Solar Wind
A continuous supersonic stream of fully ionized magnetoplasma (protons, electrons, alpha particles) expanding outward from the Sun's corona into interstellar space.
Governing formula
v_sw ≈ 300–800 km/s, n_e ≈ 5 cm⁻³ at 1 AU
SI unit
km/s (Velocity) & cm⁻³ (Density)
In depth
Driven by extreme coronal thermal pressure (~10⁶ K). The solar wind carries the interplanetary magnetic field (IMF) throughout the solar system, carving out the heliosphere and interacting with planetary magnetospheres.
Examples in the real world
Driving geomagnetic storms, shaping comet ion tails, and generating polar auroras on Earth and Jupiter.