Shock waves in space, considered as an acceleration mechanism of cosmic rays, are vital physical phenomena. Collisionless shock waves, generated in space plasma without particle collisions but through electromagnetic fields, remain a complex and critical research topic in astronomy and plasma physics. Hindered by the difficulty of direct observation, uncovering their mechanisms requires replicating these shock waves in laboratories to simultaneously observe local and macroscopic behaviors. Our experiment forms plasmoids with extremely high beta values (plasma pressure/magnetic pressure ～ 100%), similar to space conditions. In the presented experiments, a set of two plasmoids are generated using two conical theta-pinch formation sections and they are collided at the relative velocity of 100–600 km/s, exceeding the sound and Alfvén speeds. This process formed meter-scale collisionless shock waves, allowing for direct imaging and internal electromagnetic field measurements. This experimental approach opens new method to investigate a key process in astrophysics.

We proposed two designs of floating vertical-axis wind turbine and studied their characteristics of motion responses and wave loading through physical experiments and numerical calculations. The 1:100 scaled model tests were conducted in a wave tank equipped with wind blowers. The 5 MW three straight bladed wind turbines with NACA 0018 airfoils were modelled. The experimental observations demonstrated that the gyroscope effects of turbine rotations on roll motion response and mean wave drift force are non-negligible. The numerical analysis was performed in the framework of linear potential flow theory. The hydrodynamic performance of the floating foundations with two or four rectangular moonpools were examined. We found that the application of moonpools is helpful in reducing the horizontal mean wave drift force on barge platform at moonpool resonance frequencies. In addition, viscous damping plays an important role in estimating the resonant amplitudes of moonpool resonance and mean drift force. Conventional linear potential flow models without special modifications can predict the trend of amplitude-frequency response reasonably but fail to estimate the heave and roll responses accurately at the certain frequencies where the viscous effect of moonpool resonances and/or the gyroscopic effect of turbine rotations are non-negligible.