Equilibrium and confinement in the tight aspect ratio tokamak, START

Tokamak physics at tight aspect ratio is still in its infancy with START being the only machine to date to achieve high temperature plasmas at aspect ratios A < 1.4. This configuration provides access to a regime where many tokamak physics aspects are much enhanced, such as natural plasma elongation, plasma resistivity and bootstrap currents. To understand the observed behaviour and compare results with other more conventional tokamaks a programme of work to study equilibrium and confinement is being undertaken. In this paper, analysis and interpretation of recent experimental results as well as modelling of the time evolution of the main plasma parameters is presented