Do electrons radiate from electostatic acceleration?

[Lazarus]

There is a slight difference between an electron passing through an electromagnetic field and an electrostatic field.

 

Approximating an electron with a ring of circulating current shows the difference. Different parts of the ring are moving at different velocities so have different force vectors in different directions from the magnetic field. Although the individual vectors may not be perpendicular to the travel of the ring, the net force is perpendicular.

 

However, this would put internal stress on an electron which would not exist in a similar situation in an electrostatic field.

 

Come on, guys. That the electron “always” radiates on acceleration is a fundamental assumption of current physics theory. The mathematically derived conclusion can easily be tested in almost any physic lab. I am sure it has been done and documented. That all that I am asking for.

[swansont]

Electrons will not experience an internal stress as they have no structure. Internal stress has no meaning.

 

You've been given examples od the radiation. Bremsstrahlung is dependent on the acceleration and it's a lot smaller between the plates that add KE than in the metal that removes it. If you are sure that a specific experiment has been done, then go ahead and find it.

[Lazarus]

I am disappointed in the lack of an experiment without contaminating magnetic fields to show the radiation.

 

Your efforts to explain this issue to me are greatly appreciated.

[Lazarus]

I am un-disappointed.

 

Thanks to the last post I found a simple experiment to demonstrate radiation from electrostatic acceleration of electrons at www.rtftechnologies.org/physics/linac.htm.

 

A physicist built an electrostatic accelerator while in high school that appears to be a test of accelerating electrons. He had to add a florescent screen for the electrons being accelerated to hit in order to show that the accelerator was running. That implies that there was no radiation from the accelerated electrons.

 

Another thing I found was a description of storage rings that seems to say electrons do not lose energy by radiation in a storage ring. The excerpt and the website are below.

 

https://sites.google.com/site/4thdimensionapps/particle-accelerators

 

For some applications, it is useful to store beams of high energy particles for some time (with modern high vacuum technology, up to many hours) without further acceleration. This is especially true for colliding beam accelerators, in which two beams moving in opposite directions are made to collide with each other, with a large gain in effective collision energy. Because relatively few collisions occur at each pass through the intersection point of the two beams, it is customary to first accelerate the beams to the desired energy, and then store them in storage rings, which are essentially synchrotron rings of magnets, with no significant RF power for acceleration.

[swansont]

I am un-disappointed.

 

Thanks to the last post I found a simple experiment to demonstrate radiation from electrostatic acceleration of electrons at www.rtftechnologies.org/physics/linac.htm.

 

A physicist built an electrostatic accelerator while in high school that appears to be a test of accelerating electrons. He had to add a florescent screen for the electrons being accelerated to hit in order to show that the accelerator was running. That implies that there was no radiation from the accelerated electrons.

It implies no such thing. The author mentions how he detected the electrons. That has no implication that there is no other way to do so. A fluorescent screen is simply a straightforward way of detecting them.

 

 

Another thing I found was a description of storage rings that seems to say electrons do not lose energy by radiation in a storage ring. The excerpt and the website are below.

 

https://sites.google.com/site/4thdimensionapps/particle-accelerators

 

For some applications, it is useful to store beams of high energy particles for some time (with modern high vacuum technology, up to many hours) without further acceleration. This is especially true for colliding beam accelerators, in which two beams moving in opposite directions are made to collide with each other, with a large gain in effective collision energy. Because relatively few collisions occur at each pass through the intersection point of the two beams, it is customary to first accelerate the beams to the desired energy, and then store them in storage rings, which are essentially synchrotron rings of magnets, with no significant RF power for acceleration.

No significant RF power ≠ no power

 

If you go to the included link

http://en.wikipedia.org/wiki/Storage_ring

 

it says "The most common application of storage rings is to store electrons which then radiate synchrotron radiation." and "a storage ring, as the name suggests, keeps particles stored at a constant energy, and radio-frequency cavities are only used to replace energy lost through synchrotron radiation and other processes."

[Lazarus]

You are right. The storage ring acting differently from a synchrotron didn't seem fair.

 

You are also right that the electrostatic accelerator not producing visable radiation is a null experiment.

 

I will keep looking for a valid experiment.

[Lazarus]

This excerpt from http://www.physicsforums.com suggests that the test for radiation from electrostatic acceleration is a bit difficult. It also offers a possible means of performing the test.

 

Are they correct?

 

Q-reeus

Still a no-go for absolutely uniform acceleration owing to the extreme feebleness of any energy loss. You may find appealing a fairly simple argument based on conservation of energy given here: http://arxiv.org/abs/gr-qc/9811030 Not saying I endorse it though.

 

Universal_101

Alright, let me have another shot, suppose we have a electrostatic linear accelerator which can accelerate charges to speeds approaching 'c', Now if there is present a radiation reaction force then the speed of the particle approaching the end of the accelerator would be less than the expected speed without radiation. i.e.
E−(e2ac2/6π)=mec2(γ−1) and for appropriately chosen E of the accelerator and its length, it seems the other two energy comes close for 1.05≤γ≤1.1 and normal accelerations(a). If I did everything correctly.

