ABSTRACT
This chapter elucidates some of the fundamental issues in the treatment of plasma turbulence. It explores Fourier expansion of physical quantities with the periodic boundary conditiom appropriate to a cube of a unit volume, unless specified otherwise. The chapter considers a theory of magnetohydrodynamic turbulence appropriate to a plasma in a disk geometry. A quantity of primary interest in the description of plasma turbulence is the energy spectrum Ek contained in the wave vector k mode of the fluctuations. The wave-kinetic equations are concerned with evolution of the energy spectrum Ek of the fluctuations associated with a collective mode in the plasma. The quasilinear theory of plasma oscillations has marked an important step toward solution of the problems associated with a weakly turbulent plasma. The derivation of the spectrum is based on a weak turbulence theory.
