Using a two-dimensional relativistic hydrodynamic code, it is shown that a dense high-current ion beam driven by a short-pulse laser can be effectively focused by curving the target front surface. The focused beam parameters essentially depend on the density gradient scale length of the preplasma L_n and the surface curvature radius R_T. When L_n ≤ 0.5λ_L (λ_L is the laser wavelength) and R_T is comparable with the laser beam aperture d_L, a significant fraction of the accelerated ions is focused on a spot much smaller than d_L, which results in a considerable increase in the ion fluence and current density. Using high-contrast multipetawatt picosecond laser pulses of relativistic intensity (～ 10~(20) W/cm~2), focused ion (proton) current densities approaching those required for fast ignition of DT fuel seem to be feasible.
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