T. D. Kaladze

Planetary electromagnetic waves in the ionospheric E-layer

Abstract The linear theory for the large-scale (λ>10 3 km ) electromagnetic (EM) waves in the middle-latitude ionospheric E-layer is developed. The general dispersion relation for these waves is derived. It is shown that the latitudinal inhomogeneity of the geomagnetic field and the angular velocity of the Earths rotation can lead to the appearance of wave modes in the form of slow and fast EM planetary waves. The slow mode is produced by the dynamo electric field and it represents a generalization of the ordinary Rossby type waves in a rotating atmosphere when the Hall effect in the E-layer is included. The fast mode is a new mode, which is associated with the oscillations of the ionospheric electrons frozen in the geomagnetic field. It represents the variation of the vortical electric field and it arises solely due to the latitudinal gradient of the external magnetic field. The basic characteristics of the wave modes, such as the wavelength, the frequency and the Rayleigh friction, are estimated. Other types of waves, termed slow magnetohydrodynamic (MHD) waves, which are insensitive to the spatial inhomogeneity of the Coriolis and Ampere forces are also reviewed. It is shown that they appear as an admixture of slow Alfven (SA) and whistler type waves. Such waves can generate variations in the magnetic field from a few tenth to a few hundreds nT. It is stressed that the basic features of the considered waves agree with the general properties of the magnetic perturbations observed at the world network of magnetic and ionospheric stations.

Acoustic nonlinear periodic (cnoidal) waves and solitons in pair-ion plasmas

Electrostatic acoustic nonlinear periodic (cnoidal) waves and solitons are investigated in unmagnetized pair-ion plasmas consisting of the same mass ion species with different temperatures. It is found that the temperature difference between negatively and positively charged ions appropriates the dispersion property to linear acoustic waves and this difference has a decisive role in nonlinear dynamics as well. Using a reductive perturbation method and appropriate boundary conditions the Korteweg–de Vries equation is derived. Both cnoidal wave and soliton solutions are discussed in detail. In the special case, it is revealed that the amplitude of a soliton may become larger than what is allowed by the nonlinear stationary wave theory, which is equal to the quantum tunneling by a particle through a potential barrier effect. The serious flaw in the results obtained for ion acoustic nonlinear periodic waves by Yadav et al (1995 Phys. Rev. E 52 3045) in two-electron temperature plasmas and Chawla and Misra (2010 Phys. Plasmas 17 102315) in electron–positron–ion plasmas is also pointed out.

Electromagnetic inertio-gravity waves in the ionospheric E-layer

The effect of the Ampere force on inertio-gravity (IG) waves in the partially ionized ionospheric E-layer is considered. Electromagnetic IG waves are then studied. It is shown that the free energy necessary for linear instability of electromagnetic IG waves arises from the field-aligned current. Furthermore, it is found that atmospheric vortex motions can induce substantial variations in the geomagnetic field and field-aligned currents.

Rossby–Khantadze electromagnetic planetary vortical motions in the ionospheric E-layer

It is shown that in the earths conductive ionospheric E-region, large-scale ultra low-frequency Rossby and Khantadze electromagnetic waves can propagate. Along with the prevalent effect of Hall conductivity for these waves, the latitudinal inhomogeneity of both the earths angular velocity and the geomagnetic field becomes essential. Action of these effects leads to the coupled propagation of electromagnetic Rossby and Khantadze modes. Linear propagation properties of these waves are given in detail. It is shown that the waves lose the dispersing property for large values of wave numbers. Corresponding nonlinear solitary vortical structures are constructed. Conditions for such self-organization are given. It is shown that nonlinear large-scale vortices generate the stronger pulses of the geomagnetic field than the corresponding linear waves. Previous investigations are revised.

