PhD in Geophysics: Modelling Core Flow to Study Earth's Magnetic Reversals

PhD in Geophysics: Modelling Core Flow to Study Earth's Magnetic Reversals

Quick Decision

Strong but verify fit. This is a defined computational deep-Earth project: analyse existing core-flow simulations, run new models of reversals and long-term reversal-frequency change, and compare the results with paleomagnetic observations. The named Leeds supervisors work directly on geodynamo dynamics, mantle-core coupling and numerical modelling. The YES-DTN FAQ says the award covers full university fees, including the international fee difference, which materially improves its funding case.

Resolve the application opening-date conflict first. One network page says the October 2027 applications opened on 2 November 2026; the detailed instructions say they open on 12 November at 10:00 GMT and that forms will not be available before then. Both list a 12 January 2027, 13:00 GMT deadline. The 2027/28 stipend, project-specific coding/HPC expectations and the relationship between the 3.5-year award and Leeds registration also need confirmation. Before applying, check portal access with the network and, as its instructions recommend, contact the supervisors with focused project questions.

Research Problem and Doctoral Work

What Is Unsolved and Why It Matters

Earth's magnetic field is generated by fluid motion in the electrically conducting outer core, yet its strength, structure and reversal frequency have changed across geological time. The project page gives a useful contrast: the recent field reverses about five times per million years, while the Cretaceous Normal Superchron lasted close to 40 million years with no or very few reversals. Why the dipole sometimes switches polarity, and why the long-term rate changes, remain open questions in deep-Earth geophysics. Official project page.

A central modelling difficulty is that many numerical reversals have not reproduced the balance between magnetic and kinetic energy expected for Earth's core. Such models may give inertia too much influence in triggering reversals. Recent low-inertia approaches make it possible to test reversal behaviour in a stronger-field regime. Jones and Tsang report reversing numerical dynamos in which magnetic energy is much greater than kinetic energy except close to a reversal; the project is explicitly built around a newer theoretical and numerical approach of this kind. Jones and Tsang, Low inertia reversing geodynamos.

The longer-timescale question is how heat extracted across the core-mantle boundary changes as mantle convection and plate tectonics evolve. The project's motivating mismatch is important: some earlier combinations of mantle-circulation models and dynamo simulations predict high reversal frequency in the Cretaceous, opposite to the observed long superchron. Mound and Davies link heterogeneous lower-mantle heat flow to the longitudinal structure of Earth's magnetic field, while Frasson and colleagues find that different heat-flux patterns can affect zonal flow and dipole stability. These results make mantle control plausible, but they do not settle the causal pathway or reversal-rate prediction. Mound and Davies, 2023, Frasson et al., 2025.

Recent work also illustrates why observation-model comparison remains difficult. Mason, Davies, Clarke and Constable compared 20 numerical simulations with paleomagnetic field models spanning the last 100,000 years. The match depended on properties such as dipolarity, and both the accessible simulation regime and the resolution of paleomagnetic reconstructions limit what can be inferred. A separate recent team paper combines paleomagnetic datasets and dynamo simulations to examine how mantle heterogeneity influences the ancient field. Mason et al., 2024, Biggin et al., 2026.

There is not a single accepted reversal mechanism. Aubert and colleagues propose a stable-top-core kinematic mechanism involving the balance between subsurface upwellings and circulation near the core surface. This offers a useful competing explanation to examine when asking how boundary conditions change reversal rates. The project is timely partly because its main inference has to be tested against such alternatives, not assumed in advance. Aubert et al., 2025 manuscript.

Work, Methods and Potential Outputs

The advertised work has four connected parts:

1. Analyse an extensive existing suite of core-flow simulations to characterize flow features that may trigger reversals.
2. Run new core simulations to investigate individual magnetic reversals.
3. Run simulations of longer-term reversal-frequency change as mantle convection patterns evolve.
4. Compare simulated reversals with paleomagnetic observations, building on established Leeds collaborations with the University of Liverpool and Scripps Institution of Oceanography.

The project description does not state a particular software language, numerical code, simulation parameter range, HPC allocation or split between analysis and new computation. A plausible research sequence is to track candidate flow diagnostics through dipole weakening, compare controlled heat-flux patterns, and assess reversal statistics and field morphology against the geological record. That is an analyst's interpretation of the stated aims, not a guaranteed protocol or output. Ask which diagnostics, datasets and model limitations the supervisors expect the student to prioritize. Official project page.

