Electrical shielding against ionizing radiation?

Axel Walthelm wrote:
>
> Hi Steve,
>
> Assuming a single charge on the particle (e.g. fast
> protons)
> that would match. Nuclei with many neutrons or which are not completely
> ionized would need a bit more.
>
> How to get rid of the charge? Well, if you're in free space, shoot them
> away with an energy of 15 GeV per electron.
>

I don't think you need to match proton for proton, like an antimissile
missile, in this circumstance. What you want to do is use same-charge
repulsive force to decelerate the charged particles until they pose no
danger to the inhabitants of the space settlement. You need a charged
field whose repulsion is sufficient to slow collision-course 10GeV protons
to a nominal zero during the time they are in the field, and redirect
indirect-path charged particles into tangential tracks, bypassing the settlement.

> Electical resistance of vacuum ... is a somewhat undefined term,
> like asking for the temperature of vacuum. Free electrons would be
> attracted very much. Hm, beta radiation is electrons, right?
> So this might make it a energy-hungry way of shielding.
>

A vacuum has both poor thermal conductivity and poor dielectric capability,
which is why Thermos bottles and vacuum tubes and neon lights work. I
believe that if you set a Van De Graff generator in a vacuum-filled room,
it would not work because the charge you can build up on the globes at
atmospheric pressure would just dissipate in the vacuum. You would have an
electron breeze flowing from points of negative potential to their opposites.

> I'm sure I saw some other publications on the topic of active shielding,
> which did seriously consider both electrical and magnetical shielding.
> It also involved some effects of strong electric and magnetic fields
> on humans...
>

As The Dane said, stroking a balloon with a piece of felt, "Aye, there's
the rub!" I think static charges stay on the outside of curved surfaces,
but I don't know whether any of the field could be felt inside. It's
probably not conducive to good health to live 24/7 with your hair sticking
straight out. :-)

Steve