Shear flow driven Rossby-Khantadze electromagnetic planetary vortices in the ionospheric E-layer

A system of equations describing the nonlinear interaction of coupled Rossby-Khantadze electromagnetic waves with a sheared zonal flow in the Earths ionospheric E-layer is obtained. For the linear regime the corresponding region of phase velocities is analyzed and the appropriate stability condition of zonal flow is deduced. It is shown that the sheared zonal flow may excite solitary vortical structures in the form of a row of counter-rotating vortices whose amplitudes decrease with the increase of the zonal flow parameter. This conclusion is consistent with the stabilizing idea of a sheared zonal flow. The possibility of an intense magnetic-field generation is shown.

Generation of zonal flow and magnetic field in the ionospheric E-layer

We review the generation of zonal flow and magnetic field by coupled electromagnetic ultra-low-frequency waves in the Earth’s ionospheric E-layer. It is shown that, under typical ionospheric E-layer conditions, different planetary low-frequency waves can couple with each other. Propagation of coupled internal-gravity–Alfven, coupled Rossby–Khantadze and coupled Rossby–Alfven–Khantadze waves is revealed and studied. A set of appropriate equations describing the nonlinear interaction of such waves with sheared zonal flow is derived. The conclusion on the instability of short-wavelength turbulence of such coupled waves with respect to the excitation of low-frequency and large-scale perturbation of the sheared zonal flow and sheared magnetic field is deduced. The nonlinear mechanism of the instability is based on the parametric triple interaction of finite-amplitude coupled waves leading to the inverse energy cascade towards longer wavelength. The possibility of generation of an intense mean magnetic field is shown. Obtained growth rates are discussed for each case of the considered coupled waves.

Generation of zonal flow and magnetic field by coupled Rossby–Alfvén–Khantadze waves in the Earth's ionospheric E-layer

It is shown that in the Earths weakly ionized ionospheric E-layer with the dominant Hall conductivity, a new type of coupled Rossby–Alfven–Khantadze (CRAK) electromagnetic (EM) planetary waves, attributable by the latitudinal inhomogeneity of both the Earths Coriolis parameter and the geomagnetic field, can exist. Under such coupling, a new type of dispersive Alfven waves is revealed. The generation of a sheared zonal flow and a magnetic field by CRAK EM planetary waves is investigated. The nonlinear mechanism of the instability is based on the parametric excitation of a zonal flow by interacting four waves, leading to the inverse energy cascade in the direction of a longer wavelength. A three-dimensional (3D) set of coupled equations describing the nonlinear interaction of pumping CRAK waves and zonal flow is derived. The growth rate of the corresponding instability and the conditions for driving them are determined. It is found that the growth rate is mainly stipulated by Rossby waves but the generation of the intense mean magnetic field is caused by Alfven waves.

Fast magnetohydrodynamic cnoidal waves and solitons in electron-positron plasma

Linear and nonlinear propagation of fast magnetohydrodynamic waves (or magnetoacoustic waves) are studied in homogeneous, magnetized and warm collisionless electron-positron (e-p) plasma by using two fluid magnetohydrodynamic model. In the linear limit, the wave dispersion relation is obtained and wave dispersion effect which appears through inertial length in e-p plasma system is also discussed. Using reductive perturbation method, the Korteweg-de Vries (KdV) equation for small but finite wave amplitude of magnetoacoustic waves is derived with appropriate boundary conditions. The cnoidal wave and soliton solutions are obtained using well known Sagdeev potential approach for magnetoacoustic waves in e-p plasmas propagating in the direction perpendicular to the external magnetic field. The phase portrait analysis and numerical illustration of magnetoacoustic cnoidal waves and solitons is also presented by using the parameters such as magnetic field intensity, plasma density and temperature of electron and ...

Interaction of Alpha Particles with Irregular and Regular Structures of Thermonuclear Plasma

The interaction of alpha particles with low-frequency fast magnetosonic and Alfven waves in toroidal configuration is studied. The interaction of alpha particles with high-frequency one-dimensional magnetosonic solitons and low-frequency two-dimensional drift vortices in the approximation of the straight uniform magnetic field is examined. It is shown that as a result of these interactions the amplification of above structures of plasma takes place, which can lead to the complementary diffusion of plasma particles and losses of heat.