools off as I leave.  Yet I'm warm all the time.  Is heat real?   For whom is work being done?

Put it another way; when I went and picked up the flaming torch, I warmed up.  Eventually when I set it down, I'll cool off.

Yes but in the case of the magnetic field , heat , the flaming torch , electron , is cold when I try to warm my hands. Only when I run past the torch can I feel the heat. Or I can stand still and have the torch move this way or that to feel the heat. It is as if movement relative to the torch causes heat not the torch itself. An electron can be right next to a strong magnet and not be effected. If it move it will but not if it stands still. However the charge of the electron is always there moving or not. My 2 cents this means the charge , Coulomb force , is real but magnetic field is not real in the sense that you can not feel the heat of the flame if not moving. 

[John Heath]

I like this analogy: if I have a tube full of marbles and I add a marble to one end forcing another marble out the other end, how fast are the marbles moving?

The most sensitive circuits I have regularly worked with had a bias current of 2 femptoamps which is about 6000 electrons per second.

If your circuit at 2 f amps per second was sensitive to .002 f amps then 6000 electrons would be 6 electrons per second. Would you start to hear a ticking sound of individual electrons at 6 per second. If so then your 2 f amp circuit should be make noise in the 6 KHz audio range as electrons pass by. It would be interesting to see if this is true. 

[John Heath]

I'm curious, how fast does an electron move in ye average through air static spark?

...and how far?

This is a great question. Electrons thrown off by the sun can take days to arrive at earth. However this is not a static spar. More like throwing as base ball. How fast are electrons moving in a lightning strike? I can say the the impedance to the electron in a static spark is low. I connected a neon bulb to a 5 amp fuse then plugged it into a wall socket. The 5 amp fuse blew so fast that it was black on the inside of the glass. This would mean that a lightning strike sees the air as a short circuit when in the heated plasma tube of the lightning strike.

[John Heath]

I have a current meter that will measure the strength of a magnetic field only and from that information can predict current in amps as magnetic field equals current of electrons moving past a boundary as stated in wiki quote. I will put 1 m amp , 6.2415 x 10^15 electrons , through a copper wire . Electrons are moving on average 1 inch per second , ball park number. The magnetic field is X therefore current must be 1 m amp. I will now adjust the CRT current of a small black and white TV to 1 m amp , 6.2415 x 10^15 electrons. I will place the same current meter around the CRT neck and it will measure the magnetic field as X therefore the current is 1 m amp. The velocity of the CRT electrons at the neck is 10 to 20 percent c not 1 inch per second. You see the problem.

So far, I don't see a problem. What problem do you see?

Try a simple thought experiment.

Let's measure the rate of traffic flow on a road by counting the number of cars that pass a boundary every second. Let's call this the traffic current.

Road A is a suburban road, and on this road we count one car per second passing the boundary. So the traffic current is one car per second, or 60 cars per minute. On this road the cars are moving at an average speed of 20 mph.

Road B is a major highway, and on this road we also count one car second passing the boundary. So the the traffic current here is also 60 cars per minute. However, on this road the cars are moving at an average speed of 70 mph.

Does our intuition here also have a problem? I suggest not. We are very familiar with roads, and therefore everything seems fine.

The explanation, if we look for it, is that on road A the individual cars are bunched up close together with small gaps between them. We could say the traffic density is higher. Whereas on road B the cars are much more spaced out with larger gaps between them. Here the traffic density is lower.

Cars moving at 20 MPH generate a puff of wind when passing by. Cars at 100 MPH generate a greater puff of wind when passing by. I will call this puff of wind the magnetic field generated by an electron passing by. My magnetic clamp probe can only measure the puff of wind , magnetic field. 100 electrons moving at 20 MPH or 100 MPH are generating the same puffs of wind regardless of their speed and therein is the problem from my shoes. I say this as my magnetic probe will always tell me what the current is regardless of electron velocity.

[TimFox]

In solids, there is an important parameter "mobility" that applies to charge carriers. 
See:  https://en.wikipedia.org/wiki/Electron_mobility
In general, there is a different mobility for positive holes and negative electrons in the device.  The drift velocity is proportional to the electric field, with the proportionality constant called the "mobility" for that carrier.  Note that holes moving to the left and electrons moving to the right in response to a field pointing to the left both give a net current to the left.  The drift velocity is limited by scattering off the atoms in the lattice.  Otherwise, applying a field to a charge carrier gives a net acceleration, rather than a limited velocity. 

