Abstract: A method of generating electromagnetic fields comprises the step of using the interaction between a laser source and an appropriate target, as the source for generating high-intensity electromagnetic fields. A strong positive charge is generated in the target hit by the laser. The target has a structure consisting of at least two different elements. The method can be used to obtain the acceleration, deceleration, deflection, focusing or selection of moving charges. Such charges have been previously accelerated by a completely separate process, and therefore the two processes of pre-acceleration and subsequent processing of the beam of particles are completely separate and therefore separately tunable and optimizable Such electromagnetic fields can be used in other fields than those previously indicated, such as—merely by way of example—medicine, biology, studies on materials, electromagnetic compatibility, and generation of terahertz radiation.