中尺度磁绳结构的行星际观测

由磁绳结构主导、平均尺度约二、三十个小时的行星际磁云是日冕物质抛射在行星际膨胀、传播的体现。最近，Moldwin等人报道在太阳风中还观测到一些尺度在几十分钟的小尺度磁绳结构，并认为太阳风中的磁绳结构在尺度分布上可能具有双峰特征，在全面检视了WIND卫星(1995年-2000年)和ACE卫星(1998年-2000年)的观测资料后，发现了在行星际太阳风中一些尺度为几个小时的中尺度磁绳结构，利用初步整理的其中28个中尺度磁绳结构事件，认为太阳风中的磁绳结构在尺度分布上可能是连续的，这对行星际太阳风中磁绳结构物理起源的研究可能提出重要的物理限制。

Observations of Medium-scale Magnetic Flux Ropes in Interplanetary Space

Magnetic clouds are the manifestation of coronal mass ejections propagating and expanding in the interplanetary medium. The average duration of magnetic clouds is about 20-30 hours and usually the magnetic field configuration of a magnetic cloud can be well described by a magnetic flux rope structure. Recently, Moldwin et al. reported several small-scale magnetic flux ropes identified from solar wind observations and suggested that the size distribution of solar wind magnetic flux ropes might be a bimodal one. In opposition to Moldwin, after a systematical survey of the data of WIND (from 1995 through 2000) and ACE (from 1998 through 2000) , twenty-eight medium-scale magnetic flux ropes were identified. The existence of these medium-scale magnetic flux ropes suggests that the size distribution of solar wind magnetic flux ropes might be continuous. This result will probably provide an important physical constraint on the origin of solar wind magnetic flux ropes.