Nonlinear excitation of zonal flows and streamers in plasmas

Abstract

Nonlinear excitation of zonal flows and streamers in plasmas is considered. The emphasis is given to the nonlinear interaction of low- and high-frequency drift waves which can result in the excitation of zonal flows and streamers in a plasma of fusion devices. For this purpose, an inhomogeneous nonisothermal plasma in a strong external magnetic field whose characteristic frequencies are lower than the ion Langmuir frequency but higher than the collision frequency is studied. The excitation of a long-wavelength low-frequency drift wave during the development of the nonlinear modulational interaction of a high-frequency drift pump wave is investigated. The growth rates of the modulational instability are obtained, and the conditions for its development are determined. Self-organized structures described by solutions of evolutionary equations for the modulational interaction are associated with zonal flows and streamers. A possible relation of the modulational interaction in Earth’s ionospheric plasma to the formation of dust flows and transport of dust particles in the ionosphere is also discussed. It is shown that one of the ways of transport of dust particles in the ionosphere is vertical flows (streamers), which are generated by dust vortices as a result of development of the modulational instability.

The DNA of Bacteria of the World Ocean and the Earth in Cosmic Dust at the International Space Station

“…The result of this transfer is a steady presence of a microbial community in the stratosphere ( Table 2 , line 2), thus raising the question of the upper boundary of the biosphere [ 13 , 20 , 21 ]. Transfer from the stratosphere to the ionosphere might be possible with the ascending branch of the global electrical circuit [ 23 , 24 ] due to a variety of coupled mechanisms of turbulent electrothermodiffusion accompanied by mass transfer of dispersible material although these processes need further exploration [ 25 , 26 ]. It is clear that there are different possible ways of dust transport to (and from) ISS not excluding the possibility of interstellar or interplanetary panspermia [ 3 – 5 , 37 ] ( Figure 5 ).…”

“…We might conjecture that viable forms or at least intact DNA can be transferred to the ISS orbit with the ascending branch of the global electric circuit (GEC) [ 22 ], which is discussed in the works of Williams and Rycroft [ 23 , 24 ]. A possible mechanism for the transfer of dispersed particles from the stratosphere to the ionosphere has been recently proposed [ 25 , 26 ], but this idea has not been worked out in detail yet. In this paper samples of space dust from the exterior surface of the ISS were subjected to PCR analysis followed by sequencing of the PCR products.…”

Frequency-Resolved Nonlinear Turbulent Energy Transfer into Zonal Flows in Strongly HeatedL-Mode Plasmas in the HL-2A Tokamak

“…Furthermore we then use these approaches to make the first systematic study of the evolution of the nonlinear coupling of turbulence to ZFs and GAMs as the L-H transition is approached. The results show that turbulent fluctuations drive both ZFs and GAMs through nonlinear interactions; i.e., these large-scale shear flows are amplified by the transfer of kinetic energy and momentum out of the ambient drift wave spectrum [1,27,28]. The ZFs and GAMs compete with each other for the transfer of turbulent energy, and the transfer of turbulent energy into ZFs begins to dominate as the plasma auxiliary heating begins to dominate the total heat input to the plasma.…”

Confirmation of Microbial Ingress from Space

“…On the other hand, there are articles which claim to show that the transfer of small particles from the troposphere into the lower stratosphere can be accomplished by slowly rotating synoptic vortices that are constantly present in the atmosphere and can reach stratospheric heights (Besedinaa et al, 2009). It has been argued that one of the means of transport of dust particles in the ionosphere is via vertical flows (streamers) which are generated as a result of the development of the modulational instability in the ionospheric plasma (Benkadda et al, 2011). Layers of dust particles in the ionosphere about a kilometer thick, formed at altitudes less than 120 km, are posited to spread in the field of vortical structures.…”

“…Layers of dust particles in the ionosphere about a kilometer thick, formed at altitudes less than 120 km, are posited to spread in the field of vortical structures. As a result, dust vortices may appear at an altitude of 110-120 km, and it becomes possible to transport particles to altitudes of 130 km and perhaps even higher (Popel et al, 2010(Popel et al, , 2011Benkadda et al, 2011). Because the implications of the discovery of an extraterrestrial input of microbiota for evolutionary biology as well as for epidemiology are so profound and far-reaching, it is most desirable that this mechanism of transport must be demonstrated -both theoretically and experimentally -to be effective or not, as the case may be.…”