[John Heath]

That's called shot noise in electronics.  Once the statistical variability of current flow due to the discreteness of the number of electrons flowing becomes significant it does act as a noise source producing "bursts" of noise as bigger or smaller bunches of charge carriers flow.
https://en.wikipedia.org/wiki/Shot_noise#Electronic_devices
 
If your 'bunch size' is 6000 mean value with a standard deviation of say 600 on some particular time scale then you'd see the mean value plus or minus some statistically variable number.

If you could count every particle then you'd indeed see a pulse with each electron's arrival.  And it is possible to count discretely photon or electron flow.  The detectors like they use in particle physics, for instance, can register individual particle flux similar to the ticking you hear in a geiger counter or something like that.  Once the rate becomes sufficiently large or the time scale does it becomes basically random noise that approaches closer and closer to a mean value with less observed deviation.

I like this analogy: if I have a tube full of marbles and I add a marble to one end forcing another marble out the other end, how fast are the marbles moving?

The most sensitive circuits I have regularly worked with had a bias current of 2 femptoamps which is about 6000 electrons per second.

If your circuit at 2 f amps per second was sensitive to .002 f amps then 6000 electrons would be 6 electrons per second. Would you start to hear a ticking sound of individual electrons at 6 per second. If so then your 2 f amp circuit should be make noise in the 6 KHz audio range as electrons pass by. It would be interesting to see if this is true.

This brings to mind Mr Red LED. It is somewhat like a diode with a forward voltage drop of a little over a volt. If one electron jumps the voltage barrier of this LED the energy of this event would be the current in amps of 1 electron time the voltage drop of 1 volt. This energy is radiated away as a photon. This means the energy of that photon for this event of 1 electron hop is the energy of voltage 1 times current or 1 electron.   I have that at 6.2415 x 10^-18 amps times 1 volt for an event energy of 6.2415 x 10^-18 Joules. Here is where it gets interesting. Mr Planck says if I divide that number by his constant h it will tell me the frequency of that photon for that amount of energy.  E=fh so f=E/h therefore 6.24 x 10^-18 Joules divided by h 6.62 × 10-34 = 942 X 10^18 CPS .I think I forgot to carry the 2 somewhere ?? In any event if I did it properly the frequency in cycles per second would equal red light.  How cool is that. 

[David Hess]

I like this analogy: if I have a tube full of marbles and I add a marble to one end forcing another marble out the other end, how fast are the marbles moving?

The most sensitive circuits I have regularly worked with had a bias current of 2 femptoamps which is about 6000 electrons per second.

If your circuit at 2 f amps per second was sensitive to .002 f amps then 6000 electrons would be 6 electrons per second. Would you start to hear a ticking sound of individual electrons at 6 per second. If so then your 2 f amp circuit should be make noise in the 6 KHz audio range as electrons pass by. It would be interesting to see if this is true.

In most cases circuits like this rely on integration so all high frequency content is removed and current and voltage noise are not important except at very low frequencies.  The current noise over a 1 Hz bandwidth was specified to be 1/10th of the input bias current so still 2 orders of magnitude too great to see 6 electrons per second anyway.

Leakage is obviously an important consideration and if an air dielectric capacitor is used, cosmic ray impacts will affect the output because of its great capture volume so a Teflon dielectric capacitor is more suitable despite higher leakage.

This is not exactly what I was doing but this article discusses these issues.

And that article points to an article from Keithley which shows how to get down to attoamps but again through integration at low frequencies.

[T3sl4co1l]

There's on the order of 10^24 cm^-3 electrons in a metal, and only (current) many in the vacuum.  So those in the vacuum must be going faster -- indeed, that many times faster!

In semiconductors, where the carrier density is smaller than a metal (on the order of 10^18 cm^-3), the velocity must be higher, and other effects are more prominent, like the Hall effect (magnetic field deflecting the path of current flow within a solid).  (This is how integrated Hall effect sensors are so common today.)

When the greater velocity (in a semiconductor) interacts with the material properties, interesting things happen, like impact ionization (the cause of avalanche breakdown in silicon), or saturation (the cause of negative resistance in bulk doped GaAs -- Gunn "diodes").

Tim

[John Heath]

By further analogy one can say that motion or kinetic energy are also "real" or "not real" since they're entirely relative to the reference frame of the observer.  We sit on a planet that is rotating at 1000 MPH while travelling around the sun at 66,000 MPH while travelling around the galaxy core at X rate while moving relative to some other galaxy at Y rate and yet we feel like we're "not moving".

