The solar origins of the Sun-Earth connection events on April 1999 and February 2000

Geomagnetic activity during the Sun-Earth connection events on April 1999 and February 2000

“…It is the objective of the present paper to study the geomagnetic activity during two different magnetic storms: April, 16-17 1999, driven by a magnetic cloud (MC) and February 11-12 2000 storm, driven by a complex event (CE) resulting of the interaction of two ICMEs. This paper is an extension of a combined study about the solar origins (Balmaceda et al, 2004) and the interplanetary aspects (Echer et al,2006) of these two sun-earth connection events.…”

“…The magnetic storm of February 2000 was caused by the interaction of two interplanetary remnants of CMEs. Three CMEs were observed by SOHO on February 8, 9 and 10 2000 (Balmaceda et al, 2004) and the interplanetary remnants of two ICMEs as well as their shocks were observed at ACE on February 2000. The second ICME seems to have engulfed the first one (Echer et al, 2006).…”

“…The April 1999 magnetic storm was caused by a magnetic cloud. On April 13, 1999, a halo CME earthward directed was observed in LASCO C2 at 03:30 UT with a velocity of 291.2 km/s (Balmaceda et al, 2004). The interplanetary remnant of this CME was fast enough to drive an interplanetary shock that reached ACE spacecraft on 10:30 UT April 16, 1999 (Echer et al, 2006).…”