UKAEA Journals

Showing 21 - 30 of 81 Journals Results
2015
CCFE-PR(15)03

The fuelling of plasmas by shallow frozen pellets with simultaneous mitigation of edge- localised modes (ELM) by external magnetic perturbation is demonstrated on the MAST tokamak. In these plasmas post-pellet particle loss is dominated by ELMs. It is shown that the size of post-pellet ELMs can be controlled by external magnetic perturbations. Post…

Preprint Published
2015
CCFE-PR(15)50

The results of a comprehensive investigation into the effects of toroidicity- induced Alfven eigenmodes (TAE) and energetic particle modes on the NBI-generated fast-ion population in MAST plasmas are reported. Fast-ion redistribution due to frequency-chirping TAE in the range 50 kHz to 100 kHz, and frequency-chirping energetic particle modes known …

Preprint Published
2015
CCFE-PR(15)48

Carbon and nitrogen impurity transport coefficients are determined from gas puff experiments carried out during repeat L-mode discharges on the Mega-Amp Spherical Tokamak (MAST) and compared against a previous analysis of helium impurity transport on MAST. The impurity density profiles are measured on the lowfield side of the plasma, therefore this…

Preprint Published
2015
CCFE-PR(15)08

Tokamak plasmas rotate even without external injection of momentum. A Doppler backscattering system installed at MAST has allowed this intrinsic rotation to be studied in Ohmic L-mode and Hmode plasmas, including the first observation of intrinsic rotation reversals in a spherical tokamak. Experimental results are compared to a novel 1D model, whic…

Preprint Published
2015
CCFE-PR(17)22

The Mega Amp Spherical Tokamak (MAST) is the centre piece of the UK fusion research programme.In 2010, a MAST Upgrade programme was initiated with three primary objectives, to contribute to: (1)testing reactor concepts (in particular exhaust solutions via a flexible divertor allowing Super-X and otherextended leg configurations); (2) adding to the …

Preprint Published
2015
CCFE-PR(15)20

Edge-localised modes (ELMs) can carry significant fractions of their energy as far as main chamber plasma-facing components in divertor tokamaks. Since in future devices (e.g. ITER, DEMO) these energies could cause issues for material lifetime and impurity production, the energy and temperature of ions in ELMs needs to be investigated. In MAST, nov…

Preprint Published
2015
CCFE-PR(15)116

The application of resonant magnetic perturbations (RMPs) produces splitting of the divertor strike point due to the interaction of the RMP field and the plasma field. The application of a rotating RMP field causes the strike point splitting to rotate, distributing the particle and heat flux evenly over the divertor. The RMP coils in MAST have been…

Preprint Published
2015

The transport of particles via intermittent filamentary structures in the private flux region (PFR) of plasmas in the MAST tokamak has been investigated using a fast framing camera recording visible light emission from the volume of the lower divertor, as well as Langmuir probes and IR thermography monitoring particle and power fluxes to plasma-fac…

Published
2014

The high pressure gradients in the edge of a tokamak plasma can lead to the formation of explosive plasma instabilities known as edge localised modes (ELMs). The control of ELMs is an important requirement for the next generation of fusion devices such as ITER. Experiments performed on the Mega Amp Spherical Tokamak (MAST) at Culham have shown that…

Published
2014

Compressional Alfven and ion-ion hybrid waves excited by energetic beam ions are studied in plasmas with two ion species. In our experiment, a hydrogendeuterium (H-D) plasma is used to produce instabilities similar to those likely to be present in the burning deuterium-tritium plasmas of future tokamaks. Modes are suppressed in the deuterium cyclot…

Published