Major Solar Flares without Coronal Mass Ejections

N. Gopalswamy, S. Akiyama, S. Yashiro

NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA

Coronal mass ejections (CMEs) are known to be the most energetic phenomena in the heliosphere. Recent observations indicate that there is a close relationship between solar flares and CMEs: whenever the eruption happens on the visible side of the Sun, each CME is associated with a soft X-ray flare. However, there are many flares that are not associated with CMEs. This is especially true when we consider smaller flares (e.g., C-class in soft X-rays). More surprising is the fact that more than a dozen X-class flares are not associated with observable CMEs. We examine the source properties of these flares such as the magnetic field configuration, flare duration, Hα importance, and particle acceleration (hard X-rays, microwaves, and metric/interplanetary radio bursts) and compare them with a sample of X-class flares with CMEs. This will help us understand how free energy in the eruption region are distributed between mass motion (CMEs) and heating (soft X-ray flares).