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Spatio-temporal measurements of the impurity ion temperature, density, and rotation profiles around the plasma edge region have been made in the JT-60U tokamak, allowing the determination of radial electric field, E r, with the key dimensionless parameter (poloidal Mach number, U pm) at the L-H transition in a number of operational regimes. We found that there is variation in the L-H transition in terms of its time-scale; not only 'hard' type transition with a faster time-scale than that seen in the plasma transport (as represented by an energy confinement time, τ E) as seen in the many conventional tokamaks, but also 'soft' one with a slow time-scale (≈ τ E) is possible solution, including a complex multi-stage E r transition in the later H-phase. The most important point is that the critical condition for the L-H transition predicted by ion-orbit loss model could be applicable only for 'hard' transition (occurred at U pm ≥ 1), and not necessary for 'slow' one (occurred even at U pm < 1). Characteristics of the turbulent density fluctuation with the frequency range of 100 kHz at the plasma edge region, in addition to a uniform toroidal MHD oscillation (i.e., n = 0), during ELM-free H-phase are also reported. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]