A key element of our approach has been the development, in tandem with our algorithmic research, of an experimental code named COGENT (COntinuum Gyrokinetic Edge New Technology) to provide a vehicle for assessing algorithm effectiveness on realistic edge plasma problems. COGENT is built upon the Chombo adaptive mesh refinement library under development in the FASTMath SciDAC Institute. The underlying model in COGENT is a 4D, Eulerian, gyrokinetic Vlasov-Poisson system with imposed magnetic field defined on a domain the spans from the core region, across the magnetic separatrix, and into the scrape-off layer. In addition to providing a testbed for algorithm development, COGENT has served as a common platform for an ongoing collaboration with fusion physicists under the banner of the Edge Simulation Laboratory (ESL). Funded as a complementary project by the Fusion Energy Sciences theory program, our collaborators are investigating a variety of edge physics questions and are serving as the first consumers of the basic numerical methods research being developed by this project. COGENT is also being used as a component in the Advanced Tokamak Modeling (AToM) fusion simulation workflow SciDAC project.
The COGENT source code will soon be released under a BSD license to facilitate its further development and broader application in the magnetic fusion community. The COGENT software distribution will consist of source code (in C++ and Fortran) and a collection of test problems to verify its proper installation. In addition to utilities normally found on Unix-based platforms (e.g., GNU Make), COGENT requires the Chombo, hypre, and HDF5 packages.