Lower atmospheric signatures of solar eruptive events

• Main Author: Pedram, E.
• Published: University College London (University of London) 2013
• Subjects: 500
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.626398

Solar eruptive events are the most energetic events in the solar system which are driven by the reconfiguration of solar magnetic field. They are catagorised into two groups: Solar flares or Coronal Mass Ejections (CME). The released energy is ejected both downward towards the solar surface and its interior and outward into the interplanetary space. The work presented in this thesis represents a contribution towards better understanding the impact of solar eruptive events on the solar surface and lower atmospheric layers. This thesis uses observations from a wide range of multi-wavelength data set involving SDO/HMI, SDO/AIA, Hinode, TRACE, SOHO/MDI, SOHO/EIT, RHESSI, and GONG to investigate the nature of solar flares induced seismic waves and the formation of "dimming regions" following the eruption of some CMEs. Observational signatures and consequences of Hard X-ray (HXR) and White Light (WL) emission were analysed for two sets of acoustically -active and —quiet solar flares. The rate of energy deposition and the area over which the energy is being deposited suggested that in general acoustically active flares are associated with larger and more impulsive deposition of electron energy. However, this does not always correspond to a higher WL contrast. Dimming regions formed during some CME events and their relation to the topology of magnetic fields embedded in the dimming areas were investigated. Analysis of the magnetic field strength and its associated tilt angle together with the intensity variation of the dimming regions revealed that reconfiguration and stretching of the magnetic field lines results in formation of the dimming regions. However, the study was not conclusive for weaker CMEs.