The values of each of the electric and magnetic field components are transformed and interchanged by the mathematics of relativistic transformations as one's frame of reference varies.  So one combination of electrostatic or magnetic fields in one reference frame will look like another in another.   

https://en.wikipedia.org/wiki/Relativistic_electromagnetism
http://galileo.phys.virginia.edu/classes/252/rel_el_mag.html
http://physics.stackexchange.com/questions/38151/does-special-relativity-make-magnetic-fields-irrelevant
 

Thank you for taking the time for a long answer evb149 and Nerull I hear you , can not go c if you have mass.

I am going to have some more fun with this. I am now in space with 2 magnetic probes and 1 electron. The electron wizes past the first magnetic probe and measures a magnetic field around the electron. The second magnetic probe is moving with the electron and measures no magnetic field around the electron. Two identical magnetic probes yet one says magnetic field around the electron and the other says no magnetic field around the same electron. The only difference between the probes is one is moving with the electron and the other not.  How can magnetism be real if the magnetic field magically disappears when you catch up to the electron ? The electric negative field , Coulomb force , of the electron is real as my movement relative to that field can not make it disappear. This is not true of a magnetic field as I can make it disappear by catching up the the electron. A magnetic or electric field in a vacuum is either real or not real in that vacuum. . In the case of a magnetic field does not seem to be real if it is only there when I move relative to a charge. I am open to counter arguments on this as I am not entirely sure I have it right.

Great links for the subject at hand. With so many roads to go down I feel liberated to pick one I like. "does-special-relativity-make-magnetic-fields-irrelevant". This one requires length contraction , a Minkcowski idea. A little history. Minkowski was Einstein's old math teacher that thought little Albert will never amount to anything with his odd ideas and drifting mind. Years later when a giant in physics , Planck , is taking an interest in little Albert Mr Minkowski comes out of the wood word as Einstein's best friend with a hand stretched to shake the hand of the great Dr Planck. Sound like a fair weather friend to me and lets face it Minkowski , a fine mind to give this balance , was not an Einstein. Unfortunately the length contraction Minkowski interpretation of special relativity had the star trek appeal of 4 dimensions and became the way it is taught in schools today. The original paper on the electrodynamics of moving bodies uses an increase in the Coulomb force at right angles only without the need of a fourth dimension. I will now get off my soap box. In either case the magnetic field can be written off as a Coulomb force only therefore a magnetic field is no longer a fundamental force in nature. Good reddens as it is one less to worry about.

[orolo]

I am going to have some more fun with this. I am now in space with 2 magnetic probes and 1 electron. The electron wizes past the first magnetic probe and measures a magnetic field around the electron. The second magnetic probe is moving with the electron and measures no magnetic field around the electron. Two identical magnetic probes yet one says magnetic field around the electron and the other says no magnetic field around the same electron. The only difference between the probes is one is moving with the electron and the other not.  How can magnetism be real if the magnetic field magically disappears when you catch up to the electron ? The electric negative field , Coulomb force , of the electron is real as my movement relative to that field can not make it disappear. This is not true of a magnetic field as I can make it disappear by catching up the the electron. A magnetic or electric field in a vacuum is either real or not real in that vacuum. . In the case of a magnetic field does not seem to be real if it is only there when I move relative to a charge. I am open to counter arguments on this as I am not entirely sure I have it right.

Very good point, I wondered at this when first studying relativity. My understanding is that looking at the moving electrons in a wire doesn't tell the whole story. The charged ions in the metal also count. The wire is electrically neutral because there are two currents, one of electrons and one of holes, with opposite charges and opposite velocities. The total current in the wire is the sum of both currents: since the charges are opposite, and the velocities are opposite, both add constructively and give the total intensity on the wire.

Mathematically, if N is the number of moving electrons, v their speed, and e the electron charge:

I (electrons) =  e · N · v
I (holes)       = -e · N · (-v) ) = I (electrons)

So, I (total) = I (electrons) + I (holes) = 2 · e · N · v

Now, if you are comoving with the electrons, they are at rest, but the holes move at twice the speed:

I (total comoving) = I (electrons comoving) + I (holes comoving ) = e · N · 0 + (-e) · N · (-2v) = 2 · e · N · v = I (total at rest)

That is, the current doesn't change. Maxwell's laws hold, after all.

