Comparison of particle-in-cell and fluid simulations for the asymmetric structure effects in a capacitively coupled plasma*

In low pressure plasmas where electrons are able to move freely without collisions, electron heating and electron energy consumptions by collisions have different spatio-temporal profiles and the non-local kinetic effect becomes important. In such a non-local regime in which electron energy relaxation length becomes similar to or larger than the length scale of a plasma device, fluid models are not able to describe non-local effects due to the intrinsic properties of fluid equations. In this research, the two-dimensional hybrid plasma equipment model (HPEM) and two-dimensional graphics processing unit (GPU) particle-in-cell (PIC) simulation were applied to capacitively coupled plasma equipment with two different structures. Non-local heating region was showed at low pressure asymmetric structure case in GPU PIC simulation. In case of longer electrodes, non-local heating effect increases and spatial electron temperature show big discrepancy with that of fluid simulation. As a result, we suggest the criterion for choosing a simulation method when investigating plasma properties.