Type of Project: Analytical and Numerical Modeling, Data Analysis

Skills/Interest Required: A successful student will have an interest in the physics of solar phenomena, computer programming and satellite observations. Mathematica skills a plus.

Mentor/Point of Contact: Dr. Kathy Reeves
Email: kreeves_at_cfa.harvard.edu

Solar coronal mass ejections (CMEs) are often, but not always, accompanied by brightenings of coronal loops referred to as solar flares. Many authors have noticed a correlation between the peak acceleration of the CME and the derivative of the X-ray flux from the flare site [e.g. 1, 2]. The assumption made from these observations is that the same energy release mechanism is driving both the CME acceleration and the energization of the flare loops. Models offer unique insight into this process, since all of the relevant quantities can be calculated and examined in detail. For example, Reeves (2006) [3], using a semi-analytical model of solar eruptions, found that the correlation between CME acceleration and thermal energy release depended on the background magnetic field and the reconnection rate of the magnetic fields.

During the summer, the student will take the research presented in [3] one step further and compare flare emissions (rather than just thermal energy release) and CME acceleration using a model of solar eruptions developed in part by the mentor of the project. The student will model the emissions from flares with a variety of input parameters, though great attention will be focussed on the reconnection rate. The results of these simulations will be used to understand the relationship between the flare emissions and the CME acceleration. If time allows, the student will also use this model to reproduce emissions from specific flares observed by TRACE, XRT, SoHO and GOES.

Caption: Temperature (left panel) and density (right panel) of a flare arcade calculated using many 1D hydrodynamic loops with energy input from the analytic model.

[1] Zhang et al, 2004, A Study of the Kinematic Evolution of Coronal Mass Ejections

[2] Qiu et al, 2004, Magnetic Reconnection and Mass Acceleration in Flare-Coronal Mass Ejection Events

[3] Reeves, 2006, The Relationship between Flux Rope Acceleration and Thermal Energy Release in a Model of Eruptive Solar Phenomena