ABER-SSP
Joe Hutton

Research & Publications - Solar Data Archive - Contact Info - LinkedIn - ResearchGate

Automated detection of coronal mass ejections in three-dimensions using multi-viewpoint observations

J. Hutton & H. Morgan

Institute of Mathematics, Physics & Computer Sciences, Aberystwyth University, Penglais, Aberystwyth, Ceredigion, SY23 3BZ, UK

Published in Astronomy & Astrophysics, Volume 599, article id. A68, 11 pp. (2015). (A&A Homepage)

Full pdf HERE.

Arxiv e-print HERE.

Abstract:

A new, automated method of detecting coronal mass ejections (CMEs) in three dimensions for the LASCO C2 and STEREO COR2 coronagraphs is presented. By triangulating isolated CME signal from the three coronagraphs over a sliding window of five hours, the most likely region through which CMEs pass at 5 solar radii is identified. The centre and size of the region gives the most likely direction of propagation and approximate angular extent. The Automated CME Triangulation (ACT) method is tested extensively using a series of synthetic CME images created using a wireframe flux rope density model, and on a sample of real coronagraph data; including halo CMEs. The accuracy of the angular difference between the detection and true input of the synthetic CMEs is 7.14 degrees, and remains acceptable for a broad range of CME positions relative to the observer, the relative separation of the three observers and even through the loss of one coronagraph. For real data, the method gives results that compare well with the distribution of low coronal sources and results from another instrument and technique made further from the Sun. The true three dimension (3D)-corrected kinematics and mass/density are discussed. The results of the new method will be incorporated into the CORIMP database in the near future, enabling improved space weather diagnostics and forecasting.

Erupting Filaments with Large Enclosing Flux Tubes as Sources of High-mass Three-part CMEs, and Erupting Filaments in the Absence of Enclosing Flux Tubes as Sources of Low-mass Unstructured CMEs

J. Hutton & H. Morgan

Institute of Mathematics, Physics & Computer Sciences, Aberystwyth University, Penglais, Aberystwyth, Ceredigion, SY23 3BZ, UK

Published in The Astrophysical Journal, Volume 813, Issue 1, article id. 35, 23 pp. (2015). (ApJ Homepage)

Full pdf HERE.

Arxiv e-print HERE.

Supplementary videos HERE.

Abstract:

The 3-part appearance of many coronal mass ejections (CMEs) arising from erupting filaments emerges from a large magnetic flux tube structure, consistent with the form of the erupting filament system. Other CMEs arising from erupting filaments lack a clear 3-part structure and reasons for this have not been researched in detail. This paper aims to further establish the link between CME structure and the structure of the erupting filament system and to investigate whether CMEs which lack a 3-part structure have different eruption characteristics. A survey is made of 221 near-limb filament eruptions observed from 2013 May 03 to 2014 June 30 by Extreme UltraViolet (EUV) imagers and coronagraphs. Ninety-two filament eruptions are associated with 3-part structured CMEs, 41 eruptions are associated with unstructured CMEs. The remaining 88 are categorized as failed eruptions. For 34% of the 3-part CMEs, processing applied to EUV images reveals the erupting front edge is a pre-existing loop structure surrounding the filament, which subsequently erupts with the filament to form the leading bright front edge of the CME. This connection is confirmed by a flux-rope density model. Furthermore, the unstructured CMEs have a narrower distribution of mass compared to structured CMEs, with total mass comparable to the mass of 3-part CME cores. This study supports the interpretation of 3-part CME leading fronts as the outer boundaries of a large pre-existing flux tube. Unstructured (non 3-part) CMEs are a different family to structured CMEs, arising from the eruption of filaments which are compact flux tubes in the absence of a large system of enclosing closed field.

The Sun in 2017

An image of our Sun each day throughout the year 2017, captured by NASAs Solar Dynamics Observatory (SDO) satellite using the Atmospheric Imaging Assembly (AIA) in extreme ultra-violet. The images are processed using Multi-Scaling Gaussian Normalisation (MGN). This technique normalises the image at many different spatial scales, such that information at the finest scales is revealed, while enough of the larger scale information is maintained to provide context.
The processing is repeated for three different wavelength channels, and the three images corresponding in time are layered together to make an rgb image. This movie uses a combination of the wavelengths; 211Å, 193Å & 171Å.

Transit of Mercury 2016

The transit of Mercury captured by NASAs Solar Dynamics Observatory (SDO) satellite using the Atmospheric Imaging Assembly (AIA). Using a 30 second cadence, the images of the Sun, captured in extreme ultra-violet, are processed using Multi-Scaling Gaussian Normalisation (MGN). This technique normalises the image at many different spatial scales, such that information at the finest scales is revealed, while enough of the larger scale information is maintained to provide context.
Finally, The processing is repeated for three different wavelength channels, and the three images corresponding in time are layered together to make an rgb image. This movie uses a combination of the wavelengths; 211Å, 193Å & 171Å.

Cymru

Solar Physics in Wales

I noticed a while back that the UK Solar Physics (UKSP) website has the Union Flag made up of a mosaic of Solar images as a logo. I thought the work done on solar physics here at Aberystwyth University deserved something similar.

This flag is made up of images taken of the Sun in extreme ultraviolet by SDO/AIA 304Å (red), 193Å (white) and 171Å (green). I know the people at NASA like to reserve green for the 94Å channel, but I thought 171Å (usually coloured yellow) looked nicer for this composition.