The global magnetic field is divided into a basic and an anomalous components. The dates when these components intersect in each solar cycle are called “equilibrium points”. It is stated that the equilibrium points determine the natural scale of magnetic cycles. The odd-zonal potential part of the field at the poles and at the equator is considered. It is shown that the anomalous part is much larger than the basic one. It is commonly believed that magnetic coupling between the solar hemispheres exists only at the minimum of the cycle. However the analysis of experimental data has shown that the coupling between the hemispheres in the epochs of maximum is as close as in the epochs of minimum. Characteristics of large-scale fields in the Sun can be determined by using the main reference points of the solar cycle. The phase of minimum of the solar cycle can be determined more precisely by using the magnetic field recurrence index and the two-dimensional correlation of the large-scale solar field. One can use indirect information on the polarity of large-scale fields to reveal a quasi- 17-year cycle. One can go further and calculate the source surface field using Ha observations. The obtained field structure proves to agree amazingly well with the characteristics obtained from Stanford magnetic measurements.

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The nonlinear behavior of the double tearing mode with shear flow parallel to the magnetic filed is investigated numerically in cylindrical geometry. The double tearing instability is found to be unstable with two peak current density profile, and under the influence of shear flow, it exhibits a complicated behavior in the physical and parameter space. With a Sech form shear flow, it is found that when the velocity shear near the resonant surface is small, the shear flow has a stabilizing effect, but for larger velocity shear, the double tearing modes are destabilized. The Possible physical implications of the coupling of double tearing instability with shear flow for the triggering of solar flares are discussed.

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Tidal theory analysis, 2-D numerical modelling of a large-scale planetary transient waves excitation by external forcing and data analysis has revealed the possibility for resonant response of the middle atmosphere. Such reaction has a nature of a barotropic motions and looks like atmospheric Rossby waves. Two types of forcing has been realised in model runs: solar UV 27-day variability (from above) and tropospheric periodical disturbances (from below). The results of model calculations has shown that the middle atmosphere of the Earth has its own periods and may be excited by a weak signal. Some of these periods are near to solar rotation period and others to the meteorological periodicities (5-7 and 12-14 days). The amplitudes of the waves in terms of geopotential heights increase from below to the higher levels and reach the quantities of about 50-80 gpm in the lower mesosphere. A special 2-D statistical method for transient waves detecting has shown that the real waves with similar spatial structure and character periods are really exist in the troposphere and lower stratosphere.

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The impulsive behaviour of the green emission line corona brightness over the years is emphasized and illustrated by means of butterfly diagrams constructed for the last five solar cycles. This peculiar property of the solar coronal activity is supposed to be reflected by the heliospheric medium, as well. Evidence of coincidences of the coronal impulsive periods with the maximum values in the solar modulation of galactic cosmic rays is presented.

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Estimations are presented concerning the contribution of MHD waves propagating from the low boundary of chromosphere-corona transition layer in the energy balance of magnetically open outer solar atmosphere. The corresponding energy-momentum sources are shown to be sufficient for coronal heating and solar wind acceleration. Selfconsistent model of wave driven solar corona and solar wind is constructed, in the frame of which the locations of coronal temperature maximum and solar wind transonic region coincide with the regions of effective wave damping. Wave energy flux into the corona is controlled by the value of magnetic field induction at the coronal base, and the wave energy distribution into the main channels of losses is determined by the magnetic field structure in the inner and middle corona.

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“Electrostatic Shocks” and field-aligned currents are associated with discrete auroral arcs and low-altitude particle acceleration. We show that accounting for the two new elements with respect to the previous “static” and “Alfvén wave” models, namely the transverse wave-guide for shear Alfvén waves and plasma density dip in the center of the structure, is necessary in order to explain the basic features of this phenomenon. The characteristics dimensions of the structure correspond to the “stirring scales” of the auroral turbulence.

