Planetary Radiation Belt Physics

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Within the magnetic fields of planets that extend into space are regions of trapped energetic particles that are hazardous to spacecraft and humans. The way these radiation belts vary in intensity is a major focus of scientific endeavour in space science. Understanding the principles of how these dangerous regions in space behave is very important in predicting the level of hazard they pose to spacecraft.At Earth there have been two major advances in radiation belt science: first, that intense electromagnetic waves can increase the energy of electrons to extremely high, relativistic energies via a process called cyclotron resonant wave-particle interactions, and second, that electron transport and acceleration are substantially increased by ultra low frequency (ULF) waves. These two results have transformed generally accepted ideas on the Earth's radiation belts that have lasted 40 years or more, and have spurred new satellite missions such as NASA's Van Allen Probes mission to test these ideas. Intense electromagnetic waves are also observed inside the magnetic fields of Jupiter and Saturn which suggests that the same resonant acceleration, transport and loss processes could be important for all planetary radiation belts. The goal of this proposal is to test the hypothesis that cyclotron resonant wave-particle interactions are major electron acceleration and loss processes at Jupiter and Saturn, and play a major role in the formation of radiation belts at these planets. The results will help determine whether resonant wave acceleration and loss of electrons is a universal process that is more widely applicable to the Sun and stars, as wells the newly discovered planets outside our Solar System. It will help set new research goals for future spacecraft missions to the planets, provide research training for young scientists, develop computer models that will be of use to the space industry in planning future missions to the outer planets, and leave a legacy of understanding that will last long after the completion of the project.