Role of perturbed parallel magnetic field effects in predicting turbulent transport in NSTX

McClenaghan, J.; Neiser, T. F.; Halpern, F. D.; Thome, K. E.; Turnbull, A. D.; DeShazer, E. W.; Meneghini, O. M.; Avdeeva, G.; Lestz, J. B.; Candy, J.

doi:10.1088/1361-6587/adc9e2

Role of perturbed parallel magnetic field effects in predicting turbulent transport in NSTX

Journal Article · Tue Apr 22 00:00:00 EDT 2025 · Plasma Physics and Controlled Fusion

DOI:https://doi.org/10.1088/1361-6587/adc9e2· OSTI ID:2560929

; ; ; ; Turnbull, A. D.; DeShazer, E. W.; ; ; ;

Abstract

This study presents analysis of gyrokinetic simulations on the National Spherical Torus Experiment (NSTX) to investigate the effects of electromagnetic fields on plasma turbulence and transport. The simulations, performed with varying levels of fidelity using the gyrokinetic CGYRO code, include electrostatic (ES), single-field electromagnetic (EM1), and two-field electromagnetic (EM2) models. A detailed comparison across the simulation database reveals that electromagnetic effects increase both predicted growth rates and quasilinear fluxes, with EM2 simulations producing stronger turbulence than ES and EM1 cases. Quasilinear modeling using QLGYRO demonstrates that while the perturbed parallel magnetic field $(δ B_{∥}$ ) does not drastically affect the total flux at experimental gradients, it leads to a shift in the dominant instability, altering mode structures from microtearing to kinetic ballooning modes (KBMs). The proximity of the plasma profiles to the KBM threshold is explored, with the experimental conditions being near the onset of KBM-driven transport. The KBM, with its large growth rates, is identified as a potential driver of electron temperature flattening, as it can rapidly transport heat across flux surfaces. Performing stability analysis shows core-localized unstable a low- $n_{tor}$ mode that could contribute to the flattening at the early times of the discharge. TGYRO predictive modeling, incorporating both TGLF and QLGYRO, indicates that the inclusion of $δ B_{∥}$ significantly improves the accuracy of temperature profile predictions in NSTX high-beta plasmas, although challenges remain in modeling the sharp flux discontinuities caused by KBM-driven instabilities.

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Sponsoring Organization:: USDOE

Grant/Contract Number:: AC02-09CH11466

OSTI ID:: 2560929

Alternate ID(s):: OSTI ID: 2550680
OSTI ID: 2574062

Journal Information:: Plasma Physics and Controlled Fusion, Journal Name: Plasma Physics and Controlled Fusion Journal Issue: 5 Vol. 67; ISSN 0741-3335

Publisher:: IOP PublishingCopyright Statement

Country of Publication:: United Kingdom

Language:: English

References (29)

