Date: Sun, 27 Jul 1997 00:05:02 +0000 (GMT)
From: aufsj@IMAP2.ASU.EDU
Subject: Re: ??? Plasma mirror propulsion...
Organization: Arizona State University
Newsgroups: sci.physics,sci.physics.plasma


: : Is there some big fundamental flaw I'm missing? Has this idea
: : been fleshed out before?

: Can't say I'm an expert on plasma mirrors, but if I were to
: hazard a guess I'd say further calculations would show that you
: spend exactly as much energy blueshifting the radiation in front
: of the mirror as is gained redshifting the radiation behind.

If there were such a relationship, couldn't one simply ensure
that more energy is 'behind' it than in 'front' of it? Put a powerful
energy source behind and head in a direction with less energy "in the
way" and you should get the unbalanced force with the results as
promulgated by Newton. There seems to be a very clear analogy to sailing
(for example, you could head 'into' powerful energy sources by tacking).
A very hypothetical spacecraft, for example, going from earth
might

#1. Get boosted by traditional technology and orbital swings.
#2. Reach high speeds. Using the relatively nearby sun as an
energy source sail towards some distant star (tacking if need be).
#3. Craft accelerates to high speed and eventually reaches point
where the Sun's energy from behind is distant and weak, and the target
star's energy is strong (you can get close by tacking).
#4. Pull in the sails. Use your momentum to complete the journey.
In addition, since you are now probably close to your target, gravity
from it will help "reel you in".

: Of course, I could be way off. Do the calculations :):).

But I don't like math! Not only do I often come up with wrong
answers, but when I get correct ones they often contradict my
theories :-) :-). Talk about a Hobson's choice.... ;-)

regards,

-------------------------------------------------------------------
Occam's Razor:
I've walked on the razors edge, like it was a balance beam,
And I've learned that complixity, may not be what it seem,
The simplest acts, propogated through time,
Creat a confusion that clouds one's mind.

Steven j Forsberg at aufsj@imap2.asu.edu Wizard 87-01