Of course, matters would be different if you followed a beam of free electrons. In that case, if you comoved with the beam, you would experience a pure coulomb field from the beam, but no magnetic field.
 

[T3sl4co1l]

There are no holes in a metallic conductor, and the fact that there are holes in some types of conductors doesn't change the fact that there is an overall current flow.  Indeed, holes have opposite charge and direction, so they contribute identically to the same positive current.

There is nothing violated about relativity, regardless: indeed, for the same reason that a transformer exists and that a motor is merely a rotating transformer, one must necessarily expect to measure different amounts of fields (E vs. M) when moving relative to a source!

It was this insight, that E and M are interchangeable under relative motion, and that no motion can affect the observed speed of light, which led inexorably to the discovery of Relativity. 

Tim

[salbayeng]

And EVB149's wiki article links to https://en.wikipedia.org/wiki/Faraday_paradox .

If you build the homopolar motor/generator in figure1 (easily done with a D-cell , disc magnet, drywall screw, and a piece of finely stranded wire ) you can test it yourself.
That it worked at all was a paradox to Faraday.
But the interesting thing is that the motor works the same whether the magnet is stationery(magnet stuck to battery) or if the magnet is rotating (magnet stuck to the drywall screw) ,  so what you do is show some smart-arse with a PhD the motor operating with the stationary magnet, and ask "how does this work" he will provide some condescending answer (that usually requires a stationery magnet) then you swap the magnet around and ask whether it will still work, then apply power and prove him wrong.

The important takeaway is that a magnetic field does not move, you can change its amplitude and its direction and that's all.  The profile of a magnetic field can move, but the field is stationery (technically the field is not an "it", so "it" can't have attributes of position or velocity), similar to the way a wave travels across water without carrying water with it.

Also you don't need electrons for a magnetic field, a radiowave propagating through a vacuum generates a magnetic field (and an electric field) as it races past.


* drywall = plasterboard= gyprock

[orolo]

There are no holes in a metallic conductor, and the fact that there are holes in some types of conductors doesn't change the fact that there is an overall current flow.  Indeed, holes have opposite charge and direction, so they contribute identically to the same positive current.

There is nothing violated about relativity, regardless: indeed, for the same reason that a transformer exists and that a motor is merely a rotating transformer, one must necessarily expect to measure different amounts of fields (E vs. M) when moving relative to a source!

It was this insight, that E and M are interchangeable under relative motion, and that no motion can affect the observed speed of light, which led inexorably to the discovery of Relativity. 

Tim

I was not meaning 'holes' in the semiconductor sense, but referring to the charged atoms in the metal conductor. A conductor is formed by charged atoms and a gas of free electrons in the valence band. The whole is neutral.

The paradox is: it's a fact that a flow of moving charges in a wire generates a magnetic field. But the electrons in a conductor move very slowly. So if I walk at the same speed than the electrons and parallel to the wire, the magnetic field should disappear. And that doesn't happen! Why? The answer is that, while the electrons are not moving relative to you, the charged atoms are (with opposite charge and velocity), so you still measure the same current, and experience the same magnetic field. But this magnetic field is now generated by positive charges moving in the opposite direction, and that was I was calling 'holes'. I was using the electron/hole language, typical for semiconductors, in this situation, with a slight change for the meaning for 'hole'.

[John Heath]

I am going to have some more fun with this. I am now in space with 2 magnetic probes and 1 electron. The electron wizes past the first magnetic probe and measures a magnetic field around the electron. The second magnetic probe is moving with the electron and measures no magnetic field around the electron. Two identical magnetic probes yet one says magnetic field around the electron and the other says no magnetic field around the same electron. The only difference between the probes is one is moving with the electron and the other not.  How can magnetism be real if the magnetic field magically disappears when you catch up to the electron ? The electric negative field , Coulomb force , of the electron is real as my movement relative to that field can not make it disappear. This is not true of a magnetic field as I can make it disappear by catching up the the electron. A magnetic or electric field in a vacuum is either real or not real in that vacuum. . In the case of a magnetic field does not seem to be real if it is only there when I move relative to a charge. I am open to counter arguments on this as I am not entirely sure I have it right.

Very good point, I wondered at this when first studying relativity. My understanding is that looking at the moving electrons in a wire doesn't tell the whole story. The charged ions in the metal also count. The wire is electrically neutral because there are two currents, one of electrons and one of holes, with opposite charges and opposite velocities. The total current in the wire is the sum of both currents: since the charges are opposite, and the velocities are opposite, both add constructively and give the total intensity on the wire.

