A coding pipeline to quickly analyze turbulence for stellarator optimization*

Turbulence within a stellarator can lead to significant core heat loss and low temperature profiles that are not conducive to achieving fusion. As such, the plasma dynamics and stability need to be carefully considered when designing an optimal plasma configuration. We are constructing a framework of code that will accurately and quickly yield predictions of plasma turbulence given a magnetic field configuration of a stellarator. This framework will be a three-step pipeline of code consisting of a magnetohydrodynamic equilibria solver (VMEC), a magnetic coordinate transformation code (GIST and FIGG), and a gyrokinetic solver (GS2). Emphasis is placed on calculating the critical temperature gradient for the ion-temperature-gradient (ITG) mode of microinstability for a series of stellarators based on the results from GS2. The ITG mode is used because of its significant role in turbulent transport in stellarators. Once this pipeline is constructed and optimized, it can be connected to an algorithm that generates stellarator designs to find the ones that would potentially yield the least amount of turbulence.