A new study has accurately estimated the physical parameters of thermal and magnetic field structures of solar coronal holes which have significant influence on space weather that affects satellites, as well as the Indian summer monsoon rainfall.
What are Coronal holes?
Coronal holes, which are dark regions in X-ray and extreme ultraviolet images of the Sun, have open magnetic field lines and are hence important for understanding the interplanetary medium and space weather.
Discovered in the 1970s by X-ray satellites, “coronal holes” in the sun’s atmosphere (corona) are dark in the X-ray and extreme ultraviolet (EUV) wavelengths, and are low-density regions that have open magnetic field structures in the interplanetary space.
These solar activity phenomena are intense sources of fast (450-800 km/sec) solar wind—streams of charged particles that escape from the sun, more easily into space.
They appear dark because they are cooler, less dense regions than the surrounding plasma and are regions of open, unipolar magnetic fields.
This open, magnetic field line structure allows the solar wind to escape more readily into space, resulting in streams of relatively fast solar wind and is often referred to as a high speed stream in the context of analysis of structures in interplanetary space.
At present, this high-speed solar wind can interact with the Earth’s magnetic field, causing disturbances like geomagnetic storms. Effects of sunspots on the Earth’s atmosphere and climate are well recorded.
(Source: PIB and NOAA)
