Coronal hole

Definition

Coronal holes are regions on the Sun's corona that appear darker and have lower temperatures and densities than surrounding areas. These areas are associated with open magnetic field lines, allowing solar wind to escape more easily.

5 Must Know Facts For Your Next Test

1. Coronal holes are sources of high-speed solar wind streams that can affect space weather near Earth.
2. They appear darker in ultraviolet and X-ray images due to their lower temperature and density.
3. The frequency and size of coronal holes vary with the Sun’s 11-year solar cycle.
4. Solar wind from coronal holes can interact with Earth's magnetosphere, causing geomagnetic storms.
5. Coronal holes predominantly occur at the Sun's polar regions during periods of low solar activity but can appear at any latitude during higher activity phases.

Review Questions

Related terms

Solar Wind:

A stream of charged particles released from the upper atmosphere of the Sun, consisting mostly of electrons, protons, and alpha particles.

Magnetosphere:

The region around Earth dominated by its magnetic field, which protects the planet from solar wind and cosmic radiation.

Geomagnetic Storm: A temporary disturbance of Earth's magnetosphere caused by a surge in solar wind or coronal mass ejection.