Microwave energy storage

Stanley514

I know there exist methods to store a microwave in a vacuum superconducting or dielectric chamber.From first sight it looks as promising energy storage device,more safe then a flywheel.Even if chamber will be broken microwave will just left and fly into space.
Unfortunately,I was not able to find any mentions on maximal amount
of energy that could be stored in this way.Maybe somebody could help
with approximate calculations?Or some clue on how could it be calculated?

Antiphon

This isn't practical but works in principle.

When the peak electric field intensity in the vacuum is greater than than twice the rest mass of the electron, you could end up creating particle pairs.

The safety is not so clear and has to do with how quickly energy is released. Suppose your microwave box had 10^15 Joules in it. What would happen if you hit it with a hammer? Hint: a U235 fission nuke might release 1/10th as much when it goes off.

Stanley514

I think one of the problems could be that there is no pure vacuum and
even rare atoms will start to make some interruptions.I'm not going
to create new particles,but rather something similar or bit surpassing hydrocarbon fuels in energy density.Why do you think it is not practical?Maybe more practical than hydrogen storage researches?
Do you think we could create some similar resonances in intramolecular space?There is nothing between large molecules,it could be regarded as absolute "vacuum".

Stanley514

"When the peak electric field intensity in the vacuum is greater than than twice the rest mass of the electron, you could end up creating particle pairs."

Do you mean hypothetical Hawking radiation?
Somebody still needs to prove experimetally it does exist.

Antiphon

Not hypothetical Hawking radiation. This is the very real production of (non-virtual) electron-positron pairs. You may need a nucleus (or stray proton maybe) but it will happen if the fields get high enough.

DaleSpam

Yes, pair production could be important:
http://en.wikipedia.org/wiki/Pair_production

In addition, there would generally be large amounts of pressure due to the fields:
http://en.wikipedia.org/wiki/Maxwell_stress_tensor

Stanley514

Will dielectric breakdown of vaccuum prevent energy storage
at some point of electric field strenghts?Or there is no such issue?

Could you calculate approximately how much it will limit energy density?