Solar wind

Interplanetary space is permanently swept by a wind of electrically charged particles from the Sun.

This wind is extremely light (10 particles per cubic centimetre), but very fast (400 to 800 km/s). It is a supersonic wind (moving faster than sound waves). The solar wind is mainly composed of electrons, protons and helium nuclei. The solar wind fluctuates greatly.

Shock waves travel through the solar wind. It emits radio waves.