Bernstein–Greene–Kruskal modes
Type of nonlinear electrostatic waves / From Wikipedia, the free encyclopedia
Bernstein–Greene–Kruskal modes (a.k.a. BGK modes) are nonlinear electrostatic waves that propagate in a collisionless plasma. They are nonlinear solutions to the Vlasov-Poisson system of equations in plasma physics,[1] and are named after physicists Ira B. Bernstein, John M. Greene, and Martin D. Kruskal, who solved and published the exact solution for the one-dimensional unmagnetized case in 1957.[2]
BGK modes have been studied extensively in numerical simulations for two- and three-dimensional cases,[1][3][4][5] and are believed to be produced by the two-stream instability.[6][7] They have been observed as electron phase space holes (electrostatic solitary structures). [8][9][10][11] and double layers[12] in space plasmas, as well as in scattering experiments in the laboratory.[13]