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Observation results of the Jovian decameter wave emissions in the period of the passages of fragments of Shoemaker-Levy 9 comet through the Jovian magnetosphere indicated extremely large enhancements of Jovian decameter wave radiations (JDR), being caused by dust-plasma clouds moving across the Jovian magnetic fields. The total emission power of the decameter wave radiations was increased to the level of approximately 10 times larger than the regular maximum level of the emissions of the Jovian decameter radiation in a corresponding frequency range. The Jovian decameter wave radiations have continuously been emitted for six months, long after the passage of the fragments of Shoemaker-Levy 9 comet; the evidence suggests that the Jovian plasma environment has been completely changed by the remnants of dust clouds that were left behind the Shoemaker-Levy 9 comet fragments.

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Polarization measurements of Io-related Jovian decametric radiations (DAM's) were made in a frequency range from 20.5 to 25.5 MHz at the Zao observatory of Tohoku University, Japan. In the analyses of axial ratios of polarization ellipses, the following two factors were particularly investigated which were expected to deform the original axial ratios of Io-related DAM's; i.e., i) interferences caused by reflected wave components from ground, and ii) mutual cross-talks between one free-space mode wave to another free-space mode wave in anisotropic magnetized plasma along the ray paths. Totally 20 Io-related radio storms and 2 non-Io-A radio storms were selected for the analyses. Our major results are as follows: i) Most of Io-related DAM events indicate highly right-handed (RH) elliptical polarization and the mean value of the axial ratios for RH events is -0.31 ± 0.09 (standard deviation). ii) Io-A and 10-13 related DAM events indicate the significant difference in their axial ratios; i.e., -0.35 ± 0.08 and -0.26 ± 0.06 for RH Io-A and RH Io-B related DAM events, respectively. iii) Io-related DAM events indicate slightly more linear polarization than non-Io-A DAM events.

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In this paper, we have derived the nonlinear wave equations of the shear flow at the magnetotail from compressible MHD equations by the two-dimensional reductive perturbation method, and then discussed the nonlinear processes of energy dissipation and transfer at different region in the magnetotail. At last, the effects of disturbed electric field was discussed.

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A new approach toward an understanding of the nature of ULF-ultra low frequency-em. waves observed in the magnetosphere is given in this paper. The work is based upon results derived from detailed studies of the Fourier spectra of experimental magnetic field data obtained at a number of different geomagnetic locations around the world: Cascade (L = 2.9; Iowa, U.S.A.), Iqaluit - NP (L= 13; Northwest Territories, Canada), Amundsen-Scott Station - SP (L = 13; Antarctica), and also at Tuckerton (L = 2.6; New Jersey), and Point Arena (L = 2.6; California). The frequency band of the examined oscillations is F ≅ (0.7·10^-3-5·10^-2) Hz and overlaps the frequencies of the so-called (Pc2-Pc5) micropulsations. We show that the em. oscillations of these packets of waves exist in any time both in quite and disturbed conditions in the em. background of the magnetosphere. They appear to be resonance oscillations occurring in the magnetosphere on the whole or on its parts. During the intervals studied, in the examined frequency range 12 fundamental resonance frequencies were found in the spectra of the NP and SP data and more than 20-25 resonance frequencies in the Tuckerton and Point Arena data.* The other resonance maxima disappear in the weak oscillations of the noise. In general, the em. background of the magnetosphere is of a “lined” structure. It is composed of the resonance oscillations (frequency maxima of its spectra), and by more weak oscillations-by noise. All these oscillations can be set swinging, producing isolated, short-lived packets of waves. The conditions for producing the swinging can be impulse/shock-excitations of the magnetospheric plasmas, swinging of the background oscillations by gyro-resonance instability, dynamic effects such as changes in the neutral winds, etc. Thus, the wellknown multiple manifestations of hydromagnetic ULF waves and wave packets observed in the magnetosphere are considered to be the result of a single physical phenomenon: the fundamental em. oscillatory nature of the background magnetospheric plasma environment.

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The characteristics of the Fourier spectral frequency maxima F_{s, max} in the frequency band (F = 7-50) MHz which compose the extra low frequency e.m. waves-so called Pc2-Pc5 micropulsations, created in the magnetosphere are considered in this paper. It should be considered as an extended part of the data analysis presented in paper II (Alpert et al., 1995). The obtained characteristics of the spectra are compared with spectra of signals which can simulate the shapes of the envelopes of the examined records of the unfiltered magnetic field B(t). They are also confronted with spectral frequency maxima of different signals and with resonance frequencies of different resonators. This analysis confirms our conclusion that the found spectral maxima can be resonance frequencies-eigenvalues of a magnetospheric oscillating system. The resonance swinging of the background plasma oscillations, which creates strong packets of waves is also simulated by simple calculations. The variety, of shapes of the filtered packets of waves as observed in the magnetosphere is obtained by these calculations.

