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The physics of the tokamak pedestal is still not fully understood, for example there is no fully predictive model for the pedestal height and width. However, the pedestal is key in determining the fusion power for a given scenario. If we can improve our understanding of reactor relevant pedestals we will improve our confidence in designing potential fusion power plants. Work has been carried out as part of a collaboration on reactor relevant pedestal physics. We report some of the results in detail here and review some of the wider work which will be reported in full elsewhere. First, we attempt to use a gyrokinetic-based calculation to eliminate the pedestal top density as a model input for Europed/EPED pedestal predictions. We assume power balance at the top of the pedestal, that is, the heat flux crossing the separatrix must be equal to the heat source at the top of the pedestal and investigate the consequences of this assumption. Unfortunately, the transport assumptions of the EPED model mean that this method does not discriminate between different pairs of density and temperature profiles for a given pressure profile. Second, we investigate the effects of non flux surface density on the bootstrap current. Third, type I ELMs will not be tolerable for a reactor relevant regime due to the damage that they are expected to cause to plasma facing components. In recent years various methods of running tokamak plasmas without large ELMs have been developed. These include small and no ELM regimes, the use of resonant magnetic perturbations and the use of vertical kicks. We discuss the quiescent H-mode here. Finally we give a summary and directions for future work. [ABSTRACT FROM AUTHOR]

Analyzes the ideal magnetohydrodynamic stability of the tokamak edge, with particular emphasis on radially localized instabilities. Edge pressure gradient limits and edge localized modes; Data and stability calculations from DIII-D tokamak equilibria; Two types of instability that are important.

Describes the development of the instrumentation for the measurement of electron temperature and density profiles at the boundary of COMPASS-D tokamak plasmas from helium I line intensities. Application of the technique; Recording of the spectra from eight viewing chords observing a thermal helium jet.

Describes a spatially scanning, combined vacuum-ultraviolet and visible range spectrometer system for the spectroscopy of tokamak plasmas. Schematic representation of its optical principle; Features; Specifications.