RECURRENT SOLAR JETS INDUCED BY A SATELLITE SPOT AND MOVING MAGNETIC FEATURES

2015. The American Astronomical Society. All rights reserved. doi:10.1088/0004-637x/815/1/71 RECURRENT SOLAR JETS INDUCED BY A SATELLITE SPOT AND MOVING MAGNETIC FEATURES Jie Chen 1, Jiangtao Su 1, Zhiqiang Yin 1, T. G. Priya 1,2, Hongqi Zhang 1, Jihong Liu 3, Haiqing Xu 1, and Sijie Yu 1 1 Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China; chenjie@bao.ac.cn 2 University of Chinese Academy of Sciences, China 3 Shi Jiazhuang University, Shi Jiazhuang, 050035, China Received 2013 December 27; accepted 2015 October 30; published 2015 December 10 ABSTRACT Recurrent and homologous jets were observed to the west edge of active region NOAA 11513 at the boundary of a coronal hole. We find two kinds of cancellations between opposite polarity magnetic fluxes, inducing the generation of recurrent jets. First, a satellite spot continuously collides with a pre-existing opposite polarity magnetic field and causes recurrent solar jets. Second, moving magnetic features, which emerge near the sunspot penumbra, pass through the ambient plasma and eventually collide with the opposite polarity magnetic field. Among these recurrent jets, a blowout jet that occurred around 21:10 UT is investigated. The rotation of the preexisting magnetic field and the shear motion of the satellite spot accumulate magnetic energy, which creates the possibility for the jet to experience blowout right from the standard. Key words: magnetic reconnection Sun: activity Sun: atmosphere Sun: magnetic fields 1. INTRODUCTION Jet activities are very common phenomena in the solar atmosphere that are observed both in hot and cool plasma ejections such as X-ray jets, extreme ultraviolet (EUV) jets, and Hα surges (Shibata et al. 1994; Canfield et al. 1996; Shimojo et al. 1996, 1998; Shimojo & Shibata 2000; Liu & Kurokawa 2004; Jiang et al. 2007; Guo et al. 2010). Solar coronal jets were discovered in X-rays using the Soft X-ray Telescope on board the Yohkoh satellite (Tsuneta et al. 1991). Shimojo et al. (1996, 1998) carried out statistical studies for 100 X-ray jets and found that these jets have the following characteristics: the typical length is in the range of a few 104 ~ 4 105 km and the width is 5 103 ~ 105 km, the apparent velocities are 10 ~ 1000 km s 1 with an average velocity of about 200 km s 1, the lifetimes range from a few minutes to 10 hours with most of them associated with small flares; 72% of them occurred at the mixed polarity regions. X-ray jets were studied further after the launch of the Hinode satellite. By examining many X-ray jets with the Hinode/X-ray Telescope (XRT), Moore et al. (2010) found that about twothirds are standard jets and one-third are non-standard jets, which are called blowout jets. Based on the observations of the Solar Dynamics Observatory (SDO), blowout jets associated with miniature versions of coronal mass ejections were reported by Liu et al. (2011) and Shen et al. (2012). Jets/surges emanating from almost the same location tend to occur repeatedly (Schmieder et al. 1995; Asai et al. 2001; Wang et al. 2006; Chifor et al. 2008b; Wang & Liu 2012; Zhang et al. 2012). Cirtain et al. (2007) detected an average of 10 jet events per hour during 100 hr of observations and found that the jets frequently occurred in the same X-ray bright points or locations that were extremely close to the previous jetinitiation sites. Jiang et al. (2007) observed three surges occurring intermittently within a period of about 70 minutes. It is believed that jet activities are associated with flux cancellation and emergence. Chae et al. (1999) observed several EUV jets, which look like Yohkoh soft X-ray jets, repeatedly occurring in regions of magnetic cancellation between pre-existing magnetic flux and newly emerging flux of opposite polarity. Brooks et al. (2007) analyzed a surge that was provoked by the interaction of the emerging flux region with moving magnetic features (MMFs). Chifor et al. (2008a, 2008b) reported a recurring X-ray jet that happened on 2007 January 15/16 and found a correlation