ИСТИНА

The studies of multicluster plasmas are closely related to the problem of acceleration of highenergy ions. A multicluster target is a cloud of clusters embedded in a background underdense plasma. The cluster size is of the order or less than the laser wavelength, whereas an intercluster distance is substantially larger than the laser wavelength. By its absorption and transparency properties, a multicluster target occupies an intermediate position between gaseous and bulk solid targets. We present the results of two-dimensional (2D) particle in cell (PIC) simulations of ion acceleration during the interaction of two counter-propagating highintense laser pulses with a slab of underdense plasma and with a multicluster target. Our studies focus on regimes where the high-energy ion acceleration is achieved. It is shown that during the interaction of two counter-propagating laser pulses with a slab of underdense plasma or a multicluster target, ions are accelerated most efficiently in the case when ion density filaments are formed inside the channels formed by the laser pulses.