School, Programme and Field Context

The project is hosted by the University of Leeds School of Earth and Environment and recruited through the Yorkshire Environmental Sciences doctoral network. The application instructions require a Leeds Online Application as well as the network's separate form. No joint award or other degree-awarding institution is stated; Liverpool and Scripps are named as research collaborators, which does not by itself imply a joint degree. Confirm the formal registering school and award name in the offer. Project page, network application instructions.

Leeds reports 2026 QS subject results covering earth-science fields. The School also reports that 93% of its Earth and Environment submission in REF 2021 was rated world-leading or internationally excellent. These are useful signals about broad subject and research environment; neither measures the quality of this individual project or predicts a student's outcome. The School describes active research, Doctoral College support, professional-skills provision and links with industry and other academic institutions. Leeds 2026 QS subject ranking release, School research-degree environment, REF 2021 UOA7 environment statement.

Leeds describes a standard full-time PhD period of three years, whereas the network funds this project for 3.5 years, potentially 3.75 years with an eligible three-month placement. The award duration is not enough to infer the registration or thesis-submission period. Leeds PGRs agree an individual training plan with supervisors within the first three months, are allocated ten training days per year, and receive research-integrity, data-management, research-skills and career-development support. Leeds research-degree types, training plan, PGR training and research skills.

Supervisor and Lab Assessment

Jon Mound is the named primary supervisor and a Leeds Professor of Global Geophysics. His listed interests include fluid dynamics, geomagnetism, magnetohydrodynamics and space weather. Chris Davies is the named academic supervisor and a Leeds Professor of Theoretical Geophysics; his profile focuses on Earth's deep interior, the core-mantle system, numerical modelling, geodynamo theory and high-performance computing. This is a close match to the advertised simulation programme. Their profiles do not specify expected meeting frequency or divide supervisory responsibilities. Mound profile, Davies profile.

The Leeds Centre for Planetary Core Dynamics provides a relevant local group: its members describe research on rotating convection, dynamo action, numerical methods, model-observation comparison and core-mantle interaction. The group identifies use of the Leeds Spherical Dynamo Code. University-wide Advanced Research Computing has opened Calder, a CPU/GPU and storage service for modelling and data-intensive research. These pages establish a capable environment, but they do not promise that this student will use a specific code or receive a particular compute allocation. Planetary Core Dynamics team, Calder HPC service.

Recent Important Publications

• Mound and Davies (2023), “Longitudinal structure of Earth's magnetic field controlled by lower mantle heat flow.” Their modelling links heterogeneous lower-mantle heat flow to longitudinal field structure, supporting the project's interest in boundary forcing and non-axisymmetric diagnostics. The result does not establish that heat flow determines reversal frequency. Nature Geoscience.
• Mason, Davies, Clarke and Constable (2024), “Insights into the last 100 ky of geomagnetic field variability using numerical dynamo simulations.” The authors compare 20 dynamo simulations with time-varying paleomagnetic models. Agreement depends on model characteristics including dipolarity; finite simulation regimes and observation resolution remain important limits. This is a direct precedent for the proposed simulation-observation comparison. Earth and Planetary Science Letters.
• Naskar, Davies, Mound and Clarke (2025), “Force balances in spherical shell rotating convection.” This study compares force and curled-force balances across rotating-convection regimes and shows that the apparent balance varies with direction, scale and regime. It informs how candidate reversal-triggering flows should be characterized rather than prescribing a specific result for this PhD. Journal of Fluid Mechanics.
• Biggin, Davies, Mound and colleagues (2026), “Mantle heterogeneity influenced Earth's ancient magnetic field.” Combining paleomagnetic datasets and dynamo simulations, the study strengthens the case that core-mantle heat-flux heterogeneity affects long-term field morphology. It supports active team expertise in the relevant field, while addressing ancient/time-averaged behaviour rather than resolving reversal-rate mechanisms. Nature Geoscience.
• Frasson and colleagues (2025), “Geomagnetic dipole stability and zonal flows controlled by mantle heat flux heterogeneities.” Their results associate heat-flux patterns with changes in zonal flows and dipole stability, but the effect depends on model regime and pattern. This offers a candidate mechanism and underlines the need for sensitivity analysis and cautious extrapolation to Earth. Geophysical Journal International.
• Jones and Tsang (2025), “Low inertia reversing geodynamos.” They report reversing models at numerically accessible settings where magnetic energy is much greater than kinetic energy except close to reversal. This is closely connected to the advertised modelling advance, but one approach does not settle the real-Earth mechanism. Newcastle ePrints.
• Aubert, Landeau, Fournier and Gastine (2025), “Core-surface kinematic control of polarity reversals in advanced geodynamo simulations.” Their alternative stable-top-core mechanism links reversal onset to surface circulation and subsurface upwellings. It makes the project's comparison of mechanisms more important; check the final published version and model assumptions when discussing it. Manuscript.

