2.3.3.  November 6, 1997

Strongly speaking, in this case an associated CME does not belong to the halo type, but as one can see on  Figure 15, it was an impressive large hanger-like CME, extending over the whole W limb, and took place in a combination with a powerful 2B/X9.4 flare picked at about 11:55 UT in the same SW active complex AR 8100  (points 1 and 2 on Figures 15, 16).  This event is of great interest also due to that it was accompanied by the largest solar proton flux increase in the present cycle with J(E>10 MeV)~490 pfu and 12 % ground-level enhancement (GLE) (See the ISTP page http://www-istp.gsfc.nasa.gov/istp/events/1997nov4/ ). It is remarkable, that similar to the previous event, the brightest leg of the given CME was observed again not over the SW limb but over the NW one. Radio and LASCO signatures of this event are considered by Maia et al. (1999).

The large-scale chains, visible on the modified SOHO/EIT images and  movie  at 195 Å, provide additional evidences that the flare mentioned above was only a part of the much more global activity which extended the whole solar disk and included also the NW sector.

Figures 16a,b display a complicated evolving  system of the large-scale chains at the pre-CME stage. The main active complex 1-2 is connected with all remote active centers on the disk particularly by chains 1-2-7-5, 1-11, 1-14-8, 1-19-17, 2-15-23-10, 1-8. There are two additional knots 3,4 and 9,11 in which many chains meet and cross, particularly such as chains 5-3-9-11, 3-10, 3-17, 4-3-19-14 (partly in absorption), 5-4-10, 4-13, 11-19-15-16, 11-10, 11-18-12, 11-20-6-18, 19-9-17. One more chain 17-14 connects the NE and W limbs.

Directly after the flare and CME eruption (c),  a chain 2-8 flushes up (it seems that it isn’t artificial). Then (d), during the propagation of the coronal wave, chains 3-6-8, 3-9, 5-15-9, 9-15-7-1, 15-14-8 become pronounced.

At the post-CME stage (e,f) chains are observed on the background of a snowstorm caused by protons coming to the SOHO spacecraft. During several hours, a diffuse chain 3-11 neighbors with a thin chain 5-11. There are also some other diffuse chains (7-5-3, 11-20-6-12, 22-9-17, 9-10, 6-13) as well  as some thin ones (1-15-19-11, 1-21-8, 1-19-3, 3-10). Some of these chains can be seen also at 171 Å (Figure 15d) although the quality of this snowstorm image is not so good. The Yohkoh/SXT image (Figure 15b) reveals also close connection between all active centers and display some analogs of the EUV chains.

The Javascript movie at 195 Å shows that the strong evolution of the chains 3-11 and 5-11 and other chains westward the line 3-11-12 continues at least during the first half of the next day.