Figure 2: (a) is a comparison of energy confinement time in a hydrogen plasma and in a deuterium plasma obtained through a turbulence simulation. Compared to the hydrogen, in the deuterium plasma the flow (zonal flow) that suppresses the turbulence is formed more robustly, the energy confinement is improved, and the energy confinement time is increased. From (b) to (d) are comparisons of the distribution of turbulences in LHD plasma. Strong eddies and waves are being generated in the dark red color area. The large, long red areas that can be seen in (c) hydrogen plasma are in deuterium plasma (d) ground into small and short by the zonal flow, the disturbance is suppressed, and the energy confinement is being improved. Further, the colors from (b) to (d) show the strength of the fluctuations of the plasma density.