2020 Seminar Abstracts

Thebe Medupe, North West University

Title: 23 min period pulsations in a Herbig Ae Star: HD 68695

Pulsations in stars provide a powerful means to probe their interior structure. Herbig Ae stars are young and in their pre main sequence phase of stellar evolution. They are characterized by emission lines and infrared excess as well as irregular light variability. Their masses range from 2 and 8 solar masses. Some, like HD68695 I will discuss in my talk, have delta Scuti pulsations. This is not surprising as their evolutionary tracks pass through delta scuti instability strip on the way to the main sequence. HD68695 was discovered in the KELT-South data. We have discovered more than five frequencies in this star. I will discuss some of the physical properties we can find in this star from these sets of frequencies.

Eugene Vasiliev, University of Cambridge

Dynamical modelling of stellar systems in the Gaia era

I review the landscape of methods for constructing equilibrium models of stellar systems constrained by observational kinematic data, in particular, the ones provided by the Agama framework.
I then focus on the wealth of data brought by the second data release (DR2) of the Gaia mission, and illustrate the dynamical modelling workflow with three examples:
1) internal structure of the Large Magellanic Cloud,
2) internal structure of globular clusters, and
3) kinematics of globular clusters in the Milky Way and constraints on the Galactic potential.

Iain Crosley, Hosokawa Micron

Creation and Application of Advanced Functional Materials in Industry

Hosokawa Micron is well known as a leader in the design and supply of powder processing equipment and systems. In order to develop the next generations of equipment and understand the future needs of the processing industries, Hosokawa engage closely with academic and industrial partners. These partnerships enable Hosokawa to understand the challenges that are faced in producing these new materials. These challenges include how these materials can be handled as their physical properties change rapidly as the particle size of the material decreases, from the micron to the nanometre scale.
At the centre of this R&D work is the Hosokawa Powder Technology Research Institute and this paper will look at some of their areas of activity in terms of materials being produced and the technologies they are utilising.
Established over fifty years ago, the original aim of the Institute was to further develop powder and particle technology. This initiative continues today.
The market needs higher quality for powder processing in fields such as secondary battery, materials for electronic devices, toner, medicine and functional foods. Solutions for materials in the environment and energy as well as powder characterisation techniques are also important.
Other challenges include the HS&E issues in dealing with nanomaterials on a production scale as well as the process control and understanding of the complex processes used to produce functional nanomaterials and how these are to be scaled up, plus the application of the Internet-of-Things (I-o-T) to these processes.
The program of research work is conducted on a global basis and discussed at International R&D Meetings where members of the R&D teams from Japan, Germany, Holland, USA and UK decide upon the research topics and strategy to meet the challenges of the future technologies.

Gary Hogben, Feedwater Ltd

Preventing water borne infections in a post antibiotic world

The world faces an infection crisis in relation to the rise of antimicrobial resistance, the failure to develop new antibiotics and the emergence of new  strains of bacteria with increased pathogenicity. This triple-whammy signals the end of a golden period in infection control, where antibiotics could be used to deal with infections previously considered untreatable. The bacteria have fought back – and they are winning. Other microbes are also emerging, for example the recent emergence of a novel coronavirus in China and the MERS virus in Saudi  Arabia, have  ring alarm bells with Public Health professionals and members of the public alike.  The potential for a catastrophic influenza pandemic remains very substantial.
We will review the historical treatment of infections and look at these new infections emerging, with a particular emphasis on waterborne infections. The role of chemical treatments for prevention will be discussed, especially in relation to low level dosing control strategies and the possible problems with those strategies.
We will also consider the possible future role of nanomaterials in infection control, particularly in healthcare where infection control is central to patient care and the opportunities for novel materials are very substantial.

Annabel Cartwright, Cardiff University

Making new ideas work

Many recent ideas and new technological aids in Physics Education are well established and reported in the literature. Actually implementing them and measuring their effectiveness is a challenge. Here I will talk about our motivation in introducing recent innovations in Physics teaching in Cardiff, including on line coursework, multiple choice exams, lecture capture, problem based learning and flipped teaching. I will review our experience, and what results we are seeing.

Dato Kuridze, Aberystwyth University

High-resolution Measurement of the Magnetic Field of Solar Coronal Loops

The magnetic field is key to the dynamics, evolution, and heating of the solar atmosphere, yet direct measurements are rare and highly uncertain. In this seminar I will discuss about the techniques and challenges of measuring the magnetic field in the corona. I will then present the results from my current work where we report on the unique observations of the flaring coronal loops at the solar limb using high resolution imaging spectropolarimetry from the Swedish 1-meter Solar Telescope. The vantage position, orientation and nature of the chromospheric material that filled the observed flare loops allowed us to determine their magnetic field with unprecedented accuracy. Our analysis reveals coronal magnetic field strengths as high as 350 Gauss at heights up to 25 Mm above the solar limb. These measurements are substantially higher than a number of previous estimates and could have considerable implications for our current understanding of the extended solar atmosphere.

Clive Tadhunter, University of Sheffield

How are quasars triggered?

Discovered more than 50 years ago, quasars are the most luminous objects in the Universe and are thought to play
a key role in the evolution of galaxies. However, despite their importance, we still do not fully understand how they are triggered.
Following a review of the quasar triggering problem and past results in this field, I will present new results based on deep optical
imaging and far-IR photometry of nearby quasar-like AGN, emphasising in particular recent Herschel results.

