Abstract Details
Abstracts
Author: Neeraj Kumar
Requested Type: Consider for Invited
Submitted: 2024-03-28 19:30:23
Co-authors: M. Reynolds, G. Avdeeva, J. Candy, G. Staebler, E. A. Belli, C. P. McNally and GF Team
Contact Info:
General Fusion Inc.
6020 Russ Baker Way
Richmond, BC V7B 1B4
Canada
Abstract Text:
General Fusion (GF) is developing a Magnetized Target Fusion (MTF) concept as a path towards commercial fusion power production. In MTF, a spherical target plasma is formed by coaxial helicity injection into a liquid metal flux conserver that is then compressed to fusion conditions. PI3 at GF is a non-compressing device with solid lithium walls used to study and improve MTF targets to design future machines. Before a reactor-scale demonstration, an understanding of plasma behaviour and thermal transport in an existing MTF device is needed. This work presents the thermal transport analysis of PI3 plasmas using gyrokinetic simulations to characterize turbulent transport and microinstabilities present in the system. Here, gyrokinetic analysis has been extended for the first time to completely different plasma conditions of PI3, which has low temperature and high collisionality as compared to standard tokamaks. Linear and nonlinear (NL) gyrokinetic flux tube simulations are performed for PI3 shot 18669 at four radial locations r/a=0.60, 0.65, 0.70, and 0.75, using the gyrokinetic code CGYRO [1]. Linear simulations indicate that ITG and TEM are the dominant modes in the ion-scale range. In the NL regime, the dominant transport channels for turbulent heat losses are ITG modes at small wavenumber, whereas TEM modes are suppressed due to high collisionality. Significant findings are that the plasma beta stabilizes turbulent transport at all radial locations, consistent with linear behaviour, except at r/a=0.75, where the spectra peak at the lowest wavenumber k_y ρ_i=0.05 and contribute to large heat fluxes. Moreover, the turbulence has a bursty nature, with intermittent periods of very large transport due to self-regulated zonal flows. The ongoing work is to compare CGYRO fluxes with reduced quasilinear code TGLF [2] to validate these models for GF plasma conditions.
[1] J Candy et al., JCP 324, 73 (2016)
[2] G Staebler et al., PoP 14, 055909 (2007)
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