Speed of Sound in Plasma


The speed of sound is the distance travelled per unit of time by a sound wave propagating through an elastic medium.
The speed of sound in a plasma for the common case that the electrons are hotter than the ions (but not too much hotter) is given here.
In contrast to a gas, the pressure and the density are provided by separate species, the pressure by the electrons and the density by the ions. The two are coupled through a fluctuating electric field.

Related formulas


csspeed of sound in plasma (m/s)
γadiabatic index (dimensionless)
Zcharge state (dimensionless)
kBoltzmann constant
Teelectron temperature (K)
miion mass (kg)