Quantcast
  • Register
PhysicsOverflow is a next-generation academic platform for physicists and astronomers, including a community peer review system and a postgraduate-level discussion forum analogous to MathOverflow.

Welcome to PhysicsOverflow! PhysicsOverflow is an open platform for community peer review and graduate-level Physics discussion.

Please help promote PhysicsOverflow ads elsewhere if you like it.

News

New printer friendly PO pages!

Migration to Bielefeld University was successful!

Please vote for this year's PhysicsOverflow ads!

Please do help out in categorising submissions. Submit a paper to PhysicsOverflow!

... see more

Tools for paper authors

Submit paper
Claim Paper Authorship

Tools for SE users

Search User
Reclaim SE Account
Request Account Merger
Nativise imported posts
Claim post (deleted users)
Import SE post

Users whose questions have been imported from Physics Stack Exchange, Theoretical Physics Stack Exchange, or any other Stack Exchange site are kindly requested to reclaim their account and not to register as a new user.

Public \(\beta\) tools

Report a bug with a feature
Request a new functionality
404 page design
Send feedback

Attributions

(propose a free ad)

Site Statistics

145 submissions , 122 unreviewed
3,930 questions , 1,398 unanswered
4,853 answers , 20,624 comments
1,470 users with positive rep
501 active unimported users
More ...

Is it possible to create a photon with energy lower than the plasma frequency inside a plasma?

+ 1 like - 0 dislike
82 views

Suppose we have a plasma with corresponding plasma frequency $\omega_{\text{pl}}$. Next, assume that there is some scattering inside the plasma, due to which photons can be created. Is it possible to create a photon with the energy $E < \omega_{\text{pl}}$? Or such process is impossible?

asked May 22 in Phenomenology by NAME_XXX (1,010 points) [ no revision ]

2 Answers

+ 3 like - 0 dislike

Yes, it is possible. Note, a thick plasma at the temperature $T$ radiates all frequencies, like a black body.

answered May 23 by Vladimir Kalitvianski (22 points) [ no revision ]
+ 3 like - 0 dislike

As Vladimir Kalitvianski says, it is very much possible in a microscopic sense. Highly ionized plasma is a soup of charged particles bumping into each other via Coulombic interaction and thus radiating braking radiation all the time. However, once this radiation is created, it does not take long to encounter another charged particle which scatters it in a different direction. As a result, many plasmas can be understood as optically thick below the plasma oscillation frequency - immediately absorbing and reradiating light with a thermal spectrum in random directions.

I.e., plasmas are full of radiation of every frequency chaotically scattering around the place, it is just that ordered electromagnetic waves can arise only as collective plasma oscillations (plasmons) with specific dispersion relations.

answered May 23 by Void (1,505 points) [ revision history ]

Your answer

Please use answers only to (at least partly) answer questions. To comment, discuss, or ask for clarification, leave a comment instead.
To mask links under text, please type your text, highlight it, and click the "link" button. You can then enter your link URL.
Please consult the FAQ for as to how to format your post.
This is the answer box; if you want to write a comment instead, please use the 'add comment' button.
Live preview (may slow down editor)   Preview
Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:
If you are a human please identify the position of the character covered by the symbol $\varnothing$ in the following word:
p$\hbar$ysic$\varnothing$Overflow
Then drag the red bullet below over the corresponding character of our banner. When you drop it there, the bullet changes to green (on slow internet connections after a few seconds).
To avoid this verification in future, please log in or register.




user contributions licensed under cc by-sa 3.0 with attribution required

Your rights
...