Liouville Theorem

Taking into account the conservation of the particles, the phase space density is conserved as well:

ddtF(x,v,t)=0=(t+vx+dvdtv)F(x,v,t)

Where dvdt is given by the equation of motion for a particle under the action of electromagnetic fields

ddtvi(t)=qm[Em(xi(t),t)+vi(t)×Bm(xi(t),t)]

where the fields E and B are given by the microscopic Maxwell's equations. This holds true for collisionless plasma and in the absence of Diffusion and Scattering

Also we shouldn't have any sources or sinks -- #Question