Linker IT Software
Google
Web www.oraxcel.com
menubar-top-links menubar-top-rechts
Home Help Search Login
Welcome, Guest. Please Login.
SQL*XL: Database to Excel bridge litLIB: Excel power functions pack ExcelLock: Locking and securing your valuable Excel spreadsheets encOffice: Protect your Excel file easy and safe encOffice: Protect your Excel file easy and safe
Pages: 1
Plasma (Read 2205 times)
Gerrit-Jan Linker
YaBB Administrator
*****




Posts: 75
Plasma
25.10.09 at 13:50:17
 
Plasma
 
The plasma state is often referred to as the fourth state of matter. Most matter in the universe is found in the plasma state. Examples include the sun and other stars, inter stellar matter and the terrestrial ionosphere. Naturally occurring plasmas on Earth are rare and include lightning and flames.
 
A plasma is characterized by the presence of free positive (and sometimes also negative) ions and negatively charged electrons in a neutral background gas.  
A plasma is globally quasi neutral, meaning that the plasma contains overall an equal number of positive and negative charges.
 
The electrons in the plasma have a mean kinetic energy that can range from less than 0.01 eV in an interstellar plasma to more than 10 keV in fusion plasmas.
 
Definition:
Plasma is a partially ionized gas, in which a certain proportion of electrons are free rather than bound to an atom or molecule.  
 
Definition:
Plasmas,  a  complex  non-equilibrium  medium  which  contains  apart  from
neutral particles, free electrons, (molecular) ions, radicals and excited atoms
and  molecules.
 
The ability of the positive and negative charges to move somewhat independently makes the plasma electrically conductive so that it responds strongly to electromagnetic fields.
 
Source:
Plasma - Wikipedia
http://en.wikipedia.org/wiki/Plasma_%28physics%29
Encyclopedia of Chemical Physics and Physical Chemistry
Back to top
 
« Last Edit: 31.12.09 at 22:08:00 by Gerrit-Jan Linker »  

Gerrit-Jan Linker
Linker IT Software
Email WWW Gerrit-Jan Linker   IP Logged
Gerrit-Jan Linker
YaBB Administrator
*****




Posts: 75
Plasma oscillation - plasma frequency
Reply #1 - 28.10.09 at 21:35:16
 
Plasma oscillation - plasma frequency
 
A charge imbalance in a plasma can occur due a local deviation from charge neutrality.
This results in a motion of the electrons which will lead to oscillations of the electrons with the electron plasma frequency ωpl (Langmuir frequency)
 
The Langmuis frequency ωp is the frequency of plasma oscillations in an equilibrium charge distribution. The Langmuir frequency is given by ωp  = (4π ne e2 /m) where ne is the charge density, e is the electron charge, m the effective mass of the electron.
Back to top
 
« Last Edit: 28.10.09 at 21:45:56 by Gerrit-Jan Linker »  

Gerrit-Jan Linker
Linker IT Software
Email WWW Gerrit-Jan Linker   IP Logged
Pages: 1