Article
Physics, Fluids & Plasmas
Wenbin Liu, Yihang Chen, Rui Ke, George McKee, Zheng Yan, Kairui Fang, Zengchen Yang, Zhe Gao, Yi Tan, George R. Tynan
Summary: Theory and simulation propose the existence of an E x B staircase in the plasma core, and the evidence from HL-2A L-mode discharges supports this idea, showing multiple gradient corrugations in T e and n e profiles. Eddy tilting and propagation direction reversals observed in turbulent density fluctuation measurements coincide with profile corrugations, indicating the influence of an ExB staircase on particle and heat transport in L-mode discharges.
PHYSICS OF PLASMAS
(2021)
Article
Physics, Fluids & Plasmas
B. Ph van Milligen, I Voldiner, B. A. Carreras, L. Garcia, M. A. Ochando
Summary: In this study, we measured turbulent quantities inside the plasma edge in the TJ-II stellarator using a Langmuir probe during rotational transform scans. We found that the poloidal plasma velocity and radial electric field have a radial structure that relates to the rotational transform profile and lowest order rational surfaces. The particle flux and flow shear suppression term also exhibit a radial pattern, but their relation to the low-order rational surfaces is less clear. The results suggest the presence of an unknown term, the instability growth rate, in the turbulence evolution equation.
Article
Environmental Sciences
Giuseppe Consolini, Virgilio Quattrociocchi, Simone Benella, Paola De Michelis, Tommaso Alberti, Mirko Piersanti, Maria Federica Marcucci
Summary: This study investigates the properties of plasma motion in the topside ionosphere using measurements from the Chinese Seismo-Electromagnetic Satellite (CSES-01). The results show the turbulent characteristics of the E x B drift velocity and provide evidence of intermittent convective turbulence in the plasma motion at various scales in the auroral region.
Article
Nuclear Science & Technology
A. A. Pshenov, A. S. Kukushkin, A. V. Gorbunov, E. D. Marenkov
Summary: In high recycling and detached plasma regimes, the recycling region defines the properties of the whole scrape-off layer plasma by setting up the density and temperature profiles. As detachment approaches, the plasma temperature near the divertor targets drops and the density increases, making the recycling region less transparent to hydrogen radiation. This paper reviews the effects of hydrogen radiation trapping on the tokamak divertor plasma and demonstrates its impact on the divertor plasma parameters and spectroscopic diagnostics.
NUCLEAR MATERIALS AND ENERGY
(2023)
Article
Physics, Multidisciplinary
L. A. Osorio-Quiroga, G. C. Grime, M. Roberto, R. L. Viana, Y. Elskens, I. L. Caldas
Summary: In this study, the influence of electric and magnetic field profiles on plasma transport in tokamaks is investigated. It is found that sheared electric and magnetic fields can reduce particle transport, and nonmonotonic fields can produce shearless transport barriers, which are highly resistant to perturbations and further decrease the transport coefficient.
BRAZILIAN JOURNAL OF PHYSICS
(2023)
Article
Nuclear Science & Technology
V. Rozhansky, E. Kaveeva, I. Baranovsky, R. A. Pitts
Summary: This paper investigates the regulation of ion transport by neutral particle motion in detached plasma regimes. The results show that in partially ionized plasma, ion transport is strongly influenced by the neutral particles being dragged along the magnetic field and diffusing in the perpendicular direction.
NUCLEAR MATERIALS AND ENERGY
(2022)
Article
Multidisciplinary Sciences
Woonghee Han, Randall A. Pietersen, Rafael Villamor-Lora, Matthew Beveridge, Nicola Offeddu, Theodore Golfinopoulos, Christian Theiler, James L. Terry, Earl S. Marmar, Iddo Drori
Summary: This study applies motion tracking to identify and track turbulent filaments in fusion plasmas using high-frequency videos obtained from Gas Puff Imaging diagnostics. The accuracy of the techniques is confirmed through comparisons of different methods on synthetic and real-world data, and a publicly available dataset and benchmark are provided to facilitate plasma research.
