We have analyzed high-resolution Ha 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 Y ohkoh soft X-ray data of 2000 February 17. Two sympathetic M-class solar Ñares 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 Ðrst Ñare in AR 8869 and the cause of the second Ñare in AR 8872. The activation started in the form of a surge just after a Ðlament eruption and its associated Ñare 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 Ñare followed in less than an hour after the arrival of the disturbances at AR 8872. The moving disturbances appeared in absorption in both Ha and EUV 195 The A images. disturbances may represent mass transfer, which had a signiÐcant velocity component perpendicular to the Ðeld lines and, hence, caused the transport of Ðeld 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.ÏÏ 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.

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The area ratio of umbra to penumbra (Au/Ap) was investigated for a series of 126 sunspots observed around the maximum of solar activity in 1980. Plotting log (Au) as function of log (Ap) a linear relation is obtained with a slope of 1.10, yielding an average ratio Au/Ap of 0.24 for small spots and of 0.32 for large spots. This deviates noticeably from the commonly adopted constant value of Au/Ap = 0.21 (Allen, 1973) used e.g. for modelling the sunspot irradiance deficit (cf. Willson et al., 1981) from the Solar Geophysical Data.

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