5.2 Poisson’s equation

In terms of the reduced distribution function F, Poisson’s equation is written

          (      ∫        )
  d2ϕ   e-         ∞
− dx2 = 𝜀0  nion − − ∞F dvx  ,
(79)

where nion is the number density of ions, which are assumed to be uniform in x and not evolving with time.