3D Modeling of Planar Discharge of a CO2 LaserJ. Schüttler ,
 Rofin-Sinar Laser GmbH, Hamburg, Germany
High power CO2 lasers have been the workhorses for sheet metal cutting, welding and many more applications in materials processing during the past decades. Even though a significant replacement by fiber coupled lasers takes place, there are still many applications that benefit from the characteristics of CO2 lasers with a high beam quality. Modeling the plasma behavior is essential for optimizing, e.g. the homogeneity of the discharge, cooling design, gas dynamics inside the laser and the electrical properties of the system. Due to the complex pumping scheme of a CO2 laser, many species and collisions have to be considered. In this paper, a multilevel approach to a full 3D model of the planar discharge is presented. Due to the dimensions of the system under investigation and limitations of computational resources, a fully coupled 3D plasma and RF simulation is no feasible approach. Instead, the problem is partitioned into manageable tasks in a hierarchical way.