Modeling electron temperature profiles in the pedestal with simple formulas for ETG transport

Hatch, D.R.; Kotschenreuther, M.T.; Li, P.-Y.; Chapman-Oplopoiou, B.; Parisi, J.; Mahajan, S.M.; Groebner, R.

doi:10.1088/1741-4326/ad3972

Cited by 2 publications

(3 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the vicinity of the narrow and wide GCP branches, where the KBM becomes marginally stable, the KBM turbulent transport ratios such as χ e /D e and χ e /D Z vary significantly. This also has implications for reduced transport models in the pedestal [19,35,113,116], given that the KBM can produce significant particle and heat flux.…”

Section: Discussionmentioning

confidence: 99%

“…Negative values of (χ i + χ e )/D e have been reported and were explained by a particle pinch [56], which could explain why we find χ e /D e < 0 for TEM. While nonlinear simulations [112] are required for accurate flux ratios, the strong variation of χ e /D e close to marginal stability presents challenges to reduced transport-based pedestal models [19,113].…”

Section: Gyrokinetic Stability and Transportmentioning

confidence: 99%

“…Additionally, for simplicity, in this work we only consider KBM contributions to q e /Γ e . See [19,35,113,116] for pedestal transport models with contributions from various instabilities.…”

Section: Aspect Ratio Dependencementioning

confidence: 99%

See 2 more Smart Citations

Stability and transport of gyrokinetic critical pedestals

Parisi,

Nelson,

Guttenfelder

et al. 2024

Nucl. Fusion

Self Cite

View full text Add to dashboard Cite

A gyrokinetic threshold model for pedestal width-height scaling prediction is applied to multiple devices. A shaping and aspect-ratio scan is performed on NSTX equilibria, finding $\Delta_{\mathrm{ped}} = 0.92 A^{1.04} \kappa^{-1.24} 0.38^{\delta} \beta_{\theta,\mathrm{ped}}^{1.05}$ for the wide-pedestal branch with pedestal width $\Delta_{\mathrm{ped}}$, aspect-ratio $A$, elongation $\kappa$, triangularity $\delta$, and normalized pedestal height $\beta_{\theta,\mathrm{ped}}$. A width-transport scaling is found to vary significantly if pedestal height is varied either with fixed density or fixed temperature, showing how fueling and heating sources affect the pedestal density and temperature profiles for the kinetic-ballooning-mode (KBM) limited profiles. For an NSTX equilibrium, at fixed density, the wide-branch is $\Delta_{\mathrm{ped} } = 0.028 \left(q_e/\Gamma_e - 1.7 \right)^{1.5} \sim \eta_e ^{1.5}$ and at fixed temperature $\Delta_{\mathrm{ped} } = 0.31 \left(q_e/\Gamma_e - 4.7 \right)^{0.85} \sim \eta_e ^{0.85}$ where $q_e$ and $\Gamma_e$ are turbulent electron heat and particle fluxes and $\eta_e = \nabla \ln T_e / \nabla \ln n_e$ for electron temperature $T_e$ and density $n_e$. Pedestals close to the KBM limit are shown to have modified turbulent transport coefficients compared to strongly driven KBMs. The role of flow-shear is studied as a width-height scaling constraint and pedestal saturation mechanism for a standard and lithiated wide pedestal discharge. Finally, the stability, transport, and flow-shear constraints are combined and examined for a NSTX experiment.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Gyrokinetic Stability and Transportmentioning

confidence: 99%

See 1 more Smart Citation

Stability and transport of gyrokinetic critical pedestals

Parisi,

Nelson,

Guttenfelder

et al. 2024

Nucl. Fusion

Self Cite

View full text Add to dashboard Cite

show abstract

Core performance predictions in projected SPARC first-campaign plasmas with nonlinear CGYRO

Rodriguez-Fernandez,

Howard,

Saltzman

et al. 2024

Physics of Plasmas

View full text Add to dashboard Cite

This work characterizes the core transport physics of SPARC early-campaign plasmas using the PORTALS-CGYRO framework. Empirical modeling of SPARC plasmas with L-mode confinement indicates an ample window of breakeven (Q > 1) without the need of H-mode operation. Extensive modeling of multi-channel (electron energy, ion energy, and electron particle) flux-matched conditions with the nonlinear CGYRO code for turbulent transport coupled to the macroscopic plasma evolution using PORTALS reveals that the maximum fusion performance to be attained will be highly dependent on the near-edge pressure. Stiff core transport conditions are found, particularly when fusion gain approaches unity, and predicted density peaking is found to be in line with empirical databases of particle source-free H-modes. Impurity optimization is identified as a potential avenue to increase fusion performance while enabling core-edge integration. Extensive validation of the quasilinear TGLF model builds confidence in reduced-model predictions. The implications of projecting L-mode performance to high-performance and burning-plasma devices is discussed, together with the importance of predicting edge conditions.

show abstract

Modeling electron temperature profiles in the pedestal with simple formulas for ETG transport

Cited by 2 publications

References 44 publications

Stability and transport of gyrokinetic critical pedestals

Stability and transport of gyrokinetic critical pedestals

Core performance predictions in projected SPARC first-campaign plasmas with nonlinear CGYRO

Contact Info

Product

Resources

About