Short, large-amplitude speed enhancements in the near-Sunfast solar wind
Short, large-amplitude speed enhancements in the near-Sunfast solar wind
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DOI：
10.1093/mnras/sty953
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发表时间：
2018-08
影响因子：
4.8
通讯作者：
T. Horbury;L. Matteini;D. Stansby
中科院分区：
文献类型：
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作者：
T. Horbury;L. Matteini;D. Stansby
我们报告存在间歇性的，短的离散增强等离子体的速度在近太阳的高速太阳风。在0.3 Au的航天器测量中持续数十秒到几分钟，这些增强体内部的速度可以达到1000 km s-1，相当于大规模高速太阳风动能的两倍。这些事件发生的时间约为5%，具有大磁场偏转的Alfvénic性质，与周围等离子体的温度相同，与具有良好的正速度-温度相关性的大规模快风形成对比。这些速度增强的起源尚不清楚，但它们可能是与色球层或日冕中的瞬态事件相关的离散喷流的特征。如此大的短期速度变化对即将到来的帕克太阳探测器和太阳轨道飞行器任务来说是一个测量和分析的挑战。
We report the presence of intermittent, short discrete enhancements in plasma speed in the nearSun high-speed solar wind. Lasting tens of seconds to minutes in spacecraft measurements at 0.3 au, speeds inside these enhancements can reach 1000 km s−1, corresponding to a kinetic energy up to twice that of the bulk high-speed solar wind. These events, which occur around 5 per cent of the time, are Alfvénic in nature with large magnetic field deflections and are the same temperature as the surrounding plasma, in contrast to the bulk fast wind which has a wellestablished positive speed–temperature correlation. The origin of these speed enhancements is unclear but they may be signatures of discrete jets associated with transient events in the chromosphere or corona. Such large short velocity changes represent a measurement and analysis challenge for the upcoming Parker Solar Probe and Solar Orbiter missions.