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> -----Original Message-----
> From: firstname.lastname@example.org
> [mailto:email@example.com]On Behalf Of Kelly St
> Sent: Wednesday, January 14, 1998 12:32 PM
> To: firstname.lastname@example.org
> Subject: Re: RE: RE: ICAN (Was RE: starship-design: What is safest?)
> No you missed the point. By bleeding off exaust stream into a MHD
> you convert some/all te kinetic energy of that part of the exuast streem
> electricity. You then use that electricity to add kinetic energyu to
> of the exaust stream. Effectivly your not adding any kinetic energy to
> exaust streem, your just shuffling it around. How does that add effective
> thrust per pound of fusion fuel?
Oh, I see what you're saying. You are assuming the magnetic nozzle is also
an accelerator - I wasn't. It may be that it is, in which case you are
correct, that would clearly be an example of an entropy device! I will have
to check the research and see exactly what it is meant to accomplish. I am
afraid I did not read that paper all the way through, just the abstract, one
can only read so much, especially when it isn't really job related...
If you want to create an accelerator type of device out of magnetic fields
there would have to be some sort of auxiliary power as well. My guess would
be one or more fusion reactors of a more conventional sort. I think we can
probably get sufficient ISP and thrust to weight figures without
accelerators though. If we can up the strength of the nozzle field
sufficiently then we can reduce the containment volume producing higher
pressures than we could withstand with purely material walls.
I still believe that we are looking at more than fifty years though.
Any sufficiently advanced technology is indistinguishable from magic.
Arthur C. Clarke's "Third Law"