Re: Space based VLBI - next steps beyond Hubble

On 22 Apr, 13:26, Willie.Moo...@xxxxxxxxx wrote:
On Apr 21, 2:36 pm, Ian Parker <ianpark...@xxxxxxxxx> wrote:





There is one decisive reason why Tokomaks are the preferred choice and
this is the nature of the thermonuclear reaction. 80% of the energy of
fusion goes into neutrons in the case of Tritium and protons in the
case of He3. A pellet is much too small to hold this energy. If we are
using magnetic containment protons will spiral in the magnetic field
and contribute to plasma heating.

To get He3/D to fuse requires twice the temperature of T/D but is
gives off protons not neutrons. To use a tritium reaction you need a
heavy blanket of material which is heated/transmuted by neutrons. This
is why I spole of He3 as the fuel of space. He3/D will if magnetically
contained produce a self sustaining reaction. Hot He4/H which is what
we have is the final and only product. It may well be eaasier to
SUSTAIN He3/D than T/D for this reason.

As I have said inertial containment of a pellet loses 80% of the
energy. This is true of both He3 and Tritium.

  - Ian Parker

I see.  Well, power to weight and thrust to weight are what you want
to optimize.  Using an aneutronic fusor makes things rather efficient
with respect to neutron loss.  You seem to be generally knowledgeable
about what's going on around you, you are still clueless about rocket
design however.  Consider that as long as 80% of the energy is
directed into a jet producing thrust - it doesn't matter for rocket
applications if its lost to the reaction..- Hide quoted text -

- Show quoted text -

Protons and neutrons are omnidirectional. To have a rocket you need to
use something like liquid hydrogen as a working fluid. Doing this you
will get 10km/s approx. The Nerva SI if I recall was about 900secs.
BTW - I prefer km/s to secs as a SI has gravity as one of its units.
10km/s is set roughly by the temperature structures can withstand.

My query is can an implosion thermonuclear reaction ever be self
sustaining, bearing in mind that you have to charge your lasers up
again. Implosions are viiewed not as thermonuclear solutions but as
research tools. The question of heat loss is relevant in terms of
sustainability, as well as everything else.


- Ian Parker
.

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