Gyrokinetic simulation of pedestal degradation correlated with enhanced magnetic turbulence in a DIII-D ELMy H-mode discharge

Jian, X; Chen, J; Holland, C; Chan, V S; Zhang, X R; Yu, G; Yan, Z

doi:10.1088/1361-6587/ad268e

Cited by 1 publication

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References 42 publications

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“…It is predicted that MTM contributes mostly to the electron heat flux and little to the particle and ion heat flux. It is seen from the figure that both Γ e /Q e (red line) and Q i /Q e (blue line) are an order of magnitude lower for the unstable mode k y ρ s ∼ 0.07-0.1, consistent with the transport fingerprints of MTM [17].…”

Section: Gyro-kinetic Simulations For Different Q 95supporting

confidence: 64%

Inter-ELM pedestal turbulence dynamics dependence on q₉₅ and temperature gradient

Yan,

McKee,

Xia

et al. 2024

Nucl. Fusion

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A series of dedicated experiments from DIII-D tokamak provide spatially and temporally resolved measurements of electron density and temperature, and multiscale and multichannel fluctuations over a wide range of conditions. Measurements of long wavelength density fluctuations in the type-I ELMing H-mode pedestal routinely revealed a coexistence of multiple instabilities that exhibit dramatic different dynamic behaviors as q95 and temperature gradient are varied, apparently responsible for limiting pedestal temperature profiles. Two distinct frequency bands of density fluctuations are modulated with ELM cycle with frequency above 200kHz propagating in the electron diamagnetic direction in the lab frame (electron mode) and below 200kHz propagating in the ion diamagnetic direction (ion mode). The electron mode amplitude peaks near the electron temperature gradient region and increases with q95 which seems to be correlated with the increased χe at higher q95, similar to the characteristics expected for Micro-tearing Mode (MTM). At higher q95, during the inter-ELM period, the ion mode decays at later phase of the ELM cycle. Consistently, the poloidal correlation length of the ion mode is also found to reduce which suggests the possible E×B flow shear suppression of ion mode at later phase of the ELM cycle as the Er well recovers. In contrast, the electron mode grows during the ELM cycle and reaches saturation at around 50-60% of ELM period. Linear gyrokinetic simulations find the MTMs as the most unstable mode in the pedestal electron temperature gradient region. The higher q95 and lower magnetic shear destabilize MTMs. These observations provide key insights of the underlying physics of multifield properties and rich dataset of experimental ‘fingerprints’ that enable new tests of the theoretical pedestal models and lead to developing a predictive model for pedestal formation on ITER and future burning plasma experiments.

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Section: Gyro-kinetic Simulations For Different Q 95supporting

confidence: 64%

Inter-ELM pedestal turbulence dynamics dependence on q₉₅ and temperature gradient

Yan,

McKee,

Xia

et al. 2024

Nucl. Fusion

Self Cite

View full text Add to dashboard Cite

show abstract

Gyrokinetic simulation of pedestal degradation correlated with enhanced magnetic turbulence in a DIII-D ELMy H-mode discharge

Cited by 1 publication

References 42 publications

Inter-ELM pedestal turbulence dynamics dependence on q₉₅ and temperature gradient

Inter-ELM pedestal turbulence dynamics dependence on q₉₅ and temperature gradient

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Gyrokinetic simulation of pedestal degradation correlated with enhanced magnetic turbulence in a DIII-D ELMy H-mode discharge

Cited by 1 publication

References 42 publications

Inter-ELM pedestal turbulence dynamics dependence on q95 and temperature gradient

Inter-ELM pedestal turbulence dynamics dependence on q95 and temperature gradient

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Inter-ELM pedestal turbulence dynamics dependence on q₉₅ and temperature gradient

Inter-ELM pedestal turbulence dynamics dependence on q₉₅ and temperature gradient