Big Questions for Cluster-II
Cluster is a European Space Agency program with major NASA involvement. The 4 Cluster spacecraft are providing a detailed three-dimensional map of the magnetosphere, with surprising results. This mission is part of SMD's Heliophysics Research program.
- What are the fundamental physical processes of the space environment?
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The sun, interplanetary space, planetary magnetospheres, and most of the rest of the universe are made up of plasma, which is an electrically-charged gas. Because they are plasma, electro-magnetic forces are extremely important. There is a tight coupling between the matter (in the form of sub-atomic particles) and the electric and magnetic fields. Motion of plasma in the sun generates the solar magnetic field, and the magnetic stresses built up are what cause the sun to vary. Magnetic reconnection, a rapid reconfiguration of the magnetic field, can accelerate matter up to very high energies and make hazardous radiation. Other more gradual processes can also accelerate particles up to hazardous energies. Understand the intricate interplay between matter and electro-magnetism in the space environment is what requires a system-level study that we call Heliophysics.
- How does solar variability affect human society, technological systems and the habitability of planets?
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Geomagnetic storms (magnetic storms on Earth due to solar activity) produce the awe-inspiring Aurora borealis and Aurora australis -- the Northern and Southern lights. However, they can also cause a variety of highly undesirable consequences. Electrical current surges in power lines, interference in the broadcast of radio, television, and telephone signals, and problems with defense communications are all associated with magnetic storms.