Amount of a magnetic force to alter the trajectory of a photon

[ectro]

hello, I was just thinking since a photon trajectory is affected by a magnetic force.then I would like to know how much force does it take to do just so.

 

[Bobbywhy]

ectro, Welcome to Physics Forums!

As far as I know a photon's trajectory will not be affected by a magnetic field.

Can you give us some reference for your source of this idea?

 

[ectro]

well its a built up conclusion from various textbooks.
if does not then what would effect its trajectory ?

 

[Vanadium 50]

A photon's path is not affected by a magnetic field. If you think your texts say otherwise, please give us a citation.

 

[Drakkith]

well its a built up conclusion from various textbooks.
if does not then what would effect its trajectory ?

Gravity would, along with interactions with just about any material.

 

[meldraft]

Or, put differently, out of all the fields we know, only the gravitational field can change the trajectory of a photon. And, of course, as suggested, also interactions with matter (diffraction, refraction, reflection)

 

[ectro]

Thanks to whom replied and corrected my conclusion. Now since its affected by gravity then how would I if possible to create an artificial field of gravity

 

[Drakkith]

Thanks to whom replied and corrected my conclusion. Now since its affected by gravity then how would I if possible to create an artificial field of gravity

Artificial Gravity is not possible according to our current knowledge.

 

[ectro]

well, what about theories?

 

[Drakkith]

well, what about theories?

Nope.

 

[trueacoustics]

Artificial gravity can be simulated in a zero gravity environment through rotation. However, an actual gravitational field cannot.

 

[mrspeedybob]

Thanks to whom replied and corrected my conclusion. Now since its affected by gravity then how would I if possible to create an artificial field of gravity

Continuous acceleration of your frame of reference. If you were in a rocket with the engine always on you would feel a gravity-like force pulling you toward the rear of the rocket.

 

[Drakkith]

Continuous acceleration of your frame of reference. If you were in a rocket with the engine always on you would feel a gravity-like force pulling you toward the rear of the rocket.

I think the OP is asking about something that would change the path of light like a normal gravitational field would. This would not.

 

[mrspeedybob]

I think the OP is asking about something that would change the path of light like a normal gravitational field would. This would not.

If I were in the rocket I would observe the light to have a curved path, just like gravity would produce. The rocket reference frame is no less valid then a frame in which the light travels straight.
The principal that gravitation and acceleration are equivalent is the foundational idea of GR. At least that is my understanding.

 

[Drakkith]

But we are not talking about how it appears, but about actually changing the path of the photon. This requires a real gravitational field.

 

[mrspeedybob]

I'm not talking about illusion. If I am on the rocket the beam of light is actually curved. Furthermore this curvature causes it to take a longer path from point A to point B which it will take at the same speed as it would a straight path, thus it will take longer. So there we have time dilation, just like a "real" gravitational field would cause.

The way I understand relativity it is not about describing illusions, It's about describing reality which can be different between 2 frames of reference. A path can be both curved and straight. They are not mutually exclusive concepts.

 

[Drakkith]

I'm not talking about the difference between two reference frames, I'm talking about changing the direction of light. This change would appear in BOTH frames.

 

[DrDu]

In matter this can be observed: A magnetic field can change the index of refraction in certain directions which leads to a refraction of the light passing through that material . Search wikipedia for Faraday and Kerr effect.
I am convinced that sufficiently strong magnetic fields will theoretically also interact with light in vacuo.
However, these effects from quantum electrodynamics are extremely small and have not jet been detected experimentally.

 

[ectro]

In matter this can be observed: A magnetic field can change the index of refraction in certain directions which leads to a refraction of the light passing through that material . Search wikipedia for Faraday and Kerr effect.
I am convinced that sufficiently strong magnetic fields will theoretically also interact with light in vacuo.
However, these effects from quantum electrodynamics are extremely small and have not jet been detected experimentally.

so we would need a very powerful force fo gravity to alter the path if the light can we use magnetic force as such.

 

[Drakkith]

so we would need a very powerful force fo gravity to alter the path if the light can we use magnetic force as such.

I can't understand your post. Could you try to use a little better grammar?

EDIT: Ok, I think I understand after a minute of going over it. I believe a very very stong magnetic field can Polarize the vacuum, but this is not the same as gravity altering the path of the light. Short answer is no, you cannot use a magnetic force to alter the path of light.

 

[ectro]

ok thanks.

 

[mrspeedybob]

I'm not talking about the difference between two reference frames, I'm talking about changing the direction of light. This change would appear in BOTH frames.

Consider a beam of light traveling through a free falling elevator. An occupant of the elevator will see a straight beam while someone standing on the floor will see a beam curved due to gravity. Curvature is not frame independent.

 

[Drakkith]

Consider a beam of light traveling through a free falling elevator. An occupant of the elevator will see a straight beam while someone standing on the floor will see a beam curved due to gravity. Curvature is not frame independent.

That's nice, but that is not what I'm talking about. Re-read the thread a few times and get back to me if you still don't understand.

 

[HallsofIvy]

But we are not talking about how it appears, but about actually changing the path of the photon. This requires a real gravitational field.

The path of the photon relative to what? Locally, acceleration is indistinguishable from gravity.

 

[Drakkith]

The path of the photon relative to what? Locally, acceleration is indistinguishable from gravity.

To both an inertial and non inertial frame. Throw a star in between us and the light has changed its path in both frames thanks to the stars gravity.

 

[Neandethal00]

Gravity would, along with interactions with just about any material.

Is it safe to say, magnetic field does not affect path of a photon because photons have no mass ? I do not see any other reason why photons are unaffected by magnetic or electric field.

A magnetic field may change the polarization of light (electro-magnetic wave) due to interaction between two magnetic fields. Any such experiments?

 

[Drakkith]

Is it safe to say, magnetic field does not affect path of a photon because photons have no mass ? I do not see any other reason why photons are unaffected by magnetic or electric field.

A magnetic field may change the polarization of light (electro-magnetic wave) due to interaction between two magnetic fields. Any such experiments?

I don't think it has anything to do with the mass of the photon, but more to do with the fact that a photon is uncharged and is an EM wave, not a regular particle like an electron.

 

[Sam M.]

If you are thinking about creating an invisibility cloak by magnetically influencing the photons which are coming at you (and therefore bouncing off you creating the light other people see) then you are out of luck without some really futuristic tech.

I was thinking about solar power and was wondering if in the future we will discover it efficient to create an artificial energy field capable of harvesting photons. It's amazing how many hurdles you need to clear before you can even begin to design it. Like how do you absorb multiple wavelengths and what kind of energies/materials (or energized {anti}-materials?) would interact with "photonic" radiation? To make a cloak for humans would be easy, we only see part of the spectrum no need to absorb/deflect above uv or below infrared. Of course in a human "cloaker" you would have to expend energy to absorb and then re-emit the visible photons correctly.

Right now we need clean energy though, not cloaking devices.

 

[Drakkith]

Sam, there is no such thing as an "energy field". Energy is not "something" in and of itself. To absorb photons and create energy from light you need a material that will do so. Currently we use semiconducters arranged a certain way. Also, "photonic" radiation is called Electromagnetic radiation.

 

[DrDu]

Is it safe to say, magnetic field does not affect path of a photon because photons have no mass ? I do not see any other reason why photons are unaffected by magnetic or electric field.

A magnetic field may change the polarization of light (electro-magnetic wave) due to interaction between two magnetic fields. Any such experiments?

As I said, in principle photons and magnetic fields do interact. That this effect is so weak is not due to photons being massless but to photons carrying no electric charge.