Incorporating Statistical Analysis of the Extensive SAMPEX Dataset to Improve Space Weather Modelling

Lead Research Organisation: University College London
Department Name: Mullard Space Science Laboratory


STFC: Samuel D. Walton: 2062533

Near-Earth space holds two major surprises that scientists are yet to understand, one of which is the Van Allen Radiation Belts. As an astrophysical object, the Earth's magnetosphere would seem to be a rather small and insignificant item bathed by the wind that emanates from the Sun. However, this space contains an exotic zoo of high energy particles and electromagnetic waves that pose a significant hazard to space exploration. In the solar wind, the Earth's magnetic field is altered such that its bar magnet field becomes a bullet-shaped cavity that shields the Earth from the harmful output from the Sun. Only in specific circumstances can the solar wind penetrate this shield, and it is under these circumstances that the Earth's space environment becomes the most interesting and dynamic.

The Earth's Radiation Belts were discovered by James Van Allen some 50 years ago quite by chance. These belts are doughnut-shaped regions of high-energy particle radiation trapped by Earth's magnetic field. These electrons are energised to significant fractions of the speed of light but as yet, scientists can offer no definitive explanation for how they are accelerated to such high energies. Since the discovery of the radiation belts, scientists have linked the acceleration and resultant loss of these electrons to the impact of large geomagnetic storms caused by explosive output from the Sun (such as Coronal Mass Ejections) on near-Earth space. However, no conclusive evidence has been put forward which can adequately explain this link. Understanding how these electrons are accelerated to very high energies (and then lost) is of critical importance to the exploitation of near-Earth space for human and technological gain. Most communication and military satellites must orbit through this harsh radiation environment. In fact, several satellite failures have been attributed to component failure during geomagnetic storms. It is essential, therefore, to monitor this "space weather" in order to protect the multi-billion pound space industry.

This placement will be taken by Samuel Walton under the guidance of Professor Ian Mann, and will focus on the energetic electron dynamics in the Van Allen Radiation Belts from a long-lasting NASA spacecraft mission and, coupled with another NASA mission, be able to understand the dynamics of the radiation belts from the relative safety of low-earth orbit using novel techniques developed at the University of Alberta.

The proposed project is therefore the natural culmination of methods and ideas developed separately in the UK and Canada, to advance our understanding of Van Allen radiation belt dynamics, improving current models and ultimately improving our ability to predict the behaviour.


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