  Internal transport barrier (ITB) has been obtained in full lower hybrid
current driven (LHCD) plasmas on a superconducting tokamak, TRIMA-1M (R=0.84m,
a x b=0.12mx0.18m, BT<8T). The formation of ITB depends on the current density
profile, j(r), varied by the power deposition of the lower hybrid (LH). The
plasma with ITB can be maintained by the LH power deposited around the foot
point of ITB up to 25 sec, which corresponds to more than 100 times of current
diffusion time, $\tau$L/R. ITB is terminated by the reduction of current drive
efficiency caused by metal impurities accumulation. In some condition,
self-organized slow sawtooth oscillations (SSSO) of plasma current, density,
temperature, and so on with the period comparable to the current diffusion time
have been also observed during ITB discharge. The oscillation has the
capability of particle exhaust, as the result, it may play an role in the
avoidance of the impurity accumulation and the dilution in the future steady
state fusion plasma with ITB, as the edge-localized mode in H-mode.
