Enhancing Electric Field Concentration on Electrodes through Focused Techniques

[thinktank1985]

I have been trying to think of some way to concentrate an electric field, locally on a given electrode. It is possible by using a very sharp tip on the opposite one, but is it possible by any other means such as an external magnetic field or by introducing different materials within the two electrodes.

 

[Antenna Guy]

I have been trying to think of some way to concentrate an electric field, locally on a given electrode. It is possible by using a very sharp tip on the opposite one, but is it possible by any other means such as an external magnetic field or by introducing different materials within the two electrodes.

A source at one focus of an ellipsoidal reflective surface will focus the radiated energy at the other focus.

Regards,

Bill

 

[thinktank1985]

A source at one focus of an ellipsoidal reflective surface will focus the radiated energy at the other focus.

Regards,

Bill

Thanks a lot for your reply...I am bit new to electromagnetism...so could you point me to some books or websites where I could find some more information.

When you talk of a source, do you mean a source of electromagnetic waves? and is the ellipsoidal reflective surface similar to that of a dish antenna that we commonly see.

thanks

dibyadeep

 

[Danger]

Although I'm not sure, I think that Bill is referring to the type of reflector used in some laser cavities. It looks something like a standard car muffler (cross-section is similar to a medicine capsule). Each of the curved surfaces has its own focal distance, so something that occurs at one is focused on the other. In a laser, for instance, you would have a xenon flash tube lying along one focal plane and your lasing medium rod along the other. When the tube fires, the light is focused on the rod to begin pumping.

 

[thinktank1985]

Although I'm not sure, I think that Bill is referring to the type of reflector used in some laser cavities. It looks something like a standard car muffler (cross-section is similar to a medicine capsule). Each of the curved surfaces has its own focal distance, so something that occurs at one is focused on the other. In a laser, for instance, you would have a xenon flash tube lying along one focal plane and your lasing medium rod along the other. When the tube fires, the light is focused on the rod to begin pumping.

I guess what you are talking about is something similar to an optical lens. However, if I have to concentrate the electric field, the equations will be completely different. Will an optical lens ever focus an electric field?

 

[Danger]

No, it's not a lens; it's a reflector.
An optical lens will not focus an electric field. It will focus electromagnetism, since that's what light is. In any event, a lens is not what Bill meant.
This is really not one of my specialties, so I'll refrain from further comment. Bill or someone else will have to carry this on.

 

[Antenna Guy]

Thanks a lot for your reply...I am bit new to electromagnetism...so could you point me to some books or websites where I could find some more information.

Look for info on "gregorian antenna". A gregorian antenna uses an ellipsoidal subreflector to feed a parabolic main reflector (the ellipsoid and parabola have a focal point in common).

Regards,

Bill

 

[Redbelly98]

It sounds like thinktank wants to focus an electrostatic field. A reflecting surface as used for optical-frequency electromagnetic waves will not do this.

The only way I can think of to do this is to have a sharp tip on the electrode where you want the field to be high. Sharpening the opposite electrode would actually weaken the field where you want it strengthened.

 

[Antenna Guy]

It sounds like thinktank wants to focus an electrostatic field.

If so, that would be a different problem.

Perhaps a hemisphere of pointy electrodes (directed inward) would work in a similar fashion - with the center of the sphere as the "focus" of the static field.

Regards,

Bill