invisible Plasma?
donna
I read in the web
"A plasma can in principle never be completely dark because there will
be radiation emitted as the protons and electrons recombine. However,
if the plasma is so dense and energetic that no individual atoms can
form (like in the interior of the sun), then there won't be any
recombination and radiation"
<snip> ".... in this sense it is well possible that a large plasma
mass at the center of galaxies might go undetected"
But isn't it that what made the plasma so dense and energetic is
itself the source of the radiation even without recombination? It
gives the sun core as example.. but the sun core still radiate energy.
What example of plasma object doesn't radiate because it is so dense
and energetic that the protons and electrons can't recombine if it is
at all possible and true?
Thomas Smid
Yes, if the plasma is too dense and/or too energetic for neutral atoms
too form, electrons and protons can''t recombine. What you see of the
sun is only the (less dense) atmosphere where the plasma can recombine
into neutral atoms (see http://www.plasmaphysics.org.uk/research/sun.htm
for a more detailed treatment of this issue).
Thomas
johan Wevers
On 12-01-2011 0:31, Thomas Smid wrote:
> Yes, if the plasma is too dense and/or too energetic for neutral atoms
> too form, electrons and protons can''t recombine. What you see of the
> sun is only the (less dense) atmosphere where the plasma can recombine
> into neutral atoms (see http://www.plasmaphysics.org.uk/research/sun.htm
> for a more detailed treatment of this issue).
If a plasma is very hot it will radiate anyway due to moving
electrically charged particles. Recombination is not necessary. Fusion
plasmas are hotter than the nucleus of the sun but they do radiate
(although not much in the visible spectrum, you'd need UV and Roentgen
measurement devices to "see" them).
I don't know of any plasma's that are very dense everywhere, and then
you would still have the surface that would still radiate.
--
ir. J.C.A. Wevers // For Physics and science fiction information:
joh...@vulcan.xs4all.nl // http://www.xs4all.nl/~johanw/index.html
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Thomas Smid
On Jan 13, 5:37=A0pm, johan Wevers <joh...@vulcan.xs4all.nl> wrote:
> On 12-01-2011 0:31, Thomas Smid wrote:
>
> > Yes, if the plasma is too dense and/or too energetic for neutral atoms
> > too form, electrons and protons can''t recombine. What you see of the
> > sun is only the (less dense) atmosphere where the plasma can recombine
> > for a more detailed treatment of this issue).
>
> If a plasma is very hot it will radiate anyway due to moving
> electrically charged particles. Recombination is not necessary. Fusion
> plasmas are hotter than the nucleus of the sun but they do radiate
> (although not much in the visible spectrum, you'd need UV and Roentgen
> measurement devices to "see" them).
The recombination radiation for a plasma with a temperature of
10^7-10^8 K would also be in the X-ray region, so it would be
difficult to distinguish the two.
I have in fact given an estimate on my page http://www.physicsmyths.org.uk/=
synchrotron.htm
which shows that even the radiation emitted by a synchrotron could be
due to recombination rather than bremsstrahlung.
Likewise I have made detailed computations that managed to model the
radio spectrum of the sun in terms of recombination radiation rather
than free-free radiation as traditionally assumed (see
http://www.plasmaphysics.org.uk/research/solradio.htm ).
Thomas