UKAEA Papers

Showing 1 - 10 of 233 UKAEA Paper Results
2022
UKAEA-CCFE-PR(22)21

This paper describes the development of electromagnetic plasma burn-through model. Full circuit equations describing the currents in solenoid, poloidal field coil, and toroidally conducting passive structure have been integrated into the differential equation system of the plasma energy and particle balances in DYON. This enables consistent calcula…

Preprint
2022
UKAEA-CCFE-PR(22)19

A systematic numerical investigation is carried out to understand the effect of variation of the equilibrium pressure pedestal structure on the H-mode plasma response to the applied resonant magnetic perturbation (RMP) field in tokamaks. The plasma response to the n=1−4 (n is the toroidal mode number) RMP fields is computed and …

Preprint
2022
UKAEA-CCFE-PR(22)14

Helium ash alpha-particles at  100keV in magnetically confi ned fusion plasmas may have the same Larmor radius, as well as cyclotron frequency, as the energetic beam-injected deuterons that heat the plasma. While the velocity-space distribution of the helium ash is monotonically decreasing, that of the energetic deuterons is a delta-function in…

Preprint
2022
UKAEA-CCFE-PR(22)12

In many fields of the natural sciences, from biology to physics, advanced data analysis tools are acquiring more and more importance to investigate difficult problems. A typical application is synchronization experiments, which involve coupled quantities, a “target” and a “driver”, with quasi-periodic behaviours. Unfortunately, in comple…

Preprint
2022
UKAEA-CCFE-PR(22)09

Experiments in ASDEX Upgrade (AUG) and JET with the ITER-like wall (JET-ILW) are performed to separate the pedestal and core contributions to confinement in H-modes with different main ion masses. A strong isotope mass dependence in the pedestal is found which is enhanced at high gas puffing. This is because the ELM type changes when going fro…

Preprint Published
2022
UKAEA-CCFE-PR(22)08

MAST-U has recently started operating with a Super-X divertor, designed to increase total flux expansion and neutral trapping, both predicted through simple analytic models and SOLPS calculations to reduce the plasma and impurity density detachment thresholds. In this study, utilising the SOLPS-ITER code, we are quantifying the possible gain allowe…

Preprint
2022
UKAEA-CCFE-PR(22)06

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 two-dimensional plane perpendicular to the magnetic field. Two different cases are considered, one describing resi…

Preprint Published
2022
UKAEA-CCFE-PR(22)05

The analysis of quiescent discharges exhibiting edge harmonic magnetoydrodynamic activity in the JET-Carbon wall machine is presented. It is observed that the quiescent phase with multiple-n harmonic oscillations is sustained until a threshold in pedestal electron density and collisionality is crossed. The macroscopic pedestal parameters associated…

Preprint Published
2022
UKAEA-CCFE-PR(22)03

This paper reports on the development of reduced models for electron temperature gradient (ETG) driven transport in the pedestal. Model development is enabled by a set of 61 nonlinear gyrokinetic simulations with input parameters taken from the pedestals in a broad range of experimental scenarios. The simulation data has been consolidated in a new …

Preprint