Cradle-to-Grave Evolution and Explosiveness of the Magnetic Field from Bipolar Ephemeral Active Regions (BEARs) in Solar Coronal Holes

We report on the entire magnetic evolution and history of magnetic-explosion eruption production of each of 7 bipolar ephemeral active regions (BEARs) observed in on-disk coronal holes in line-of-sight magnetograms and in coronal EUV images. One of these BEARs made no eruptions. The other 6 BEARs together display three kinds of magnetic-explosion eruptions: (1) blowout eruptions (eruptions that make a wide-spire blowout jet), (2) partially-confined eruptions (eruptions that make a narrow-spire standard jet), (3) confined eruptions (eruptions that make no jet, i.e., make only a spireless EUV microflare). The 7 BEARs are a subset of a set of 60 random coronal-hole BEARs that were observed from the advent to the final dissolution of the BEAR's minority-polarity magnetic flux. The emergence phase (time interval from advent to maximum minority flux) for the 60 BEARs had been previously visually estimated using the magnetograms, to find if magnetic-explosion eruption events commonly occur inside a BEAR's emerging magnetic field (as had been assumed by Moore et al 2010, ApJ 720:757). That inspection found no inside eruption during the estimated emergence phase of any of the 60 BEARs. In this new work, for each of the 7 BEARs, we obtain a more reliable determination of when the emergence phase ended by finding the time of the BEAR's maximum minority flux from a time plot of the BEAR's minority flux measured from the magnetograms. These plots show: (1) none of the 7 BEARs had an inside eruption while the BEAR was emerging, and (2) for these 7 BEARs, the visually-estimated emergence end time was never more than 6 hours before the measured time of maximum minority flux. Of the 60 BEARs, in only 6 was there an inside eruption within 6 hours after the visually-estimated end of emergence. The above two results for the 7 BEARs, together with the previous visual inspection of the 60 BEARs, support that a great majority (at least 90%) of the explosive magnetic fields from BEARs in coronal holes are prepared and triggered to explode by magnetic flux cancellation, and that such flux cancellation seldom occurs inside an emerging BEAR. The visual inspection of the magnetograms of the 60 BEARs showed that the pre-eruption flux cancellation was either on the outside of the BEAR during or after the BEAR's emergence or on the inside of the BEAR after the BEAR's emergence.