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Magnetised plasma turbulence can have a multiscale character: instabilities driven by mean temperature gradients drive turbulence at the disparate scales of the ion and the electron gyroradii. Simulations of multiscale turbulence, using…

Plasma Physics · Physics 2020-11-25 M. R. Hardman , M. Barnes , C. M. Roach

Differential rotation is known to suppress linear instabilities in fusion plasmas. However, even in the absence of growing eigenmodes, subcritical fluctuations that grow transiently can lead to sustained turbulence. Here transient growth of…

Plasma Physics · Physics 2015-08-26 A. A. Schekochihin , E. G. Highcock , S. C. Cowley

The characteristics of ion temperature gradient (ITG) turbulence in the presence of a magnetic island are numerically investigated using a gyrokinetic model. We observe that in the absence of the usual ITG drive gradient, a solitary…

Plasma Physics · Physics 2023-12-29 Jingchun Li , J. Bao , Z. Lin , J. Q. Dong , Yong Liu , Y. R. Qu

The physical processes taking place at the edge region are crucial for the operation of tokamaks as they govern the interaction of hot plasma with the vessel walls. Numerical modeling of the edge with state-of-the-art codes attempts to…

Plasma Physics · Physics 2020-08-26 I. Keramidas Charidakos , J. R. Myra , S. Ku , R. M. Churchill , R. Hager , C. S. Chang , S. Parker

Global electromagnetic gyrokinetic simulations are performed with the Particle-in-Cell code ORB5 for an ITER Pre-Fusion-Power-Operation (PFPO) plasma scenario, with half-field (2.65 T) and half-current (7.5 MA). We report on a 'multi-scale'…

Plasma Physics · Physics 2022-10-12 T. Hayward-Schneider , Ph. Lauber , A. Bottino , A. Mishchenko

Linear gyro-kinetic simulations of the classical tearing mode in three-dimensional toroidal geometry were performed using the global gyro kinetic turbulence code, GKW . The results were benchmarked against a cylindrical ideal MHD and…

The study and characterization of the diversity of spatiotemporal patterns generated when a rectangular layer of fluid is locally heated beneath its free surface is presented. We focus on the instability of a stationary cellular pattern of…

Pattern Formation and Solitons · Physics 2009-01-21 Montserrat A. Miranda , Javier Burguete

The local stability of ion-temperature gradient driven mode (ITG) in the presence of a given radial electric field is investigated using gyrokinetic theory and ballooning mode formalism with toroidal effect accounted for. It is found that,…

Plasma Physics · Physics 2021-11-24 Ningfei Chen , Hanyuan Hu , Xiangyu Zhang , Shizhao Wei , Zhiyong Qiu

In this paper, we propose a one-dimensional disordered plasmonic structure composed of a graphene single layer placed on a random grating composed of InAs. The propagation of a plasmonic wave through this structure is investigated…

Optics · Physics 2018-09-11 Abbas Ghasempour Ardakani , Marzieh Sedaghat Nejad

We examine the role of the gravitational instability in an isothermal, self-gravitating layer threaded by magnetic fields on the formation of filaments and dense cores. Using numerical simulation we follow the non-linear evolution of a…

Solar and Stellar Astrophysics · Physics 2015-06-19 Sven Van Loo , Eric Keto , Qizhou Zhang

GX is a code for solving the nonlinear gyrokinetic system for low-frequency turbulence in magnetized plasmas, particularly tokamaks and stellarators. In GX, our primary motivation and target is a fast gyrokinetic solver that can be used for…

Plasma Physics · Physics 2024-04-30 N. R. Mandell , W. Dorland , I. Abel , R. Gaur , P. Kim , M. Martin , T. Qian

First results from the optimized helias Wendelstein 7-X stellarator (W7-X) have shown that core transport is no longer mostly neoclassical, as is the case in previous kinds of stellarators. Instead, turbulent transport poses a serious…

This paper presents the first gyrokinetic (GK) simulations of edge and scrape-off layer (SOL) turbulence accelerated by a velocity-space spectral approach in the full-f GK code GENE-X. Building upon the original grid velocity-space…

Plasma Physics · Physics 2024-11-15 B. J. Frei , P. Ulbl , J. Trilaksono , F. Jenko

We introduce the longitudinal and transverse static surface modes and use them to solve the full-wave electromagnetic scattering problem from penetrable objects. The longitudinal static modes are the eigenmodes with zero surface curl of the…

Mesoscale and Nanoscale Physics · Physics 2023-08-16 Carlo Forestiere , Giovanni Gravina , Giovanni Miano , Guglielmo Rubinacci , Antonello Tamburrino

Rotational mixing, the key process in stellar evolution, transports angular momentum and chemical elements in stellar radiative zones. In the past two decades, an emphasis has been placed on the turbulent transport induced by the vertical…

Solar and Stellar Astrophysics · Physics 2020-03-25 Junho Park , Vincent Prat , Stéphane Mathis

Microinstabilities exhibit a rich variety of behavior in stellarators due to the many degrees of freedom in the magnetic geometry. It has recently been found that certain stellarators (quasi-isodynamic ones with maximum-$J$ geometry) are…

Plasma Physics · Physics 2015-06-17 J. H. E. Proll , P. Xanthopoulos , P. Helander

Boundary plasma physics plays an important role in tokamak confinement, but is difficult to simulate in a gyrokinetic code due to the scale-inseparable nonlocal multi-physics in magnetic separatrix and open magnetic field geometry. Neutral…

Plasma Physics · Physics 2017-01-26 S. Ku , R. M. Churchill , C. S. Chang , R. Hager , E. S. Yoon , M. Adams , E. D'Azevedo , P. H. Worley

The conventional ion temperature gradient or \eta_i mode is known to propagate in the ion diamagnetic direction. Investigation of a generic drift fluid model with warm ions and adiabatic electrons, reveals that as \eta_i decreases, the…

Plasma Physics · Physics 2022-03-17 Z. Y. Liu , Y. Z. Zhang , S. M. Mahajan , T. Xie

Several simulations of turbulence in the Large Plasma Device (LAPD) [W. Gekelman et al., Rev. Sci. Inst. 62, 2875 (1991)] are energetically analyzed and compared with each other and with the experiment. The simulations use the same model,…

Plasma Physics · Physics 2013-05-16 B. Friedman , T. A. Carter , M. V. Umansky , D. Schaffner , I. Joseph

It is usually assumed that tunneling current is fairly independent of temperature. By performing an atomistic transport simulation, we show, to the contrary, that the subthreshold tunneling current in a graphene nanoribbon (GNR)…

Mesoscale and Nanoscale Physics · Physics 2009-10-01 Youngki Yoon , Sayeef Salahuddin