Laboratory studies of the variation of the magnetosphere with solar wind properties

A scale model laboratory experiment simulating the effect of the solar wind on the magnetosphere has been performed. On the basis of photographic and magnetic field measurements, two distinct types of interactions, depending on the properties of the solar wind, can be distinguished. The ‘standoff’ interaction shows a complete standoff of the impinging solar wind plasma at several earth radii away from the terrella. No visible injection of the ‘wind’ into the region of the terrella is observed. A very steep gradient of the magnetic field at the position of the standoff and the formation of discrete inner regions of plasma are found. The ‘injection’ interaction is characterized by the injection at high latitudes of plasma into the vicinity of the terrella merging into a single wake or tail. The visible plasma regions to windward generally exhibit considerable radial thickness and diffuse edges. Magnetic measurements show a much more gradual compression of the magnetic field and no discrete inner regions.