Mechanism and duration of the disruption thermal quench
In plain words
In a disruption the plasma loses nearly all its heat in about a millisecond, much faster than normal leakage. How the magnetic field becomes tangled to allow this, and where the heat goes, is not predictable.
Precise statement
Identify what sets the thermal quench duration (about 1e-3 s or less in large tokamaks): magnetic stochastization by global MHD modes, radiative collapse, and parallel heat transport in stochastic fields. Predict the quench time, the radiated versus conducted energy fraction and the wall heat-load distribution for ITER. An answer is 3D nonlinear MHD with validated kinetic heat-flux closures reproducing measured quench times across devices.
What would settle it
3D nonlinear MHD simulations that reproduce measured thermal-quench times and radiation fractions on at least three tokamaks.