CMEs with multiple reconnection sites : A model for energetic particle injection

Magnetic reconnection in the solar atmosphere is believed to be the driver of most solar explosive phenomena. Therefore, the structure and dynamics of the coronal magnetic field are central to understanding solar and heliospheric activity. Important heliospheric manifestations of intense energy release linked to solar activity include the impact at the Earth of energetic particles accelerated during solar eruptions. Observationally, the magnetic configuration of active regions where solar eruptions occur, agrees well with the standard model of an eruption consisting of a flare and a coronal mass ejection (CME). According to the standard model, particles accelerated at the flare reconnection site should remain trapped in the CME. However, flare-accelerated particles frequently reach the Earth long before the CME does. We present a new model that may lead to injection of energetic particles onto open magnetic flux tubes connecting to the Earth. Our model is based on the well-known 2.5D breakout topology, which has a coronal null point (null line) and a four-flux system. A key new addition, however, is that we include an isothermal solar wind. Depending on the location of the open flux with respect to the null point, we find that the flare reconnection can consist of two distinct phases. At first, the flare reconnection involves only closed field, but if the eruption occurs close to the open field, we find a second phase involving interchange reconnection between open and closed. We argue that this second reconnection episode is responsible for the injection of flare-accelerated particles into the interplanetary medium. We will report on our recent work toward understanding how flare particles escape to the heliosphere. This work uses high-resolution 2.5D MHD numerical simulations performed with the Adaptively Refined MHD Solver (ARMS). This research was supported, in part, by the NASA SR&T and TR&T Programs.