bare Coulomb acceleration of a particle by another one is modified by a contribution mediated by all other particles, a signature of Debye shielding (see section 8 of ). When starting from random particle positions, the typical time-scale for shielding to set in is the time for a thermal particle to cross a Debye length, i.e. the inverse of the plasma frequency. Therefore in a weakly collisional plasma, collisions play an essential role by bringing a cooperative self-organization process: Debye shielding. This shielding is important to get a finite diffusion coefficient in the calculation of Coulomb scattering (Coulomb collision). In a non-isothermic plasma, the temperatures for electrons and heavy species may differ while the background medium may be treated as the vacuum and the Debye length is where λD is the Debye length, ε0 is the permittivity of free space, kB is the Boltzmann constant, qe is the charge of an electron, Te and Ti are the temperatures of the electrons and ions, respectively, ne is the density of electrons, nj is the density of atomic species j, with positive ionic charge zjqe Even in quasineutral cold plasma, where ion contribution virtually seems to be larger due to lower ion temperature, the ion term is actually often dropped, giving although this is only valid when the mobility of ions is negligible compared to the process's timescale. Typical values In space plasmas where the electron density is relatively low, the Debye length may reach macroscopic values, such as in the magnetosphere, solar wind, interstellar medium and intergalactic medium. See the table here below: In an electrolyte solution In an electrolyte or a colloidal suspension, the Debye length for a monovalent electrolyte is usually denoted with symbol κ−1 where I is the ionic strength of the electrolyte in number/m3 units, ε0 is the permittivity of free space, εr is the dielectric constant, kB is the Boltzmann constant, T is the absolute temperature in kelvins, is the elementary charge, or, for a symmetric monovalent electrolyte, where R is the gas constant, F is the Faraday constant, C0 is the electrolyte concentration in molar units (M or mol/L). Alternatively, where is the Bjerrum length of the medium in nm, and the factor derives from transforming unit volume from cubic dm to cubic nm. For deionized water at room temperature, at pH=7, λB ≈ 1μm. At room temperature (), one can consider in water the