Therefore, now by injecting these accelerated particles in a magnetic fields and separating them by their energies can easily show if the particles radiated or not. If I assume my calculations are correct.

[Enthalpy]

For four decades, computer monitors that use electron beams are being spied through their uncontrolled radiation. Though, I can't tell whether the electron beam radiates during the electrostatic acceleration, or the modulating electrodes and circuits, or something else.

 

X-rays are produced by the electrostatic deflection of electrons at heavy nuclei: what kind of other proof is necessary?

[Lazarus]

HAPPY NEW YEAR

 

 

Enthalpy said:

For four decades, computer monitors that use electron beams are being spied through their uncontrolled radiation. Though, I can't tell whether the electron beam radiates during the electrostatic acceleration, or the modulating electrodes and circuits, or something else.

 

Reply:

It appears that the radiation from the electrostatic acceleration in a CRT would be infinitesimal .

 

Enthalpy said:

X-rays are produced by the electrostatic deflection of electrons at heavy nuclei: what kind of other proof is necessary?

 

Reply:

That is a good point to consider.

There are magnetic fields around a nuclei to confuse the issue. Also, there is deceleration involved. The electrons around the nucleus have an effect.

[swansont]

 

That is a good point to consider.

There are magnetic fields around a nuclei to confuse the issue. Also, there is deceleration involved. The electrons around the nucleus have an effect.

 

That's a point that I've brought up. Have you not been considering it already?

 

The magnetic fields are much smaller, and deceleration is just a specific subset of acceleration. The electrostatic forces are responsible.

[Lazarus]

Swansont said:

The magnetic fields are much smaller, and deceleration is just a specific subset of acceleration. The electrostatic forces are responsible.

 

Reply.

A decrease in "speed" requires something to compensate for the lost kinetic energy. An increase in "speed" does not require a compensation.

 

As strict as you are about solid proof, it should be fair that there would be experimental evidence clearly influenced solely by electrostatic acceleration.

[swansont]

Swansont said:

The magnetic fields are much smaller, and deceleration is just a specific subset of acceleration. The electrostatic forces are responsible.

 

Reply.

A decrease in "speed" requires something to compensate for the lost kinetic energy. An increase in "speed" does not require a compensation.

 

As strict as you are about solid proof, it should be fair that there would be experimental evidence clearly influenced solely by electrostatic acceleration.

 

What do you mean by compensation? Both require a force to be exerted and work to be done. The only difference is in the direction of the force with respect to the displacement.

[Lazarus]

Swansont said:

What do you mean by compensation? Both require a force to be exerted and work to be done. The only difference is in the direction of the force with respect to the displacement.

 

Reply:

When an electron decelerates it looses kinetic energy. The lost energy could conceivably be in a radiated photon. When an electron is accelerated by an electrostatic force its kinetic energy is increased. No energy left to radiate a photon.

[swansont]

When an electron is accelerated by an electrostatic force its kinetic energy is increased. No energy left to radiate a photon.

 

You don't actually know this unless you compare the energy transferred to it and the kinetic energy it has as a result.

[Lazarus]

Swansont said:

You don't actually know this unless you compare the energy transferred to it and the kinetic energy it has as a result.

 

Reply:

It takes quite a leap of faith to assume that electrostatic force not only accelerates the electron but throws in some extra energy to blast out a photon.

 

If you don't beleve that there is a difference between acceleration and deceleration try accelerating to a stop sign. (Just being facetious, sorry)

[swansont]

It takes quite a leap of faith to assume that electrostatic force not only accelerates the electron but throws in some extra energy to blast out a photon.

 

It requires no more faith than trusting any other part of Maxwell's equations, which have been shown to work extremely well over the years.

 

Anyway, do you know how a radio antenna transmits? You accelerate electrons at some frequency, and they radiate at that frequency.

 

If you don't beleve that there is a difference between acceleration and deceleration try accelerating to a stop sign. (Just being facetious, sorry)

 

The thing is I do it all the time, and so do you. You sound like you believe acceleration means to speed up, and that's not the case. Acceleration is the rate of change of velocity, and velocity is a vector. So any change in velocity, be it in magnitude or direction, is an acceleration. If you speed up, that's an acceleration. If you slow down, that's an acceleration. If you change direction, that's an acceleration. The difference is in the direction of the acceleration with respect to the velocity.

[Lazarus]

Swansont said:
It requires no more faith than trusting any other part of Maxwell's equations, which have been shown to work extremely well over the years.

 

Reply:

And the equation for the Roulette proves the sun and the planets rotate around the earth.

 

Swansont said:
Anyway, do you know how a radio antenna transmits? You accelerate electrons at some frequency, and they radiate at that frequency.

 

Reply:

The electrons do not have time to run the length of the antenna in half a cycle. So that is no proof.

 

Swansont said:
The thing is I do it all the time, and so do you. You sound like you believe acceleration means to speed up, and that's not the case. Acceleration is the rate of change of velocity, and velocity is a vector. So any change in velocity, be it in magnitude or direction, is an acceleration. If you speed up, that's an acceleration. If you slow down, that's an acceleration. If you change direction, that's an acceleration. The difference is in the direction of the acceleration with respect to the velocity.

