Investigating Magnetic Energy Injection in Solar Active Regions

Silva, André Chicrala Amaral (2021) Investigating Magnetic Energy Injection in Solar Active Regions. Doctoral thesis, Northumbria University.

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Text (Doctoral thesis) chicrala-amaral-silva.andre_phd_17016451.pdf - Submitted Version Download (22MB) | Preview

Abstract

Active regions (ARs) are the manifestation of magnetic fields on the solar surface (i.e., the photosphere). The amount of energy injected through the photosphere can be calculated by the vertical Poynting flux that has two components related to the emergence / shearing of magnetic flux. Part of this energy is stored on the magnetic field for later release as energetic events (i.e., flares). Vector magnetic field data from the Helioseismic Magnetic Imager (HMI) were used to derive photospheric velocities with a Python version of the Di_erential A_ne Velocity Estimator for Vector Magnetograms (DAVE4VM). This thesis work focuses on the interplay between the emergence and shearing components of Poynting flux, using data covering the transit of 51 ARs that are representative of Solar Cycle 24. Given the diversity in morphology and temporal sampling of the data, the results obtained provide a step forward in understanding the general aspects of the Poynting flux in ARs and how its evolution is related to their morphology and flare activity.
In Chapter 5, 3 flaring ARs were compared to 5 non-flaring ARs. Removal of field-aligned flows was verified as not a_ecting total Poynting flux, but pixels can change by _109 erg cm

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