Nonlinear Kinetic Fluid Equations

Fluid equations are derived that describe wave-particle resonances, which usually require kinetic theory. Unlike previous such efforts the closure is not linearized, and so retains many nonlinear wave-particle effects never before described by fluid equations. To demonstrate utility, we show that the new equations can retain trapping, time reversibility, and rectify a discrepancy between full kinetic theory and linear kinetic fluid closures.