A plasma vertical control system able to control high elongation (∼2.5) plasmas at moderate internalinductance (∼0.9) is analysed, including both active and passive components in a closed loop system.The analysis is based on the RZIp rigid plasma model and this is extensively validated using present dayMAST discharges, especially at the limits of controllability. Special consideration is given to the unusualMAST geometry (coils inside the main vacuum vessel) and general conclusions regarding system designare drawn wherever possible.