between continuous magnetic flux cancellation close to pore and recurring X-ray jets. Guo et al. (2013) presented three EUV jets recurring repetitively in phase in one hour with the peaks of absolute electric current and the maximum of electric current preceding the 171 Å flux for about 10 minutes. Magnetic reconnection is considered to play an important role in the driving mechanism of the jets (Shibata et al. 1994). Based on the structure and development of typical jets observed in soft X-ray images, Shibata et al. (1992) suggested a standard two-dimensional jet model: a small bipolar magnetic arcade emerging into a surrounding unipolar open field such as a coronal hole, with the magnetic reconnection between the closed field of the bipole and the external open field, which leads to an explosive release of energy. This model was confirmed in two- and three-dimensional simulations (Yokoyama & Shibata 1995, 1996; Miyagoshi & Yokoyama 2004; Moreno-Insertis & Galsgaard 2013). Pariat et al. (2009, 2010) presented a threedimensional numerical model with null-point and fan-separatrix topology, the recurrent quasi-homologous jets were generated by imposing twisting motions in the photosphere continuously. Features of three-dimensional spine-fan reconnection around a null point were also demonstrated by Pontin et al. (2013). Yang et al. (2013) constructed a 2.5-dimensional numerical MHD simulation of anemone jets, which is produced by magnetic reconnection between MMFs and pre-existing ambient magnetic field. The reconnection is driven by the horizontal motion of the magnetic structure in the photosphere. In summary, previous numerical models presented photospheric motions that triggered the generation of recurrent jets. Most of the previous observational studies were focused on analyzing the properties of jets and the variation of associated magnetic flux. However, the reconnection model of jets needs to be confirmed observationally with higher resolution data. The driving mechanism of quasi-homologous jets related to the photospheric motions and detailed magnetic field evolution needs to be studied further. Launched in 2010, SDO provides 1

unprecedented observing capabilities that can help us to investigate this issue. By analyzing SDO data, we identify about 20 jets occurring to the west edge of active region (AR) NOAA 11513 at the boundary of a transequatorial coronal hole from 2012 July 2 to 3. Subsequently, we study two types of magnetic cancellation associated with the generation of the recurrent and homologous jets and analyze the evolution of a blowout jet and the relation with the photospheric magnetic field variation in detail. This paper is organized as follows. In Section 2, we introduce the observation and data reduction, and, in Section 3, we present a brief description of AR NOAA 11513. A variation of the satellite spot is given in Section 4. The evolution of recurring jets and the relation with photospheric magnetic field are demonstrated in Section 5. In the last section, we present the conclusion and a discussion. 2. OBSERVATION AND REDUCTION The Atmospheric Imaging Assembly (AIA; Lemen et al. 2012) on board SDO takes full-disk images of the Sun in seven EUV channels and three UV-visible channels, whose spatial and temporal resolutions are 0 6 pixel 1 and 12 s, respectively. Among the 10 different wavelength channels, 6 wavelengths (131, 171, 193, 211, 335, 94 Å) are centered at strong iron lines (Fe VIII, IX, XII, XIV, XVI, XVIII), covering the coronal temperature range from T» 0.6 MK to 16 MK. In this study, the data from 304 and 171 Å channels are used to detect the jets occurring at the west edge of AR NOAA 11513 in the upper chromosphere and transition region, which were obtained from 2012 July 02 17:00 UT to July 03 3:00 UT. The images were calibrated using the standard AIA procedure (aia_prep.pro) in the Solar SoftWare. Another instrument, the Helioseismic and Magnetic Imager (HMI, Scherrer et al. 2012) on board SDO, takes full solar disk images in the photospheric absorption line Fe I centered at the wavelength 6173.3 Å with a 45 s