2.3.2.  November 4, 1997

This next-day event included a quasi-impulsive 2B/X2.1 flare, which occurred at ~06 UT in the same active complex AR 8100 (points 1 and 2 on Figures 13,14), as well as a halo CME and a proton flux increase of J(E>10 MeV)~72 pfu. The corresponding GOES-9 X-ray plot is shown on Figure 13b. Some features of this event is described by Chernov et. al. (1999). The accompanying severe geomagnetic storm with the amplitude Dst~ -110 nT on November 7 at 05 UT appears to have a composite character. (See the ISTP page http://www-istp.gsfc.nasa.gov/istp/events/1997nov4/ ).

The CME  is characterized as a structured halo (Figure 13a). Over the W limb, the NW component is brighter than the SW one although the main flare region 1-2 is located in the SW quadrant. The very bright material over the SE limb appeared to originate some early relatively the 06 UT flare, perhaps as a result of a near-the-SE-limb filament activity. Perhaps, just this activity stimulated large-scale instability, resulting in the halo CME, and explosive energy release in local magnetic field of the region 1, observed as the flare.

According to the modified EIT 195 Å images ( Figure 14 ) and movies , the situation of the previous event continued in the sense of the close connection between all active structures on the disk and presence of  a number of large-scale chains.

On the morning image (a), a system of chains 19-1-4-5, 5-2-1, 3-20-5, 21-7-1-14 unites all active centers of the S hemisphere. In turn, this system is connected with the N-hemisphere centers by a number of chains 1-6, 1-22-8, 3-9, 3-10, 14-9-10, 4-9, 5-9-11-23, and others. In the N hemisphere itself, several additional large chains 10-11-12, 6-8 are also present.

On the after-the-flare image (b), one can find a number of new pronounced chains. Several of them are concentrated around point 3 in the SE quadrant: a bright chain 3-21 appears to joint a pre-existing chain 21-7-1; chains 3-16-10 (or 16-24) and 3-8 manifest itself. A spectacular thin (partly double) chain 13-15-6 with some branches to the region 1 are visible on the background of remnants of a large dimming area formed after propagation of a coronal wave. Besides, chains 1-25, 1-14-8, 9-25-15, and others are enhanced somewhat.

At the post-CME stage, at first (c,d) a large trans-equatorial loop-like chain 1-14-10 (the same as was observed in the previous event) develops gradually, as well as chains 3-16-10 (and 16-9), 3-9, 3-21-7-1, 5-9 (or 5-11), 1-15-12, 1-14-8-12, 1-25-9-10, 21-25, and some others.

Later (e,f), chains  3-5-7-2, 3-17, 3-16-6-12, 3-17-8 (perhaps in absorption partly), 1-17-9, 1-5-21, 1-14-8, 11-18, 26-9, 10-11-28-29, 1-27-28-29 predominate. It testifies particularly to that the NW quadrant plays an important role in this global activity being responsible for the bright NW component of the halo CME.

A global character of the activity is obvious also from the Yohkoh/SXT image (Figure 13b) as well as from SOHO/EIT images (Figure 13c,d) on which many of large-scale chains, extending through the whole solar disk and mentioned above, are visible not only at 195 Å but also at 171 Å.

Analyzing the later large-scale chains and other activity, one should keep in mind that one more multi-part large loop-like CME occurred over the W limb on November 5 starting from 00:18 UT.