Observation of the limit cycle in asymmetric plasma divided by a magnetic filter

An asymmetric plasma divided by a magnetic filter is numerically simulated by the one-dimensional particle-in-cell code VSIM1D [Koga et al., J. Phys. Soc. Jpn. 68, 1578 (1999)]. Depending on the asymmetry, the system behavior is static or dynamic. In the static state, the potentials of the main plasma and the subplasma are given by the sheath potentials, φM≒3TMe/e and φS≒3TSe/e, respectively, with e being an electron charge and TMe and TSe being electron temperatures (TMe>TSe). In the dynamic state, while φM≒3TMe/e, φS oscillates periodically between φS,min≒3TSe/e and φS,max≒3TMe/e. The ions accelerated by the time varying potential gap get into the subplasma and excite the laminar shock waves. The period of the limit cycle is determined by the transit time of the shock wave structure