Reading solar system science

The projects within this proposal advance our common research area of effects and nature of energetic particles within the sun's atmosphere, the earth's magnetosphere and the heliosphere. Modulation of energetic particles from both the sun and galactic sources determines their abundance and energies in the Sun-earth environment, which, together with wave-particle interaction within the radiation belts establishes the longevity of such particles within the radiation belts. Exposure to energetic particles is an important parameter in the reliability of spacecraft instrument systems. Characterising changes in the Heliospheric Magnetic Field associated with short and rapid variations in the solar wind, such as Coronal Mass Ejections and Co-rotating Interaction Regions, are important in determining the effectiveness with which these large Space Weather disturbance impact the Earth's space environment.

The common theme throughout this proposal is an improved understanding of how energetic particles interact with magnetic fields. Solar and geomagnetic fields vary over centennial, decadal, diurnal and hourly timescales. This leads to modulation of energetic particles (of both solar and galactic origins) over similar timescales with implications for long-term changes in the flux, acceleration and energy spectrum of particles in the heliosphere. The space environment and atmosphere at Earth are sensitive to the efficiency of these processes, as are modern technological systems such as spacecraft, aircraft and ground-based power grids. Our research will improve the ability to predict the environmental and economic impact of such events.

Direct beneficiaries of our research will include;
- Commercial airlines requiring information about the radiation environment and reliability of HF communications for high-altitude long-haul aircraft. The atmospheric profile of a particle population is determined by its energy spectrum, which affects the radiation environment of aircraft.

- Meteorologists studying phenomena that are sensitive to the presence of charge in the atmosphere such as cloud charging, lightning, pollution and the monitoring of global weather systems via the Global Electric Circuit.

- Satellite operators requiring enhanced information about the potential impact of changes to the Earth's space environment both in terms of the immediate impact of coronal mass ejections but also through an improved understanding of the Earth's radiation belts. Understanding wave-particle interaction in the radiation belts is desirable for improved prediction of particle acceleration, loss to the Earth's atmosphere and the timescales such particles would be retained within the radiation belts. The passage of spacecraft through the Earth's radiation environment can decrease the lifetime and reliability of spacecraft. The expansion of the thermosphere is a function of the energy spectrum of precipitating particles. Thermospheric expansion is important in predicting atmospheric drag on low-altitude satellites.

- Space weather forecasting services such as the UK Met Office who could use information about heliospheric magnetic field structures to assess the geoeffectiveness of solar wind transients thereby improving the accuracy and lead-time of their forecasts. Using STEREO data to locate such structures, while studying their modulation of GCRs will enable us to remotely sense the magnitude of a CMEs enhanced field.

- The UK government who list extreme space weather events in the national risk register. Investigating the efficiency with which solar wind transients propagate through the heliosphere under the wide variety of solar wind conditions constructed from historic data will constrain the current uncertainty in extreme space weather events at Earth.

The general public will benefit indirectly through improved airline efficiency, more reliable power systems and spacecraft operations such as GPS navigation systems, communications and remote sensing of the Earth.

Our group works closely with the UK Met Office, already contributing to their current operational space weather service. We are experienced at promoting our science, both to specialist audiences (through peer-reviewed articles and international scientific conferences) and to more general audiences (through public talks, TV, radio and magazine articles). We will continue to apply ourselves to such tasks in order to maximise the impact of our science.