From a8d31faecc733fa4d63fde58ab98a5e9d11029c2 Mon Sep 17 00:00:00 2001 From: Prefetch Date: Sun, 2 Apr 2023 16:57:12 +0200 Subject: Improve knowledge base --- source/know/concept/boltzmann-relation/index.md | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'source/know/concept/boltzmann-relation') diff --git a/source/know/concept/boltzmann-relation/index.md b/source/know/concept/boltzmann-relation/index.md index b528adf..b3634f3 100644 --- a/source/know/concept/boltzmann-relation/index.md +++ b/source/know/concept/boltzmann-relation/index.md @@ -8,15 +8,16 @@ categories: layout: "concept" --- -In a plasma where the ions and electrons are both in thermal equilibrium, -and in the absence of short-lived induced electromagnetic fields, -their densities $$n_i$$ and $$n_e$$ can be predicted. +In a plasma where the ions and electrons are in thermal equilibrium, +in the absence of short-lived induced electromagnetic fields, +the densities $$n_i$$ and $$n_e$$ can be predicted. -By definition, a particle in an [electric field](/know/concept/electric-field/) $$\vb{E}$$ +By definition, a charged particle in +an [electric field](/know/concept/electric-field/) $$\vb{E} = - \nabla \phi$$ experiences a [Lorentz force](/know/concept/lorentz-force/) $$\vb{F}_e$$. This corresponds to a force density $$\vb{f}_e$$, such that $$\vb{F}_e = \vb{f}_e \dd{V}$$. -For the electrons, we thus have: +For electrons: $$\begin{aligned} \vb{f}_e @@ -74,10 +75,9 @@ $$\begin{aligned} But due to their large mass, ions respond much slower to fluctuations in the above equilibrium. Consequently, after a perturbation, -the ions spend more time in a transient non-equilibrium state +the ions spend more time in a non-equilibrium state than the electrons, so this formula for $$n_i$$ is only valid -if the perturbation is sufficiently slow, -such that the ions can keep up. +if the perturbation is sufficiently slow, such that the ions can keep up. Usually, electrons do not suffer the same issue, thanks to their small mass and hence fast response. -- cgit v1.2.3