Noneigenmode instabilities

A new class of tokamak instabilities has been predicted which is associated with the pumping of nonpotential, especially Alfven modes. These instabilities can be excited both in a ''classical'' tokamak containing an almost Maxwellian plasma and, especially, information regarding the heating of plasmas using fast neutrals and the idea of a two-component tokamak. The effect of the increase in the wave number with time is discussed and the behavior of an initial perturbation in the form of the wave packet in a cold inhomogeneous plasma is examined. The role of hydrodynamic effects associated with the finite temperature of the bulk plasma component, such as drift and spreading of the packet, is examined. An analysis is presented of the simplests case of Langmuir oscillations excited by an electron beam. The instability of Alfven waves in a tokamak with a fast ion beam is examined and results are discussed