 

That is why I like to use speed instead of acceleration. Speed change causes a change in kinetic energy. Acceleration may not.

[swansont]

Swansont said:

It requires no more faith than trusting any other part of Maxwell's equations, which have been shown to work extremely well over the years.

 

Reply:

And the equation for the Roulette proves the sun and the planets rotate around the earth.

I have no idea what this is supposed to mean.

 

 

Swansont said:

Anyway, do you know how a radio antenna transmits? You accelerate electrons at some frequency, and they radiate at that frequency.

 

Reply:

The electrons do not have time to run the length of the antenna in half a cycle. So that is no proof.

It was not claimed that they do, so this is not a valid objection. The fact remains that electrons undergo electrostatic acceleration and you get radiation as a result.

 

Swansont said:

The thing is I do it all the time, and so do you. You sound like you believe acceleration means to speed up, and that's not the case. Acceleration is the rate of change of velocity, and velocity is a vector. So any change in velocity, be it in magnitude or direction, is an acceleration. If you speed up, that's an acceleration. If you slow down, that's an acceleration. If you change direction, that's an acceleration. The difference is in the direction of the acceleration with respect to the velocity.

 

That is why I like to use speed instead of acceleration. Speed change causes a change in kinetic energy. Acceleration may not.

Physics claims that you get radiation when charges are accelerated, so you can't get away from using acceleration. And it's what you used in posing your question.

[Lazarus]

I understand what you are saying but this thread has not demonstated that electrons in positive linear acceleration from electrostatic force must radiate, to a level of evidence that would be up to your standards.

[swansont]

I understand what you are saying but this thread has not demonstated that electrons in positive linear acceleration from electrostatic force must radiate, to a level of evidence that would be up to your standards.

 

That wasn't your question, though. You asked if accelerating an electron causes radiation, and the answer is yes, and several examples were given. Since for some reason you won't accept radio waves as an answer even though it's from an electrostatic source (I mean, there's a reason you use coaxial cables for AC signals), I'm afraid you'll have to get someone else to answer. I don't know that anyone would have done the very specific experiment you are looking for.

[Lazarus]

I really appreciate your posts.

 

The question was as apposed to accelerated electrons "always" radiate.

 

I suspect that if you were on the opposite side of the discussion that you would insist on better evidence.

 

Thanks again.

[swansont]

On the contrary, I don't for example, insist that the gravity of the moon to have been measured everywhere on its surface to accept that it is about 1/6 of that on the surface of the earth. Newtonian gravity is well-established, so a calculation suffices. I don't need to continually monitor GPS satellites' clocks to ensure they run at the correct rate that relativity predicts; I have confidence that my GPS receiver will give me proper coordinates.

 

It helps to have an appreciation of the overwhelming breadth and depth of scientific evidence that supports the theories and models.

 

Maxwell's equations predict that any accelerated charge radiates, and Maxwell's equations are well-tested.

[Lazarus]

Swansont said:

Maxwell's equations predict that any accelerated charge radiates, and Maxwell's equations are well-tested.

 

Reply:

 

OK, I will tackle Maxwell.

 

Maxwell’s Laws

 

Law 1 Gauss’ Electrostatic Law.

Basic idea is that similar charges repel, opposite charges attract and distance between them is significant.

 

Law 2, Gauss’ Electromagnetic Law.

Boils down to the magnetic field wraps around an electrical current. A hand holding a wire with thumb pointing in the direction of the current has the direction of the flux in the direction of the fingers.

 

Law 3, Faraday’s Law.

Turns out to be the 3 finger rule (right hand, left hand rules) for changing current, magnetic flux and force.

 

Law 4, Ampere’s original Law.

The essence is that the magnetic field is proportional to the changing current.

 

So far so good.

 

Law 4.5, Maxwell’s modification to Ampere’s Law.

The assumption is that a changing charge generates a magnetic field.

 

Mathematically, it is just fine to change a point charge. In the real world a charge cannot change without a current involved.

 

There is no such thing as a continuous current. The current is the sum of the effects of discrete charges.

 

The concern about a circuit with a condenser (Oops, New name, capacitor) is why it was thought modification was needed. When you look at the sum of the individual fields of the electrons there is no problem. The requirement that a current has to complete a circuit is not always applicable. Pour some electrons into a capacitor and you have a changing current. Pull the plug on the source and you now have too many electrons sitting on one side of the capacitor which shows that it is possible to have a current that just stops. The same kind of thing can be done with a piece of wire.

 

It the capacitor were 2 sheets of metal a meter apart, it should be possible to detect a dip in the strength of the magnetic field half way between the sheets.

 

Maxwell’s Laws do not demonstrate that an accelerated electron always radiates, without the presence of a magnetic field.

[swansont]

 

Maxwell’s Laws do not demonstrate that an accelerated electron always radiates, without the presence of a magnetic field.

 

You'll pardon me if I don't accept your "proof" of this.

[Strange]

There was a proof?