Fokker-Planck Equation for Plasmas
The kinetic equation describing the time evolution of a plasma velocity distribution function subject to small-angle Coulomb collisions.
Governing formula
(∂f / ∂t)_coll = -∇_v · (A f) + ½ ∇_v ∇_v : (B f)
SI unit
Kinetic Collision Operator
In depth
Because long-range Coulomb forces cause accumulating small-angle deflections, plasma particle collisions are modeled as a continuous diffusion process in velocity space using friction vector A and diffusion tensor B.
Examples in the real world
Calculating runaway electron velocity distributions during tokamak disruption events.