| Solar spicules are rapidly evolving jets seen on the solar limb, extending from the bottom of the chromosphere to the corona. Spicule is the most common feature observed in the chromosphere. Recent observations indicate that spicules can be divided into two types, type Ⅰ and type Ⅱ. Type Ⅰ spicule has a life time of several minutes to15minutes, an average length between6500km and9500km, an average width of several km to2000km. Type Ⅰ spicule usually goes up with a velocity of25km/s and falls down to the photosphere in a same or another different path after arriving at the maximum height. Compared to type Ⅰ, type Ⅱ spicule evolves more quickly, forms much more rapidly (<10s), and has much larger upward velocity (50-150km/s), much shorter lifetime (90-150s) and much thinner edius (around200km). Type Ⅱ spicule can be heated to the transition region temperature or corona temperature in a very short time. The amount of mass flux carried by spicules is estimated to be100times that of the solar wind. Therefore, spicules are usually considered to play a very important role on the overall mass and energy balance of the chromospheres and corona. Beside spicules. there is another type of jet whose root shows inverse Y shape called chromospheric anemone jets. According to previous studies, chromospheric anemone jets have a length of1000-2000km. a width of100-400km. a lifetime about100-500s. The upward velocity of chromospheric anemone jets is around5-20km/s.In this thesis, we will carry out a case analysis of spicules and anemone jets using the high-spatial and-temporal resolution data obtained with SOT in the chromospheric Ca II H line. The major results including:(1) In the study of spicules in coronal hole region, we find that sometimes there will be a coherent motion of multi-spicules. In the case we studied, two adjacent spicules rotating periodically around each oilier, like an untwisting process, which lasts for two cycles in around5minutes. There is transportation of magnetic helicity in this untwisting process, the upward transportation speed of which is more or less the chromospheric A liven speed (about130km/s). We treat the two spicules as two magnetic flux tubes and estimate the magnetic helicity rate and the magnetic helicity accumulation, finding that the magnetic helicity rate is at37orders of magnitude which is3orders smaller than that obtained in active regions and the accumulation of magnetic helicity is at the order of1035Mx2. Because the rate of magnetic helicity that we analyzed is about two spicules in a small coronal hole (CH) region with small magnetic density and small areas, the three orders of magnitude difference is comprehensible. This study may improve our understanding of the chromospheric dynamics, and is helpful for us to acquaint the transport process of the magnetic helicity in CH open field regions through the chromosphere to the corona and interplanetary space.(2) We have studied an interesting jet eruption on the edge of an active region with a long lifetime of around one hour, which is in inverse’Y’shape and propably caused by intermittent magnetic reconnection. Seen from the lightcurves. there are roughly two quasi-periods. one of which is more or less50-60s while the other is around400-600s. The root of the jet tends to moving toward the positive direction of Y-axis with a speed of0.4km/s, which is propably a signature that the magnetic reconnection happened between the moving closed magnetic loop and the surrounding closed magnetic loop in much larger size. In the region above the foot of the jet. there are many very thin intermittent jets moving continously towards the negative direction of Y-axis with a velocity of11-21km/s The jet carrys substantial transverse oscillations, the period of which spreads between61-104s and the mean period is around88s. The max displacement is0.26arcsecond. The velocity distributes between4-14.4km/s. and the wavelength is between4-14Mm. |
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