2-D PIC Simulation on Electron Sheath Formation in Magnetized Plasmas

In order to analyze electron sheath formation we performed two dimensional PIC (Particle In Cell) simulations in magnetized plasmas. We investigated the influence of the probe geometry on the electron sheath formation in terms of the aspect ratio of the plane probe. The dependence of the magnetic field and voltage bias of the probe on the electron sheath were also taken into consideration. The sheath thickness was also analyzed to compare with the theoretical formula described by the Child Langmuir (CL) law and the experimental observations. We found that alteration of the plane probe geometry from rectangular to square decreased sheath thickness, resulting in a close to cylindrical CL sheath, rather than a planar one. These results demonstrate that the behavior of electrons surrounding the probe is directly affected by the geometry of the probe. Further, it is found that the sheath thickness is determined by the ratio between the probe width and the Larmor radius of the electron.