Considerations on Monitoring Tearing Modes Stability in Toroidally Rotating MHD Equilibria

In tokamak operation the control of dangerous MHD instabilities, possibly in real-time sce- narios, must rely on prompt and robust diagnostics of the state and stability of the system. The information on the current J profile details is generally considered undetectable from out- side the plasma boundary, but it can be conjectured that it is somehow mapped onto the sur- face providing a Shannon-Bekenstein information entropy [1], associated to the probability that some internal profile feature ("mode") exists.