Generation of long-lived strong magnetic fields in laser targets with cylindrical micro-channels

We consider generation of large magnetic fields based on electron inertia in cylindrical shells and microchannel target irradiated by circular polarized intense ultrashort laser pulses. The optimal (for large and long life magnetic field) laser and target parameters were found by using the analytical model and 3D PIC simulations. It is shown that such fields slow down the structure expansion, which can be used to obtain ultrahigh energy densities in focal volume laser plasma.