Everything Totally Explained


Ask & we'll explain, totally!
Distribution function
Totally Explained


  NEW! All the latest news in the worlds of computer gaming, entertainment, the environment,  
finance, health, politics, science, stocks & shares, technology and much, much, more.  


View this entry using RSS

Everything about Distribution Function totally explained

» This article describes the distribution function as used in physics. You may be looking for the related mathematical concepts of probability density function or cumulative distribution function.

In molecular kinetic theory in physics, a particle's distribution function is a function of seven variables, f(x,y,z,t;v_x,v_y,v_z), which gives the number of particles per unit volume in phase space. It is the number of particles having approximately the velocity (v_x,v_y,v_z) near the place (x,y,z) and time (t). The usual normalization of the distribution function is » n(x,y,z,t) = int f ,dv_x ,dv_y ,dv_z

» N(t) = int n ,dx ,dy ,dz

Here, N is the total number of particles and n is the number density of particles - the number of particles per unit volume, or the density divided by the mass of individual particles.
   Particle distribution functions are often used in plasma physics to describe wave-particle interactions and velocity-space instabilities. Distribution functions are also used in fluid mechanics and statistical mechanics.
   The basic distribution function uses the Boltzmann constant k and temperature T with the number density to modify the normal distribution:
» f = frac ight)

Related distribution functions may allow bulk fluid flow, in which case the velocity origin is shifted, so that the exponent's numerator is m((v_x - u_x)^2 + (v_y - u_y)^2 + (v_z - u_z)^2); (u_x, u_y, u_z) is the bulk velocity of the fluid. Distribution functions may also feature non-isotropic temperatures, in which each term in the exponent is divided by a different temperature.
   Plasma theories such as magnetohydrodynamics may assume the particles to be in thermodynamic equilibrium. In this case, the distribution function is Maxwellian. This distribution function allows fluid flow and different temperatures in the directions parallel to, and perpendicular to, the local magnetic field. More complex distribution functions may also be used since plasmas are rarely in thermal equilibrium.
   The mathematical analog of a distribution is a measure; the time evolution of a measure on a phase space is the topic of study in dynamical systems.
   

Further Information

Get more info on 'Distribution Function'.


External Link Exchanges

Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:

    <a href="http://distribution_function.totallyexplained.com">Distribution function Totally Explained</a>

Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
   As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned.



Copyright © 2007-8 totallyexplained.com | Licensed under the GNU Free Documentation License | Site Map
This article contains text from the Wikipedia article Distribution function (History) and is released under the GFDL | RSS Version