Non-inductively current driven H mode with high betaNand high betapvalues in JT-60U

Attainable β p and β N values were widely improved in JT-60U by peaking of the current profile and broadening of the pressure profile. In a quasi-steady state of ELMyy H mode, β p approximately 2.5-3, β N approximately 2.5-3.1 and H factor approximately 1.8-2.2 were sustained for approximately 1 s simultaneously under the full current drive condition (bootstrap current 60%, beam driven current 48% at I p = 0.5 MA). In a transient case, the maximum values of β p , β p and β N reached 4.7, 1.2 and 4.2, respectively. The achievable β p value increases systematically with safety factor at the edge. To obtain these improved high β plasmas, it is essential to control MHD activities; suppression of β p collapse and medium m/n (poloidal mode number/toroidal mode number) modes by the modification in current and pressure profiles and control of ELM activity by suitable selection of the heating power