Inferring Fast Ion Dynamics in the C-2W FRC via Integrated Data Analysis

In TAE Technologies’ current experimental device, C-2W (also called “Norman”) [1], record breaking, advanced beam-driven field reversed configuration (FRC) plasmas are produced and sustained in steady state utilizing variable energy neutral beams (15 – 40 keV, total power up to 20 MW), advanced divertors, end bias electrodes, and an active plasma control system. Fast ions produced via neutral beam injection are critically important for FRC heating, current drive, and stabilization.  Due to the high-beta nature of the C-2W FRC, fast ion orbits are large, with orbit radii of the same order as the plasma size. This has significant advantages, offering stability to the plasma and de-coupling the fast ions from local turbulence [2], but it also introduces difficulty in analyzing or measuring their behavior directly. This creates an incentive to leverage fast ion diagnostic data as efficiently as possible though the use of forward modeling and integrated data analysis techniques. We present the framework for an integrated data analysis workflow, utilizing Monte Carlo (MC) simulations of fast ion trajectories to forward model diagnostic data which depend on fast ion behavior – neutral particle analyzers (NPAs), scintillating neutron detectors, fast ion D-alpha (FIDA), and bolometry, among others. These modelled signals are then compared to experimental results, and iterated until cohesive, experimentally-validated models for fast ion behavior can be produced. We also examine the application of this framework to several topics of interest, demonstrating the effectiveness of these techniques.

 

[1] H. Gota et al, Nucl. Fusion 59, 112009 (2019)

[2] M. Binderbauer et al., Phys. Plasmas 22, 056110 (2015).