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UKAEA-CCFE-PR(24)2252023
JET’s frequency-modulated continuous wave (FMCW) reflectometers have been operating well with the current design since 2005 and density profiles are being automatically calculated intershot since then. However, the calculated profiles had long suffered from several shortcomings – poor agreement with other diagnostics; sometimes inappropriate…
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UKAEA-CCFE-CP(23)442022
Due to their relatively higher Vbeam/VAlvén ratio, spherical tokamaks are ideal to investigate high-frequency modes such as Compressional Alfvén Eigenmodes (CAEs) and Global Alfvén Eigenmodes (GAEs), and so they have been previously studied in MAST [1, 2]. Besides, the recently installed scintillator-based Fast-Ion Loss …
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UKAEA-CCFE-PR(22)592022
Sequential numerical methods for integrating initial value problems (IVPs) can be prohibitively expensive when high numerical accuracy is required over the entire interval of integration. One remedy is to integrate in a parallel fashion, “predicting” the solution serially using a cheap (coarse) solver and “correcting” these values using an …
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UKAEA-CCFE-PR(22)562022
Parareal is a well-studied algorithm for numerically integrating systems of time-dependent differential equations by parallelising the temporal domain. Given some initial values at each temporal sub-interval, the algorithm iteratively locates a solution in a fixed number of iterations using a predictor-corrector, stopping once a tolerance is met. T…
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UKAEA-CCFE-CP(23)302021
Many of the essential data analysis procedures for a tokamak experiment rely on the knowledge of the magnetic field structure obtained from MHD force balance. On JET, the code that is responsible for computing the magnetic equilibrium is called EFIT++. Interpretation of JET data has been challenging due to inconsistencies between diagnostic meas…
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UKAEA-CCFE-PR(20)652020
A novel approach using Bayesian inference has been implemented to interpret the filamentary dynamics measured by a Langmuir probe fixed to a reciprocating assembly on MAST. The model describes the system as a superposition of time-displaced filaments and a fixed background component. Each filament is parameterised in terms of a characteristic rise …
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UKAEA-CCFE-CP(19)402019
In magnetic confinement devices, boundary turbulence is responsible for transporting plasma and energy from the well-confined region towards the material surfaces where it can severely harm reactor relevant machines. It is therefore essential to develop a solid understanding of the mechanisms behind the transport in the edge of the plasma. Large fl…
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UKAEA-CCFE-CP(18)032018
Recent results from MAST address key physics issues for ITER operations and the design of future devices, by advancing our understanding of through analysis of high-resolution data and numerical modelling. Modelling of the interaction between filaments with BOUT++ indicates filaments separated by more than 5x their width move independently, and …
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CCFE-PR(17)682017
In many tokamaks ferromagnetic material, usually referred to as an iron-core, is present in order to improve the magnetic coupling between the solenoid and the plasma. The presence of the iron core in proximity to the plasma changes the magnetic topology with consequent e ects on the magnetic field structure and the plasma boundary. This paper cons…
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CCFE-PR(17)402015
Journal publications, as the final product of research activity, are the result of an extensive complex modelling and data analysis effort. It is of paramount importance, therefore, to capture the origins and derivation of the published data in order to achieve high levels of scientific reproducibility, transparency, internal and external data reus…
Showing 1 - 10 of 29 UKAEA Paper Results