Magnetic diffusion process in cylindrical implosion magnetic flux compression experiment

When a strong magnetic field (above megagauss) diffuses into a solid metal, the magnetic field will diffuse into the metal in the form of a sharp-front wave. The phenomenon of sharp-front magnetic diffusion wave is studied using 1D MHD simulation for cylindrical implosion magnetic flux compression experiment, in which the liner is stainless steel304. Results indicate that sharp-front magnetic diffusion wave will happen when the magnetic field in cavity is compressed above 350 T. The magnetic diffusion wavefront advances rapidly from the inner of the liner to the outer, causing partial leakage of the magnetic field. It is adverse to the magnetic flux compression process. At the same time, as the inner of the liner is rapidly heated to the ionization temperature, a plasma layer will be formed near the inner, which greatly slows down the velocity of the magnetic field diffusing from the cavity to the liner. In the process of magnetic flux compression, sharp-front magnetic diffusion wave and the plasma layer have opposite effects to magnetic diffusion. They compete with each other in the development, and play the dominant role in different stage respectively.