English

Solar cycle variation of real CME latitudes

Astrophysics 2015-05-13 v1

Abstract

With the assumption of radial motion and uniform longitudinal distribution of coronal mass ejections (CMEs), we propose a method to eliminate projection effects from the apparent observed CME latitude distribution. This method has been applied to SOHO LASCO data from 1996 January to 2006 December. As a result, we find that the real CME latitude distribution had the following characteristics: (1) High-latitude CMEs (θ>60\theta>60^{\circ} where θ\theta is the latitude) constituted 3% of all CMEs and mainly occurred during the time when the polar magnetic fields reversed sign. The latitudinal drift of the high-latitude CMEs was correlated with that of the heliospheric current sheet. (2) 4% of all CMEs occurred in the range 45θ6045^{\circ}\leq\theta\leq60^{\circ}. These mid-latitude CMEs occurred primarily in 2000, near the middle of 2002 and in 2005, respectively, forming a prominent three-peak structure; (3) The highest occurrence probability of low-latitude (θ<45\theta< 45^{\circ}) CMEs was at the minimum and during the declining phase of the solar cycle. However, the highest occurrence rate of low-latitude CMEs was at the maximum and during the declining phase of the solar cycle. The latitudinal evolution of low-latitude CMEs did not follow the Sp\"{o}rer sunspot law, which suggests that many CMEs originated outside of active regions.

Keywords

Cite

@article{arxiv.0708.0270,
  title  = {Solar cycle variation of real CME latitudes},
  author = {Song Wenbin and Feng Xueshang and Hu Yanqi},
  journal= {arXiv preprint arXiv:0708.0270},
  year   = {2015}
}

Comments

4 pages, 4 figures, accepted by ApJ Letter

R2 v1 2026-06-21T09:04:09.440Z