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UKAEA-CCFE-PR(24)2392021
One of the main capabilities of Atom Probe Tomography (APT) is the ability to not only identify but characterise early stages of precipitation at scales that are not achievable by other techniques. The most popular method, based on the Density-Based Spatial Clustering of Applications with Noise (DBSCAN), is used extensively in many branches of r…
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UKAEA-CCFE-CP(23)222021
Previous studies of the European Demonstration fusion reactor concept (DEMO) have shown that the expected amounts of radioactive waste at end of life (EOL) are of the order of 104 tonnes. These studies also suggested that comparable amounts of waste will be classified as low level waste (LLW) and intermediate level waste (ILW) 100 yea…
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UKAEA-CCFE-PR(22)012021
Electromagnetic instabilities and turbulence driven by the electron-temperature gradient are considered in a local slab model of a tokamak-like plasma, with constant equilibrium gradients (including magnetic drifts but no magnetic shear). The model describes perturbations at scales both larger and smaller than the electron inertial scale de…
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UKAEA-CCFE-PR(21)022021
In quiescent H-mode (QH-mode) regime, edge harmonic oscillations (EHOs) are believed to provide necessary radial transport to prevent occurrence of large edge localized modes. A systematic modeling study is performed here on the low-n EHOs in a DIII-D QH-mode plasma [Chen et al. 2016 Nucl. Fusion 56 076011], by utilizing the MARS-Q code [Liu et a…
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UKAEA-CCFE-CP(20)962020
EDGE2D-EIRENE simulations of upstream density and radiative power scans in JET H-mode type plasmas in vertical target predict a linear relationship between the electron and ion temperatures, and power across the separatrix. This is in contradiction to the two-point model equations which states that the upstream temperature scales at the po…
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UKAEA-CCFE-PR(20)212020
Local linear gyrokinetic simulations show that electron temperature gradient (ETG) instabilities are the fastest growing modes for kyρi >~ 0.1 in the steep gradient region for a JET pedestal discharge (92174) where the electron temperature gradient is steeper than the ion temperature gradient. Here, ky is the wa…
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UKAEA-CCFE-PR(20)1112019
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 equations valid in the limit of infinite scale separation, reveal novel cross-scale interaction mechanisms in …
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UKAEA-CCFE-PR(19)282019
We study the amplitude modulation of the radial electric field constructed from the Langmuir probe plasma potential measurements at the edge of MAST. The Empirical Mode Decomposition technique is applied, which allows us to construct fluctuations on temporal scales of plasma turbulence, the Geodesic Acoustic Mode and these associated with the res…
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UKAEA-CCFE-PR(19)132018
Multiple space and time scales arise in plasma turbulence in magnetic confinement fusion devices because of the smallness of the square root of the electron-to-ion mass ratio and the consequent disparity of the ion and electron thermal gyroradii and thermal speeds. Direct simulations of this turbulence that include both ion and electron space-ti…
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CCFE-PR(16)672016
We show that a central characteristic of Super-X divertors, parallel area expansion fR (de ned as the ratio of the elementary area normal to the magnetic field at the target to that at the X-point, also known as total flux expansion), significantly changes the characteristics of the target plasma for fixed upstream conditions. To isolate the effect…
Showing 21 - 30 of 61 UKAEA Paper Results