| Numerical particle-in-cell simulations usually assume one or several sorts of ions with constant charges during the whole simulation run. This approach is justifiable in the most common case, when we study the acceleration of protons from thin metal foils. However, in the case of smaller targets (such as clusters or water droplets), dielectric targets, or, even in the case of acceleration of heavier ions from the metal foils, the ionization dynamics during laser-target interaction could play an important role. In this contribution, we discuss the possibilities of including field and collisional ionization into PIC simulations – our implementation of ionization into the PIC code, its impact on the calculation time, and complexity of such numerical simulations. We also demonstrate the ionization dynamics for various targets. In small targets and on the surface of larger targets, the field ionization dominates, whereas the collisional ionization prevails in the interior of larger targets. However, the field ionization dominates in the (surface) region much thicker than the laser skin depth. (authors: J. Psikal, O. Klimo, J. Limpouch) |
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