Probing the solar atmosphere via ground-based visible light and space-based ultraviolet observations

  • Gabriel Muro

Traethawd ymchwil myfyriwr: Traethawd Ymchwil DoethurolDoethur mewn Athroniaeth


The low corona is a missing link in solar physics due to the weak signal and lack of visible light spectrometers. We utilized a 3-channel spectrometer centered on Fe X, XI, and XIV ion emission wavelengths during the total solar eclipses in Rodeo and Neuqu´en, Argentina over 2 years. This thesis describes the instrument, data calibration, analysis and results of that study. In 2019, thermal broadening was consistent with 4 MK for Fe X and XI lines, and 6 MK for Fe XIV line. The Doppler shift correspond to bulk plasma motion ranging from -12 to +2.5 km s −1. These results are interpreted as different density scale heights within isolated, isothermal flux tubes. These measurements show bulk motions which are likely associated with the dominant longitudinal orientation of the magnetic field at the streamer bases within 0.4 solar radii (R⊙) of the limb. In 2020, a coronal mass ejection (CME) perturbed the corona before totality and provided a rare opportunity to study the effect. Line of sight Doppler velocities were estimated at up to 50 kms−1 and thermal broadening was estimated at 15 MK for Fe XIV. Equatorial measurements showed a consistent 6 MK for the lowest 0.5 R⊙ for all Fe ions. These results were combined with Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory (SDO/AIA) and The Large Angle and Spectrometric Coronagraph (LASCO) data to generate a wire-frame model of the CME, with estimated velocity at 700 kms−1 and CME width at 57.6°. Improvements upon the Time-Normalized Optical Flow (TNOF) image processing of SDO/AIA images successfully mapped a proxy magnetic field similar to coronal loop structure from Solar Orbiter’s Extreme Ultraviolet Imager (SOLO/EUI) at a different viewpoint during the quadrature between the two spacecraft. We describe the synthetic testing methodology, show results of a recent case study, and show different optical flow visualization approaches. This thesis describes the aforementioned projects as well as an overall introduction to the Sun, and future research pathways.
Dyddiad Dyfarnu2022
Iaith wreiddiolSaesneg
Sefydliad Dyfarnu
  • Prifysgol Aberystwyth
GoruchwyliwrHuw Morgan (Goruchwylydd) & David Kuridze (Goruchwylydd)

Dyfynnu hyn