Flux rope proxies during 2013 detected by the Solar Dynamics Observatory^⋆

Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, 100012 Beijing, PR China
e-mail: zjun@nao.cas.cn

Received: 19 June 2014
Accepted: 26 May 2015

Abstract

Context. The relationship between flux ropes and coronal mass ejections (CMEs) is of great importance for understanding the CME initiation, but we do not know how many flux ropes in the atmosphere can be detected.

Aims. We aim to determine the number of flux rope proxies and understand the distribution of the proxies over the visible solar disk.

Methods. By employing the observations from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory, we counted the number of the flux rope proxies from 2013 January to 2013 December.

Results. We detected 1354 (3.7 every day) rope proxies during this period and classified them into three types according to their temperature properties and particular (sigmoid) structures. The first type is that the rope proxies are detected in both lower and higher temperature lines. The second is that the rope proxies can only be detected in higher temperature lines, and the third is that the proxies display sigmoid structures in extreme ultraviolet channels. Six hundred and fifty-eight proxies of the 1354 that belong to the first type are tracked by active or eruptive material of filaments or prominences. Four hundred and eighty-seven proxies appear to be rising from the lower atmosphere or brightening in the corona, and belong to the second type. The remaining 209 display sigmoid structures, and they are attributed to the third type. We detected 497 rope proxies, which is 37% of the total, in the northern hemisphere.

Conclusions. Our findings imply a significantly asymmetric distribution of the rope proxies over the visible solar disk.