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Related papers: Burst statistics in Alcator C-Mod SOL turbulence

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Plasma fluctuations in the scrape-off layer of the Alcator C-Mod tokamak in ohmic and high confinement modes have been analyzed using gas puff imaging data. In all cases investigated, the time series of emission from a single…

Plasma Physics · Physics 2018-04-18 O. E. Garcia , R. Kube , A. Theodorsen , B. LaBombard , J. L. Terry

Fluctuations in the boundary region of the Alcator C-Mod tokamak have been analyzed using gas puff imaging data from a set of Ohmically heated plasma density scan experiments. It is found that the relative fluctuation amplitudes are modest…

Plasma Physics · Physics 2017-09-13 A. Theodorsen , O. E. Garcia , R. Kube , B. LaBombard , J. L. Terry

Intermittent plasma fluctuations in the boundary region of the Alcator C-Mod device were comprehensively investigated using data time-series from gas puff imaging and mirror Langmuir probe diagnostics. Fluctuations were sampled during…

The Alcator C-Mod mirror Langmuir probe system has been used to sample data time series of fluctuating plasma parameters in the outboard mid-plane far scrape-off layer. We present a statistical analysis of one second long time series of…

We study long time series of the ion saturation current and floating potential, sampled by Langmuir probes dwelled in the outboard mid-plane scrape off layer and embedded in the lower divertor baffle of Alcator C-Mod. A series of ohmically…

Plasma Physics · Physics 2016-02-18 Ralph Kube , Odd Erik Garcia , Audun Theodorsen , Brian LaBombard , James L. Terry

Single-point measurements of fluctuations in the scrape-off layer of magnetized plasmas are generally found to be dominated by large-amplitude bursts which are associated with radial motion of blob-like structures. A stochastic model for…

Plasma Physics · Physics 2013-05-30 O. E. Garcia

Statistical properties of the scrape-off layer (SOL) plasma fluctuations are studied in ohmically heated plasmas in the Alcator C-Mod tokamak. For the first time, plasma fluctuations as well as parameters that describe the fluctuations are…

Plasma Physics · Physics 2020-11-11 R. Kube , A. Theodorsen , O. E. Garcia , D. Brunner , B. LaBombard , J. L. Terry

An improved time delay estimation method is used to calculate the velocity of cross-field blob motion in the scrape-off layer of Alcator C-Mod for an ohmic and two high confinement (H-mode) plasmas; an edge localized mode free and an…

Plasma Physics · Physics 2025-01-27 A. D. Helgeland , J. M. Losada , J. L. Terry , O. E. Garcia

Large-amplitude, intermittent fluctuations are ubiquitous in the boundary region of magnetically confined plasmas and lead to detrimental plasma-wall interactions in the next-generation, high duty cycle fusion power experiments. Using gas…

Plasma Physics · Physics 2018-10-08 A. Theodorsen , O. E. Garcia , R. Kube , B. LaBombard , J. L. Terry

Radial profiles of the ion saturation current and its fluctuation statistics are presented from probe measurements in L-mode, neutral beam heated plasmas at the outboard mid-plane region of KSTAR. The familiar two-layer structure, seen…

Intermittent fluctuations in the TCV scrape-off layer have been investigated by analysing long Langmuir probe data time series under stationary conditions, allowing calculation of fluctuation statistics with high accuracy. The ion…

Plasma Physics · Physics 2018-05-04 A. Theodorsen , O. E. Garcia , J. Horacek , R. Kube , R. A. Pitts

A stochastic model for a superposition of uncorrelated pulses with a random distribution of amplitudes, sizes, and velocities is analyzed. The pulses are assumed to move radially with fixed shape and amplitudes decreasing exponentially in…

Plasma Physics · Physics 2024-01-11 J. M. Losada , O. Paikina , O. E. Garcia

Intermittent fluctuations in the boundary of magnetically confined plasmas are investigated by numerical turbulence simulations of a reduced fluid model describing the evolution of the plasma density and electric drift vorticity in the…

Isothermal fluid turbulence simulations have been performed in the edge and scrape-off-layer (SOL) of an analytic stellarator configuration with an island divertor, thereby providing numerical insight into edge turbulence in regions around…

Plasma Physics · Physics 2024-03-28 Brendan Shanahan , David Bold , Ben Dudson

Particle density fluctuations in the scrape-off layer of magnetically confined plasmas, as measured by gas-puff imaging or Langmuir probes, are modeled as the realization of a stochastic process in which a superposition of pulses with a…

Plasma Physics · Physics 2015-01-07 Ralph Kube , Odd Erik Garcia

Two dimensional stochastic time model of scrape-off layer (SOL) turbulent transport is studied. Instability arisen in the system with respect to the stochastic perturbations of both either density or vorticity reveals itself in the strong…

Plasma Physics · Physics 2009-11-10 D. Volchenkov , R. Lima

Analysis of the time series obtained with the O-Mode reflectometer (Rhodes et al 1997 Plasma Phys. and Control. Fusion 40 (1998) 493-510) and the gas puff imaging (Cziegler, I. et al 2010 Phys. of Plasmas 17, No. 5 (2010) 056120) systems on…

Plasma Physics · Physics 2017-04-25 Ziyan Zhu , Anne White , Troy Carter , Seung Gyou Baek , Jim Terry

The reliability of Langmuir probe measurements for plasma-turbulence investigations is studied on GEMR gyro-fluid simulations and compared with results from conditionally sampled I-V characteristics as well as self-emitting probe…

Plasma Physics · Physics 2015-06-03 B. Nold , T. T. Ribeiro , M. Ramisch , Z. Huang , H. W. Müller , B. D. Scott , U. Stroth , ASDEX Upgrade Team

We investigate time-series obtained from gyrofluid simulations in coupled edge/scrape-off layer turbulence characteristic for fusion edge-region plasmas. Blob birth near the separatrix produces intermittent signals whose statistics depend…

Plasma Physics · Physics 2017-11-22 Ole Hauke Heinz Meyer , Alexander Kendl

Numerical simulations of interchange turbulence in the Scrape-Off Layer are performed in a regime relevant for a specific L-mode MAST (Mega Ampere Spherical Tokamak) discharge. Such a discharge was diagnosed with a reciprocating arm…

Plasma Physics · Physics 2014-08-13 F. Militello , P. Tamain , W. Fundamenski , A. Kirk , V. Naulin , A. H. Nielsen , the MAST team
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