A high-accuracy Eulerian gyrokinetic solver for collisional plasmas Candy, J.; Belli, E. A.; Bravenec, R. V. Journal of Computational Physics, Vol. 324 https://doi.org/10.1016/j.jcp.2016.07.039	journal	November 2016
Beta scaling of transport in microturbulence simulations Candy, J. Physics of Plasmas, Vol. 12, Issue 7 https://doi.org/10.1063/1.1954123	journal	July 2005
A theory-based transport model with comprehensive physics Staebler, G. M.; Kinsey, J. E.; Waltz, R. E. Physics of Plasmas, Vol. 14, Issue 5 https://doi.org/10.1063/1.2436852	journal	May 2007
Gyrokinetic turbulence simulations at high plasma beta Pueschel, M. J.; Kammerer, M.; Jenko, F. Physics of Plasmas, Vol. 15, Issue 10 https://doi.org/10.1063/1.3005380	journal	October 2008
Tokamak profile prediction using direct gyrokinetic and neoclassical simulation Candy, J.; Holland, C.; Waltz, R. E. Physics of Plasmas, Vol. 16, Issue 6 https://doi.org/10.1063/1.3167820	journal	June 2009
Fully electromagnetic gyrokinetic eigenmode analysis of high-beta shaped plasmas Belli, E. A.; Candy, J. Physics of Plasmas, Vol. 17, Issue 11 https://doi.org/10.1063/1.3495976	journal	November 2010
The role of zonal flows in the saturation of multi-scale gyrokinetic turbulence Staebler, G. M.; Candy, J.; Howard, N. T. Physics of Plasmas, Vol. 23, Issue 6 https://doi.org/10.1063/1.4954905	journal	June 2016
Global Alfvén modes: Theory and experiment* Turnbull, A. D.; Strait, E. J.; Heidbrink, W. W. Physics of Fluids B: Plasma Physics, Vol. 5, Issue 7 https://doi.org/10.1063/1.860742	journal	July 1993
Microtearing instabilities and electron thermal transport in low and high collisionality NSTX discharges Rafiq, T.; Kaye, S.; Guttenfelder, W. Physics of Plasmas, Vol. 28, Issue 2 https://doi.org/10.1063/5.0029120	journal	February 2021
Linear ion-scale microstability analysis of high and low-collisionality NSTX discharges and NSTX-U projections Clauser, C. F.; Guttenfelder, W.; Rafiq, T. Physics of Plasmas, Vol. 29, Issue 10 https://doi.org/10.1063/5.0102169	journal	October 2022
Transition from ITG to MTM linear instabilities near pedestals of high density plasmas McClenaghan, J.; Slendebroek, T.; Staebler, G. M. Physics of Plasmas, Vol. 30, Issue 4 https://doi.org/10.1063/5.0141179	journal	April 2023
Electron temperature gradient instability and transport analysis in NSTX and NSTX-U plasmas Clauser, C. F.; Rafiq, T.; Parisi, J. Physics of Plasmas, Vol. 32, Issue 2 https://doi.org/10.1063/5.0232697	journal	February 2025
Anomalous electron transport due to multiple high frequency beam ion driven Alfvén eigenmodes Gorelenkov, N. N.; Stutman, D.; Tritz, K. Nuclear Fusion, Vol. 50, Issue 8 https://doi.org/10.1088/0029-5515/50/8/084012	journal	July 2010
Exploration of the equilibrium operating space for NSTX-Upgrade Gerhardt, S. P.; Andre, R.; Menard, J. E. Nuclear Fusion, Vol. 52, Issue 8 https://doi.org/10.1088/0029-5515/52/8/083020	journal	August 2012
Integrated modeling applications for tokamak experiments with OMFIT Meneghini, O.; Smith, S. P.; Lao, L. L. Nuclear Fusion, Vol. 55, Issue 8 https://doi.org/10.1088/0029-5515/55/8/083008	journal	July 2015
Nonlinear electromagnetic gyrokinetic simulations of tokamak plasmas Jenko, F.; Dorland, W. Plasma Physics and Controlled Fusion, Vol. 43, Issue 12A https://doi.org/10.1088/0741-3335/43/12A/310	journal	November 2001
Kinetic calculation of neoclassical transport including self-consistent electron and impurity dynamics Belli, E. A.; Candy, J. Plasma Physics and Controlled Fusion, Vol. 50, Issue 9 https://doi.org/10.1088/0741-3335/50/9/095010	journal	July 2008
Accuracy of kinetic equilibrium reconstruction of NSTX and NSTX-U plasmas and its impact on the transport and stability analysis Avdeeva, G.; Thome, K. E.; Berkery, J. W. Plasma Physics and Controlled Fusion, Vol. 66, Issue 11 https://doi.org/10.1088/1361-6587/ad788a	journal	September 2024
Recent progress in understanding electron thermal transport in NSTX Ren, Y.; Belova, E.; Gorelenkov, N. Nuclear Fusion, Vol. 57, Issue 7 https://doi.org/10.1088/1741-4326/aa4fba	journal	March 2017
Verification of a quasi-linear model for gyrokinetic turbulent transport Staebler, G. M.; Belli, E. A.; Candy, J. Nuclear Fusion, Vol. 61, Issue 11 https://doi.org/10.1088/1741-4326/ac243a	journal	September 2021
Energy transport analysis of NSTX plasmas with the TGLF turbulent and NEO neoclassical transport models Avdeeva, G.; Thome, K. E.; Smith, S. P. Nuclear Fusion, Vol. 63, Issue 12 https://doi.org/10.1088/1741-4326/acfc56	journal	October 2023
NSTX-U research advancing the physics of spherical tokamaks Berkery, John W.; Adebayo-Ige, Promise Oluwagbope; Al Khawaldeh, H. Nuclear Fusion https://doi.org/10.1088/1741-4326/ad3092	journal	March 2024
On the importance of parallel magnetic-field fluctuations for electromagnetic instabilities in STEP Kennedy, D.; Roach, C. M.; Giacomin, M. Nuclear Fusion, Vol. 64, Issue 8 https://doi.org/10.1088/1741-4326/ad58f3	journal	July 2024
Correlation between Electron Transport and Shear Alfvén Activity in the National Spherical Torus Experiment Stutman, D.; Delgado-Aparicio, L.; Gorelenkov, N. Physical Review Letters, Vol. 102, Issue 11 https://doi.org/10.1103/PhysRevLett.102.115002	journal	March 2009
Channeling of the Energy and Momentum during Energetic-Ion-Driven Instabilities in Fusion Plasmas Kolesnichenko, Ya. I.; Yakovenko, Yu. V.; Lutsenko, V. V. Physical Review Letters, Vol. 104, Issue 7 https://doi.org/10.1103/PhysRevLett.104.075001	journal	February 2010
Electromagnetic Transport from Microtearing Mode Turbulence Guttenfelder, W.; Candy, J.; Kaye, S. M. Physical Review Letters, Vol. 106, Issue 15 https://doi.org/10.1103/PhysRevLett.106.155004	journal	April 2011
Coupling of Neutral-Beam-Driven Compressional Alfvén Eigenmodes to Kinetic Alfvén Waves in NSTX Tokamak and Energy Channeling Belova, E. V.; Gorelenkov, N. N.; Fredrickson, E. D. Physical Review Letters, Vol. 115, Issue 1 https://doi.org/10.1103/PhysRevLett.115.015001	journal	June 2015
Ideal MHD Limited Electron Temperature in Spherical Tokamaks Jardin, S. C.; Ferraro, N. M.; Guttenfelder, W. Physical Review Letters, Vol. 128, Issue 24 https://doi.org/10.1103/PhysRevLett.128.245001	journal	June 2022
Scaling of Electron and Ion Transport in the High-Power Spherical Torus NSTX Kaye, S. M.; Bell, R. E.; Gates, D. Physical Review Letters, Vol. 98, Issue 17 https://doi.org/10.1103/PhysRevLett.98.175002	journal	April 2007

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