Abstract

Quasilinear theory and methods have been invoked frequently during the ADI Program. Quasilinear theory, including its foundations, validity, applications andevolution, have been studied intensively in plasma physics since the pioneeringcontributions of Sagdeev et al. in the early 1960s. This body of work merits somediscussion. Here, we present a critical analysis of quasilinear theory, primarily in thecontext of the Vlasov-Poisson system. This system describes the Hamilton evolution ofthe (phase space) distribution function in a 2D phase space, and thus is structurallysimilar to the oft-discussed system which describes potential vorticity evolution on abeta plane.This talk will address the foundations and validity of quasilinear theory and willdiscuss some of the challenges to it. Special attention is focused on the effects of modecoupling — or equivalently, phase space density granulations, akin to “eddys”. Theimplications of the traveling wave tube experiment of Tsunoda et al. are discussed indetail. We also take a look at more recent work on related energetic particle phenomenaand (magnetically) trapped particle-driven drift wave turbulence.If this talk is successful, all parties with a vested interest in the matter ofquasilinear theory (either for or against) should depart at least somewhat unhappy.