Cluster observations of high-altitude cusp during multiple fast-turning IMF

摘要: Using coordinated observations from the Cluster, DMSP and ESR radar, high-altitude cusp was investigated for a time period characterized by four fast reversals of IMF B Z. On February 12, 2003, Cluster flying sunward at duskside over Northern Hemisphere, across northern twice. Both two crossings are during steady northward interval, whereas ion fluxes detected quite different. The in first crossing is “typical” northward-IMF one, with short-lived injections evident “reversed” dispersion signatures. In second crossing, however, appears to be region reminiscent Stagnant Exterior Cusp (SEC). addition, upward-flowing O+ bursts, possibly original polar ionosphere, also together enhancement trapped magnetospheric-like electron fluxes. We suggest that SEC-like likely on newly closed field lines, which were reconnected (being opened) low latitudes later again closed) poleward cusp.