Shock acceleration is a research area in astrophysics that studies the process by which particles gain energy through interactions with shock waves, such as those produced by supernovae or the shock fronts of cosmic rays. This process is believed to be responsible for the acceleration of cosmic rays to extremely high energies in the universe. Shock acceleration is of interest to scientists because it can help explain the origin and distribution of cosmic rays, as well as the processes that occur in various astrophysical environments, such as supernova remnants and active galactic nuclei. By studying shock acceleration, researchers hope to gain a better understanding of the physics of particle acceleration in extreme environments and the role it plays in shaping the structure and evolution of the universe.