Cleo Loi, University of Cambridge

Magneto-gravity waves in red giant stars: a 3D ray tracing study

Stars are fluid bodies in which many kinds of waves can propagate. The constructive interference of these waves gives rise to global modes of oscillation, the frequencies of which depend on the interior properties of the star. With the aid of sufficiently sensitive photometry, these oscillations can and have been detected in many distant stars, giving rise to the field of asteroseismology. Analysis of these signals, combined with a theoretical understanding of wave propagation, provides a wealth of information about stellar interiors not obtainable through other means.

In this talk, I discuss a problem in observational asteroseismology involving dipole oscillation modes having amplitudes too low to be explained by standard theory (the “dipole dichotomy” problem). This phenomenon occurs selectively in red giant stars previously thought to have generated a magnetic field inside their cores. Using ray tracing techniques, I present a theoretical study of wave propagation inside red giant cores harbouring magnetic fields, examining the effect of various parameters including wave frequency, field strength and evolutionary state. The predictions of the theory match many aspects of the observations, suggesting that magnetic fields may be a viable explanation for the dipole dichotomy problem.

John Armstrong, University of Glasgow

Learning to Invert a Flaring Atmosphere with RADYN Physics

During a solar flare, it is believed that reconnection takes place in the corona followed by fast energy transport to the chromosphere. The resulting intense heating strongly disturbs the chromospheric structure and induces complex radiation hydrodynamic effects. Interpreting the physics of the flaring solar atmosphere is one of the most challenging tasks in solar physics. We present a novel deep learning approach, an invertible neural network, to understanding the chromospheric physics of a flaring solar atmosphere via the inversion of observed solar line profiles in Hα and Ca II λ8542. The network is trained using flare simulations from the 1D radiation hydrodynamic code RADYN as the expected atmosphere and line profile. This model is then applied to whole images from an observation of an M1.1 solar flare taken with the Swedish 1 m Solar Telescope/CRisp Imaging SpectroPolarimeter instrument. The inverted atmospheres obtained from observations provide physical information on the electron number density, temperature and bulk velocity flow of the plasma throughout the solar atmosphere ranging in height from 0 to 10 Mm. Our method can invert a 1k x 1k field-of-view in approximately 30 minutes and we show results from the whole image inversions and error calculations on the inversions. Furthermore, we delve into the mammoth task of analysing the wealth of data we have accumulated through these inversions.

Soko Matsumura, University of Dundee



Stijn Wuyts, University of Bath



David Williams, University of Oxford



Heike Arnolds, University of Liverpool

Proteins at surfaces – from single crystals to fabrics


Matthew Bate, University Exeter



3 June



Jim Wild, University of Lancaster



Natasha Jeffrey, Northumbria University

Solar Flares: Our Local Laboratory for Studying Particle Acceleration

Solar flares, the observational product of magnetic reconnection in the Sun’s atmosphere, are highly efficient particle accelerators and prime laboratories for studying acceleration processes in astrophysics. Over the last decade, our understanding of flare particle acceleration has been enhanced by multi-wavelength observations from X-rays to (E)UV to radio, and by recent advances regarding the diagnostics of energetic particles at the Sun. However, many questions remain about how and where energetic particles are accelerated, and how different plasma environments (e.g., collisions, turbulence) affect the transport and observed properties of energetic particles. Further, data from a new generation of observatories (e.g. Parker Solar Probe and Solar Orbiter) will help to understand the connection between energetic particles at the Sun and those measured in situ in the heliosphere.

Phil Sutton, University of Lincon

The Importance of Planetary Rings as Astrophysical Laboratories

The Solar System hosts one of the best natural laboratories for the study of astrophysical processes. Saturn’s rings are close enough that we have been able to study them in great detail with the use of the in-situ spacecraft, Cassini, for over a decade. In this talk, with the use of Saturn’s rings, we will cover the key physics of planetary rings, their interactions with nearby moons and how they can be used to strengthen our planet formation theories. The talk will finish by applying what we have learnt from Saturn’s rings to some recently discovered rings orbiting exoplanets (exorings), and how we can discover unseen exomoons by the signatures they leave within the rings.

John Ilee, University of Leeds

Massive discs around young stars

Protoplanetary discs are one of the most extreme environments in astrophysics, spanning a huge range of temperatures and densities. As such, modelling their chemical evolution is challenging, and has often been reduced to the study of 2-dimensional, axisymmetric discs. However, the advent of ALMA has shown that many protoplanetary discs do not conform to this axisymmetry. Dust traps, warps, embedded planets and spiral arms have all recently been observed in discs, complicating matters further. In particular, the influence of the dynamic evolution of the disc on the chemical evolution is not well known.

From an observational perspective, we have shown that the Atacama Large Millimetre/submillimetre Array (ALMA) will be an essential tool in catching these phenomena ‘in the wild’, and I will discuss our recent observational campaigns. In the longer term, the Square Kilometre Array (SKA) will also provided much needed cm-wavelength observations of planet-forming discs, and I will show some of the first predictions of what we expect this transformative instrument to observe in the late 2020’s.