Magnetic storms: The simultaneous development of the main phase (DR) and of polar magnetic substorms (DP)

The development during magnetic storms of the main phase (DR) and of polar magnetic substorms (DP) is examined by comparing several Honolulu H magnetograms (for the DR) and the values of the corresponding planetary ap index (for the DP). It is shown that the DR and DP fields develop simultaneously. However, the storm-time increase in the aolar plasma pressure, sudden or continuous, does not seem to be related in any simple way to the increase of particle kinetic energy density of the ring current or of the auroral particles.