Aurorae
Definition
Aurorae are natural light displays in the Earth's sky, predominantly seen in high-latitude regions around the Arctic and Antarctic. They occur due to interactions between charged particles from the solar wind and the Earth's magnetic field.
5 Must Know Facts For Your Next Test
- Aurorae are caused by the collision of solar wind particles with atoms in the Earth's atmosphere, primarily oxygen and nitrogen.
- The Earth's magnetic field directs these charged particles towards the polar regions, resulting in auroral activity.
- Auroral colors are determined by the type of gas involved and its altitude; oxygen typically produces green or red lights, while nitrogen results in blue or purple hues.
- Aurorae are more frequent during periods of high solar activity, such as solar flares and coronal mass ejections.
- The motion of charged particles within a magnetic field is governed by Lorentz force, causing them to spiral along magnetic field lines.
Review Questions
- What causes the different colors observed in aurorae?
- How does Earth's magnetic field influence the occurrence of aurorae?
- Explain how Lorentz force relates to the motion of charged particles that create auroral displays.
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Related terms
Solar Wind: A stream of charged particles released from the upper atmosphere of the Sun, consisting mainly of electrons and protons.
Magnetic Field: A vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials.
Lorentz Force: $F = q(E + v \times B)$; The force exerted on a charged particle moving through an electric field $E$ and a magnetic field $B$.
