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mfb- t1_je1a0gr wrote

If there is an electric field then it's not an ideal vacuum.

A field in that range is strong enough to produce electron/positron pairs from the energy in the electric field. It has some similarity to pair production from photons.

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pewpewbrrrrrrt t1_je1zbl7 wrote

Replying to mfb- (#2,423,372)

I'm sorry if this is stupid, my understanding of what space/time is would mean there's no way to not have an electric field. Even if you made a vacuum with no charge you would have to use an electric field to make the vacuum inside have no charge therefore there would always be an electric field.

Is that a flawed understanding?

Is an ideal vacuum a theoretical or mathematical concept that is technically impossible in our understanding of physics?

Thank you for any clarification, I think I have a good idea of high school level math + a high level of modern physics concepts so ELI16?

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mfb- t1_je40csp wrote

Replying to pewpewbrrrrrrt (#2,427,660)

You can have an electric field strength of zero, that is commonly called "no electric field". You could argue that zero is the strength of the existing field, but that's just semantics. In practice you won't achieve a field strength of exactly zero, of course, but that's just an experimental limit.

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mfb- t1_je4eu6y wrote

Replying to [deleted] (#2,442,973)

In practice you focus beams of electromagnetic radiation to collide with each other. You can't reach fields anywhere close to the Schwinger limit with charged walls, so again, this has nothing to do with walls.

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QuentaAman t1_je6oy0t wrote

Replying to pewpewbrrrrrrt (#2,427,660)

You can shield against electric fields by using a faraday Cage. This is above highschool level but the wuick answer is that, using maxwells equations, you find the the electric potential inside such a cage is exactly 0 no matter what charges there may be outside the cage. And since the electric field is the gradient of the potential (again, sorry if that's too advanced for you) it is also 0.

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El_Sephiroth t1_je8y2on wrote

As I understand it, dielectric breakdown voltage is the energy necessary to disrupt an insulator into a conductor. Therefore, if you have a perfect vacuum, there is no matter to disrupt. But, a high enough voltage could still create electron-positron pairs out of the vacuum and therefore make a conductor in something empty. It's called schwinger effect. It is only a prediction of quantum electrodynamics.

So if there is nothing there, electricity could pass through when "matter" (here electron and positron) are created in it.

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