cadence and 0 5 spatial resolution, respectively. Based on the Milne Eddington approximation, HMI vector magnetograms are recovered from Stokes parameters I, Q, U, and V at six wavelengths along the Fe I 6173 Å spectral line in six polarization states using a VFISV algorithm (Borrero et al. 2011). The 180 azimuthal ambiguity is resolved with the minimum energy method (Metcalf 1994; Leka et al. 2009). These data are used to trace magnetic field evolution and intensity variation of the AR on the photosphere. In order to reveal magnetic topology, we resorted to full-sun extrapolation using the potential field source surface model (Schrijver & De Rosa 2003). Using the data from SDO, we can combine the observations from photosphere, chromosphere, and transition regions with photospheric magnetic field measurements at high spatial and temporal resolution. 3. AR NOAA 11513 AR NOAA 11513 was a bg-type AR that was located at N16 E03 on 2012 July 02. Its positional and morphological information is shown in Figure 1. A full-disk image at 171 Å obtained by AIA is shown on the left panel, a full-disk line-ofsight (LOS) magnetogram and corresponding magnetic topology structure is shown on the right panel. In the right image, the purple and green lines represent open negative and positive magnetic field lines, respectively. By examining X-ray images obtained by XRT, a big coronal hole was found across the equator toward the west edge of AR 11513, which is the area where the purple lines existed (the right panel of Figure 1). Based on this, we believe that the homologous jets occurred at the boundary of the trans-equatorial coronal hole with negative polarity magnetic field. Detailed information of AR NOAA 11513 is demonstrated in Figure 2. The two images in the top panel were obtained from AIA instruments at wavelengths of 171 and 304 Å, the contours superimposed on the images are the LOS magnetic fields from HMI. The blue (green) contour represents the positive (negative) value of the LOS magnetic field. Figures 2(c) and (d) are the corresponding filtergram and LOS magnetogram observed by the HMI instrument. In order to show the configuration clearly, different colors represent different intensities in Figure 2(c). 4. VARIATION OF THE SATELLITE SPOT At the footpoint of the jet series, there exists a positive magnetic polarity region that is surrounded by negative polarity regions (in Figures 2(c) and (d)). This region is a satellite spot. The intensity diagrams of the satellite spot from 15:00 UT to 21:00 UT were shown in Figure 3(a). It demonstrates that the satellite spot moved toward the southwest direction with an average velocity of 0.29 km s 1 during this period. After removing the motion of the satellite spot, we calculate the relative intensity (obtained with each intensity subtracted mean intensity of all the data divided by mean intensity) for the regions that are highlighted by a red box in Figure 3(a). The variation of relative intensity for the region from 15:00 UT on July 02 to 1:00 UT on July 03 is shown in Figure 3(c). In the filtergram, the satellite spot disappeared around 21:10 UT. The light curve demonstrates that the relative intensity was initially negative and became positive then on, which indicates that the small spot was decaying until it disappeared. To calculate the magnetic flux more accurately, the motion of the spot has to be removed. The evolution of the satellite spot s magnetic field after removing its motion is shown in Figure 3(b). The white patch is the corresponding satellite spot with positive magnetic polarity. The magnetic flux variation for this positive polarity patch is plotted in Figure 3(d) using a blue line. During this period, the magnetic flux gradually decreased from 2 10 20 to 1.0 10 20 Mx, which demonstrates that there is magnetic cancellation occurring between the satellite spot and its nearby magnetic region. 