View Single Post
  #7  
Old October 14th 07, 04:15 AM posted to sci.astro,sci.physics,sci.physics.relativity,sci.physics.fusion,sci.energy
Craig Markwardt
external usenet poster
 
Posts: 232
Default Startling amounts of stored energy in fully ionized plasmas.


Robert Clark writes:

On Oct 13, 3:00 pm, Craig Markwardt
wrote:
Robert Clark writes:
...
Thanks for the informative response. Quite key here is that these are
*non-neutral* plasmas. That means the charges are all of the same
sign, all positive or all negative. In your formula you gave note this
would result in the Bremsstrahlung emissivity being zero since one of
the types of charge would be absent.


Huh? First of all, that equation assumed a Boltzmann equilibrium,
which would not be the case if one conveniently "removed" *all*
electrons.

But is that plausible? No. First, fully ionizing a species like
Xenon would still required effectively heating the atoms to
temperatures of kB T ~ 100 keV. Before one could somehow magically
transfer (just) the ions to the storage tank, the energy would be lost
by thermal bremsstrahlung radiation very quickly. Second, a plasma
made up of positive ions *still* radiates by thermal bremstrahlung, so
one can't just pretend the effect is zero.

However, neither of these issues is the real fatal flaw...

There has been alot of research on non neutral plasmas showing they
can be stored in magnetic/electrostatic traps for several days:


Really? Have you considered how much Coulomb energy is required to
separate the charges even by 1 cm? For even 1 cubic cm of the Xenon
you mentioned, the Coulomb energy is tens of thousands of times larger
than the ionization energy density, at voltages of many tens of
megaVolts. In other words, the "trap" would simply be crushed due to
Coulomb forces. A lab setup with a few thousand ions is far different
from your scenario, which is totally implausible.


You are right it would take quite a bit of energy to create the fully
ionized plasmas and quite alot of energy to separate the electrons.
This is clearly not a means of getting "free" energy such as nuclear,
solar, or fossil fuels. It is only a way of storing it.
According to the web site I linked, the positive ions in their traps
could be stored as long as they want if the magnetic/electrostatic
containment fields are sufficiently uniform:

....

You seem to be missing the point. If it takes many thousand times as
much energy to separate the charges as it does to ionize them, then
you've built a 99.999% capacitor + 0.001% ion storage device. But
there are much safer and straightforward ways to build a capacitor, so
why bother with the ionization part at all?

CM