Funding, Application and Living Cost

The network FAQ describes a full-time studentship of 3.5 years, with a UKRI-rate personal stipend and support for research costs, fieldwork, training and conference travel. A three-month industry placement can extend funding to 3.75 years, but the project is listed as neither CASE nor a collaborative project; placement availability for this project needs confirmation. The FAQ states that university fees, including the home/international difference, are covered. It says up to 30% of full awards may go to international candidates: this is a network-wide maximum, not a guarantee of selection. UKRI itself contributes tuition only up to the home-rate cap, which makes the network's explicit fee commitment important. YES-DTN FAQ, UKRI student funding guidance, Leeds research fees.

The published UKRI minimum from October 2026 is GBP 21,805 for 2026/27. The rate for an October 2027 start was not confirmed as of 4 November 2026. Leeds's provisional 2026/27 guide estimates an average GBP 320 per week, or GBP 16,640 for a 52-week year for a single student; average self-catered university rent is GBP 198/week and average private rent GBP 210/week. At the current stipend floor, the simple annual difference from Leeds's average budget is GBP 5,165, about GBP 430/month. Treat this as an indicative comparison only: it assumes the 2026/27 amount, excludes tuition, and leaves visa/IHS, travel, relocation and personal circumstances to budget separately. The YES-DTN FAQ also cautions that tax may be due in an international student's home country. UKRI student funding guidance, Leeds living-cost guide, YES-DTN FAQ.

The application date conflict is material. The network's general /apply page says applications opened 2 November 2026 at 10:00; its detailed How to Apply page says they open 12 November 2026 at 10:00 GMT and that the forms will not be available before that date. Both pages list the deadline as 12 January 2027 at 13:00 GMT. As of 4 November 2026, the official pages do not resolve whether the application system is actually open. Contact the network to confirm; do not rely on one date without checking. Join us / apply page, detailed How to Apply page.

The detailed route requires two forms: the Leeds Online Application (OLA) and the YES-DTN JISC form. Select the NERC YES DTN Yorkshire Environmental Sciences programme in the Leeds application. The network guidance requires project code YES-27-D-16, but does not establish which form field requires it; confirm its placement with the network. Leeds issues a student ID (SID); the network form requires that SID, so the instructions recommend submitting the OLA at least two days before the deadline because delivery can take over 24 hours. Upload degree certificates and transcripts, provisional transcripts if still studying, and certified English translations for non-English documents. The network form combines CV and a structured personal statement covering qualifications, relevant work history, motivation for a PhD, why this project, and why the network; it replaces separate CV and personal-statement files. One application can list a first choice and an optional second choice from the same school. Late applications are not accepted. How to Apply.

Applicant Fit and Preparation

The project lists applied mathematics, computer science/computing, Earth science, geophysics, mathematics, natural sciences and physics as relevant backgrounds. The School's general minimum for PhD study is a relevant 2:1 honours degree or equivalent, or good performance in a relevant Master's course; it says a first-class degree is usually needed to be competitive for scholarship funding. That is general School guidance, not a published YES-DTN project-specific award cutoff. The School lists IELTS 6.0 overall with at least 5.5 in each component as one English-language route; check accepted alternatives and certificate validity for the intended start. Project page, School entry requirements, YES-DTN FAQ.

