# Accumulating large charges

1. Jul 24, 2014

### Axe199

I was reading about high voltages machines that accumulate charges and i found out that we cant accumulate much , because eventually the voltage will break down the air near the surface of the sphere ( corona discharge) , what if we put it at the bottom of the sea , where water ( with bigger dielectric strength ) surround the sphere , wouldn't that allow us to accumulate more charge?
( this is a theoretical question , i know it wont work in reality because of the air inside the sphere and the salt in the water and many other reason)

2. Jul 24, 2014

### e.bar.goum

Why put it in the sea? Why not a nice pool of distilled water?

But sure, you could use it to suppress sparks. We could never use it in practise, for much the reasons you've outlined. Water is also heavy!

But! You can do the same trick with high-vacuum or SF6 gas. For example, in electrostatic particle accelerators, the accelerating tube is put inside a large tank of ~100 psi SF6 gas to suppress sparks. In that way, you can get terminal voltages up to 25 MV (the old Oak Ridge tandem accelerator, which I beleive was the largest tandem accelerator every built) with ease.

3. Jul 24, 2014

### Axe199

do you think we can suppress the sparks with solid? like glass , we would have the same problem with the inner surface, but just theoretically.

4. Jul 24, 2014

### e.bar.goum

... I don't see why not? I'm fairly sure it's just the dialetric constant you care about. Completely unfeasable in reality, though, as you point out, which is why gasses are used in practice (even nasty ones like SF6!).

If we're talking theoretically, the best choice would be a perfect vacuum.

5. Jul 25, 2014

### Axe199

but again , perfect vacuum is unfeasable , :D
thanks