The intensity of the main phase of geomagnetic storms in relation to the parameters of the solar wind

Summary On the basis of investigating 10 storms (1965–1967) good correlation was found between the density of the solar wind energy (₂=1/2mNv²) and the intensity of the main phase of the geomagnetic storms, expressed in terms of the maximum decrease of the horizontal intensity (B=H/cos). The relation between ₂, or Nv², and B could then be used to determine the quantities and ₀ ( is the factor expressing the increase in energy density in the magnetosphere, ₀ is the energy density of the particles in a quiet magnetosphere). A comparison with the directly observed distribution of the energy density of the particles in the magnetosphere indicates that the computed value of ₀ seems to be realistic. The magnitude of the factor will have to be checked again.