# Electric field and light and stuff

• crx
In summary, the conversation discussed the possible effects of a strong electric field on a light beam, such as in the case of a laser passing through a parallel plate capacitor or a large metallic sphere at high electric potential. While Maxwell's equations suggest that there would be no effect in a steady electric field, there may be a small effect during the build up of an electric field or in the presence of a nonlinear medium. Quantum mechanics predicts that in a strong enough electric field, light particles can turn into an electron and a positron. Additionally, the electromagnetic fields of the light beam and the electric field can interact gravitationally. The Faraday effect also suggests that light passing through a medium can be affected by a magnetic field, and a similar effect
crx
Is there any effect on a light beam in a strong electric field? I'm thinking to a laser beam that passes trough a very long parallel plate capacitor. And what if we have an nonuniform, electric field, like in the case of a very large metallic sphere at a high electric potential? Thanks!

Maxwell's equations are linear, so I don't think there would be an effect. The only way I could see there being an effect would be in the presence of a nonlinear medium instead of free space.

crx said:
Is there any effect on a light beam in a strong electric field? I'm thinking to a laser beam that passes trough a very long parallel plate capacitor. And what if we have an nonuniform, electric field, like in the case of a very large metallic sphere at a high electric potential? Thanks!

I would have thought that there would be no effect in a steady electric field but there might be a very very small effect during the build up of an electric field or an alternating electric field.

Quantum mechanics predicts that in a strong enough electric field, two light quanta of sufficient energy can turn into an electron and a positron. Actual real particles with mass, fermionic spin, charge and all.

Someone will no doubt point out that other conditions are needed, but the equations indicate that the probability of particle creation depends on the electric field strength.

That is a good point. I should emphasize that I was speaking in strictly classical terms.

If the field is Very strong, one could also add the effect of gravitational bending of the beam passing close to the region of higher field, but it would be due to the field's high energy density and not to the fact that it's an electric field.

Electromagnetic fields are not self interacting, per Dalespams post #2.

As lightarrow points out, there is a small gravitational interaction since the electromagnetic fields (the light beam and the electromagnetic field) both carry energy. (energy is a component of the Einstein stress/energy/momentum tensor.)

Another way to think of the answer:all radiation is affected by gravity...following the above logic.

sorry but have any of you heard of the Faraday effect?

light traveling through a medium IS effected by magnetic field and I presume, similarly an electric field.

right?

## 1. What is an electric field?

An electric field is a region in space surrounding an electrically charged object or particle. It exerts a force on any other charged object or particle that enters its field.

## 2. How is an electric field created?

An electric field is created by the presence of an electric charge. Positive charges create an outward electric field, while negative charges create an inward electric field.

## 3. What is the relationship between electric fields and light?

Electric fields and light are both forms of electromagnetic radiation. Light is a type of electromagnetic wave that is created by accelerating electric charges. Therefore, electric fields play a crucial role in the production and propagation of light.

## 4. Can electric fields be shielded or blocked?

Yes, electric fields can be shielded or blocked by certain materials. Conductive materials, such as metals, can block electric fields by conducting the charge away from the area. Insulating materials, such as rubber, can shield against electric fields by preventing the flow of charge.

## 5. How do electric fields interact with matter?

Electric fields interact with matter through the attraction or repulsion of charges. Positively charged objects will be attracted to areas with a negative electric field and repelled by areas with a positive electric field. Similarly, negatively charged objects will be attracted to areas with a positive electric field and repelled by areas with a negative electric field.

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