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The bow shock, magnetopause, plasma sheet and plasma sheet boundary layer are the regions in the plasma environment of the. Earth, where intensive conversion of energy takes space. In present paper these regions are called the active regions. Low frequency plasma waves which can control the dynamics of the ions in collision free plasma play very important role in the formation and behaviour of these regions. This paper presents review of the observations of low frequency plasma waves (0.1-105 Hz), which were done by the PROGNOZ-8 satellite in the vicinity of the bow shock, at the dayside and nightside magnetopause within the flux transfer events and in the magnetotail. Common features of the studied regions are accelerated plasma streams, hot electron populations and very strong wave activity, particularly at the low frequencies. The detailed study of the wave spectra together with the distribution function for electrons indicate the correlation between presence of the lower-hybrid waves and the population of the particles with higher energy then in the surrounding space. The orbit of PROGNOZ-8 (apogee 32R_E inclination 65°) allows us to study regions where the ISEE-1, 2 and AMPTE satellites did not operate.

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An arc observed at Eureka (88.9°N, 318°E CGM) on November 15, 1993, was also observed at Resolute Bay (84.5°N, 316°E CGM) and Cambridge Bay (77.6°N, 306°E CGM) and seen to extend from the central polar cap to the nightside oval. The auroral activity continued for 10 hours with its maximum intensity up to 20 kR (557.7 nm). The transpolar arc was mapped into the magnetotail by using Tsyganenko' s magnetic field model (T89). It is found that the source region was located at central plasma sheet boundary layer and extended to the tail lobe. It is also found that there is a sunward electrojet along the transpolar arc, based on analysis of magnetic signatures. The arc occurred during a period of strongly northward IMF B_z and time varying B_y, from negative to positive, which controlled the motion of the transpolar arc in the dawn-dusk direction.

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The present paper deals with a detail study of the dynamics of the polar cap boundaries. The study involves the data from two satellites of the APEX project, and the data from three DMSP satellites. The APEX (Active Plasma Experiment) satellites moving along the polar orbit provide charged particle measurements in a small spatial scale (due to changeable distance between both spacecrafts), up to 2000 km. The large scale changes are studied by the comparison of the APEX and the DMSP (Defense Meteorological Satellite Program) data. Different regions are identified using the characteristics of the precipitating particles in the energy range 0.1-20 keV which have been registered onboard of all satellites. This satellite configuration allows us to determine the evolution of the small structures as well as the motion of the whole precipitating region. The main attention is concentrated on the rising phase of the substorms when the width of the auroral oval decreases with the increasing geomagnetic activity and the velocity of the auroral oval motion can reach 0.2° per minute. The observed phenomena are compared with the changes of the interplanetary magnetic field and the solar wind parameters as provided by the IMP-8 spacecraft.

