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arXiv 0910.5186astro-ph.SR
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Hinode观测到的一个有趣的色球喷流:I。精细结构运动学与解捻证据

An Intriguing Chromospheric Jet Observed by Hinode: I. Fine Structure Kinematics and Evidence of Unwinding Twists

Wei Liu, Thomas E. Berger, Alan M. Title, Theodore D. Tarbell

摘要:

本文报道了日之出太阳光学望远镜观测到的一个持续时间超过1小时的色球喷流,其细节是前所未有的。喷射发生在间隔12-14分钟的三个事件中,材料的量和速度随时间而减少。向上的速度范围为438至33公里/秒,而向下的速度的物质回落有较小的值(平均值:-56公里/秒)和较窄的分布(标准偏差:14公里/秒)。由抛物线时空轨迹推断出的平均加速度为141 m/s^2,只是太阳引力加速度的一小部分。喷流由细线(0.5-2.0弧秒宽)组成,这些细线表现出垂直于喷流轴线和围绕共同平衡位置的连贯的振荡横向运动。这些运动沿着喷流向上传播,在喷流的前缘处具有744 +/- 11 km/s的最大相速度。横向振动速度为151 ~ 26 km/s,振幅为6.0 ~ 1.9 μ m,周期为250 ~ 536 s。振荡随着时间的推移而减慢,并在材料开始回落时停止。下落的物质几乎沿直线沿原来的上升方向运动,没有横向运动。这些观测结果与喷流涉及解旋螺旋线的假设是一致的,螺旋线绕着单个大圆柱体的轴旋转,并将磁螺旋度释放到高层大气中。

英文摘要:

We report a chromospheric jet lasting for more than 1 hr observed by Hinode Solar Optical Telescope in unprecedented detail. The ejection occurred in three episodes separated by 12-14 min, with the amount and velocity of material decreasing with time. The upward velocities range from 438 to 33 km/s, while the downward velocities of the material falling back have smaller values (mean: -56 km/s) and a narrower distribution (standard deviation: 14 km/s). The average acceleration inferred from parabolic space-time tracks is 141 m/s^2, a fraction of the solar gravitational acceleration. The jet consists of fine threads (0.5-2.0 arcsec wide), which exhibit coherent, oscillatory transverse motions perpendicular to the jet axis and about a common equilibrium position. These motions propagate upward along the jet, with the maximum phase speed of 744 +/- 11 km/s at the leading front of the jet. The transverse oscillation velocities range from 151 to 26 km/s, amplitudes from 6.0 to 1.9 Mm, and periods from 250 to 536 s. The oscillations slow down with time and cease when the material starts to fall back. The falling material travels along almost straight lines in the original direction of ascent, showing no transverse motions. These observations are consistent with the scenario that the jet involves untwisting helical threads, which rotate about the axis of a single large cylinder and shed magnetic helicity into the upper atmosphere.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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