According to the magnetic diffusion equation, the ratio of the normalized current density and the temperature sawteeth should lie between 2/3 and 3/4 on the tokamak magnetic axis if, as is the case in TEXTOR, the q = 1 magnetic surface remains still during the sawtooth ramp phase, and if the sawtooth amplitude is moderately small and rises linearly with time. We present experimental confirmation of this theoretical result in TEXTOR. The implication is that the electrical conductivity is neoclassical over most of the ramp phase.
Polarimetric measurement of m = 1 sawtooth precursor oscillations in the TEXTOR tokamak