The role of the cusp as a source for magnetospheric particles: A new paradigm? Original Research Article

New observations from the NASA GGS POLAR satellite of cusp energetic particle [CEP] events indicate that the mechanism(s) in the dayside cusp accelerate the solar wind plasma to 100s and 1000s of kiloelec-tronvolts energies. The mechanism seems to be active much of the time but is impulsive in nature with an event having a lifetime of 45–60 minutes. This mechanism is capable of producing an energetic particle layer that straddles the magnetopause along the flanks of the magnetosphere. These energetic particles can enter the magnetosphere as a result of gradients in the magnetic field and the resultant drifts they cause; ions entering along the dawn flank drifting to the west and electrons entering along the dusk flank drifting east will carry a current. Since these particles will drift to distances less than six earth radii in the nightside equatorial plane, their variations in time probably control the dynamics of the magnetosphere in the range 6 < L < 13 and these particles are probably the source of the plasma sheet energetic particle population. This result has the potential to be a new paradigm for the way we view the dynamics of the magnetosphere.