What is Solar Activity?

Solar activity is caused by a helical dynamo in the sun's core and a chaotic dynamo near the surface that generate the sun's magnetic field.
The main solar phenomena associated with HF radio propagation on Earth are:

1. Sunspots (last from a few days to a few months); the number of spots varies in 11-year solar cycle (a deterministic chaos)
2. Flares (last from tens of seconds to several hours)
3. solar wind propels energetic particles.
4. CME - Coronal mass ejections

Overall, solar activity is an important field of study for scientists and has significant implications for a range of technologies and systems that rely on reliable communication and power distribution. Solar monitoring and prediction is therefore an important area of research, and various instruments and satellites are used to monitor solar activity and provide early warning of potential disruptions to the Earth's environment.