Astronomy and Astrophysics – Astrophysics – Solar and Stellar Astrophysics
Scientific paper
2009-08-05
Astronomy and Astrophysics
Astrophysics
Solar and Stellar Astrophysics
23 pages, 9 figures. accepted by ApJ
Scientific paper
Using observations from the SOHO, STEREO and Hinode, we investigate magnetic field evolution in an equatorial coronal hole region. Two dipoles emerge one by one. The negative element of the first dipole disappears due to the interaction with the positive element of the second dipole. During this process, a jet and a plasma eruption are observed. The opposite polarities of the second dipole separate at first, and then cancel with each other, which is first reported in a coronal hole. With the reduction of unsigned magnetic flux of the second dipole from 9.8*10^20 Mx to 3.0*10^20 Mx in two days, 171 A brightness decreases by 75% and coronal loops shrink obviously. At the cancellation sites, the transverse fields are strong and point directly from the positive elements to the negative ones, meanwhile Doppler red-shifts with an average velocity of 0.9 km s-1 are observed, comparable to the horizontal velocity (1.0 km s-1) derived from the cancelling island motion. Several days later, the northeastern part of the coronal hole, where the dipoles are located, appears as a quiet region. These observations support the idea that the interaction between the two dipoles is caused by flux reconnection, while the cancellation between the opposite polarities of the second dipole is due to the submergence of original loops. These results will help us to understand coronal hole evolution.
Borrero Juan Manuel
Yang Shuhong
Zhang James J.
No associations
LandOfFree
Dipolar Evolution in a Coronal Hole Region does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Dipolar Evolution in a Coronal Hole Region, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dipolar Evolution in a Coronal Hole Region will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-254293