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From the upper hybrid frequency data observed by PWS onboard the Akebono satellite, the entire plasma density profile along the satellite paths have been obtained being based on the plasma neutrality condition. The analyses of the plasma density deduced from the upper hybrid frequency reveal the dynamical variation of the plasmaspheric plasma density profile (PPDP). The PPDP variation is especially characterized by the intimate correspondence to the time variation of Dst that indicates the time derivative-coefficient larger than 5 nT/hour. Variation phenomena of PPDP are divided into two categories depending on the phases of Dst variations; these are the phenomena which occur in the phase of the positive time derivative-coefficient (PDC) of Dst; and the phenomena which occur in the phase of the negative time derivative-coefficient (NDC) of Dst. Both in PDC, and NDC phases, the plasmapause structures show the sharpening of their cliff feature of the plasma density distribution, but a few hours later, all these traditionally convinced enhancement effects of the plasma convection in the neighboring plasma sheet regions are taken. over by the effects of plasmapause disruption without depending on the local time of the consideration. These plasmapause disruptions are caused by the exodus of the plasmaspheric plasma in the NDC phase while the hot plasma sheet plasma immigrates into the plasmasphere in the phase of PDC. Because of extreme inhomogeneity of the plasma temperature between the original plasmaspheric warm plasma and hot plasma from the plasma sheet region, there exist sharp discontinuous boundaries across the magnetic field lines in the plasmasphere. The evidence has been detected as the “donkey ears” phenomena by the observation of PWS onboard the Akebono satellite. It is disclosed that the exodus of plasma from the plasmasphere in NDC phase of Dst, and the immigration of plasma into the plasmasphere in PDC phase are caused by E × B drift due to the induction electric field that is strictly related to ∂B/∂t. The arrival of the front of the injected hot plasma delays with times ranging from 15 h to 2.5 h corresponding to the time derivative-coefficient of Dst, respectively from 5 nT/hour to 30 nT/hour. As higher the time derivative-coefficient becomes, the faster the drift velocity is increased; i.e., the delay time of arrival of the hot plasma front from the original plasmapause position to the satellite level becomes short for the fast E × B drift.

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Ionospheric manifestation of ssc-associated ULF magnetic pulsations is investigated by analyzing the simultaneous data of HF Doppler frequency shift and magnetic H component on the ground. The theoretical Doppler velocities associated with magnetic pulsations are also calculated using the method of Sutcliffe and Poole (1989). Comparison of the observed phase difference between the ionospheric and magnetic pulsations with the one by theory reveals that in several of the pulsation events the ionospheric response can be controlled by the advection and/or compression mechanisms attributable to the pulsation EM fields.

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Frequency power spectra are analyzed from zonal and meridional wind velocities observed continuously in a height range below 2.5 km with the Kyoto University Boundary Layer Radar (BLR) in Serpong, Indonesia (6.4°S, 106.7°E). We find that (i) the spectral slope in a period range from a few hours to a few days is approximately -1; (ii) the power spectral densities in the rainy season are at least about two times larger than those in the dry season; (iii) the diurnal component is dominant both in dry and rainy seasons; (iv) components with periods of about 4 and 10 days are probably associated with mixed Rossby-gravity wavelike cloud clusters and Kelvin wavelike super cloud clusters, respectively; and (v) the power spectral amplitudes increase at least one order of magnitude from the bottom to the top of the equatorial Planetary Boundary Layer (PBL), and the values at the top of the PBL are comparable to those in the upper troposphere over mid-latitudes. The last feature suggests that the equatorial PBL is probably a major source of kinetic energy of the earth's atmosphere.

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We present the 0I 630.0 nm night airglow (nightglow) observation data obtained with a ground-based scanning photometer at Watukosek (7.6°S, 112.7°E), Indonesia. We made the first observation in December, 1986 in order to study ionospheric F region plasma behavior from the ground. The airglow pattern over equatorial anomaly region is closely related to the distribution of equatorial F region electron density. Plasma turbulence in ionospheric F layer can be reflected on space configurations for 0I 630.0 nm airglow emission; plasma bubbles are observed as structured depletion regions in nightglow intensity. During the second observation campaign of September 26, 27, and 28, 1989, we observed multiple depletion structures in intensity of 0I 630.0 nm nightglow moving eastward. We measured almost the same depletion feature at two directions, zenith and 30° north from the zenith. We suggest that we observed the nearly field-aligned depletion structures. In 1993 from May through November we made nightglow observations for 46 nights. However, we observed few distinct phenomena such as plasma bubbles. Plasma drift velocities derived from these measurements of nightglow depletion events are presented and briefly discussed.

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Orthonormal wavelet analysis is applied for the first time to two-dimensional (time and height) data obtained from three-week continuous MU radar observations in June-July, 1991. It is confirmed that monochromatic wave structures are generally localized both in time and in altitude. We find the dominant temporal scale of wave activity in this case study is 2-4 days. The dominant vertical wavelength seems to decrease from -4 km to - 1 km, upwards through the tropopause-lower stratosphere region, which is almost independent of temporal scales in the 1-4 day range.

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