Investigation of the parameters of modified Lorentzian distribution function on plasma expansion into vacuum process

Expansion of one-dimensional collisionless plasma into vacuum is studied in absence of magnetic field. In this paper, expansions of plasmas containing initial Maxwellian and modified Lorentzian (r,q) velocity distributions and the effect of q and r parameters on expansion are investigated and then compared by use of simulation of kinetic theory equations. In this simulation code, the electrons dynamic is determined by Vlasov equation and the ions dynamic obeys fluid equations. It is shown that the plasmas containing different initial velocity distributions for the electrons will be expand with different velocities. The results show that in the cases which initial electron distribution has more energy, then the ions will have more velocity.