Plasma Parameter
A fundamental dimensionless number in plasma physics measuring the average number of electrons contained within a Debye sphere.
Governing formula
Λ = n_e λ_D³ ≫ 1
SI unit
Dimensionless Number of Particles in Debye Sphere
In depth
When Λ ≫ 1, long-range collective electrostatic interactions dominate over binary short-range particle collisions, defining an ideal, weakly coupled plasma where gas kinetic theory applies.
Examples in the real world
Classifying high-temperature low-density tokamak fusion plasmas (Λ ~ 10⁸) vs dense non-ideal cold plasmas.