| We performed a detailed numerical study of the dynamics of radiation pressure-driven ion acceleration mechanisms in overdense plasmas (electron density n_e>n_c, the cut-off density). Linearly polarized pulses with dimensionless amplitude a0 ~ n_e/n_c drive solitary waves or multipeak structures depending on the pulse duration. Such nonlinear waves drive secondary ion acceleration in the plasma bulk, the acceleration dynamics being more complex than ''specular'' reflection of ions from the wave front. Formation of ''true'' shock waves with a steady ion reflection occurs in the case of warm ions. Circularly polarized pulses drive hole boring or ''pure piston'' acceleration at the plasma surface and do not generate nonlinear waves in initially cold plasmas. |
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