David Williams

Instrument Operations Scientist, Solar Orbiter

 

Main Research Fields

I’m a physicist who specialises in studying the wispy but explosive atmosphere of our star, the Sun.

 

I look at the Sun in ultraviolet light, where it's covered in rope-like filaments, tenuous bright magnetically-shaped loops and puzzlingly hot ionised gas (plasma). Filaments are truly fascinating structures hovering in the corona, at the interface between low and high states of ionisation, density, plasma β and temperature. This begs us to understand not only their structure, but also their creation and often explosive destruction.

 

Solar active regions, areas of intense and often complex magnetic fields on the Sun, play host to some filaments. But they are also interesting for another reason: in the unusually hot solar corona, these are the hottest sites of all, and they can release energy violently as well as constantly from the reordering of these magnetic fields. This ongoing magnetic furnace can throw our usual easy rules-of-thumb about plasma behaviour out the window. Understanding how plasma is heated, and whether it behaves like a normal Maxwellian "gas", or has a long-lasting population of high-energy particles, is something we can probe through UV and X-ray spectroscopy (something Solar Orbiter will really help us to do).

 

In my career so far, I have used, operated, and helped design and prepare space missions that tell us about the Sun that we can't see from inside Earth's own, protective atmosphere. The techniques I use split the Sun's UV light into its individual colours to tell us what it's made of, how it moves and what the conditions are that produce strange heating and violent explosions like flares and coronal mass ejections.


Ongoing collaborations

I'm involved in several active collaborations with researchers in France, the US, Japan, and UK, among other countries. See my publications (below) for more.

Publications

A reasonably up-to-date record of my scientific publications is kept on OrcID here . (OrcID is incredibly useful when you have a name as common as mine!)

Project/mission at ESA

My role at ESA is as one of three Instrument Operations Scientists for Solar Orbiter. Our job is to liaise between a) the teams building the scientific instruments, and b) the Science Operations Centre at ESAC which will organise how the mission is run to achieve its scientific aims.

 

I look after three of the ten payload instruments: STIX (X-ray spectral imager), Metis (a coronagraph working in visible and ultraviolet light) and SPICE (an Extreme-UV imaging spectrometer). My colleagues Anik De Groof and Andrew Walsh look after the remaining seven instruments in the mission's scientific payload.