From: Mathew Owens – m.owens@imperial.ac.uk

The Department of Meteorology at the University of Reading is pleased to invite applications for a 3-year NERC-funded PhD studentship in “Galactic cosmic rays, the Sun’s magnetic field and climate change”, supervised by Dr. Mathew Owens and Prof. Mike Lockwood.

The expected start date is October 2010. The departmental open day is March 10th, so anyone with a potential interest should e-mail Mathew Owens (m.owens@imperial.ac.uk) as soon as possible. Further details about funding and the application process can be found at http://www.met.reading.ac.uk/pg-research/pgropportunities.html

Galactic cosmic rays, the Sun’s magnetic field and climate change

Galactic cosmic rays (GCRs) are extremely high energy particles which originate far outside our solar system and travel at almost the speed of light. The effects of these particles, and of the cascade of secondary particles that they produce in Earth’s atmosphere, have a number of known and postulated effects on Earth’s atmosphere, surface and lifeforms. The GCR flux incident on Earth’s atmosphere can be measured using space- or ground-based monitors. Such observations have shown that the Sun’s magnetic field (in what is termed the heliosphere) partially shields the inner solar system from energetic particles, allowing GCRs to be used as proxies for the solar magnetic field strength – and hence the Sun’s brightness – when direct measurements are not available. Prehistoric GCR fluxes are inferred from isotopic depositions in reservoirs such as ice cores, ocean sediments and tree trunks and are used in reconstruction of solar irradiance thousands of years in the past, vital for quantifying the role of solar variability in terrestrial climate change on centennial and millennial timescales. However, the justification of the use of these proxies is somewhat superficial and detailed studies of the heliospheric structure, how it shields Earth from GCRs, and how it relates to the changes in the solar photosphere are required. The student will undertake analysis and modelling of spacecraft and ground-based data to relate GCR shielding to solar magnetic activity and heliospheric structures, with an eventual goal of improving reconstruction of Sun’s irradiance for use in climate modelling.