Figure 4

Spatio-temporal evolution of normalized scale length of ion temperature (\(R/L_{{T_{i} }}\)) and \(E_{r}\)-gradient for (a,f) 8 MW, (b,g) 10 MW, (c,h) 11 MW, and (d,i) 12 MW discharges, respectively. Black markers and white lines show the location of \(q_{min}\) and BFs, respectively. Gray lines in (a–d) indicate the contour at \(R/L_{{T_{i} }}\) = 20. (e) Density fluctuation levels obtained by the reflectometer. Note that the fluctuation level of the 8 MW discharge shown in the graph is multiplied by 3. (j) \(dE_{r} /dr\) and its pressure term (\(d\left( {\nabla p_{c} /Z_{c} en_{c} } \right)/dr\)) averaged in \(\rho\) = 0.35–0.45 for 11 and 12 MW discharges. (k) Time slices of \(T_{i}\) and \(R/L_{{T_{i} }}\) for the case of 12 MW discharge. (l) Radial profiles of \(E \times B\) shearing rate (\(\overline{\omega }_{E \times B}\)) and maximum linear growth rate of turbulence (\(\overline{\gamma }_{max}\)), which are time-averaged during \(R/L_{{T_{i} }}\) above 20.