We have analyzed high-resolution Hα full disk data from Big Bear Solar Observatory (BBSO); magnetograph and EUV data from the Michelson Doppler Imager, Large Angle and Spectrometric Coronagraph, and Extreme Ultraviolet Imaging Telescope on board SOHO; and Yohkoh soft X-ray data of 2000 February 17. Two sympathetic M-class solar flares erupted in succession in NOAA Active Region 8869 and 8872, respectively. The eruption from AR 8872 was followed by an extremely symmetric halo coronal mass ejection (CME). We demonstrate the loop activation, which appears to be the consequence of the first flare in AR 8869 and the cause of the second flare in AR 8872. The activation started in the form of a surge just after a filament eruption and its associated flare in AR 8869. The surge quickly turned into a set of disturbances that propagated at a speed of about 80 km s-1 toward the other active region AR 8872. The second flare followed in less than an hour after the arrival of the disturbances at AR 8872. The moving disturbances appeared in absorption in both Hα and EUV 195 Å images. The disturbances may represent mass transfer, which had a significant velocity component perpendicular to the field lines and, hence, caused the transport of field lines. In this case, the disturbances may be considered to be a special kind of surge, which we may call a "sweeping closed-loop surge." We also demonstrated large area dimmings associated with the CME in three active regions. The dimming started from AR 8869 and AR 8872 and was extended to AR 8870, which was on the opposite side of the solar equator. We believe that both the activation of inter-active region loops and the large-scale dimming are the signatures of large-scale restructuring associated with the CME.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
- Sun: activity
- Sun: coronal mass ejections (CMEs)
- Sun: flares
- Sun: magnetic fields