UK-SOSS next talk – 10:00 GMT 18th February 2021

February 10, 2021, from Jiajia Liu

Dear all,

We have the pleasure of announcing the next instalment of the UK-SOSS which will take place at 10am (GMT) on 18th February 2021. Our speaker will be Dr. Huw Morgan from the Aberystwyth University. We look forward to welcoming you all to the talk at that time. The zoom link is:

Please find all other relevant details below.

All the best,
Jiajia Liu (on behalf Marianna Korsos and Chris Nelson)

The Characteristics of Coronal Streamers Over a Solar Cycle: Resolving the Line-of-Sight with Coronal Rotational Tomography

Dr Huw Morgan

Aberystwyth University

Date: 10:00 (UK time) 18th February 2021

Abstract: Any remote measurement of the solar corona in white light (or other) wavelength is an integration of emission along an extended line of sight. Historically, most studies necessarily assumed an axi-symmetric distribution to the density, thus derived properties contained an inherent and unquantified uncertainty. From the SOHO era onwards, space-based coronagraphs (LASCO/SOHO, and COR/STEREO) make frequent, uninterrupted, and high-quality observations of the corona which allow estimates of the true density distribution using coronal rotational tomography (CRT). A recent breakthrough in CRT is revealing a new view of the corona which is gained directly from observation. For the first time, we can view long-term trends in the coronal rotation rate, find meaningful links between coronal and interplanetary density structures, and use estimated densities at a range of heights to constrain outflow velocity and acceleration. The density distributions provide a ground truth for model extrapolations of the photospheric magnetic field, and new empirical boundary conditions for solar wind models. Tentative evidence of the Parker spiral onset can be seen close to the Sun. The next step in CRT methods is the inclusion of a time-dependent density distribution: initial results show promising correlations with Parker Solar Probe measurements, and the discovery of large variations on daily timescales not associated with mass ejections.