We study, via computer simulations, the fluctuations in the net electric charge in a two-dimensional, one component plasma (OCP) with uniform background charge density -ep in a region Λ inside a much larger overall neutral system. Setting e = 1, this is the same as the fluctuations in NΛ, the number of mobile particles of charge e. As expected, the distribution of NΛ has, for large Λ, a Gaussian form with a variance which grows only as κ̂ |∂Λ|, where |∂Λ| is the length of the perimeter of Λ. The properties of this system depend only on the coupling parameter Γ = kT, which is the same as the reciprocal temperature in our units. Our simulations show that when the coupling parameter Γ increases, κ̂(Γ) decreases to an asymptotic value κ̂(∞) ∼ κ̂(2)/2 which is equal (or very close) to that obtained for the corresponding variance of particles on a rigid triangular lattice. Thus, for large Γ, the characteristic length ξL, = 2κ̂/p associated with charge fluctuations behaves very differently from that of the Debye length, ξD ∼ 1/√Γ which it approaches as Γ→0. The pair correlation function of the OCP is also studied.
All Science Journal Classification (ASJC) codes
- Statistical and Nonlinear Physics
- Mathematical Physics
- Charge fluctuations
- One-component plasma
- Perimeter law
- Two dimensions