RELEVANCE OF SOUTHWARD MAGNETIC-FIELDS IN THE NEUTRAL SHEET TO ANISOTROPIC DISTRIBUTION OF ENERGETIC ELECTRONS AND SUBSTORM ACTIVITY

The implications of southward magnetic fields at the magnetotail neutral sheet to the development of streaming anisotropy of energetic electrons and magnetospheric substorm activity are examined. Magnetic field and energetic particle measurements from the Imp 6 spacecraft, the AE index, and global auroral images from DMSP spacecraft are utilized in this study. Criteria are developed to identify events of southward magnetic fields at the neutral sheet which imply the presence of X-type magnetic neutral lines. The results are discussed in detail.