5. RECURRING JETS In this study, the recurring jets for 10 successive hours from 17:00 UT on July 02 to 3:00 UT on July 03 were investigated. One of those that occurred at 18:00 UT on July 02 is shown in Figure 2. Footpoints of the jet are marked by white squares (Figures 2(a) and (b)), and in this area there are mixed magnetic field polarities. The strand-like structures marked by two white dotted lines are the jets of interest. Figure 2(c) is the corresponding HMI filtergram, in the black square, there is a small satellite spot (the green dot) at the footpoint of the jet, which possesses positive magnetic polarity. After calibration, the images obtained from AIA 171 and 304 Å for 10 hr were registered and derotated. In order to detect the recurring jets, a virtual slit of 100 pixels in length and 41 pixels in width is taken along the white dotted lines, which are 2

Figure 1. Full disk images on 2012 July 02. Left: an image from AIA 171 Å at 18:04:11 UT. Right: magnetic field topology, full-sun extrapolation using the potential field source surface model. The white line represents the closed field, and the purple and green lines represent open negative and positive magnetic fields, respectively. The position of NOAA AR 11513 is plotted using a square. shown in top panel of Figure 2. The time distance diagram is presented in Figure 4. The initial point on the y-axis corresponds to the base of the jet shown by the dotted white line within the square regions (Figures 2(a) and (b)) and x axis represents the time sequence. The time distance diagrams of AIA 171 and AIA 304 Å present an overall view of the series of jets occurring during 10 successive hours. Each strip represents a jet, and about 20 jets were identified in the figure. The strips of 171 Å are highly in phase with those of 304 Å which means that the jets have cool components. From Figure 4 (a), the light curve showing the variation of the flux in 171 Å is deduced and plotted in Figure 3(d) using a black line (each data point is acquired by the summation of the data in the y axis). Among these series, the selected six jets with strong peaks are marked in Figure 4(a). The configurations and the corresponding photospheric LOS magnetograms of the jets are presented in Figure 5. From 17:00 UT to 21:10 UT, two bright parallel patches arise at the bottom of each image (Figure 4), which demonstrate circular-shape structure at the jet-base and look like inverted-ys (Figure 5(a)). The standard two-dimensional and three-dimensional jet models (Shibata et al. 1992; Moreno- Insertis & Galsgaard 2013) demonstrate jets with inverted-ys or Eiffel tower shapes. Jets 1 and 2 show this configuration. The main negative polarity is surrounded by positive magnetic polarity regions. From 21:10 to 21:30, a strong peak with high intensity appeared, which is a blowout jet (Jet 3). Moore et al. (2010) presented the dichotomy of the standard and blowout jets. In the following subsection, we will analyze this blowout jet in detail. From 21:30 UT July 02 to 1:00 UT July 03, the two parallel patches disappeared, but several peaks still exist. Jets 4 6 occurred during this period. At the base of these three jets, the bright points lie above the inverse line between the preexisting magnetic polarity and MMFs. The configurations are different from jets 1 and 2. From 1:00 UT to 3:00 UT on July 03, no peaks were observed any more, which means the jet disappeared. 5.1. Jets before 21:10 UT Jet 1 at 17:36 UT on July 02 has an inverted-y shape (Figure 5). The typical character of this jet is a circular shape at the base. The corresponding HMI LOS magnetograms are superimposed on AIA 171 Å images. The blue (green) contours represent the positive (negative) values of the LOS magnetic field, which are the same as in Figure 2(a). The HMI LOS magnetogram in Figure 5(a) demonstrates mixed magnetic polarity regions at the jet-base. In the middle of Figure 5(a), a negative magnetic field is seen surrounded by the positive magnetic fields. When over plotted on the 171 Å image, it looks like a spine-fan structure associated with a magnetic null. This generic configuration is shown in several papers (Pariat et al. 2009; Pontin et al. 2013). The fan lines form a circular shape at the base and our observation of circular-shape structure corresponds to