Abstract Details
Abstracts
Author: Myriam Hamed
Requested Type: Poster
Submitted: 2025-02-18 15:53:01
Co-authors: D.R. Hatch, M.J. Pueschel, T.Jitsuk
Contact Info:
The university of Texas
2515 Speedway, C1600 PMA 5.208
austin, Texas 78712
USA
Abstract Text:
In magnetic confinement fusion, accurately predicting turbulent transport in tokamak edge plasmas is essential for understanding confinement properties. Microtearing modes (MTs) play a critical role in electron heat transport, contributing to turbulence-driven energy losses that affect overall plasma performance.
This study explores the different branches of MTs in both the core and pedestal regions of tokamak plasmas, using a combination of local and global linear and nonlinear gyrokinetic simulations. The dependence of MT instability on key parameters—collisionality, plasma beta, wavenumber spectra, and electron temperature gradients—is systematically examined.
To quantify MT-driven heat transport, a quasilinear heat flux formulation is developed and tested. The Solve_AP quasilinear transport model, introduced in this study, computes heat flux predictions by integrating linear growth rates. Benchmarking against nonlinear electromagnetic heat fluxes from GENE simulations confirms the strong reliability of this approach in capturing MT-driven transport trends.
Nonlinear analysis further reveals distinct MT saturation mechanisms. In the core region, electrostatic fluctuations and zonal flows suppress MT-driven transport. In the pedestal, electromagnetic fluctuations, particularly zonal fields, dominate nonlinear saturation.
Interestingly, removing electrostatic fluctuations increases heat flux despite linear stabilization, suggesting a shift in the dominant saturation mechanism.
These findings provide new insights into the distinct nature of core and pedestal MTs, their role in tokamak confinement, and the effectiveness of reduced transport models in predicting their behavior. By refining the understanding of MT-driven transport, this study offers a valuable framework for optimizing tokamak performance in future fusion experiments.
Characterization: 1.0
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