ISTTOK tokamak operates in AC mode allowing to have consecutive cycles of positive and
negative plasma current. The plasma centroid position is estimated from the reconstruction
of the signals obtained from a poloidal array of twelve magnetic probes. In the previous
setup, this reconstruction relied on a cylindrical approximation algorithm in which the error
fields generated by active coils and currents in the passive structures were not taken into
account, leading to some centroid position inaccuracy. Although this approach has been …

ISTTOK is a large aspect ratio tokamak (IST, Lisbon, Portugal) operating for almost 30 years
and which has been in constant upgrading of diagnostics, hardware acquisition system and
control algorithms (major and minor plasma radius are respectively R= 46 cm, a= 8.5 cm).
Due to the flexibility of the power supplies it is possible to perform AC discharges which
allow the fast reversal of the plasma current while maintaining a finite plasma density
between consecutive flat tops, refer to figure 1.3 in section 1.4 of reference [1]. The current …