112 Magnetic fields applied to laser-generated plasma to enhance the ion yield acceleration L. Torrisi, G. Costa, and G. Ceccio Dipartimento di Scienze Fisiche – MIFT, Università di Messina, V.le F.S. D’Alcontres 31, 98166 S. Agata (ME), Italy ltorrisi@unime.it, gcosta@unime.it, gceccio@unime.it Abstract A Nd:YAg laser operating at 10 10 W/cm 2 intensity was employed to generated non- equilibrium plasma in vacuum irradiating polyethylene and aluminium targets. Plasma properties were monitored in high vacuum using Ion Collector (IC) and Ion Energy Analyzer (IEA). Plasmas were generated with and without magnetic fields directed along to the normal to the target surface and ranging between 0.1 and 0.15 Tesla. The magnetic fields produce ion focalization along the normal direction enhancing the axial ion current. The electron traps, produced along this axis by the magnetic fields, increase the ion acceleration, has demonstrated by IC measurements in time-of-flight configuration. With the used setup the ion current was increased of about 300%, while the ion energy of about 25%. Theoretical predictions, based on COMSOL simulation code, indicate that higher increments can be obtained using higher magnetic fields and laser intensities. Introduction Laser-generated plasma and ion acceleration from plasma expansion in vacuum represent relevant topics in many scientific fields, due to their large number of applications. In many cases ion beams with adequate characteristics, such as energy distribution, charge state and current, are required to produce useful studies concerning ion sources, ion acceleration, production of nuclear reactions, high temperature plasmas, and others [1]. In this work, it is used an axially symmetrical magnetic field system to obtain an increase of ion current and energy extracted from the laser-generated plasma. The use of an axially symmetrical magnetic field placed in front of the plasma plume, alters the emission of the charge particles from the plasma. The magnetic field introduces a distortion of the trajectories of electrons and ions emitted from the target, which, under certain conditions, can produce an ion beam focalization with low emittance and high current. Recent studies have shown that electron beams emitted from target, form traps in front of the magnets, which are responsible of dynamical charge cloud separation, with formation of high electrical fields responsible of high ion acceleration [2]. In our work a magnetic field system with axially symmetry, of the order of about 0.1 T, is used to drive the plasma charge particles generated by nanosecond laser intensity at 10 10 W/cm 2 . In these conditions, it was possible to observe an increment of the ion current and energy for protons, carbon and aluminum ions. The results obtained are discussed and presented.