Hybrid computational simulation of plasma-solid interaction at low and medium pressures

The plasma-solid interaction has been generally studied by experimental, theoretical and computational methods. The increasing performance of computers allows to introduce new and more powerful computational methods. However, fully three-dimensional particle simulations are still extremely demanding and therefore usually restricted to supercomputers, etc. To overcome this difficulties, more sophisticated and efficient techniques are developed. In our contribution, we present a hybrid computational model designed to solve steady-state problems in the field of plasma-solid interaction, especially when the three-dimensional approach is inevitable. These problems include configurations with complex geometries or the presence of external electric or magnetic field in arbitrary direction. The presented method is based on a combination of a fluid model and a non self-consistent particle model. As far as possible, the hybrid model gains advantage from both of them: The fluid model is fast even in 3D, while the particle model brings detailed information about individual particles. The two parts are coupled iteratively exchanging the electric field and transport coefficients. Once the convergence is reached, the solution can be used as an initial condition of a self-consistent particle simulation to get more detailed and accurate results. Application of the hybrid model at low and medium pressures is discussed. Results of the hybrid model are compared with a standard Particle-in-Cell / Monte Carlo Collisions model and a fluid model at various pressures to show the capabilities of this approach. Finally, examples of solved problems are presented, including the interaction of magnetized low-temperature plasma with immersed solids.