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Title: Macrospicules, jets and the solar chromosphere
Author: Bennett, Samuel M.
ISNI:       0000 0004 7651 2790
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2017
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Given recent advancements in observational solar physics, both in quality and quan- tity, the time is right to revise the chromospheric feature, macrospicules. These jet- like phenomena are larger than their semi-namesake spicules, which only extend to 10 Mm as an absolute maximum and are ubiquitous in the solar chromosphere, particularly within intergranular lanes. However, macrospicules are not as large as the so-called coronal jets or the X-ray jets, generally observed in hotter temperature lines and penetrating much higher into the solar atmosphere. The aim of this work is to better classify macrospicules as a population and to detect any possible rela- tionships; such as relation to the solar cycle, impacts on coronal heating or as a solar wind accelerator, on a global scale. This is achieved first by means of a statistical sample of macrospicules. We utilise the first two and a half years of Atmospheric Imaging Assembly on board the Solar Dynamics Observatory's (AIA/SDO) operation window and measure macrospicules properties throughout. This two and a half year sample acts as a proxy for the ramp from solar minima in mid 2010 to maxima in late 2012. Over this time period we find a general increasing trend for the properties of the macrospicules. A range of charcteristic features of the macrospicules, such as: maximum length and width, maximum velocity and lifetime are stated and compared to the current literature. This same sample is then tested against the Carrington longitude to test for any relation to what has been termed, an active longitude. In this case, we find that the macrospicules do have a correlation to the so-called active longitude. Lastly, this work presents a detailed case study of a macrospicule, utilising a wide range of available imagers. The case study involves a jet-like feature that is seen at the solar limb in Crisp Imaging Spectropolarimeter at the Swedish Solar Telescope, AIA/SDO and the Extreme Ultra Violet Imager on STEREO (Solar Terrestrial Earth RElations Observatory). Applying a Markov Chain Monte Carlo method we analyse the spectroscopic data from CRISP and build a profile of the line of sight velocities of the jet. Lastly, we attempt to determine whether or not the jets have an effect on the atmosphere above it.
Supervisor: Erdelyi, Robertus Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available