SASHA Simulations of alvenic solar heating

Lead Research Organisation: University of Glasgow
Department Name: School of Physics and Astronomy


SASHA : Simulations of alvenic solar heating


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Osborne C (2019) Thyr : a volumetric ray-marching tool for simulating microwave emission in Monthly Notices of the Royal Astronomical Society

Studentship Projects

Project Reference Relationship Related To Start End Student Name
ST/R504750/1 01/10/2017 30/09/2021
1947174 Studentship ST/R504750/1 01/10/2017 15/09/2021 Christopher Montaque Osbourne
Description STFC LTA Funding
Amount £4,307 (GBP)
Funding ID ST/R504750/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 08/2019 
End 12/2019
Description Collaboration with National Solar Observatory including 4 month research visit. 
Organisation National Solar Observatory (NSO)
Country United States 
Sector Public 
PI Contribution This was a research trip (Aug-Dec 2019) to develop my knowledge of radiative transfer with the experts present at NSO, whilst contributing to the development of future machine learning based inversions through my machine learning and programming expertise. I contributed to future inversion projects, investigating methods of deconvolving spectral information from the instrumental point spread function using machine learning, and constructed a new python-based framework for solar radiative transfer calculations.
Collaborator Contribution I primarily worked with Ivan Milic, and we worked on developing a machine learning based model for inversions driven by a Markov Chain Monte Carlo model as well as the python radiative transfer code.
Impact The only output so far is the publicly available radiative transfer tool, Lightweaver, described in the software section. Work continues on the other aspects discussed above.
Start Year 2019
Description ISSI: Interrogation of Field Aligned Solar Flare Models 
Organisation International Space Science Institute (ISSI)
Country Switzerland 
Sector Academic/University 
PI Contribution This project aims to compare, contrast, and improve the existing field-aligned computer models of solar flares, by comparing them to each other and also to observations. I am participating in a comparison of the models using machine learning, and testing and improvements of the radiative transfer treatments used in these models.
Collaborator Contribution The other contributors to this project include the original creators of the main flare simulation codes who are contributing their understanding of flare physics and modelling. Other members of the team, who are also experienced in the use of these codes are running the workshops and providing observation expertise and insight. The next step of the project is a "shoot-out" between the different codes and attempting to investigate where, and why, differences arise.
Impact None yet.
Start Year 2020
Description Research Trip to Improve Knowledge of RADYN 
Organisation University of Oslo
Country Norway 
Sector Academic/University 
PI Contribution This brief (2-week) research trip was undertaken to work with Prof. Mats Carlsson and improve my knowledge of his flare simulation code RADYN, as well as some of the techniques used in its development, and discussing avenues for further development.
Collaborator Contribution Prof. Mats Carlssojn contributed many hours to explaining how the RADYN code works, in addition to productive discussions with other members of the solar group in Oslo, on the topics of radiative transfer and modern radiation hydrodynamics.
Impact None yet
Start Year 2018
Title Lightweaver 
Description Lightweaver is an optically thick radiative transfer framework, written in python, allowing a much simpler and faster method of constructing radiative transfer tools for a variety of solar physics use cases, i.e. synthesising the outgoing radiation from the solar atmosphere under the assumption of one-dimensional plane parallel geometry. It is developed from, and validated against the most commonly accepted reference code, RH, as well as an additional code, SNAPI, that implements the same basic method but fewer features. 
Type Of Technology Software 
Year Produced 2020 
Open Source License? Yes  
Impact Lightweaver forms the basis of several sub-projects associated with this award, and is being used to investigate the spectral signatures of heating the solar atmosphere in a more flexible manner than was previously available. 
Title Radynversion 
Description Radynversion is the implementation of an invertible neural network in python, that can be used to infer the atmospheric parameters during a solar flare from observations of the Hydrogen-alpha and Calcium-8542 Angstrom spectral lines, under the assumption that the RADYN code is a good description of the physics occuring in a solar flare. 
Type Of Technology Software 
Year Produced 2019 
Open Source License? Yes  
Impact Radynversion has allowed credible inversions of the chromosphere in a solar flare, for the first time without the limiting assumptions of hydrostatic equilibrium and statistical equilibrium, which are unlikely to hold in flares. Initial results are described in the Radynversion paper.