  Heavy ion inertial fusion (HIF) energy would be one of promising energy
resources securing our future energy in order to sustain our human life for
centuries and beyond. The heavy ion beam (HIB) has remarkable preferable
features to release the fusion energy in inertial confinement fusion: in
particle accelerators HIBs are generated with a high driver efficiency of ~
30-40%, and the HIB ions deposit their energy inside of materials. Therefore, a
requirement for the fusion target energy gain is relatively low, that would be
~50-70 to operate a HIF fusion reactor with the standard energy output of 1GW
of electricity. The HIF reactor operation frequency would be ~10~15 Hz or so.
Several-MJ HIBs illuminate a fusion fuel target, and the fuel target is
imploded to about a thousand times of the solid density. Then the DT fuel is
ignited and burned. The HIB ion deposition range would be ~0.5-1 mm or so
depending on the material. Therefore, a relatively large density-scale length
appears in the fuel target material. The large density-gradient-scale length
helps to reduce the Rayleigh-Taylor (R-T) growth rate. The key merits in HIF
physics are presented in the article toward our bright future energy resource.
