Electron Temperature Gradient Turbulence

Dorland, W.; Jenko, F.; Kotschenreuther, M.; Rogers, B. N.

doi:10.1103/physrevlett.85.5579

Cited by 599 publications

(718 citation statements)

References 23 publications

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“…of the ion beam. A diffusive model is often used to describe suprathermal ion transport in fusion plasmas, 31 though nondiffusive models have been successful in many cases. 32,33 Diffusion is sometimes sufficient to describe suprathermal ion transport over certain time and spatial scales, since a nondiffusive process may always be linearized as diffusion.…”

Section: Discussionmentioning

confidence: 99%

Suprathermal ion transport in simple magnetized torus configurations

et al. 2012

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Inspired by suprathermal ion experiments in the basic plasma experiment TORPEX, the transport of suprathermal ions in ideal interchange mode turbulence is theoretically examined in the simple magnetized torus configuration. We follow ion tracer trajectories as specified by ideal interchange mode turbulence imported from a numerical simulation of drift-reduced Braginskii equations. Using the variance of displacements, σ2(t)∼tγ, we find that γ depends strongly on suprathermal ion injection energy and the relative magnitude of turbulent fluctuations. The value of γ also changes significantly as a function of time after injection, through three distinguishable phases: ballistic, interaction, and asymmetric. During the interaction phase, we find the remarkable presence of three regimes of dispersion: superdiffusive, diffusive, and subdiffusive, depending on the energy of the suprathermal ions and the amplitude of the turbulent fluctuations. We contrast these results with those from a “slab” magnetic geometry in which subdiffusion does not occur during the interaction phase. Initial results from TORPEX are consistent with data from a new synthetic diagnostic used to interpret our simulation results. The simplicity of the simple magnetized torus makes the present work of interest to analyses of more complicated contexts ranging from fusion devices to astrophysics and space plasma physics.

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Section: Discussionmentioning

confidence: 99%

Suprathermal ion transport in simple magnetized torus configurations

et al. 2012

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“…To demonstrate our system, we performed our analysis on two sample PETSc applications (ex2 from the ksp package and ex5 from the snes package) [6] and GS2 [7,8]. GS2 is a physics application developed to study low-frequency turbulence in magnetized plasma.…”

Section: Resultsmentioning

confidence: 99%

Profile-Driven Selective Program Loading

Ince

Hollingsworth

2010

Euro-Par 2010 - Parallel Processing

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Abstract. Complex software systems use many shared libraries frequently composed of large off-the-shelf components. Only a limited number of functions are used from these shared libraries. Historically demand paging prevented this from wasting large amounts of memory. Many high end systems lack virtual memory and thus must load the entire shared library into each node's memory. In this paper we propose a system which decreases the memory footprint of applications by selectively loading only the used portions of the shared libraries. After profiling executables and shared libraries, our system rewrites all target shared libraries with a new function ordering and updated ELF program headers so that the loader only loads those functions that are likely to be used by a given application and includes a fallback user-level paging system to recover in the case of failures in our analysis. We present a case study that shows our system achieves more than 80% reduction in the number of pages that are loaded for several HPC applications while causing no performance overhead for reasonably long running programs.

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“…The main drawback of PIC codes is that sampling the physical particles with 'superparticles' leads to the introduction of statistical noise which can be reduced but not eliminated by optimized loading techniques [10]. On the contrary, Eulerian codes [11][12][13], which evolve the distribution function over fixed points in phase space, are not affected by statistical noise. Moreover, by construction, the Eulerian approach allows one to get information on the particle distribution function in all phase space coordinates on a structured grid, while the same is not easily reconstructed by PIC codes.…”

Section: Gyrokinetic Equations Have Been Solved Numerically Using Algmentioning

confidence: 99%

A semi-Lagrangian code for nonlinear global simulations of electrostatic drift-kinetic ITG modes

Brunetti

Grandgirard

Sauter

et al. 2004

Computer Physics Communications

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A semi-Lagrangian code for the solution of the electrostatic drift-kinetic equations in straight cylinder configuration is presented. The code, CYGNE, is part of a project with the long term aim of studying microturbulence in fusion devices. The code has been constructed in such a way as to preserve a good control of the constants of motion, possessed by the drift-kinetic equations, until the nonlinear saturation of the ion-temperature-gradient modes occurs. Studies of convergence with phase space resolution and time-step are presented and discussed. The code is benchmarked against electrostatic Particle-in-Cell codes.

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Electron Temperature Gradient Turbulence

Cited by 599 publications

References 23 publications

Suprathermal ion transport in simple magnetized torus configurations

Suprathermal ion transport in simple magnetized torus configurations

Profile-Driven Selective Program Loading

A semi-Lagrangian code for nonlinear global simulations of electrostatic drift-kinetic ITG modes

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