Article ID Journal Published Year Pages File Type
1771861 Chinese Astronomy and Astrophysics 2013 12 Pages PDF
Abstract

With the data from WIND satellite in 1995—2005, the small-scale magnetic flux tubes determined with two methods, i.e., the artificial recognition and program selection respectively, are compared. It is found that there are magnetic reconnections in the boundary layers of 41% small-scale magnetic flux tubes determined with the program selection method, which is similar to the re- sult of small-scale magnetic flux tubes determined with the method of artificial recognition. The features of magnetic reconnections, such as the magnetic shear angle, magnetic field strength, and duration of the dissipation region of recon- nection at the small-scale flux tubes’ boundaries determined from both methods have the same statistical tendency. This shows that there is no essential differ- ence in the properties of reconnections in the boundary layers of the small-scale magnetic flux tubes determined with the two methods. Hence the data yielded by both methods can be used as the samples for statistically studying the events of reconnection in the front and back boundary layers of small-scale flux ropes. There are totally 71 magnetic reconnection events selected in this paper. Our statistical result shows that in 50 events (70%) the decrease of magnetic field strength in the dissipation region of reconnection is larger than 20%, and in 47 events (66%) the magnetic shear angle is larger than 90 degrees. These indicate that the magnetic reconnections in boundaries of the small-scale magnetic flux tubes are more likely to be anti-parallel. The statistics has been performed sep- arately in the reconnections of the front and back boundary layers of small-scale magnetic flux tubes. The results show that the features of reconnections in the front and back boundaries are similar to each other, which is different from the various properties in the front and back boundaries of the magnetic clouds, and this means that the expansion in the large-scale magnetic flux tubes, such as magnetic clouds, does not happen in the small-scale magnetic flux tubes.

Related Topics
Physical Sciences and Engineering Physics and Astronomy Astronomy and Astrophysics