Robust heavy-ion-beam illumination in direct-driven heavy-ion inertial fusion

In heavy ion beam (HIB) inertial confinement fusion (HIF), implosion asymmetry should be less than a few percent in order to compress a fuel sufficiently and release fusion energy effectively. It is known that the HIB illumination nonuniformity and implosion symmetry are sensitive to a little pellet displacement from a reactor chamber center. We present a new HIB illumination scheme which is robust against the displacement of a direct-driven fuel pellet in an HIF reactor chamber. In conventional HIB illumination schemes a pellet displacement of 25–100 μm was tolerable. The new robust HIB illumination scheme is examined by three-dimensional computer simulations. In the new HIB illumination scheme the tolerable pellet displacement is about 200–300 μm.