Abstract of COCHLEA2 Project

Modern high-frequency high-power microwave sources are usually electrically and physically large and the study of the beam-wave interaction characteristics becomes a very demanding job. Gyrotrons belong to these sources and are used for fusion plasma applications and their complex electromagnetic structures. There have been developed several semi-analytical methods and codes to treat such structures; however, the required computation resources are extremely large. A code based on the FDTD method has been initiated in the previous years and can treat any cylindrical-like waveguide structure in time domain. Up to now, different sources (modal and current distributions) have been implemented in conjunction with various materials (PEC and dielectric). The main output of the code includes field components in time and space, while some post-processing procedures have been also developed to calculate other important quantities. Another significant step of the code development is the study and the implementation of the beam-wave interaction. Up to now, the necessary physics model has been developed and partially implemented in the numerical code. In parallel, the fields' calculation has already been parallelized using OpenMP, while other parts and the post-processing procedures need further parallelization and optimization. Furthermore, MPI parallelization has been partially utilized for parametric studies. Note that the FDTD scheme is based on the Yee [1] algorithm (an extensively parallelized algorithm). The aim of this project is to further parallelize and optimize the code using a hybrid OpenMP-MPI scheme and make use of Intel Xeon Phi architecture for domain - decomposition parallelization in order to reduce the computational resources. This code was awarded with an amount of CPU time in the new MARCONI-FUSION HPC of CINECA. The current proposal will be the continuation of COCHLEA-HLST project under WP15 HLST framework (October – December 2015). It should be mentioned that the mathematical formulation and the corresponding code development is included in the EUROfusion WPHCD program since 2016.

[1] K.S.Yee, "Numerical Solution of Initial Boundary Value Problems involving Maxwell's Equations in Isotropic Media". IEEE Trans. Antennas Propag, vol 14(3), 302-307, (1966).