Magnetic fields are ubiquitous in high-energy-density physics. Whether externally imposed or self-generated, they profoundly alter plasma properties at all scales. For example, they reduce the mobility of charged particles and shape supernova remnants, playing a central role both in the laboratory and the Universe. In this thesis, their effects on heat transport and collisional blast wave structure are investigated experimentally within the framework of inertial confinement fusion (ICF) and laboratory astrophysics.

In the first part, magnetized heat transport in laser-produced plasmas is studied using a platform capable of generating fields up to 20 T. The plasma conditions are characterized by a full suite of diagnostics, including temporally and spatially resolved Thomson scattering. Our results provide direct evidence of heat-flux inhibition and preheat suppression induced by the applied magnetic field, which causes a significant temperature increase. The measured electron velocity distribution function is distinctly non-Maxwellian and strongly associated with inverse bremsstrahlung heating.

In the second part of this thesis, the experimental platform and diagnostics are repurposed to demonstrate that even modest magnetic fields can affect the blast wave structure. When applied perpendicular to their direction of propagation, the blast waves deviate from the Sedov-Taylor solution, and energy is dissipated along the shock front due to resistive effects. A parallel field, on the other hand, channels the plasma, forming a jet-like structure. For this experiment, a Stark-Zeeman diagnostic is developed that, when coupled with the PPPB code, can retrieve plasma conditions and magnetic field characteristics in a non-intrusive manner.

Our findings suggest that magnetic fields of this magnitude could improve ICF schemes by raising fuel temperatures and reducing preheating. They also provide an experimental benchmark for studying magnetized blast waves, thereby forming a basis for interpreting the morphology of their astrophysical counterparts.