“…Density gradients are often steepest at the edge, so that, generally, this implies that the fluctuation level is highest where the gradient is steepest. The levels n/n are typically 0.1% to 1% in the central regions (PLT [18][19][20], ATC [15][16][17]25], TFR [22][23][24] and reach 10% to 100% at the plasma edge (Alcator [25,27], Macrotor [41], PRETEXT [46], TEXT [36], Caltech [42,43], Dite [49], Diva [50], JFT-2a [50], PDX [30]). Figure 8a, adapted from Ref.…”