Re: Re: starship-design: Pellet track

[kuo@bit.csc.lsu.edu (Isaac Kuo)]

KellySt@aol.com wrote:
>In a message dated 8/18/97 9:17:14 AM, you wrote:

>>>>As for the efficacy of electric field containment for fusion power,
>>>>I'll admit I haven't read the reference articles on this compressions
>>>>system, but it seems very optimistic to assume it will even work well
>>>>enough to break even, much less provide power.

>>>I can't follow this.  Why do you assume its so dificult?

>>Because if it were so easy, it would already be giving us cheap
>>fusion power.

>That asumes theirs a market for it.  Specifically one big enough to pay for
>the R&D.  Comercial research in exotic power sources, especially ones
>invoving nuclear, died when the fuel crises evaporated.

At the very least, this means that there is a significant R&D cost
associated with it.  However, the potential profit is so great,
that the perceived risk must also be great for commercial concerns
to avoid it.  (The perceived risk being that even after all that
R&D it won't work.)

>The system I'm reffering to is agreed (even by the government researchers) to
>be a more promising design then Magnetic fusion (possibly more then laser
>fusion).  But of course no new research programs are scheduled to be funded.
> (Mag fusion programs are grand fathered in, but only at minimal levels.)

I personally think magnetic target fusion offers the brightest
potential (it's a pulsed fusion concept), but even so the concept
is too new and the technology too immature to bank on it.  The
numbers look a _lot_ more acheivable than either magnetic
confinement or inertial confinement.

>>>Certainly it couldn't require more power then the scoop or
>>>conventional magnetic confinment systems.

>>There are difficulties in dealing with charged plasma, since
>>the more charged it is, the more it wants to fly apart (even
>>more).  The less charged it is, the more you need a stronger
>>electric potential difference.  Setting up that potential
>>difference in the right geometry is challenging as well.

>The geometry for this system is a hollow sphere by the way.  

Huh?  A conductive hollow sphere cannot generate an electric
potential gradient inside it.  You'd have to inject electrons
into the center in order to attract the (positively charged)
fuel particles to it, and rely on the charge of those electrons
alone to acheive compression.

Much better to have a hyperbolic electric charge potential trap
(along with the injected electrons to increase the potential
difference).

But tell me if I'm missing something.

>>Magnetic plasma confinement is a pain, but it is a pain we know.
>>The technology we do have is mature, so it can be safely used in
>>speculations of future technology.  We can and do acheive fusion
>>with magnetic confinement.  We just don't do it well enough to
>>acheive sustained fusion.

>We've acheaved fusion be several means.  That doesn't mean they'ld work in a
>star drive.  Or that they are stable.  Magnetic confinment is legendary for
>its instability.

Yes, which is why I only consider pulsed fusion possibilities.
-- 
    _____     Isaac Kuo kuo@bit.csc.lsu.edu http://www.csc.lsu.edu/~kuo
 __|_)o(_|__
/___________\ "Mari-san...  Yokatta...
\=\)-----(/=/  ...Yokatta go-buji de..." - Karigari Hiroshi