this part of the model. The anchored structure represents the outer spine of their model. The magnetic morphology is comparable to the magnetic structure of the circular flare investigated by Wang & Liu (2012). At the west edge of the AR, there is a moat region. MMFs emerge from the penumbra, pass through the moat region, and move toward the west. In Figures 6(a) and (b), at the middle of the image, there is a main negative polarity region (MNPR) which is located at the east of the satellite polarity. To the east and the north of MNPR, there are several MMFs. Most of them are unipolar with positive magnetic polarity. These MMFs possess polarity opposite to MNPR and move toward the MNPR. The movement of MMFs and the satellite spot are presented in Figure 6. Time distance images are made for two MMFs and the satellite spot. In Figure 6(a), around 17:00 UT, an MMF with 3

Figure 2. NOAA AR 11513 and the jet happened at 18:00 UT on 2012 July 02. (a) One AIA 171 Å image. (b) One AIA 304 Å image. Both images are superimposed with the HMI LOS magnetic field. The green/blue contours represent negative/positive magnetic field values. (c) One HMI filtergram. Different colors show different intensity and blue color shows the weakest intensity. (d) One HMI LOS magnetogram. The white and black boxes in the images show the position of the jet-base, and the red box in Figure 2(c) shows the position of the main positive polarity region. positive polarity collides with MNPR, whose time distance image is shown in Figure 6(e). The blue dashed line shows that there is magnetic cancellation occurring between them. The movement of another MMF at 20:00 UT in Figure 6(b) is also analyzed. We consider the slit marked in red line for the MMF and present a time distance image as shown in Figure 6(d) (left point is at the bottom of the y axis), where the red dashed line shows the magnetic interaction of the MMF and MNPR. The moving speed of this MMF is 0.48 km s 1. We have mentioned the satellite spot moving toward the southwest with a speed of 0.29 km s 1 in Section 4, and this motion can also be seen in Figures 6(a) and (b)(the white patch moves southwest relative to the dark patch). It indicates that there is shear motion between the positive and negative fluxes. Besides that, there is also cancellation between positive and negative fluxes. In order to show it, we make a slit between the satellite spot and MNPR, which is marked by the green line in Figure 6(b). The time distance image is shown in Figure 6(c), where we can see that the satellite spot undergoes continuous cancellation with MNPR approximately from 19:00 UT to 21:00 UT. 5.2. The Blowout Jet Moore et al. (2010) pointed out several distinguishing features of the blowout jet. One is the brightening inside the base arch in addition to the outside bright point; another is an extra jet-spire strand, which is rooted close to the bright point. The dynamic evolution process of Jet 3 in 171 and 304 Å was demonstrated in Figure 7. Originally, at around 21:00 UT, the shape of the jet-base was circular. At 21:12 UT, the shape changed to two bright arcades, and this configuration shows brightening inside and outside the base archs. Four minutes later, the shape changed to curtain-like. Besides the original spire, this configuration shows another jet-spire. After that, the jet-base became weaker and weaker; it almost disappeared finally. The evolution of Jet 3 states the typical features of the blowout jet. The morphology and evolution are almost the same in the two wavelengths, which demonstrates that the blowout jet has a cool component. In Figure 3(d), the intensity flux obtained from 171 Å shows that the flux of Jet 3 is two orders higher than other jets. Time distance diagrams in Figure 4 also show that Jet 3 is much brighter than other jets. The eruption of Jet 3 needs much more energy than other jets. Figures 7(i) and (j) show the LOS 4