Mathematically, if N is the number of moving electrons, v their speed, and e the electron charge:

I (electrons) =  e · N · v
I (holes)       = -e · N · (-v) ) = I (electrons)

So, I (total) = I (electrons) + I (holes) = 2 · e · N · v

Now, if you are comoving with the electrons, they are at rest, but the holes move at twice the speed:

I (total comoving) = I (electrons comoving) + I (holes comoving ) = e · N · 0 + (-e) · N · (-2v) = 2 · e · N · v = I (total at rest)

That is, the current doesn't change. Maxwell's laws hold, after all.

Of course, matters would be different if you followed a beam of free electrons. In that case, if you comoved with the beam, you would experience a pure coulomb field from the beam, but no magnetic field.

I was going to jump in and say no no the hole will generate the opposite magnetic field. However after reading your words "charges are opposite, and the velocities are opposite" I see your point. It is a double opposite. The hole is positive , opposite , but the direction of movement is also opposite so it complements the negative electron movement to generate the same magnetic field. Well done. I am going to write that down to not forget.  I am sensing a little mischief in your mathematics. If you think this is leading to some boring constructive criticism you are right and apologies in advance but I admire your thinking.

A hole stated as a positive charge must be consistent in the math as a hole that has a positive charge. This being the case the copper wire is now made of protons + , holes + and electrons -. You see the problem? The wire now has a net positive charge and will generate a magnetic field if moved. Moving wires do not generate magnetic fields.

There is a way around this if the hole is defined as a preferred Coulomb position where the electron , emitter , could be in the future , absorber. The cost of this compromise is every electron must be accompanied by a hole that represents its future. Can not have holes moving without the same number of electrons moving the opposite way. This way the copper wire has a charge of 0 so we are off the hook for copper wire net charge. When not sure it is always a good policy the leave the door open to place the finger of blame on someone else. I would like to say that this is a Feynman time symmetry idea not my thoughts. Unless it works in which case it was my idea , ha. 

[T3sl4co1l]

And EVB149's wiki article links to https://en.wikipedia.org/wiki/Faraday_paradox .

If you build the homopolar motor/generator in figure1 (easily done with a D-cell , disc magnet, drywall screw, and a piece of finely stranded wire ) you can test it yourself.
That it worked at all was a paradox to Faraday.
But the interesting thing is that the motor works the same whether the magnet is stationery(magnet stuck to battery) or if the magnet is rotating (magnet stuck to the drywall screw) ,  so what you do is show some smart-arse with a PhD the motor operating with the stationary magnet, and ask "how does this work" he will provide some condescending answer (that usually requires a stationery magnet) then you swap the magnet around and ask whether it will still work, then apply power and prove him wrong.

The important takeaway is that a magnetic field does not move, you can change its amplitude and its direction and that's all.  The profile of a magnetic field can move, but the field is stationery (technically the field is not an "it", so "it" can't have attributes of position or velocity), similar to the way a wave travels across water without carrying water with it.

Your direction of relative motion is wrong.

A magnet is rotationally symmetric on its axis: there is no change in flux when a uniformly magnetized piece of material is rotated parallel to its magnetization (and also has a shape that's symmetrical on the same axis, which is the case for the average cylindrical magnet).

Consider an array of spinning tops: rotating the table they are spinning on, has no effect on the total angular momentum of the ensemble.  Each top continues to spin as it will (until friction takes its toll, of course).  You can change the arrangement of tops, but if the arrangement itself is circularly symmetric (hence the requirement for a round, axially magnetized part), there isn't even a change in the distribution of angular momentum that's sitting on the table!

Of course, magnets don't "spin", but the quantum phenomenon that they exhibit is similar enough that it was given the same word!

If you imagine a magnet as always spinning, then the riddle of the homopolar generator becomes laughably trivial -- of course it doesn't matter whether the magnet spins, it's always spinning!

The rotation of the disc, itself, is a fine example of relative motion.  Note that rotating motion is accelerating motion, so it doesn't have the properties of relativistic inertial frames, it's more complicated -- but the point is it experiences a radial electric field, which isn't present in the (unaccelerated) reference frame.

There's nothing wrong with this difference -- indeed again, it's necessary; energy can be drawn from that electric field, which induces a force on the rotor, and thus there is a conversion between mechanical and electrical energy.

Tim