CDT student Rob Long reflects on research visit to UCLA

My PhD project focuses on understanding the fluid dynamical processes present in planetary systems such as in the Earth's liquid iron core. Here at the University of Leeds we tackle this problem using numerical simulations but we wanted to try and unify our results with those from laboratory experiments. In September-October 2019, I visited Prof. Jon Aurnou at SPINlab (Read more about spinlab), University of California Los Angeles (UCLA) which is a world leading lab for rotating convection experiments.

The Earth's magnetic field is maintained by convective motions of the liquid iron in the core and the dynamics are strongly dictated by the radial gravity profile and spherical geometry. Out of necessity experiments are performed in cylindrical tanks and have gravity antiparallel to the rotation axis - this then resembles a local region of fluid at high latitude. Despite core dynamics being studied for many decades and different behaviours being observed for spherical and cylindrical cases there has never been a one-to-one comparison. The main goal of the visit was to perform a series of rotating convection experiments with water in which we simultaneously measure the heat transport and flow speeds – which we did successfully! In the coming months we will perform direct comparisons between the experimental data and a loca­l cylinder harvested from our spherical simulations. This will definitively show to what extent the two classes of models agree and how we can interpret results from both in a wider context.

(left) Robert Long and Jewel Abbate standing in front of the rotating convection experiment. (right) Snapshots from experiments at different rotation rates, the tank is heated from below and cooled from above driving convection.

Alongside lab work, I was embraced as a member of the research group and participated in weekly meetings and departmental seminar series. I managed to explore quite a lot of Los Angeles, including downtown, a handful of different beaches, Hollywood and even Disneyland. My personal highlight was visiting Staples Centre – home of the Los Angeles Lakers.

I am grateful to Jon Aurnou for hosting me during my visit and being readily available for discussions. I would also like to thank Jewel Abbate who was an excellent lab partner and the wider Crust2Core group for having me as one of their own for the duration of my stay and for many insightful discussions about all things deep Earth related. The work started during my visit will make up a significant contribution to my thesis and will hopefully be of interest to the wider community. The theme of unifying laboratory experiments and supercomputer simulations will no doubt lead to further collaboration with UCLA.