Shielding question

I have no one to ask this question of, so seems the Usenet might work ;-)
Does anyone think that it might be possible to surround a vehicle with
sodium ions held in place by their charge and a magnetic field (Generated by
the vehicle) as a form of shielding for a long term journey?


--
A scholar's ink lasts longer than a martyr's blood.

On Thu, 13 Jan 2005 22:28:45 GMT
"Jim" wrote:

I have no one to ask this question of, so seems the Usenet might work
;-) Does anyone think that it might be possible to surround a vehicle
with sodium ions held in place by their charge and a magnetic field
(Generated by the vehicle) as a form of shielding for a long term
journey?

I have heard it said that the mass of hardware needed to generate the required magnetic field would on its own provide a pretty good shield.

I am not sure what part the sodium ions would play in this scheme. Surely the magnetic field is the bit which interacts with the incoming particles?
--
Michael Smith
Network Applications
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Are you thinking of a radiation shield, or a physical shield?

I'm not sure I understand why a liquid would be desireable. For
example, what advantage do you see this having over a slab of steel?

"David Summers" wrote in message
oups.com...
Are you thinking of a radiation shield, or a physical shield?

I'm not sure I understand why a liquid would be desireable. For
example, what advantage do you see this having over a slab of steel?


Radiation shield, The reasoning behind the Sodium ions is that you could
form a large gas cloud composed of metal atoms to interfere and or block
cosmic ray of various sources. It's one of the thoughts that attract a mind
at rest ;-)

My understanding is that for radiation, it doesn't really matter what
the mass is, only the amount of mass figures in. In that case, you are
probably better off using sheet metal, so that the protected volume can
be made as small as possible. (System mass scales with volume only, so
the denser your shield material the better)

On Wed, 19 Jan 2005 12:16:05 -0800, David Summers wrote:

My understanding is that for radiation, it doesn't really matter what
the mass is, only the amount of mass figures in.

Incorrent. You've forgotten secondary radiation.

The classic example is a high energy particle...if it hits water it
might be stooped, or it might pass through... but your steel shielding
stops it cold, and in stopping the particle the steel in turn releases
a blast of secondary particles into the vehicle that do far more damage
to the crew than the the original particle would have done.

The composition of a radiation shield matters very much indeed.

--
Chuck Stewart
"Anime-style catgirls: Threat? Menace? Or just studying algebra?"

My understanding is that for radiation, it doesn't really matter what
the mass is, only the amount of mass figures in.

For some types of radiation, the cross section goes as Z to the fifth power.

Jan

Which implies that for stopping solar flares, steel is fine. But it
does increase damage from cosmic rays. One option is to have a steel
inner shelter only for use in solar storms.

However, better yet is to have a water/ice shield or a polythene
shield.

For larger rotating space stations, I was thinking water beds would
give additional shielding at very low mass penalty.

In this case, you would definately not want to use a low-z material,
but instead use steel or even lead.

True, but it still should just come down to thickness. You need
multiple collisions to make your sheilding work - so really you need
the thickness to be some multiple of the mean free path, right? I
suppose that using materials where you have a heavy atomic nucleus,
tightly bound together would work best.

How much variation is there really in the binding strength of the
nucleus of (stable) atoms? Are you saying that sodium is that much
better? It would have to be significantly better to go from a nice
compact steel to a blob of liquid sodium.