Journal of Geophysical Research: Space Physics

An average image of proton plasma pressure and of current systems in the equatorial plane derived from AMPTE/CCE-CHEM measurements


  • Paola De Michelis,

  • Ioannis A. Daglis,

  • Giuseppe Consolini


The present study attempts to visualize the global equatorial current systems and the proton pressure in the near-Earth magnetosphere based on AMPTE/GCE-CHEM measured proton distributions, which were sorted by the AE index (“quiet”: AE < 100 nT, “active”: 100 nT < AE < 600 nT). The data were averaged over 2 years (from January 1985 to June 1987) in order to obtain the necessary spatial resolution with statistical significance. The results provide an average image of proton plasma pressure, proton plasma anisotropy, and current systems as a function of geomagnetic activity. In particular, the changes of pressure anisotropy with local time and the noon-midnight pressure asymmetry are studied and correlated to the current systems out of the equatorial plane that generate the closure circuits. Moreover, we identify and spatially locate two different current systems for the quiet period (the ring current and the inner portion of the quiet time cross-tail current) and three different current structures for the active period (the ring current, the partial ring current, and the region 2 current).