Understanding Solar Coronal Holes: Key Features and Their Role in Space Weather
Understanding Solar Coronal Holes: Key Features and Their Role in Space Weather What Are Solar Coronal Holes? Dark areas seen in extreme ultraviolet (EUV) and soft x-ray images of the Sun. Appear darker because they are cooler and less dense than the surrounding solar plasma. Key Features of Solar Coronal Holes: Open Magnetic Fields: Coronal holes have unipolar magnetic fields that extend into space. Unlike closed magnetic loops seen elsewhere on the Sun, these open fields allow solar particles to escape. High-Speed Solar Wind: The open magnetic structure enables high-speed solar wind streams to flow outward into the solar system. These winds are a significant source of charged particles in space. Location and Timing: Coronal holes can form at any time and anywhere on the Sun’s surface. Most commonly observed near the Sun’s poles but can appear at mid-latitudes or near the equator. Their size and frequency change with the Sun’s 11-year solar cycle. Impact on Earth: High-speed sola...