A competitive application could make quantitative preparation easy to evaluate: a modelling or coding project, the applicant's own contribution, how a result was validated, and experience working with time-series or geophysical data. Familiarity with numerical methods, rotating-fluid dynamics and uncertainty-aware comparison between simulations and observations would be useful to evidence. These are suggested strengths, not stated prerequisites: the project does not name a programming language, software package or prior HPC level. Candidates mainly seeking fieldwork or laboratory measurement may find the advertised simulation workload less aligned with their goals; this is an interpretation of the project tasks, not an admissions exclusion. Leeds's training plan and researcher-development resources provide ways to address some skill gaps after registration, but the supervisors should confirm what can reasonably be learned during the project. School entry requirements, Leeds PGR training, Planetary Core Dynamics team.

Career and Field Market

A British Geophysical Association employer survey reported around 245 UK geophysicist vacancies per year from 55 employers; 57% of respondents said roles were not easy to fill, and 78% predicted stable or growing demand, particularly in engineering and offshore surveying. A Geological Society engineering-group discussion also points to demand for applied geoscience in clean energy, carbon storage, infrastructure, water and environmental work. Government career guidance notes that specialist software and computer modelling are useful geoscientist skills. BGA employer-survey article, Geological Society applied-geoscience discussion, National Careers Service: Geoscientist.

These sources describe mostly applied geophysics/geoscience, not hiring for academic geomagnetism or geodynamo research. The most transferable elements of this PhD are numerical modelling, scientific programming, data analysis and geophysical reasoning. Plausible routes include academic research, research software/data work, and selected applied geoscience or modelling roles; availability and fit depend on the candidate's skills and future hiring conditions.

Next Actions and Questions to Verify

Before Applying

• Ask the network which opening date controls and whether the OLA/JISC forms are currently available.
• Confirm international selection conditions under the network's up-to-30% full-award cap, complete fee-difference coverage and accepted English evidence.
• Check whether the 3.5-year funded period covers the full registration/write-up arrangement and whether a three-month placement is available to this non-CASE project.
• Contact a supervisor with focused questions about the project; the network specifically advises against sending a CV, transcripts or statement unless requested.

At Interview

• Which existing simulation suite, code and numerical methods would the student use? What programming/HPC preparation is expected at entry, and what can be learned after starting?
• How will time be divided between analysing existing data and running new individual-reversal and long-term frequency simulations?
• Which flow diagnostics and mantle heat-flux patterns are central, and how will model outputs be compared with paleomagnetic records?
• How will the project handle model-to-Earth extrapolation, competing reversal mechanisms and the Cretaceous Normal Superchron mismatch?
• What roles will Liverpool and Scripps collaborators have in data access, meetings or visits?

Before Accepting an Offer

• Confirm the registering institution, school and PhD award name, as well as formal registration, funding, transfer, thesis and write-up dates.
• Obtain the final 2027/28 stipend and written confirmation of international tuition coverage throughout the award.
• Confirm all exclusions and placement terms, including visa/IHS, travel insurance, relocation and any project-specific research costs.

Evidence and Sources

Project, Programme, Funding and Application

• YES-27-D-16 project page
• Network opening-date page
• Detailed application instructions
• Network funding and international-student FAQ
• UKRI student funding guidance
• Leeds research fees
• Leeds living-cost guide

Supervisors, Group and Selected Papers

• Jon Mound profile
• Chris Davies profile
• Leeds Centre for Planetary Core Dynamics team
• Leeds Calder HPC service
• Mound and Davies (2023), lower-mantle heat flow and magnetic-field structure
• Naskar et al. (2025), force balances in rotating convection
• Mason et al. (2024), simulations and the last 100 kyr of field variability
• Biggin et al. (2026), mantle heterogeneity and the ancient field
• Frasson et al. (2025), heat-flux heterogeneity and dipole stability
• Jones and Tsang (2025), low-inertia reversing dynamos
• Aubert et al. (2025 manuscript), core-surface kinematic reversal control

School, Research-Degree and Training Context

• Leeds School research degrees
• REF 2021 UOA7 environment statement
• Leeds 2026 QS subject-ranking release
• School entry requirements
• Leeds research-degree types and PhD duration
• Leeds PGR training and research skills
• Leeds PGR training plan

Career Evidence

• National Careers Service: Geoscientist
• Geological Society: applied geoscience demand
• BGA employer-survey article, Who wants to be a geophysicist?