Two-stream instability using Patricle-in-cell simulation

Summary form only given. This work presents two-stream instability in one-dimensional collisionless plasma in electrostatic limit with the help of Particle-in-cell (PIC) simulation. The one-dimensional plasma consists of charged particles (electrons) moving about due to the self-consistent forces in the presence of fixed, uniform and heavy neutralizing ion background. The PIC simulation is initiated by accumulating the charge density on the grids from particle positions. Then, Poisson´s equation is solved on the grid to find the electric potential and electric field. Finally, the electric fields on the grid is interpolated to the particle´s position and use the interpolated force on the Newton´s equations of motion to update the position and velocity of the particles. Hence this cycle is repeated as many time steps as necessary study our system. Instability is observed in the two uniform opposing beams of particles, which is generated from particles having random velocities and set around the drift velocity. It grows in time. This instability destroys the two beams and results in five vortices which are evident in phase space plots. It is observed that five vortices merge into four with the progress of simulation time. The electrostatic potential energy is found to be increased first and reached its maximum value which retained in the simulation time interval (t = 18.1-18.3). Later it decreases and fluctuates with time. The potential energy is nearly 34% of the initial kinetic energy when it is at peak value. The overall velocity distribution curve obtained is non-Maxwellian type.