SPARC: Space Weather

The term ''space weather'' refers to the conditions in space that are deterimined by the intensity of hard radiation, the magnitude of electric and magnetic fields, the level of electric currents, and other disturbances. Space ''storms'' often result from flare or coronal mass ejection events on the Sun, events which greatly intensify the solar wind. Within a few days such disturbances may have an impact on the near Earth environment.

Space weather conditions are extremely important for the behavior of satellites and space probes. Radiation damage from high-energy particles can destroy the solar panels, upset onboard computer systems, and even cause destructive sparking in space instruments. High-energy particles can heat the atmosphere, causing it to expand and bring about satellite braking and subsequent re-entry.

Space weather conditions may also affect systems at ground level. During geomagnetic storms that bring brilliant auroras to the polar regions, currents of millions of amps may flow in the upper atmosphere at heights around 100 km. These currents induce secondary electric fields and currents at ground level--in high-voltage power lines, for instance, where they may cause failure in line protection relays and damage to transformers resulting in power outages over large regions. Extended telephone lines and other signal lines may also be disturbed and damaged. Even steel pipe-lines carrying oil and gas from fields in the arctic regions to consumers south of the auroral zone are damaged by the corrosive effects of such Geomagnetically Induced Currents (GIC).

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