Systems and methods are disclosed herein relating to fusion reactors for fusing particles via multiple periodic collisions. A fusion reactor may include a first evacuated region, such as a chamber, with a plurality of charged particles therein. A uniform magnetic field may be applied to the region to radially confine moving charged particles within the region by inducing circular trajectories. Upper and lower electrodes may be positioned on ends of the region to axially confine charged particles within the region. An energizing beam may be pulsed at a cyclotron frequency corresponding to the mass and charge of the particles to cause oscillating periodic collisions of the particles along the beam path as the particles travel in the circular trajectories with increased velocity after each pulse of the energizing beam.