University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Tuesday, September 12th 2017
12:20 pm:
Space Physics Seminar in Tate 301-20
Speaker: Andrew Inglis, NASA/Goddard
Subject: Characterizing discrete power in solar flares and the magnetosphere using the AFINO algorithm.

The search for discrete power in timeseries is an important goal throughout many areas of Heliophysics, from the physics of solar flares to understanding waves in the Earth's magnetosphere. The AFINO (Automated Flare Inference of Oscillations) code is a novel algorithm which was originally developed to search for periodic signatures in solar flares using a model comparison technique. We present the original results of AFINO, which was used to carry out a large-scale search for quasi-periodic pulsations in 675 M- and X-class flares observed by GOES in 1-8 Å soft X-rays between 2011 February 1 and 2015 December 31. For the first time, we are able to estimate the occurrence rate of periodic signatures in flares, their characteristic periods, and their dependence on other flare parameters.

Since then, we have adapted AFINO in order to search for regions of discrete and broadband wave power in the Earth's magnetosphere, in particular to search for ULF waves. ULF waves play a fundamental role in the dynamics of the inner-magnetosphere during geomagnetic storms and in particular the dynamics of energetic electron in the outer radiation belt. Here, we show the results of AFINO applied to GOES magnetometer data, and also to a moderate geomagnetic storm observed by MMS. By analyzing multiple magnetic field components simultaneously we can determine which types of ULF wave modes dominate at different L-shells, and their typical properties. These results can be combined with a novel method utilizing the close separation of the MMS spacecraft and cross-phase between wave signals to estimate the ULF wave azimuthal wave number m.

Faculty Host: Lindsay Glesener

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