Talk:Debye length
From Wikipedia, the free encyclopedia
Hannes Alfven would role over in his grave if he saw that the solar core had no magnetic field. —Preceding unsigned comment added by 75.157.177.51 (talk) 19:05, 22 February 2008 (UTC)
[edit] Electronegative Plasmas
Maybe the formula for the Debye length should be modified to take into account negative ions? Ga2re2t 17:02, 28 October 2007 (UTC)
The notion of Debye length is also used in semiconductor physics. Perhaps a section on this should be included as well?MagnusBL (talk) 07:59, 21 November 2007 (UTC)
[edit] Cold ions
The formula for a plasma is given as
and then it is stated
- The ion term is often dropped, giving
- although this is only valid when the ions are much colder than the electrons.
Mathematically, assuming quasineutrality and reasonable charge states, taking the limit 
doesn't make the ion term disappear, it makes it dominate. That makes some sense physically, since cold ions (like any cold charged particles) will cluster more compactly around foreign charges, shielding them before warm charged particles have a chance to notice them. What is wrong with this argument, and how can the article be rephrased to make mathematical and physical sense? --Art Carlson (talk) 09:52, 11 January 2008 (UTC)
I agree with Carlson, the above simplification doesn't sound right. A simple counter-example: In a neutral deuterium plasma there are only electrons and one kind of ions (charge +1), and their densities are the same (ni = ne), so the general equation can be reduced (for this particular case) to:
The mentioned simplification could only be valid if the electrons (not ions) were much colder. CharlieM, 10 May 2008 —Preceding unsigned comment added by 81.61.248.109 (talk) 19:22, 10 May 2008 (UTC)
