Symmetrized Dot Pattern as an Alternative Method to Visualize the Dynamics of Tokamak Plasma Radiation

Abstract

The unusual graphic representation of time series based on Symmetrized Dot Pattern (SDP) helps capturing subtle dynamics in the analyzed signals, otherwise difficult to identify when applying traditional techniques. SDP is creating features and forming a global percept easily readable and recognizable for a human observer. Thanks to this method, local correlations of the signals of any sampled data series can be visualized. This work describes the application of SDP to measurements of tokamak plasma radiation, namely the soft X-ray line-integrated brightness on WEST, where it was thus possible to analyze different phases of the discharge and in particular to identify sawtooth oscillations. In the future, the SDP method could be used to monitor the plasma state and to warn against the appearance of undesirable plasma behavior.