Electron internal transport barrier sustained with IBW and LHCD on the HT-7 tokamak

Electron internal transport barrier is formed and sustained for about 3 s during the synergy of lower hybrid wave current drive (LHCD) and ion Bernstein wave (IBW) on the HT-7 tokamak. And the magnetic shear, s  , is also negative within the region of ρ∼0.58ρ∼0.58. The total non-inductive current fraction is up to 70% and the bootstrap current fraction gets to about 37% during the steady state in these discharges. The peak in the bootstrap current is well aligned with the barrier location. The local reduction of transport results in an overall improvement of the energy confinement time. Confinement enhancement factor H89 is about 1.5.