Collective plasma oscillations Elementary description Debye screening and Debye sphere Langmuir and ion-sound plasma oscillations Landau damping Random collective excitations and quasi-linear interactions Distribution function for plasma oscillations Correlation function for random fields Energy density of random motion Vavilov-Cherenkov emission and Landau damping Quasi-linear equation and relaxation of beams in a plasma Fluctuations and particle collisions Averaged distributions and fluctuations Fluctuations of independent and charged particles Landau-Balescu collision integral Conservation laws Probabilities for particle collisions in a plasma General theory of non-linear interactions Classification of interactions General theory of weak non-linear interactions Non-linear plasma responses Approximate expression for the non-linear responses for Langmuir and ion-sound waves Non-linear changes in the particle distributions Stimulated scattering of waves by particles A simple physical picture Description of the stimulated scattering processes of waves Conservation laws Scattering probabilities for Langmuir and ion-sound waves Transition scattering Change in the particle distribution due to stimulated wave scattering Plasma turbulence The general concept of turbulence Langmuir and ion-sound turbulences Anomalous plasma resistivity Non-linear stabilization of a beam-plasma instability Turbulent shock waves Non-linear decay interactions General concepts The balance equation and conservation laws Probability of the decay interactions Decay processes and the turbulent spectrum Scattering in a strongly turbulent plasma Non-linear modulational interactions Non-linear frequency shift and modulational interactions Kinetic and hydrodynamic linear instabilities General theory of modulational interactions Modulational instabilities Conservation Laws Solitons. Self-contracting cavitons   LITERATURE: V.N. Tsytovich. Lectures on non-linear plasma kinetics R.Z. Sagdeev, A.A. Galeev. Nonlinear plasma theory V.N. Tsytovich. Nonlinear effects in plasma V.N. Tsytovich. Theory of turbulent plasma A. Kaplan, V.N. Tsytovich. Plasma astrophysics