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Although the basic concept of a stellarator was known since the early days of fusion research, advances in computational technology have enabled the modelling of increasingly complicated devices, leading up to the construction of…

In this paper the global mode structures of linear ion-temperature-gradient (ITG) modes in tokamak plasmas are obtained by combining results from the local gyrokinetic code GS2 with analytical theory. Local gyrokinetic calculations, using…

Plasma Physics · Physics 2015-10-08 P. A. Abdoul , D. Dickinson , C. M. Roach , H. R. Wilson

We present the Stagger-grid, a comprehensive grid of time-dependent, 3D hydrodynamic model atmospheres for late-type stars with realistic treatment of radiative transfer, covering a wide range in stellar parameters. This grid of 3D models…

Solar and Stellar Astrophysics · Physics 2015-06-15 Z. Magic , R. Collet , M. Asplund , R. Trampedach , W. Hayek , A. Chiavassa , R. F. Stein , Å. Nordlund

{We explored the {softness parameter} in the infrared, whose main purpose is the characterisation of the hardness of the incident ionising radiation in emission-line nebulae. This parameter is obtained from the combination of mid-infrared…

Recent experimental observations at JET show evidence of reduced ion temperature profile stiffness, hypothesised to be due to concomitant low magnetic shear (s) and significant toroidal rotational flow shear. Non-linear gyrokinetic…

We study a complex Ginzburg-Landau (GL) type model related to fluid instabilities in the boundary of magnetized toroidal plasmas (called edge-localized modes) with a prescribed shear flow on the Neumann boundary condition. We obtain the…

Plasma Physics · Physics 2017-06-27 Youngmin Oh , Gunsu S. Yun , Hyung Ju Hwang

The intrinsic alignment (IA) of galaxies acts as a systematic effect in weak lensing measurements and tends to introduce biases. It mimics the gravitational lensing signal which makes it difficult to distinguish it from the true…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-08 Abinash Das

Studies have shown that in sheared $\mathbf{E}\times\mathbf{B}$ flows in an inhomogeneous ionospheric plasma, the gradient drift (GDI) or the Kelvin-Helmholtz (KHI) instability may grow. This work examines the conditions that cause one of…

Plasma Physics · Physics 2021-06-02 C. Rathod , B. Srinivasan , W. Scales

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

Particle transport due to Ion Temperature Gradient/Trapped Electron (ITG/TE) mode turbulence is investigated using the gyrokinetic code GENE. Both a reduced quasilinear (QL) treatment and nonlinear (NL) simulations are performed for typical…

Plasma Physics · Physics 2015-06-18 Andreas Skyman , Hans Nordman , Daniel Tegnered

We demonstrate that the universal mode driven by the density gradient in a plasma slab can be absolutely unstable even in the presence of reasonable magnetic shear. Previous studies from the 1970s that reached the opposite conclusion used…

Plasma Physics · Physics 2015-06-23 Matt Landreman , Thomas M Antonsen , William Dorland

We apply a continuation method to recently optimized stellarator equilibria with excellent quasi-axisymmetry (QA) to generate new equilibria with a wide range of rotational transform profiles. Using these equilibria, we investigate how the…

Plasma Physics · Physics 2024-01-18 Stefan Buller , Matt Landreman , John Kappel , Rahul Gaur

Turbulent transport is known to limit the plasma confinement of present-day optimized stellarators. To address this issue, a novel method to strongly suppress turbulence in such devices is proposed, namely the resonant wave-particle…

Plasma Physics · Physics 2020-09-09 Alessandro Di Siena , Alejandro Banon Navarro , Frank Jenko

In the present work the zonal flow (ZF) growth rate in toroidal ion-temperature-gradient (ITG) mode turbulence including the effects of elongation is studied analytically. The scaling of the ZF growth with plasma parameters is examined for…

Plasma Physics · Physics 2009-11-13 J. Anderson , H. Nordman , R. Singh , J. Weiland

In this work we develop a theoretical framework for the localization of flow in the steadily flowing regime of sheared disordered solids with inertial dynamics on a microscopic scale. To this aim we perform rheology studies at fixed shear…

Soft Condensed Matter · Physics 2018-12-11 Vishwas V Vasisht , Magali Le Goff , Kirsten Martens , Jean-Louis Barrat

The magnetorotational instability (MRI) plays a crucial role in regulating the accretion efficiency in astrophysical accretion disks. In low-luminosity disks around black holes, such as Sgr A* and M87, Coulomb collisions are infrequent,…

High Energy Astrophysical Phenomena · Physics 2023-08-25 Astor Sandoval , Mario Riquelme , Anatoly Spitkovsky , Fabio Bacchini

Turbulent transport is a decisive factor in determining the pedestal structure of H-modes. Here, we present the first comprehensive characterization of gyrokinetic turbulent transport in a JET hybrid H-mode pedestal. Local, linear…

Plasma Physics · Physics 2024-05-20 L. A. Leppin , T. Görler , L. Frassinetti , S. Saarelma , J. Hobirk , F. Jenko , JET contributors

The magnetorotational instability (MRI) is a shear instability and thus its sensitivity to the shear parameter $q = - d\ln\Omega/d\ln r $ is of interest to investigate. Motivated by astrophysical disks, most (but not all) previous MRI…

Solar and Stellar Astrophysics · Physics 2015-06-22 Farrukh Nauman , Eric G. Blackman

Understanding the interaction mechanisms between large-scale magnetohydrodynamic instabilities and small-scale drift-wave microturbulence is essential for predicting and optimizing the performance of magnetic confinement based fusion energy…

Plasma Physics · Physics 2016-09-14 Olivier Izacard , Christopher Holland , Spencer D. James , Dylan P. Brennan

A theoretical investigation has been made to study the modulation stability/instability of three-dimensional dust-ion-acoustic wave packets in the warm magnetized complex plasma system in the presence of nonthermal distributed electrons and…

Plasma Physics · Physics 2023-06-12 A. Parvez , A. Mannan , M. N. Haque , A. A. Mamun