Figure 3. Evolution of a satellite spot. (a) Temporal sequence of HMI filtergrams, which demonstrates the movement of the satellite spot. (b) Magnetic field evolution of the satellite spot. (c) Variation of the relative intensity of the satellite spot in the red box (marked in Figure 3(a)). (d) Variation of the magnetic flux of the positive polarity region (blue curve) in Figure 3(b) and variation of the 171 Å flux (black curve) obtained from Figure 4(a). Figure 4. Time distance diagrams in AIA 171 Å (a) and 304 Å (b) channels obtained with 10 hr data (from July 02 at 17:00 UT to July 03 at 3:00 UT). 5

Figure 5. Maps of the six jets highlighted in Figure 4(a). The peaks of these jets occurred at 17:36 UT, 19:08 UT, 21:16 UT, 22:30 UT, 23:01 UT, and 00:53 UT. Row 1: from left to right, Jet 1, Jet 2, and Jet3 in 171 Å. Row 2: the corresponding images in 304 Å. Row 3: from left to right, Jet 4, Jet 5, and Jet 6 in 171 Å. Row 4: the corresponding images in 304 Å. Images in 171 Å are superimposed with the HMI LOS magnetic field; the different colors have the same meaning as in Figure 2. magnetic field of the jet-base at 17:00 UT and 21:15 UT, separately. The MNPR has a tilt angle of 67.0 at 17:00 UT, which increases to 77.6 at 21:15 UT. From 17:00 UT to 21:15 UT, the MNPR rotated by about 10. The rotation of MNPR built free magnetic energy. Before the eruption of Jet 3, the magnetic flux of the satellite spot began to decrease. The magnetic flux in this region decreased by about 6 10 19 Mx from 20:35 UT to 21:40 UT, which is shown in Figure 3(d). 6

Figure 6. Time slice images for the satellite spot and MMFs separately. (a) and (b) HMI LOS magnetograms at the jet-base at 17:00 UT and 20:00 UT, respectively. Blue line: a slit for one MMF; red line: a slit for another MMF; green line: a slit for the satellite spot. (c) Time distance image for the green slit. (d) Time distance image for the red slit. (e) Time distance image for the blue slit. The rotation of the MNPR and the shear motion between the satellite spot and the MNPR accumulates magnetic energy, which causes Jet 3 to have the possibility to blowout. The variation of the photospheric vector magnetic field related to the blowout jet is shown in Figure 8. The top panel shows the evolution of the LOS magnetic field; the bottom panel shows the evolution of the transverse magnetic field. Figures 8(i) and (j) show the variation of flux density of LOS and transverse magnetic field. During the eruption of Jet 3, transverse magnetic field increases, but the LOS magnetic field decreases. This result is similar to the change of magnetic field structure before and after flares (Wang & Liu 2010). 5.3. Jets 4 6 After the blowout jet, several jets recurred, but the shape of the jet-base changed completely. The morphology and magnetic configuration of Jets 4 6 are shown in Figure 5. Jet 4 has mixed magnetic polarities at the footpoint, where the positive polarity region is different MMFs moving from east to west, but the satellite spot with positive polarity is a little farther away from the jet base when seen through the HMI LOS magnetic field. Jet 5 has two brightening regions at the base, the one on the right is the same brightening region as in Jet 4, and the other on left corresponds to different MMFs. Time distance diagram of the MMF (related to Jets 4 and 5) is shown 7

Figure 7. Dynamic evolution of Jet 3. Top (a), (b), (c), (d): 171 Å; bottom (e), (f), (g), (h): 304 Å. (i) and (j) present the LOS magnetograms at 17:00 UT and at 21:15 UT. Images in 171 Å are superimposed with the HMI LOS magnetic field, the different colors have the same meaning as in Figure 2. Figure 8. Magnetic flux variation of LOS magnetic field (Bz) and transverse magnetic field (Bt) before and after the eruption of Jet 3. Top (a), (b), (c), (d): Bz; bottom (e), (f), (g), (h): Bt. (i) Variation of mean Bz in the regions that are marked by white boxes (in Figures (a), (b), (c), (d)), the blue line represents the variation of the negative magnetic polarity region and the black line represents the variation of the positive polarity region. (j) Variation of mean Bt in the regions that are marked by white boxes (in Figures (e), (f), (g), (h)). Figure 9. (a) HMI LOS magnetogram of the jet-base at 22:00 UT. Red line: a slit for the MMF. (b) A time distance image for the red slit. 8

