Temporal ring diagram and multiple wavelength analyses of plasma flows in the solar interior and atmosphere

Abstract

Ring Diagram Analysis (RDA) is one of the cornerstones of local helioseismology. The technique is used to observe f - and p-mode oscillations generated in the solar interior. RDA has been used to study plasma flows inside the solar convection zone, and the subphotospheric structure of active regions. A limitation of RDA, however, is the temporal resolution at which flow maps can be produced. This work presents the Temporal Ring Diagram Analysis (TRDA) data analysis pipeline as a novel addition to RDA. TRDA employs a sliding window technique to vastly increase the temporal resolution from 512 to 10 minutes. Sun-quakes are seismic waves triggered by solar flares and CMEs. They appear suddenly, penetrate the solar interior, and can last for up to an hour before dissipating. Until now, it has not been possible to analyse sub-photospheric plasma flows during a quake event. TRDA is used to study these flows for two Sun-quake events. One- and two-dimensional flow maps have been created for the quake of 15th January 2005. Three-dimensional flow
velocities for a region of quiet-Sun and a second quake, which occurred on 14th August 2004. Quiet-Sun flows are typically 50-70 m s−1, while up-flows under the active region reach range between 120 and 150 m s−1. Also, low-speed flow flow is observed in the north-eastern corner of the region. Flow vorticity maps are also presented for further analysis. A novel data processing pipeline for Hinode Extreme Ultraviolet Imaging Spectrometer (EIS) data is also presented. The EIS Multiple Wavelength Analysis (EMWA) pipeline has been designed to simultaneously process numerous spectral wavelengths, and arrange
the results in ascending order of ion formation temperature. EMWA has been used to analyse atmospheric plasma flows surrounding the foot-point regions of magnetic loops. The flow results for three active regions are presented. They show that strong outflows in the close to the foot-point regions have velocities 10 km s−1, and these flows expand with increasing temperature. Further analysis has revealed a low velocity but continuous supply of plasma is required to sustain these flows

Date of Award	2014
Original language	English
Awarding Institution	Aberystwyth University
Supervisor	Balazs Pinter (Supervisor)