Figure 8: Schematic representation of grains with six independent charge domains immediately following the neutralization process.
From: Self-charging of identical grains in the absence of an external field
Each charge domain is fixed at 2/3 of the mean grain radius from the center of the grain. Two contacting domain charges, qi and qj, neutralize at a contact point to become 
and 
. Size of the domain charges here represent the magnitude of the charges.
