Particle Dynamics in the RMP Ergodic Layer under the Influence of Edge Plasma Turbulence

The complex processes in edge tokamak plasma are affected (among others) both by resonant magnetic perturbation (RMP) and by plasma turbulence. RMP is nowadays considered to be a candidate for the mitigation of the edge-localized modes (ELMs). The effect of plasma turbulence inthe edge region has not been studied yet. Since both RMP and plasma turbulence should influence plasma dynamics, studies of their simultaneous effect have potential practical implications. Using a simplified model of the turbulence and single-particle simulations, we discovered that its effect at realistic amplitudes changes the ion dynamics significantly. We expect that the turbulence has a similar effect on electrons, thus potentially influencing the ELM mitigation mechanism.

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Studies on impurity seeding and transport in edge and SOL of tokamak plasma

Nuclear Fusion ◽

10.1088/1741-4326/ac44b0 ◽

2021 ◽

Author(s):

Shrish Raj ◽

Nirmal Bisai ◽

Vijay Shankar ◽

Abhijit Sen ◽

Joydeep Ghosh ◽

...

Keyword(s):

Impact Ionization ◽

Plasma Turbulence ◽

Radiation Loss ◽

Tokamak Plasma ◽

Edge Region ◽

Double Positive ◽

Radiation Losses ◽

Impurity Ions ◽

Model Equations ◽

Impurity Ion

Abstract We present numerical simulation studies on impurity seeding using Nitrogen, Neon, and Argon gases. These impurity gases are ionized by the electron impact ionization. These ions can be at multiply ionized states, recombine again with the plasma electrons, and radiate energy. The radiation losses are estimated using a non-coronal equilibrium model. A set of 2D model equations to describe their self-consistent evolution are derived using interchange plasma turbulence in the edge and SOL regions and solved using BOUT++. It is found that impurity ions (with single or double-positive charges) move in the inward direction with a velocity ∼ 0.02cs so that these fluxes are negative. These fluxes are analyzed for different strengths of an effective gravity that help to understand the impurity ion dynamics. Increased gravity shows an accumulation of certain charged species in the edge region. The radiation loss is seen to have a fluctuation in time with frequency 5-20 kHz that closely follows the behavior of the interchange plasma turbulence. The simulation results on the radiated power and its frequency spectrum compare favourably with observations on the Aditya-U tokamak. The negative fluxes of the impurity ions, their dynamics in the edge region, and the fluctuating nature of the radiation loss are the most important results of this work.

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Reduction of edge plasma turbulence via cross-phase decrease by zonal fields

Plasma Physics and Controlled Fusion ◽

10.1088/1361-6587/ab2973 ◽

2019 ◽

Vol 61 (8) ◽

pp. 085024 ◽

Cited By ~ 2

Author(s):

Chang-Bae Kim ◽

Chan-Yong An ◽

Byunghoon Min

Keyword(s):

Plasma Turbulence ◽

Edge Plasma

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Scaling of edge-plasma turbulence in the Caltech tokamak

Nuclear Fusion ◽

10.1088/0029-5515/23/12/007 ◽

1983 ◽

Vol 23 (12) ◽

pp. 1625-1641 ◽

Cited By ~ 65

Author(s):

S.J. Zweben ◽

R.W. Gould

Keyword(s):

Plasma Turbulence ◽

Edge Plasma

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Observation of spatial intermittency in Tokamak plasma turbulence

Physics of Plasmas ◽

10.1063/1.873566 ◽

1999 ◽

Vol 6 (8) ◽

pp. 3263-3266 ◽

Cited By ~ 5

Author(s):

Guiding Wang ◽

Wandong Liu ◽

Chang-Xuan Yu ◽

Yizhi Wen ◽

Chao Wang ◽

...

Keyword(s):

Plasma Turbulence ◽

Tokamak Plasma

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Anomalous diffusion and radial electric field generation due to edge plasma turbulence

Contributions to Plasma Physics ◽

10.1002/ctpp.200410029 ◽

2004 ◽

Vol 44 (13) ◽

pp. 203-204 ◽

Cited By ~ 2

Author(s):

R. Pánek ◽

L. Krlín ◽

D. Tskhakaya ◽

S. Kuhn ◽

J. Stöckel ◽

...

Keyword(s):

Electric Field ◽

Anomalous Diffusion ◽

Radial Electric Field ◽

Plasma Turbulence ◽

Edge Plasma ◽

Field Generation ◽

Electric Field Generation

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A Multiscale Method - Equation Free Projective Integration Applied to Global Gyrokinetic Particle Simulations of Plasma Turbulence

10.1109/icops35962.2018.9575769 ◽

2018 ◽

Author(s):

Junyi Cheng ◽

Scott E. Parker ◽

Yang Chen

Keyword(s):

Plasma Turbulence ◽

Multiscale Method ◽

Particle Simulations

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Multidimensional Iterative Filtering: a new approach for investigating plasma turbulence in numerical simulations

Journal of Plasma Physics ◽

10.1017/s0022377820001221 ◽

2020 ◽

Vol 86 (5) ◽

Author(s):

Emanuele Papini ◽

Antonio Cicone ◽

Mirko Piersanti ◽

Luca Franci ◽

Petr Hellinger ◽

...

Keyword(s):

Numerical Simulations ◽

Complex Dynamics ◽

Spatial Scales ◽

Plasma Turbulence ◽

Astrophysical Plasmas ◽

Plasma Dynamics ◽

New Approach ◽

Particle In Cell ◽

Multidimensional Signals ◽

Iterative Filtering

Turbulent space and astrophysical plasmas exhibit a complex dynamics, which involves nonlinear coupling across different temporal and spatial scales. There is growing evidence that impulsive events, such as magnetic reconnection instabilities, lead to a spatially localized enhancement of energy dissipation, thus speeding up the energy transfer at small scales. Capturing such a diverse dynamics is challenging. Here, we employ the Multidimensional Iterative Filtering (MIF) method, a novel technique for the analysis of non-stationary multidimensional signals. Unlike other traditional methods (e.g. based on Fourier or wavelet decomposition), MIF does not require any previous assumption on the functional form of the signal to be identified. Using MIF, we carry out a multiscale analysis of Hall-magnetohydrodynamic (HMHD) and hybrid particle-in-cell (HPIC) numerical simulations of decaying plasma turbulence. The results assess the ability of MIF to spatially identify and separate the different scales (the MHD inertial range, the sub-ion kinetic and the dissipation scales) of the plasma dynamics. Furthermore, MIF decomposition allows localized current structures to be detected and their contribution to the statistical and spectral properties of turbulence to be characterized. Overall, MIF arises as a very promising technique for the study of turbulent plasma environments.

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