A. Kotsarenko

State of the inner heliosphere as given by the G index of interplanetary scintillation and the Dst index of geomagnetic activity

[1]xa0In the study of the impact of solar activity on the terrestrial magnetosphere, the interplanetary medium plays a major role. The purpose of this work is to analyze a global index of interplanetary scintillation, G, obtained from the g maps of Cambridge Observatory, UK, in relation to the geomagnetic index Dst, to determine the possible impact of both large-scale events and small magnetic irregularities on the magnetosphere of our planet. The analysis consists of the comparison of the two time series G and Dst for the period 1991–1994. It is found that in 94% of the cases when the Dst index falls to less than −70 nT, the G index presents a positive anomaly. Furthermore, the cross correlation shows that there is a marked anticorrelation with a lag of 2 days. A superposed epoch analysis is also performed for −10 to 10 days around the occurrence of 16 of the events in the period showing a peak at day zero of 2.93 sigmas that start 2 days before. No peak was found when the analysis was performed on 16 randomly chosen dates in the period. The results indicate that the state of the inner heliosphere as given by the G index may be important in the study of the solar wind related magnetospheric activity.

Collapse of nonlinear surface dust sound waves in the dusty plasma–dielectric system

The nonlinear monopulses of surface dust sound waves in the dusty plasma–dielectric system are investigated. The dusty plasma includes positive ions as the light component and negative dust as the heavy one. The set of hydrodynamic equations for dust in addition to the Poisson equation is used. The Boltzmann distribution is used for the ions. Electric and hydrodynamic boundary conditions are applied to the smooth interface. When moderate nonlinearity manifests itself near the interface, variations of dust concentration reach extremely high values, and collapse of the surface dust sound waves occurs. Estimations have demonstrated that the above-mentioned phenomena can be observed in natural dusty plasmas such as under volcano eruptions.

Novel ST-MUSIC-based spectral analysis for detection of ULF geomagnetic signals anomalies associated with seismic events in Mexico

Recently, the analysis of ultra-low-frequency (ULF) geomagnetic signals in order to detect seismic anomalies has been reported in several works. Yet, they, although having promising results, present problems for their detection since these anomalies are generally too much weak and embedded in high noise levels. In this work, a short-time multiple signal classification (ST-MUSIC), which is a technique with high-frequency resolution and noise immunity, is proposed for the detection of seismic anomalies in the ULF geomagnetic signals. Besides, the energy (E) of geomagnetic signals processed by ST-MUSIC is also presented as a complementary parameter to measure the fluctuations between seismic activity and seismic calm period. The usefulness and effectiveness of the proposal are demonstrated through the analysis of a synthetic signal and five real signals with earthquakes. The analysed ULF geomagnetic signals have been obtained using a tri-axial fluxgate magnetometer at the Juriquilla station, which is localized in Queretaro, Mexico (geographic coordinates: longitude 100.45° E and latitude 20.70° N). The results obtained show the detection of seismic perturbations before, during, and after the main shock, making the proposal a suitable tool for detecting seismic precursors.

Interaction of linear and nonlinear ion-sound waves with inclusions of dusty plasma

Diverse phenomena exist in the ionosphere caused by the presence of dusty plasma objects. These have a bearing on problems of space communication and possibly on the Earths weather, among others. Therefore, it is very important to study them so that many questions on the subject can be answered. In this paper, the interaction of plasma waves with these objects is studied and some instrumentation to measure such interactions is proposed. In particular, the interaction of ion-sound waves (ISW) by non-soliton and soliton pulses propagating in dusty plasma is investigated. It is shown that inclusions of dusty components of the ionosphere plasma behave as resonators for non-soliton pulses, so that ISW are excited. Korteveg?de Vries (KdV) solitons practically do not resonate with the inclusions of dusty plasma. Instead, the presence of dusty plasma inclusions can lead to the presence of transverse instabilities and the eventual destruction of the KdV solitons.

