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Observational analysis of MHD waves with ROSA and HARDcam


The Sun is one of the most important astronomical objects for humankind, with solar activity driving “space weather” and having a profound effect on the Earth’s environment. It provides a unique laboratory where the study of interacting plasmas with concentrated magnetic fields can be readily achieved over an enormous range of scales. A large fraction of the phenomena that exists in the dynamic layers of our Sun is intrinsically linked to the strong magnetic fields that permeate through its entire atmosphere. It is believed that the building blocks of large-scale atmospheric structuring are present at the base (photosphere) of the solar atmosphere, and that these structures unlock the mechanisms that promote efficient energy transfer through the Sun’s layers. A prime example are sunspots, which create towering coronal loop structures extending many hundreds of thousands of km away from the visible solar surface. Propagating wave fronts in extreme ultraviolet (EUV) time series were first observed along these coronal structures in the late 1990s using space-based observatories. Numerous studies of propagating magneto-hydrodynamic (MHD) waves in coronal structures have since been undertaken, with recent high-sensitivity instrumentation revealing faint hypersonic waves with velocities exceeding 2000 km/s! However, the origins of these waves, and the mechanisms that support their efficient propagation, have always remained an elusive mystery.

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The project will be observationally driven, where the student will make extensive use of current- and next-generation facilities. These include the ground-based Rapid Oscillations in the Solar Atmosphere (ROSA) and Hydrogen-Alpha Rapid Dynamics Camera (HARDcam) facilities that have been designed in-house at QUB, and commissioned on the Dunn Solar Telescope, New Mexico, USA. Space-based instruments such as the Solar Dynamics Observatory, Hinode, and the NASA IRIS spacecraft will be used in conjunction with ground-based facilities to obtain multi-wavelength data sets covering a multitude of atmospheric layers between the photosphere and corona.

The student will devise new algorithms to analyse the characteristics of MHD waves over a wide range of spatial and temporal scales, ultimately evaluating their intrinsic propagation characteristics, energies and transmission parameters. The student will also identify MHD wave phenomena at a multitude of heights in the solar atmosphere, and establish how the measured wave characteristics (velocities, amplitudes, directional biases, etc.) ultimately relate to the underlying magnetic field complexities. Spectroscopic and imaging data will be employed to accurately determine the precise mode of oscillation, in addition to the wave generation, driving, propagation, and dissipation mechanisms that manifest at various heights and temperatures within our Sun’s atmosphere.

To rapidly drive forward advancements in solar physics, the student will undertake collaborative projects with leading national and international groups to unify observational findings with theoretical MHD wave theory. The recent commissioning of a wealth of high-resolution ground- and space-based facilities will place the student in an ideal position to develop key international collaborations, and become familiar with a wide variety of observational and theoretical approaches. Wave processes in the Sun’s atmosphere have produced a vast number of high-impact publications in journals such as Nature and Science in recent years. It is anticipated that the timely nature of this project will position the student in an ideal position to make new discoveries and drive forward solar physics research.

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Supervisor: Dr David Jess

2014_jess.1386573207.txt.gz · Last modified: 2013/12/09 07:13 by Chris Watson

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