From: henry@spsystems.net (Henry Spencer)
Newsgroups: sci.space.tech
Subject: Re: Orion Shall Rise
Date: Thu, 19 Aug 1999 14:11:09 GMT

In article <37B8ECF1.3246@ix.netcom.com>,
Scott Lowther  <lexcorp@ix.netcom.com> wrote:
>As regards X-rays... Dunno. My impression was that most X-Ray production
>was from the uberheated atmospheric fireball...

No, you start with the bomb itself heated to X-ray-hot temperatures by
the fission reaction.  Much of the energy is radiated away very quickly
indeed (black-body radiation emission goes with the fourth power of
temeprature!) as soft X-rays.  In atmosphere, those are absorbed by the
surrounding air, producing the fireball, which then grows rapidly (not
just expanding, but also heating and incorporating surrounding air).
The fireball itself doesn't produce much in the way of X-rays, although
it's responsible for much of the heat emission.

In space, you just get the X-ray pulse all by itself.  Which raises hell
with the electronics in anything it hits.  (Not directly, but by ionizing
atoms in the satellite's outer surface and creating strong electrical
effects that way -- sort of very localized EMP.)  The comment I saw was
that a single good-sized H-bomb exploded a fair ways up might well kill
every satellite in Earth orbit, except the ones which happened to be
behind Earth at the time.
--
The good old days                   |  Henry Spencer   henry@spsystems.net
weren't.                            |      (aka henry@zoo.toronto.edu)