Motion and Spreading of Inhomogeneities in a Plasma

Gurevich, A. V.; Tsedilina, E. E.

doi:10.1070/pu1967v010n02abeh003240

Cited by 41 publications

(44 citation statements)

References 53 publications

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“…There obviously exist two different methods of finding stationary solutions of the VP system: the BGK method and the pseudo-(Sagdeev) potential method. 7,8 To decide, which one may be preferred, one has to remember in which space the physics takes place, which is in the present kinetic case the phase space. It is this space where the correct initial and boundary conditions have to be imposed to formulate the mathematical problem in a correct and definite way.…”

mentioning

confidence: 99%

Comment on “Undamped electrostatic plasma waves” [Phys. Plasmas 19, 092103 (2012)]

Schamel

2013

Physics of Plasmas

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The relevance of linear “corner modes” for the description of coherent electrostatic structures, as proposed by Valentini et al. [Phys. Plasmas 19, 092103 (2012)], is questioned. Coherency in their on-dispersion simulation is instead found to be caused by particle trapping in agreement with Schamel's nonlinear wave model [Phys. Plasmas 19, 020501 (2012)]. The revealed small amplitude structures are hence of cnoidal electron hole type exhibiting vortices in phase space. They are ruled by trapping nonlinearity rather than by linearity or quasi-linear effects, as commonly assumed. Arguments are presented, which give preference to these cnoidal hole modes over Bernstein-Greene-Kruskal modes. To fully account for a realistic theoretical scenario, however, at least four ingredients are mandatory. Several corrections of the conventional body of thought about the proper kinetic wave description are proposed. They may prove useful for the general acceptance of this “new” nonlinear wave concept concerning structure formation, updating several prevailing concepts such as the general validity of a linear wave Ansatz for small amplitudes, as assumed in their paper. It is conjectured that this nonlinear trapping model can be generalized to the vortex structures of similar type found in the more general setting of driven turbulence of magnetized plasmas. They appear as eddies in both, the phase and the position spaces, embedded intermittently on the Debye length scale.

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mentioning

confidence: 99%

Comment on “Undamped electrostatic plasma waves” [Phys. Plasmas 19, 092103 (2012)]

Schamel

2013

Physics of Plasmas

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“…These problems have been considered in sufficient detail theoretically [9,10] and confirmed experimentally [11,12] by plasma decay in metal chambers (in which eddy currents are closed in chamber walls), and also in experiments on expansion of barium plasma clouds in the ionosphere [13,14].…”

Section: Specific Features Of the Diffusion And Thermal Diffusion In mentioning

confidence: 99%

“…To date, very important theoretical results have been obtained for building a general picture of the diffusion and thermal-diffusion density redistribution in the presence of an arbitrary pressure gradient in a plasma [9,10]. Consider briefly the main features of plasma diffusion and thermal diffusion in a magnetic field.…”

Section: Specific Features Of the Diffusion And Thermal Diffusion In mentioning

confidence: 99%

Laboratory modeling of physical processes in the ionosphere modified by powerful radio emission

Костров

Назаров

Starodubtsev

2007

Radiophys Quantum El

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UDC 533.9We present the results of the laboratory modeling of physical processes occurring in the ionosphere during active experiments on the ionospheric modificaton by powerful radio emission. The process of nonuniform thermo-diffusion of a magnetoplasma due to local electron heating is studied under the conditions modeling the ionospheric F layer. It is revealed by direct measurements that thermo-diffusion and diffusion are accompanied by excitation of macroscopic eddy currents. In this case, electrons and ions diffuse along and across the magnetic field, respectively, and the eddy current is carried by particles of the background plasma. As a result, a magnetic-field-aligned density depletion rapidly forms in the plasma. The possibility of trapping and guided propagation of Langmuir waves in such a plasma inhomogeneity is demonstrated. Conditions are found under which the wave trapping and the formation of the inhomogeneity occur in a self-consistent regime, i.e., Langmuir waves are trapped in a small-scale inhomogeneity which, in turn, is formed due to local plasma heating by the field of the trapped waves. Such nonlinear wave trapping takes place only above a certain threshold, which significantly increases in the vicinity of gyroharmonics.

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“…The values of D a and 6 e for different particle interaction modes, ionization degrees and magnetic field intensities are given in a large number of review articles and monographs (see, for example, Refs. 5,20,21). In the case of rough calculations, so-called elementary theory 2 2 ' 2 3 is frequently used, whereby the v a (v) averaged over the Maxwellian distribution are used in Eq.…”

Section: Initial Equations Unipolar Diffusionmentioning

confidence: 99%

Collisional diffusion of a partially-ionized plasma in a magnetic field

Zhilinskii¹,

Tsendin²

1980

Sov. Phys. Usp.

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The principal mechanisms of classical diffusion (due to binary collisions) of a partially-ionized plasma in a homogeneous magnetic field are examined. As a result of anisotropy of the transport coefficients of charged particles the problem proves to be far more complicated than the well-known problem of ambipolar diffusion in the absence of a magnetic field. The evolution of diffusion in this case is determined primarily by eddy currents flowing in the plasma. The circuit for these currents can be completed both through the background plasma giving rise to depletion regions, and by the conducting walls of the container of the plasma (the shortcircuit effect). Ambipolar diffusion which occurs when the electron and ion fluxes are equal at every point can be realized only in exceptional cases. Experiments are described in which the short-circuit effect and ambipolar diffusion were observed. Using different boundary conditions it was possible to vary the diffusion rate of the plasma by two or three orders of magnitude, and this presents the possibility of controlling the local parameters of the plasma. This review has taken into account references up to July, 1979.

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Motion and Spreading of Inhomogeneities in a Plasma

Cited by 41 publications

References 53 publications

Comment on “Undamped electrostatic plasma waves” [Phys. Plasmas 19, 092103 (2012)]

Comment on “Undamped electrostatic plasma waves” [Phys. Plasmas 19, 092103 (2012)]

Laboratory modeling of physical processes in the ionosphere modified by powerful radio emission

Collisional diffusion of a partially-ionized plasma in a magnetic field

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