Solar energy input from the Earth’s magnetosphere to its atmosphere

The interaction between the Sun’s and the Earth’s plasma environments is very dynamic and one of societal and commercial importance. A large proportion of the energy from this terawatt system is transferred from the outer magnetosphere inwards by MHD waves, which propagate along magnetic field lines and into the upper atmosphere (ionosphere), where the energy is dissipated (Fig. 1).

By undertaking this study, the student will be able to gauge the impact of geomagnetic activity on the Earth’s environment. “Space Weather” hazards are now part of the Government’s National Risk Register since geomagnetic storms are known to affect human activities on the ground and in space. Recently, it has also become apparent that nonlinear effects in the upper atmosphere may also influence tropospheric climate, including energetic particle precipitation (EPP, associated with MHD waves) effects on stratospheric ozone (e.g. Seppälä et al., 2009) and changes to the geoelectric circuit. This project will, therefore, align well with CENTA’s theme of Anthropogenic Impacts and Environmental Sustainability.

The Radio and Space Plasma Physics (RSPP) group at the University of Leicester have unique UK access to a number of important data sets including ground magnetometers (through SuperMag), ionospheric radars (including EISCAT and SuperDARN) and satellites (e.g. the Van Allen Probes, VAPs). This project will exploit these facilities to explore energy deposition in the upper atmosphere via MHD waves. MHD waves can be broadly categorised as being externally (solar wind) driven or excited through wave –particle interactions between the Earth’s magnetic field and drifting plasma in the van Allen belts. Externally-excited (large scale) waves are most readily detected by ground magnetometers (SuperMag) whereas particle-driven (smaller scale) waves are more easily observed within the ionosphere and magnetosphere. The electric field of MHD waves drive the ionosphere into motion, which is directly measurable by radars such as EISCAT and SuperDARN. The NASA VAPs will also observe waves in the magnetosphere and the NASA Wind spacecraft monitors the solar wind driver for context. The data collected will provide input to up-to-date models of MHD wave generation and solar forcing of the lower atmosphere.

Initially, utilising a newly developed analysis method (based on the Lomb-Scargle periodogram) the student will detect MHD waves in an extended (11+ year) data set provided by SuperMag. The observations will be exploited in conjunction with contemporaneous measurements from the EISCAT and SuperDARN radars to provide a detailed picture of the ionospheric conductivity, electrodynamics and EPP occurring during events identified.

In addition, examination of upstream solar wind (Wind) and geomagnetic conditions along with measurements within the magnetosphere (VAP) will provide a way of determining how the waves are generated. A database of events and their characteristics over a period of years will be derived. These will be compared with existing models of MHD waves and EPP effects on lower atmospheric climate.

The work will be undertaken in collaboration with Dr Jesper Gjerloev, PI of SuperMAG at the Johns Hopkins University, USA. New collaborations have also been established with Dr J Rae at UCL and Dr C Watt at the University of Reading, both experts in MHD waves, Dr Robert Fear, University of Southampton, possessing expertise in energetic particle precipitation and Prof David Jackson at the UK Met Office. As the PI institute of SuperDARN, Leicester also has access to all SuperDARN data and strong links with the PI institutes of the >30 constituent radars around the world.

Entry requirements
Applicants are required to hold/or expect to obtain a UK Bachelor Degree 2:1 or better in a relevant subject. The University of Leicester English language requirements apply where applicable.

How to apply
Please refer to the CENTA Studentship application information on our website for details of how to apply.

As part of the application process you will need to:
• Complete a CENTA Funding form – to be uploaded to your PhD application
• Complete and submit your PhD application online. Indicate project CENTA2-PHY7-WRIG in the funding section.
• Complete an online project selection form Apply for CENTA2-PHY7-WRIG