Debye Length
The characteristic spatial scale over which mobile charge carriers in a plasma screen out localized electrostatic potentials.
Governing formula
λ_D = √(ε₀ k_B T_e / (n_e e²))
SI unit
m (Meters)
In depth
In a plasma, mobile electrons redistribute themselves rapidly around excess charges to shield internal electric fields. Beyond a radial distance equal to the Debye length λ_D, electrostatic potentials decay exponentially, maintaining bulk quasineutrality.
Examples in the real world
Determining boundary sheath thickness near tokamak wall probes or calculating charge screening in astrophysical plasmas.