Envelope nonlinear drift structures in a non-equilibrium plasma near the boundary of marginal stability

Abstract

An explosive instability of the ion-temperature-gradient (ITG)-driven modes (ηi modes) near the boundary of marginal stability is considered as a driving mechanism for subcritical turbulence. It is shown that boundedness of the wave interaction region leads to saturation of the instability. The possibility of coherent soliton-like structure formation in both slab and toroidal geometries is demonstrated by numerical simulation. An analytical soliton solution is found in some special cases.

Heat flux effect in ηi-mode driven solitary and shock waves in electron-positron-ion plasma

“…The obtained linear and nonlinear dispersion relations are solved numerically for the purpose to show the visible effects of new terms on the considered mode. For qualitative behavior of the numerical analysis we use the data given in (Qamar et al, 2003;Davydova & Pankin 1998;Zakir et al, 2016), some of these are: m i = 1.67 × 10 −24 g, n e = 10 14 cm −3 , B = 1.4 × 10 4 G, T eo = 10 5 eV , T io = 0.1T eo , n po = 0.001n eo , T P o = 0.1T eo , η i = 2, c s = 10 6 cm/s, ion gyrofrequency ω ci = 10 4 rad/s, in new coordinates u = 10 6 cm/s and α = 0.1rad. Based on various derived relations of our study we here discuss the linear and the nonlinear outcomes of our work.…”

Kinetic ion gradient instability: bifurcation properties of a simple, kinetic ηi-unstable slab model

“…Although radial structures of the ballooning modes can be obtained (Romanelli and Zonca 1993;Taylor et al 1996;Davydova and Pankin 1998), the treatment of radially inhomogeneous profiles has been tackled in the ballooning approximation only recently, by Waltz et al (1998). Numerical simulations that treat non-local profiles have been performed with fluid equations in slab geometry by Guzdar et al (1991).…”