The eruptive events on September 30, 1998

Bagala', L. Gabriela

Abstract

The September 30, 1998 event was rather complex, involving a 2N flare, a H-alpha surge with its counterpart in the coronal green line, an eruptive prominence, and the release of several blobs. These transients were observed above the Active Region (AR) complex 8338-8340 in a time lapse of around 3 hours. During the event, changes in the coronal magnetic field topology was observed, as detected in Fe XIV emission. Although the event occurred on the limb, a sudden increase in energetic particles (i.e., protons with energies above 5 MeV) arriving at Earth was also detected.

This event was very well observed by the H-alpha telescope HASTA and the mirror coronagraph MICA, both installed in the recently inaugurated German-Argentinian Solar-Observatory at El Leoncito, San Juan, Argentina. MICA daily images the inner solar corona in two spectral ranges: the well known green (~ 1.8 MK) and red (~ 1.0 MK) coronal lines at 5303 A and 6374 A respectively. Its field-of-view ranges from 1.05 to 2.0 solar radii above the sun center. HASTA is a 110 mm refractor with a focal length of 165 cm, a tunable (+- 1 A) Lyot-Filter with a bandwidth of 0.3 A and a 1280*1024 CCD array. In this work, observations of such event as taken by both telescopes is presented.

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