Figure 10. Motions of the main positive magnetic polarity region, which is highlighted by a red box in Figure 2(c). The dashed line in (a) shows the original direction of two blue patches and that in (j) shows the final direction at 23:59 UT. Both of them (green/blue for at 14:59/23:59 UT) are shown again in (i). The center position of the bottom blue patch at 14:59 UT is marked by P1 and that at 23:59 UT by P2, shown together in (k). in Figure 9, in which the positive polarity region cancels with the negative polarity region from 22:00 UT to 23:00 UT. This means Jet 4, and part of the Jet 5, is induced by magnetic cancellation between the MMF and the pre-existing magnetic field. The same is true for Jet 6. 6. CONCLUSION AND DISCUSSION Homologous solar jets occurring on 2012 July 02 at 17:00 UT to 2012 July 03 at 3:00 UT are investigated and the evolution of the related photospheric magnetic field is analyzed in this work. The main observational results are listed as follows. 1. We find that the recurrent jets were due to the continuous magnetic reconnection in the mixed magnetic polarity regions. These jets are generated by two kinds of magnetic cancellation. One is the continuous magnetic cancellation between a satellite spot and pre-existing opposite polarity magnetic field, which causes the magnetic flux of the satellite spot to decrease and its intensity to increase. The other is the continuous cancellation between MMFs and pre-existing opposite polarity magnetic field. 2. The eruption process of a blowout jet is observed. The rotation of the magnetic field and the shear motion of the satellite spot build up free magnetic energy, which can make give the jet the ability to transform from standard to blowout. After the jet eruption, the transverse magnetic field increases and the longitudinal magnetic field decreases. As is known, jet activities are associated with magnetic emergence and cancellation. Yang et al. (2013) constructed a numerical MHD model to describe the process of magnetic reconnection between MMFs and the pre-existing magnetic field. However, there is seldom observational evidence for the jet created by MMF and pre-existing magnetic field. In this paper, we present a detailed observation of the generation of recurrent jets related to MMF. The eruption of the blowout jet needs some amount of energy. From Figures 3(d) and 4, we can see that the intensity of the blowout jet is much higher than other jets. The storage of energy is very important for the jet. The rotation of the magnetic feature and the shear motion of the satellite spot may accumulate enough magnetic energy for the eruption of the blowout jets. Wang & Liu (2010) revealed that the photospheric magnetic fields apparently change in response to the back reaction of the coronal field due to flare energy release and tends to be in a more horizontal state near the polarity inversion line after flares. Although the jet activities are small-scale reconnections, there are similar magnetic field changes as those in large flares. Here we provide some observational evidence. Due to the energy release of the blowout jet, the photospheric magnetic field tends to be in a more horizontal state: transverse magnetic field increases and LOS magnetic field decreases. Several jets before 21:10 UT have circular configurations at their footpoints, whose photospheric magnetic configurations exhibit one polarity surrounded by the opposite polarity regions, which may provide observational evidence for the dome configuration of spine and fan structures (Pariat et al. 2009; Pontin et al. 2013). The recurrent jets occurred at the boundary of a transequatorial coronal hole, which may provide matter for the solar wind. The distance between two main magnetic polarity regions increases during the observing period in AR NOAA 11513, which is an emerging AR. Motions of the positive polarity region (highlighted by a red box in Figure 2(c)) are demonstrated in Figure 10. As can be seen in the images, this region is separated into two patches. The center position of the bottom patch is marked as P1 at 14:59 UT and the same is marked as P2 at 23:59 UT. The average velocity of the bottom patch is obtained by dividing the distance between P1 and P2 by 9 hr. The positions of P1 and P2 are shown in Figure 10(k). The figure shows the motion of P1 toward the northeast direction with a speed of 0.18 km s 1. In addition, the whole region also rotates. The original direction at 14:59 UT is plotted in Figure 10(a) and the final direction at 23:59 UT is plotted in Figure 10(j), as shown in Figure 10(l) separately by green and blue lines. It rotates by 25. 