Neoclassical Computation of Temperature Anisotropy in the National Spherical Torus Experiment

Neoclassical Computation of Temperature Anisotropy in the National Spherical Torus Experiment David Perkins Department of Physics and Astronomy Bachelor of Science The National Spherical Torus Experiment (NSTX), underway at Princeton Plasma Physics Laboratory (PPPL), investigates the plasma dynamics in a spherical tokamak to understand the device’s potential as a fusion power generator. Temperature anisotropy, a characteristic that could have substantial effects on the plasma’s overall dynamics, is not well-known in NSTX. The particle code GTC-NEO, a particle-in-cell simulation developed at PPPL, allows for computational diagnosis of temperature anisotropy. The code simulates a tokamak plasma in the neoclassical limit. We present herein a computational study of temperature anisotropy in NSTX using GTC-NEO, including spatial temperature anisotropy profiles in varied regimes of particle collision frequency. Results show that anisotropy is less than 5% in NSTX. We observed that temperature anisotropy peaks near the edge of the plasma on the outboard side of the device. The magnitude of this peak varies inversely with collision frequency.