SCIENTIFIC REPORTS
(2022)
Article
Meteorology & Atmospheric Sciences
Zhuorui Wei, Lei Zhang, Yan Ren, Wei Wei, Hongsheng Zhang, Xuhui Cai, Yu Song, Ling Kang
Summary: Observational data from SACOL in July 2008 were used to analyze turbulence intermittency and its influence on land-atmosphere turbulent transport on the Loess Plateau. A new intermittent strength index LISTRevise was proposed to correct misjudgments of turbulence intermittency and better capture the diurnal variation. The study highlights the importance of thermodynamic intermittency correction in accurately quantifying turbulent mixing and transport in planetary boundary layer parameterization schemes.
ATMOSPHERIC RESEARCH
(2021)
Article
Physics, Fluids & Plasmas
Qinghao Yan, Patrick H. Diamond
Summary: This study presents a new mechanism for the formation of the E x B staircase, involving resonant and non-resonant transport. By constructing a turbulence-profile evolution system, a quasi-periodic profile corrugation pattern (the E x B staircase) is found to emerge, with flattened and steeper profiles corresponding to resonant and non-resonant transport regions, respectively. The critical value of the boundary heat flux and the scaling of the step size in the staircase pattern are estimated. The resonant turbulent transport mechanism is also related to the collisionless saturation of zonal flow.
Article
Physics, Fluids & Plasmas
Dragos Iustin Palade, Madalina Vlad, Florin Spineanu
Summary: A detailed analysis of a special type of turbulent pinch mechanism for tungsten (W) ions is presented, which is based on numerical simulations. The mechanism involves a special type of order generated by an average poloidal velocity V (p) superposed on the E x B stochastic drift, leading to a pair of radial symmetric drifts that exactly compensate. The study concludes that this turbulent mechanism can be experimentally relevant for a large domain of parameters and can be responsible for an important amount of the W ion accumulation.
Article
Physics, Fluids & Plasmas
G. M. Staebler, E. A. Belli, J. Candy, J. E. Kinsey, H. Dudding, B. Patel
Summary: This paper verifies and calibrates a new quasi-linear transport model based on a large database of gyrokinetic turbulence simulations. The modification of a key parameter in the model is found to be necessary for better fitting temperature and density gradients. The new model shows significantly improved fit in electron and ion energy fluxes compared to previous saturation models, leading to revisions in related models.
Article
Physics, Fluids & Plasmas
Zihao Wang, Zongliang Dai, Shaojie Wang
Summary: The nonlinear excitation of zonal flows (ZFs) generated by ion-temperature-gradient turbulence in a tokamak plasma is investigated. It is found that ZFs are initially driven by the nonlinear self-interaction of the eigenmode. In the nonlinear saturation, the contribution of modulational instability becomes important and can be comparable to that of the self-interaction mechanism. Additionally, both types of nonlinear wave-wave interactions can be well described by the turbulent energy flux model.
Article
Physics, Fluids & Plasmas
D. Kouprienko, A. D. Gurchenko, E. Z. Gusakov, A. B. Altukhov, L. G. Askinazi, A. A. Belokurov, V. V. Dyachenko, L. A. Esipov, V. A. Ivanov, O. A. Kaledina, S. Lashkul, S. Shatalin, A. Sidorov, N. Tropin, S. Janhunen
Summary: A detailed study of the FT-2 tokamak reveals significant differences in the behavior of deuterium and hydrogen plasmas in high density regimes. It indicates the stability of improved energy confinement in deuterium plasma.
Article
Physics, Fluids & Plasmas
G. Dong, Z. Lin
Summary: A clear understanding of wave-particle interaction and associated transport mechanisms is crucial for accurate modeling and predictions in tokamaks. Global gyrokinetic simulations reveal that electron transport is primarily driven by wave-particle resonance in collisionless trapped electron mode (CTEM) turbulence, while ion transport is mostly driven by nonlinear wave-particle scattering in both CTEM and self-consistent ion temperature gradient (ITG) turbulence. These findings emphasize the importance of considering the roles of linear resonance and nonlinear scattering when constructing reduced transport models.
PLASMA PHYSICS AND CONTROLLED FUSION
(2022)
Article
Thermodynamics
Zhenyuan Tang, Bo Shi, Xueying Li, Jing Ren
Summary: This study investigates the influence of micro-ribs on turbulent momentum and heat transport in micro-ribbed channel flow by Large Eddy Simulation. The results show that micro-ribs enhance heat transport and weaken momentum transport.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)