SSC24 July 29-30 2002 MC, CMEN34 (see text)





















29 July 10:28-11:15 UT: Series of microwaves bursts 4.5-2GHz (A) (Ondrejov) associated with a GOES X ray event (Solar flare S10-W10 10:27-11:13 UT; HESSI flare X 232 Y -289). 10:42:10 UT: Types III bursts (frequency range 170-0.1 MHz, Potsdam, DAM  and WIND/Waves); they are followed by a broad continuum at decameter wave-lengths (see middle raw, DAM right panel and upper raw, right panel from Postdam).

  • (11-14 UT 200-40 MHz, Potsdam). This event occurs in coincidence with the brightening of the trailing part of a CME which displays a slow evolution (CME1 Partial Halo 00:30 UT, P 311, W >173, V 363, 376, 280 km −1).
  • 12:02-12:10 UT: Type III burst followed by the onset of a type II burst detected by WIND/Waves, 12:10-12:45 UT (4200-1300 kHz). The radio emissions result from the interaction between CME1 and a faster CME2 (CMEN34 12:07 PA 13 Width > V 562,512, 532 km s−1), see in particular lower raw, middle and right panels.

Note that the observing coverage of the two CMEs is very poor, with no observation for two time periods (09:30-10:35 UT and 11:09 -12:07 UT). We suggest that both episodes could be associated with CMEN34 rising and interacting with and which has a smaller velocity. on July 31

This event shares the following characteristics:  Type IV (A-B) and a Type II, Encounter which  might result  from the interaction between CME1 and CME34.

CME34 continues its progression with decreasing velocity. On July 30, a new CME with an increasing velocity (CME2 July 23:30 PA 351 (deg), Width 351, V 360, 395, 420) appears in the same region as CME52. Considering their respective progression (see the SOHO catalog), their encounter is estimated to happen roughly on July31 UT at 01 UT; CME2 will continue its progression and will arrive, on August01 around 17 UT in the earth environnement. SSC26 happens the same day at 23:09 UT.

We suggest that SSC26 is associated with 2 successive CMEs: CMEN34-CME2 (July 30, 23:30 UT).