WE CONSIDER GENERATION OF LARGE MAGNETIC FIELDS BASED ON ELECTRON INERTIA IN STRUCTURE TARGETS IRRADIATED BY CIRCULARLY POLARIZED INTENSE ULTRASHORT LASER PULSES. THE OPTIMAL (FOR MULTI GGS FIELD) LASER AND TARGET PARAMETERS WERE FOUND BY USING THE ANALYTICAL MODEL AND 3DPIC SIMULATIONS. IT IS SHOWN THAT SUCH FIELDS SLOW DOWN THE STRUCTURE EXPANSION, WHICH CAN BE USED IN NUCLEAR PHYSICS