Simulation of Waves Processes in Dusty Emission of Volcano

A general method of simulation of processes in dusty based on special programs is presented here. It is pos-sible to prepare the modeling of the dusty in volcano like the dust sound waveguides. Dusty is in state of the plasma .Waveguides are formed by the distribution of dusty particles with various masses m = m(x) in trans-verse coordinate. The dust sound waves propagate along the longitudinal z-direction. In the case of contact of dusty plasma with a semi-infinite dielectric, there exists the dust acoustic mode that possesses the negative group velocity (backward wave) in the specified interval of wave numbers. For analysis it is necessary to use the special numerical methods of calculation of the equations with boundary conditions. Simulation of ion sound wave propagation shows a new dispersion between frequency and wave vector. In some region of pa-rameters of dusty the negative dispersion of wave takes place. This means that the phase and group velocities of wave are opposite (negative dispersion). This phenomenon takes place, when the mass of dust particles has the maximum in the center of the waveguide. The negative dispersion caused the instability in dusty, which open the possibility to create a new phenomenon in dusty including the high temperature and the flame.

Simulation of electromagnetic wave propagation through dielectric waveguide with p-i-n control element

Simulation of the electromagnetic wave interaction with a p-i-n control element in a dielectric waveguide is presented. The problem has been solved numerically. Our simulation gives the coefficient of propagation like a function of basic parameters of a p-i-n structure. The investigation has demonstrated an efficiency of the control element in a dielectric waveguide in mm wave range.

An Influence of Geomagnetic Field on Stimulated and Free Oscillations in Schumann Resonator

Penetration of electric and magnetic fields of the first global electromagnetic ELF resonance in the cavity Earth- ionosphere into the ionosphere is investigated numerically. In the case of stimulated oscillations possessing the real frequency a penetration height for magnetic components is 2 - 3 times greater than for electric ones and it depends essentially on the value of the geomagnetic field and its orientation with respect to the normal to the Earths surface. A penetration height for the electric field is of about 50-70 km, for the magnetic field it is 120-240 km. In the case of free oscillations the frequency is complex, and the quality factor of the mode can be estimated from the condition of minimal leakage of magnetic components.

Observation of ULF Geomagnetic Anomalies at Tlamacas Station, Volcano Popocatepetl, in 2005

First results of ULF geomagnetic anomalies observed at the Tlamacas station (98deg 37 41 W, 19deg 04 01 N) located at 4 km near the volcano Popocatepetl (active volcano, 98.62 W, 19.02 N) for the period March-July, 2005 and their analysis are presented. The geomagnetic data were collected by a 3-axial fluxgate magnetometer designed at UCLA, (1 Hz sampling rate frequency, GPS). Our analysis reveals some anomalies, which are suspected to be generated by the local volcanic origin: the EM background in the vicinity of the volcano is significantly noisier than in other reference stations; the sporadic strong noise-like geomagnetic activity observed in the H-component; some geomagnetic pulsations (without preferred polarization) observed only at the Tlamacas station. Also the dynamics of the geomagnetic fractal index for the Tlamacas station in a comparison with the reference station points out to the some changes in critical processes, which may occur in the vicinity of the volcano.

Propagation of linear and nonlinear ion-sound monopulses in dusty plasma waveguides

The propagation of monopulse (baseband) linear and nonlinear ion-sound waves in dusty plasma waveguides is investigated. These waveguides are formed by prolonged inclusions of dusty plasma within the electron-ion one. The planar and cylindrical geometries are studied numerically. It has been demonstrated that nonlinear dynamics of baseband pulse propagation in a dusty plasma waveguide possesses essentially non-solitonic behaviour. Namely, the propagation of ion-sound pulses of finite amplitudes leads to an excitation of shock-like waves and, then, to the destruction of the pulses but not to emerging stable localized nonlinear structures.

Penetration of electric and magnetic field components of Schumann resonances into the ionosphere

A penetration of electric and magnetic fields of global electromagnetic ELF resonances in the cavity Earth-ionosphere into the ionosphere is investigated numerically. It is shown that a penetration depth for magnetic components is 2-3 times greater than for electric ones and it depends essentially on the orientation of the geomagnetic field with respect to the normal to the Earths surface. A penetration height for the electric field is about 50/spl divide/60 km, for magnetic field it is 100/spl divide/150 km.