Alissa Roegge

University of Massachusetts Amherst

REU Student - Summer 2016

Montana State University

Advisors : Sean Brannon


Research project

Project Description : Flare ribbons are characteristic signatures of solar flares, and are an indirect consequence of the magnetic reconfiguration (known as reconnection) occurring higher in the solar atmosphere. It is widely understood that the location of the flare ribbon represents the bases of magnetic loops undergoing active reconnection, and are thus an indirect image of the reconnection process. As a result, the large and small scale structure of a flare ribbon as it evolves encodes information about conditions in the reconnection region. In a recent study (Brannon et al. 2015), we examined an Interface Region Imaging Spectrograph (IRIS) observation of a wave substructure along a flare ribbon. Based on our analysis of the imaging and spectral properties of the substructure, we proposed a wave origin in a current sheet instability. Our next step is to expand on this prototype event by identifying additional examples of similar flare ribbon wave substructures.

My role in this project was to find IRIS observations that may contain a similar flare ribbon substructure.I took the full list of IRIS obesrvations and narrowed it down to observations that contained flare ribbons where the flare ribbon was noted to cross the spectrograph slit of IRIS. From there I manually checked each observation to find visual evidence of oscillating flare ribbons. After visual inspection, I picked 6 ribbons for which I did an intensity plot of Si IV to determine if the oscillating pattern was really there. The results of these are in the midterm presentation linked below. From there, I did spectral line fitting for the best 3 results to determine the redshift of the Si IV, which was then plotted as a doppler velocity map. The results of one of these, the June 22 2014 observation, is included in the final presentation linked below.


Presentation Links

Midterm Presentation : Midterm Presentation

Final Presentation : Final Presentation


Resources

Here are some useful links:

IRIS Homepage

Brannon et al. 2015