Space Physics Seminar fall-2015

Probing Magnetic Reconnection in Solar Flare Observations

Energy release in solar flares is governed by magnetic reconnection taking place in the Sun's outer atmosphere, the corona. Yet in terms of observables, the immediate and more significant response usually occurs in the lower atmosphere, the chromosphere. Here, energy flux down along newly reconnected field lines (or flare loops) quickly heats up plasmas generating impulsive chromospheric emissions. The lower atmosphere is also the only place where reliable measurements of magnetic field are currently available. Whereas probes in fusion experiments or spacecrafts in the Earth's magnetosphere usually sample multiple points for direct in-situ measurements, all reconnection events in the Sun's corona resulting in significant atmosphere heating can be mapped in the chromosphere with imaging observations of the solar disk. This mapping allows us to track where reconnection takes place, and find out how much and how quickly magnetic flux is reconnected. High resolution observations reveal that fast reconnection responsbile for flare energy release is unsteady and intermittent, but at the same time organizable globally. We develop techniques to infer these properties and estimate how much energy is released by bursts of reconnection. This talk will discuss recent results and challenges in this practice.