2.1Debye Shielding
In most types of plasma, quasi-neutrality is not just an ideal equilibrium 
state; it is a state that the plasma actively tries to achieve by readjusting the 
local charge distribution in response to a disturbance.However, 
it is more useful to consider the shielding as a dielectric phenomenon: i.e., 
it is the polarization of the plasma medium, and the associated 
redistribution of space charge, which prevents penetration by an external 
electric field.