Comparing the TDIM Ionosphere Model to PFISR Measurements With Regards to the Mother's Day Solar Flares


Maggie Lewis

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Journal/Book Title/Conference

USU Student Showcase

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Faculty Mentor

Jan Sojika


The following study was performed to better understand how well the Time Dependent Ionospheric Model (TDIM) models the effects of solar flares on the ionosphere, focusing on the large X class solar flares that occurred over Mother's Day weekend 2013. NASA's EVE instrument aboard the Space Dynamics Observatory (SDO) satellite measures the irradiance spectrum of the Sun continuously, and data is available in real-time. This is the first instrument that continuously collects data making it at last possible to observe the short solar flares. The sunlight causes ionization of nitrogen and oxygen atoms and molecules in the upper atmosphere. This creates the ionosphere. The important part of the solar spectrum for this ionization is X-ray and ultraviolet light. The X-class solar flares occur in from solar eruptions that increase the X-ray irradiance by over a 1000 times normal. Using the data collected by EVE to fuel the TDIM, a model of how the ionosphere reacts and changes with regards to Sun's light is simulated. The TDIM models of the ionospheric composition and behavior were then compared to empirical measurements of the ionosphere made by the Poker Flats Incoherent Scatter Radar (PFISR). The PFISR radar is located near Fairbanks, Alaska and operates continually such that a detailed history of how the ionosphere is responding to solar variations can be obtained. From a comparison of the TDIM model and the PFISR data, an evaluation of the accuracy of the model can be made.

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