Magnetic energy is an universal source of energy in the Universe and plays a fundamental role 

in astrophysical processes such as magnetic reconnection, Gamma-ray bursts and so on, as well as 

in laboratory plasma experiments. Generation and compression of strong magnetic fields is a rapidly developing area 

of High-Energy-Density-Physics (HEDP). Laser produced plasma, in which magnetic fields are generated 

mostly due to the Biermann battery effect, can be used for studying magnetic field compression. 

We present the experimental results of the collision of parallel magnetic fields. For this, we use two dense targets

that are both irradiated by ns laser beams. As the plasmas from the laser spots radially expand, 

the aligned parallel magnetic fields are advected to the interaction region between the targets. 

By shifting the targets along their normal, we have these laterally expanding Biermann fields can collide. 

To resolve in time the topology of the compressed magnetic field we use the proton deflectometry technique, 

which clearly highlights the magnetic field compression. These results will be presented, 

as well as the results of full-scale 3D hybrid numerical simulations.