What is the constant stream of charged particles from the Sun called?

The constant stream of charged particles from the Sun is called the solar wind. It is a flow of mostly electrons and protons, along with some heavier ions, released from the Sun’s hot outer atmosphere, the corona.

The solar wind does not blow like air in an Earthly atmosphere. The corona is so hot that its particles can escape the Sun’s gravity and expand outward through interplanetary space. Near Earth, the wind commonly travels at several hundred kilometres per second, carrying the Sun’s magnetic field with it and forming much of the heliosphere.

The wind has two broad speed regimes. Fast solar wind often emerges from coronal holes, while slower wind is associated with more complex magnetic regions. Its intensity can change during solar storms, especially when a coronal mass ejection sends a much larger cloud of magnetised plasma toward Earth.

The solar wind is different from a solar flare, which is a sudden burst of electromagnetic radiation. It is also different from a prominence, which is an enormous loop of relatively cool plasma held above the solar surface. A coronal mass ejection can include solar-wind-like plasma, but it is a discrete eruption rather than the Sun’s continuous background outflow.