7 during 9 hr in a clockwise direction. The motion of the satellite spot is toward the southwest with a velocity of 0.29 km s 1 and the main positive magnetic polarity region moves toward the northeast. Besides that, the main positive magnetic polarity region rotates in the clockwise direction, which drags the satellite spot due to the role of magnetic force and may cause it to undergo shear motion. Su et al. (2012) analyzed the role of the magnetic force. 9

SDO is a mission for NASA s Living With a Star program. This work was partly supported by the National Basic Research Program of China (grant Nos. 2012CB957801, 2011CB811401, XDB09040200, and XDA04061002), the National Natural Science Foundation of China (grant Nos. 11303048, 11373040, 11178016, 11178005, 11221063, 11373044, 11427901, and 11125314), Shi Jiazhuang University XJPT002, the Young Researcher Grant of the National Astronomical Observatories, and the Key Laboratory of Solar Activity, the National Astronomical Observations, Chinese Academy of Sciences. REFERENCES Asai, A., Ishii, T. T., & Kurokawa, H. 2001, ApJL, 555, L65 Borrero, J. M., Tomczyk, S., Kubo, M., et al. 2011, SoPh, 273, 267 Brooks, D. H., Kurokawa, H., & Berger, T. E. 2007, ApJ, 656, 1197 Canfield, R. C., Peardon, K. P., Leka, K. D., et al. 1996, ApJ, 464, 1016 Chae, J., Qiu, J., Wang, H., & Goode, P. R. 1999, ApJL, 513, L75 Chifor, C., Isobe, H., Mason, H. E., et al. 2008a, A&A, 491, 279 Chifor, C., Young, P. R., Isobe, H., et al. 2008b, A&A, 481, L57 Cirtain, J. W., Golub, L., Lundquist, L., et al. 2007, Sci, 318, 1580 Guo, J., Liu, Y., Zhang, H. Q., et al. 2010, ApJ, 711, 1057 Guo, Y., Dmoulin, P., Schmieder, B., et al. 2013, A&A, 555, A19 Jiang, Y. C., Chen, H. D., Shen, Y. D., & Yang, L. H. 2007, A&A, 469, 331 Leka, K. D., Barnes, G., Crouch, A. D., et al. 2009, SoPh, 260, 83 Lemen, J. R., Title, A. M., Akin, D. J., et al. 2012, SoPh, 275, 17 Liu, C., Deng, N., Liu, R., et al. 2011, ApJL, 735, L18 Liu, Y., & Kurokawa, H. 2004, ApJ, 610, 1136 Metcalf, T. R. 1994, SoPh, 155, 235 Miyagoshi, T., & Yokoyama, T. 2004, ApJ, 614, 1042 Moore, R. L., Cirtain, J. W., Sterling, A. C., & Falconer, D. A. 2010, ApJ, 720, 757 Moreno-Insertis, F., & Galsgaard, K. 2013, ApJ, 771, 20 Pariat, E., Antiochos, S. K., & DeVore, C. R. 2009, ApJ, 691, 61 Pariat, E., Antiochos, S. K., & DeVore, C. R. 2010, ApJ, 714, 1762 Pontin, D. I., Priest, E. R., & Galsgaard, K. 2013, ApJ, 774, 154 Scherrer, P. H., Schou, J., Bush, R. I., et al. 2012, SoPh, 275, 207 Schmieder, B., Shibata, K., van Driel-Gesztelyi, L., & Freeland, S. 1995, SoPh, 156, 245 Schrijver, C. J., & De Rosa, M. L. 2003, SoPh, 212, 165 Shen, Y., Liu, Y., Su, J., & Deng, Y. 2012, ApJ, 745, 164 Shibata, K., Nitta, N., Strong, K. T., et al. 1994, ApJL, 431, L51 Shibata, K., Ishido, Y., Acton, L. W., et al. 1992, PASJ, 44, 173 Shimojo, M., Hashimoto, S., Shibata, K., et al. 1996, PASJ, 48, 123 Shimojo, M., & Shibata, K. 2000, ApJ, 542, 1100 Shimojo, M., Shibata, K., & Harvey, K. L. 1998, SoPh, 178, 379 Su, J. T., Liu, Y., Shen, Y. D., Liu, S., & Mao, X. J. 2012, ApJ, 760, 82 Tsuneta, S., Acton, L., Bruner, M., et al. 1991, SoPh, 136, 37 Wang, H., & Liu, C. 2010, ApJL, 716, L195 Wang, H., & Liu, C. 2012, ApJ, 760, 101 Wang, Y.-M., Pick, M., & Mason, G. M. 2006, ApJ, 639, 495 Yang, L. P., He, J. S., Peter, H., et al. 2013, ApJ, 777, 16 Yokoyama, T., & Shibata, K. 1995, Natur, 375, 42 Yokoyama, T., & Shibata, K. 1996, PASJ, 48, 353 Zhang, Q. M., Chen, P. F., Guo, Y., Fang, C., & Ding, M. D. 2012, ApJ, 746, 19 10