of interplanetary scintillations from extragalactic radio sources ([@Cronyn72]) lead to an average value of $\Delta n/n$ of the order of $10^{-3}$ ([@Smith79]). Nevertheless, the low intensity density fluctuations lead to significant spatial redistribution of wave energy. The numerical results obtained demonstrate that electrons propagate as a continuous stream while the Langmuir waves generated by the electrons are clumpy. Both electrons and Langmuir waves propagate in a plasma as a BPS with an almost constant velocity. However, density fluctuations lead to some energy losses.

Electron beam and density fluctuations
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The problem of one-dimensional electron beam propagation is considered in a plasma with density fluctuations. The one-dimensional character of electron beam propagation is supported by the 3D numerical solution of the kinetic equations ([@Churaev80]) and additionally by the fact that in the case of type III bursts electrons propagate along open magnetic field lines ([@Dulk85]).

Electron beam
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There is still uncertainty in the literature as to whether electron beams are strong enough to produce strong turbulence or whether the beam is so rarified that quasilinear relaxation is suppressed by damping or scattering. While some observations are in favor of the strong turbulence regime ([@Thejappa98]) others are interpreted as implying marginal 