SDO Observations of Solar Jets
SDO Observations of Solar Jets
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DOI：
10.1007/s11207-012-0190-7
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发表时间：
2013-06
期刊：
影响因子：
2.8
通讯作者：
S. Moschou;K. Tsinganos;A. Vourlidas;V. Archontis;V. Archontis
中科院分区：
文献类型：
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作者：
S. Moschou;K. Tsinganos;A. Vourlidas;V. Archontis;V. Archontis
我们利用太阳动力学观测站（SDO）上的大气成像组合仪器，对304 Å极紫外线（EUV）观测到的太阳喷流的高节奏观测结果进行了分析。我们样本中的喷流非常靠近太阳边缘，以尽量减少投影效应。其中两个事件在喷射过程中显示出明显的螺旋模式。我们还发现，一些喷流是周期性的，其中大多数无法克服太阳引力。我们通过测量射流前缘的高度作为时间的函数来研究射流的时间演化。通过拟合所得的高度-时间图，我们通过假设弹道运动推导出它们的初始弹射速度和等离子体加速度的大小。此外，我们在不假设弹道运动的情况下，根据等离子体的动态速度计算了喷流的向上加速度。在这两个模型中，加速度曲线都表明了重力以外的力的影响。特别地，我们发现了一个向上的驱动力的迹象，它减弱了太阳引力场沿喷流运动的减速作用。这个力在动力学模型中更大，这表明弹道近似不能正确地确定等离子体射流的上升运动。
We present an analysis of high cadence observations of solar jets observed in the Extreme Ultraviolet (EUV), at 304 Å, with theAtmospheric Imaging Assemblyinstrument aboard theSolar Dynamics Observatory(SDO). The jets in our sample lie very close to the solar limb to minimize projection effects. Two of the events show clear helical patterns during ejection. We also find that some of the jets are recurrent and that most of them cannot overcome solar gravity.We investigate the temporal evolution of the jets by measuring the height of their leading edge as a function of time. By fitting the resulting height–time diagrams, we derive the magnitude of their initial ejection speed and plasma acceleration by assuming ballistic motion. Moreover, we calculate the upward acceleration of the jets based on the dynamical velocity of the plasma, without assuming a ballistic motion. In both models, the acceleration profiles suggest the influence of forces other than gravity. In particular, we find indications of an upwards driving force which weakens the decelerating effect of the solar gravitational field along the motion of the jet. This force is larger in the dynamical model, which indicates that the ballistic approximation does not properly determine the rising motion of the plasma jets.