Fine-scale auroral structure: Causes and effects

Lead Research Organisation: University of Southampton
Department Name: Sch of Physics and Astronomy

Abstract

The beautiful displays of the Earth's auroras are formed as a result of the interaction between the solar wind, the Earth's magnetic field and the atmosphere. Electrically charged particles are funnelled into the atmosphere, where they hit atoms and molecules in the atmosphere. Some of the energy transferred in these collisions is given off as light, which is what provides the auroral displays.

The aurora is fascinatingly rich in structure (down to horizontal scale sizes of tens of metres), with fast motions and changes of colour. This structure is indicative of rapid changes in the way that energy is deposited into the upper atmosphere. The cause of structuring at such fine scales is unclear, and understanding the cause is one of the objectives of this research. We will investigate the structuring processes in the aurora by using very high resolution auroral cameras which the University of Southampton operates in the Arctic, and comparing these observations with state-of-the-art simulations. The cameras are called ASK (Auroral Structure and Kinetics), and by providing high time and spatial resolution images of the aurora in a frame approximately 5x5 km (at 100 km altitude), we can image the aurora down to a resolution of ~10m. ASK consists of three cameras which provide the same image at different wavelengths. By comparing the images at different wavelengths, we can glean much information about the energy of the precipitating particles which are stimulating the aurora, and calculate information about the local fine-scale ionospheric flows. These parameters are then used as input to theoretical models, which allow us to determine the processes which give rise to auroral structuring.

In the second half of the project we will also exploit the first data from a new state-of-the-art radar system called EISCAT_3D, which provides observations of the radar analogues of the auroral structure we will examine on a spatial scale approaching that of ASK itself. EISCAT_3D is a major new European facility which is currently being built; its 'first light' will occur in 2022.

The structuring of the aurora indicates underlying structuring of electric fields and currents which have a number of important consequences, such as causing changes to the rate at which the upper atmosphere is heated, which in turn has
implications for modelling of climate change and prediction of satellite orbit decay. Therefore, the spatial and temporal variability of precipitating charged particles is at the heart of the physics of the behaviour of the upper atmosphere.

Publications

10 25 50
 
Title Auroral Structure and Kinetics (ASK) data 2022-23 
Description Multi-wavelength images of the aurora in the magnetic zenith obtained from Longyearbyen, Svalbard, during the winter season 2022-2023. Images are obtained at either 20 frames per second or 32 frames per second. Approximately 12TB of data in total for 2022-2023. "Quicklook" summary plots are publicly available online. 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
Impact None yet 
URL http://ask1.esr.eiscat.no/keos.html?yr=22&mo=12
 
Title Auroral Structure and Kinetics (ASK) data 2023-24 
Description Images of the aurora in the magnetic zenith obtained from Longyearbyen, Svalbard, during the winter season 2023-2024, in the OI 777.4 nm wavelength. Images are obtained at 20 frames per second. Approximately 4TB of data in total for 2023-2024. "Quicklook" summary plots are publicly available online. 
Type Of Material Database/Collection of data 
Year Produced 2023 
Provided To Others? Yes  
Impact None yet 
URL http://ask1.esr.eiscat.no/keos.html?yr=23&mo=12
 
Description Aurora Zoo - School visits 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Aurora Zoo workshops for school children, both at schools and during visits to the University. Schools targeted for widening participation to physics and STEM subjects. In 2020 we worked with 4 specific schools on multiple visits, to promote deeper engagement. We also arranged skype chats with school children while on fieldwork on Svalbard in the high Arctic to discuss what we were doing and to answer questions. A range of evaluation methods have been used, but predominantly involve a quiz before an activity and a repeat after the activity, to assess changes in attitudes and knowledge. Children from backgrounds which are under represented in physics (girls, low income families, etc.) have reported an increased interest in pursuing a career in physics. Engagement with schools continued online during the second half of 2020 and the start of 2021, through pre-recorded videos and online presentations.
Year(s) Of Engagement Activity 2019,2020,2021,2022,2023,2024
 
Description Southampton Science & Engineering Day 2023 - Aurora Zoo 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Several hundred children and adults of all ages took part in the Aurora Zoo citizen science project and engaged with the research team during the Southampton Science & Engineering Festival. The audience included scout/guide groups. Several people discussed career choices for young adults, and how to pursue a career in science.
Year(s) Of Engagement Activity 2023
URL http://www.sotsef.co.uk