Turbulent Transport in Magnetized Plasmas

Horton, W.

doi:10.1142/8362

Cited by 76 publications

(74 citation statements)

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“…Understanding electron thermal transport and the causes giving rise to the anomalous levels experimentally observed is a key requirement in order to achieve a predictive capability for the confinement of future fusion devices such as ITER or FNSF (Fusion Nuclear Science Facility). 4 Ample theory and numerical simulations [5][6][7][8][9][10][11][12] have suggested that micro instabilities driven by the electron temperature gradient (ETG) could be responsible for anomalous electron thermal transport levels observed experimentally. The ETG toroidal instability has a characteristic scale length on the order of the electron gyro radius (k ?…”

Section: Introductionmentioning

confidence: 99%

Stabilization of electron-scale turbulence by electron density gradient in national spherical torus experiment

et al. 2015

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Theory and experiments have shown that electron temperature gradient (ETG) turbulence on the electron gyro-scale, k ? q e Շ 1, can be responsible for anomalous electron thermal transport in NSTX. Electron scale (high-k) turbulence is diagnosed in NSTX with a high-k microwave scattering system [D. R. Smith et al., Rev. Sci. Instrum. 79, 123501 (2008)]. Here we report on stabilization effects of the electron density gradient on electron-scale density fluctuations in a set of neutral beam injection heated H-mode plasmas. We found that the absence of high-k density fluctuations from measurements is correlated with large equilibrium density gradient, which is shown to be consistent with linear stabilization of ETG modes due to the density gradient using the analytical ETG linear threshold in F. Jenko et al. [Phys. Plasmas 8, 4096 (2001)] and linear gyrokinetic simulations with GS2 [M. Kotschenreuther et al., Comput. Phys. Commun. 88, 128 (1995)]. We also found that the observed power of electron-scale turbulence (when it exists) is anti-correlated with the equilibrium density gradient, suggesting density gradient as a nonlinear stabilizing mechanism. Higher density gradients give rise to lower values of the plasma frame frequency, calculated based on the Doppler shift of the measured density fluctuations. Linear gyrokinetic simulations show that higher values of the electron density gradient reduce the value of the real frequency, in agreement with experimental observation. Nonlinear electron-scale gyrokinetic simulations show that high electron density gradient reduces electron heat flux and stiffness, and increases the ETG nonlinear threshold, consistent with experimental observations. V C 2015 AIP Publishing LLC.

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Section: Introductionmentioning

confidence: 99%

Stabilization of electron-scale turbulence by electron density gradient in national spherical torus experiment

et al. 2015

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“…[1][2][3][4][5][6] The magnetic flux tubes with vortical motion are a fundamental model for understanding solar tornadoes, 7-10 astrophysical jets 11,12 and disks around rotating magnetised stars and black holes 13 as well as some configurations of confined laboratory plasmas. [14][15][16] Recent solar observations from the Atmospheric Imaging Assembly (AIA) on board NASA's space-based Solar Dynamics Observatory (SDO) and the Crisp Imaging Spectropolarimeter (CRISP) on the ground-based, Swedish 1-m Solar Telescope have generated a lot of interest in solar magnetic tornadoes as possible channels for energy transfer into the solar corona. 9,10 The acoustic gravity tornadoes can also appear in the form of twisted density structures.…”

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confidence: 99%

Tornado model for a magnetised plasma

et al. 2018

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“…The escape of magnetic field lines in a magnetically confined fusion plasma with destroyed magnetic surfaces presents fractal exit basins [7,8]. Another problem in which such fractal structures appear is the charged particle motion in a magnetized plasma under electrostatic drift waves [9], which is a relevant scenario in the study of plasma turbulence in the plasma edge in a tokamak [10,11].…”

Section: Introductionmentioning

confidence: 99%

Fractal boundaries in chaotic hamiltonian systems

Viana

Mathias

Marcus

et al. 2017

J. Phys.: Conf. Ser.

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Abstract. Fractal structures are typically present in the dynamics of chaotic orbits in nonintegrable open Hamiltonian systems and result from the extremely complicated nature of the invariant manifolds of unstable periodic orbits. Exit basins, the set of initial conditions leading to orbits escaping through a given exit, have very frequently fractal boundaries. In this work we analyze exit basin boundaries in a dynamical system of physical interest, namely the motion of charged particles in a magnetized plasma subjected to electrostatic drift waves, and characterize in a quantitative way the fractality of these structures and their observable consequences, as the final-state uncertainty.

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Turbulent Transport in Magnetized Plasmas

Cited by 76 publications

References 0 publications

Stabilization of electron-scale turbulence by electron density gradient in national spherical torus experiment

Stabilization of electron-scale turbulence by electron density gradient in national spherical torus experiment

Tornado model for a magnetised plasma

Fractal boundaries in chaotic hamiltonian systems

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