Effects of ion motion on linear Landau damping

Abstract

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Analysis of Landau damping in radially inhomogeneous plasma column

“…The theory of nonlinear damping (growth) of Langmuir waves in collisionless inhomogeneous plasma was developed by Karpman et al [37] Several important studies have been carried out on the effect of the plasma parameters on Landau damping of plasma waveguides. [38][39][40] Xu et al [38] investigated the effects of ion motion on Landau damping aided by one-dimensional Vlasov-Poisson simulation. It was shown that the ion motion can significantly change the development of linear Landau damping.…”

Propagator integral method for plasma physics kinetic equations with practical applications

“…This can lead us to assume that ion dynamics could be neglected and only the electron evolution should be computed. However, it is important to remember that small changes of the ion particle density influence the resolution of the Poisson's equation, which modify the electron motion due to their low mass, specially in the analysis of long times [21,101]. So, if there are enough computational resources, it is advisable to advance both species, also with the same time step, to not perturb the problem and to obtain a more accurate electric field.…”

“…A similar rotational ion dynamics is expected, because the electric field also influence the evolution of this species. However, slow ion variation, as well as the fast motion of the electrons, can give rise situations where electric field changes its sign and ions have not reached a periodical behaviour, creating a non-circular dynamics for this heavy species, which may end up affecting the evolution of electrons due to the changes in the charge density [101]. This is better appreciated in figure 3.10, where the trajectory of the maximum point of f α is pictured.…”

“…These terms are usually neglected due to the short-distant interaction, but they become relevant in WIP due to the high density of neutrals acting as a viscous media [24,28]. Also, dynamics of the heavy species, as ions, is usually not accounted for, which may end up modifying the electron dynamics through the self-consistent electromagnetic field [101]. Many approaches have been proposed by different authors [69,71,120,123] and by us [25] to describe dynamics of the charged species in weakly ionized plasmas, but usually require simplifications or the dumping of some dynamics and terms that may become relevant.…”

“…Its study is of mayor importance, e.g., to the analysis of an electric thruster [100] and its evolution should be included in the models if the computational resources allow it. Furthermore, its dynamics affects the evolution of a plasma as a whole, specially the self-consistent electric field when a charge separation appears [101]. Figure 5.10 shows the behaviour of ions with constant and temperature dependent collision parameters.…”