  We studied temporal changes of morphological and magnetic properties of a
succession of four confined flares followed by an eruptive flare using the
high-resolution New Solar Telescope (NST) operating at the Big Bear Solar
Observatory (BBSO), Helioseismic and Magnetic Imager (HMI) magnetograms and
Atmospheric Image Assembly (AIA) EUV images provided by Solar Dynamics
Observatory (SDO). From the NST/Halpha and the SDO/AIA~304 A observations we
found that each flare developed a jet structure that evolved in a manner
similar to evolution of the blowout jet : 1) an inverted-Y shape jet appeared
and drifted away from its initial position; 2) jets formed a curtain-like
structure that consisted of many fine threads accompanied with subsequent
brightenings near the footpoints of the fine threads; and finally 3) the jet
showed a twisted structure visible near the flare maximum. Analysis of the HMI
data showed that both the negative magnetic flux and the magnetic helicity have
been gradually increasing in the positive polarity region indicating the
continuous injection of magnetic twist before and during the series of flares.
Based on these results, we suggest that the continuous emergence of twisted
magnetic flux played an important role in producing a successive flares and
developing a series of blowout jets.
