The gyrokinetic theory of turbulent transport, and the magnetohydrodynamic theory of peeling-ballooning stability, have proven to be accurate physics models of conventional aspect ratio tokamak plasmas. The General Atomics Theory and Computational Science (GA-Theory) division has been awarded a grant to extend the validation of these theories, and reduced models for transport and pedestal structure, to the low aspect ratio geometry of the National Spherical Torus Experiment Upgrade (NSTX-U) operated by the Princeton Plasmas Physics Laboratory (PPPL).

We currently have two exciting opportunities for outstanding candidates to undertake postdoctoral positions onsite at PPPL advised by GA-Theory in close collaboration with NSTX-U researchers. Appointments are administered by Oak Ridge Associated Universities (ORAU). The successful candidates will be given training as a theoretical analyst, validating codes developed by GA-Theory for turbulent transport and pedestal structure with existing and new NSTX-U data. A theoretical analyst participates in the planning, execution, and analysis of experiments as a collaborator in the experimental program. In addition, the fidelity of reduced transport models to gyrokinetic turbulence simulations and linear stability will be verified. A validated reduced model for pedestal structure and stability is a shared goal of this grant with the NSTX-U research plan.

Two positions, one focused on transport and the other on pedestal structure are open. The training given by GA-Theory scientist will equip the candidate with state-of-the-art gyrokinetic simulation experience with the CGYRO code that is optimized for the exascale computing environment. The candidate will learn the methods used to construct the quasi-linear transport model TGLF and the pedestal structure model EPED from their primary developers. They will also learn to run a new, high resolution, version of the peeling-ballooning code ELITE and a new variable resolution gyro-fluid eigensolver that have been developed for spherical tori. This knowledge, and the experience of working in the exciting collaborative environment of NSTX-U, will build the foundation for a career in fusion energy research.