Search

The assertion that social upheaval tends to coincide with peaks of solar activity is the main result of A.L. Chizhevskii’s first famous work, published in 1924. The connection between solar activity and averaged indicators of the collective human mental state has since then been repeatedly verified by independent authors on various datasets and confirmed with certainty. However, all patterns revealed to date concern small spatial (about the size of a city) and huge time (about 10 years) scales of this correlation between solar activity and indicators of human mental states. In our research we attempt to extend proof of this correlation to a much smaller time scale and a much larger spatial scale. The effect of geomagnetic activity on the human nervous system is studied through investigating its correlation with frequencies of emotion-laden words in a database of posts from the scientific forum dxdy.ru in the years 2006–2016. A subset of emotion-laden words whose relative frequency correlates with the Kр-index at a level r = 0.4–0.6 with p

A systematic review of heliobiological studies of the last 25 years devoted to the study of the potential influence of space weather factors on human health and well-being was carried out. We proposed three criteria (coordinates), according to which the work on solar–biospheric relations was systematized: the time scale of data sampling (years, days, hours, minutes); the level of organization of the biological system under study (population, group, individual, body system); and the degree of system response (norm, adaptation, failure of adaptation (illness), disaster (death)). This systematic review demonstrates that three parameters mentioned above are closely related in the existing heliobiological studies: the larger the selected time scale, the higher the level of estimated biological system organization and the stronger the potential response degree is. The long-term studies are devoted to the possible influence of solar activity on population disasters, i.e., significant increases in morbidity and mortality. On a daily scale, a probable effect of geomagnetic storms and other space weather events on short-term local outbreaks of morbidity is shown as well as on cases of deterioration in people functional state. On an intraday scale, in the regular functioning mode, the heart and brain rhythms of healthy people turn to be synchronized with geomagnetic field variations in some frequency ranges, which apparently is the necessary organism’s existence element. The applicability of different space weather indices at different data sampling rates, the need to take into account the contribution of meteorological factors, and the prospects for an individual approach in heliobiology are discussed. The modern important results of experiments on modeling the action of magnetic storms in laboratory conditions and the substantiation of possible theoreical mechanisms are described. These results provide an experimental and theoretical basis for studies of possible connections of space weather and human health.

Until now, the sum of periodic variations was the main carrier of information in biological and heliogeophysical signals. However, not all of the time series of interest contain dominant periodic components. The relaxation analysis used in this paper makes it possible to generalize the “spectral” formalism to signals that cannot be represented as a sum of a limited number of quasiperiodic components. An algorithm for filtering noise and long-period trends is developed based on the separation of the original signal into rapidly and slowly relaxing components. The main theorem that guarantees the operability of the algorithm is proven. A method for constructing an orthonormal basis whose components have a strictly defined relaxation time is described. The result of the signal expansion over this basis is called the relaxation spectrum. It can be used to divide the time series into signal-to-noise or oscillation-trend if there are no adequate Fourier or stochastic models. The hypothesis that geomagnetic rhythms with periods of about 7 and 9 days have the most significant influence on physiological indicators of biological objects (including those of the population as a whole), as was stated earlier by the heliobiologists, is confirmed based on an automatic algorithm for extracting reliable spectral peaks of population and heliogeomagnetic time series and detecting similar peaks using the Sorensen measure.

A differential evolution algorithm was used to detect the biotropic influence of geomagnetic activity on several parameters of human vascular tone. Studies of the characteristics of vascular tone in healthy volunteers showed that arterial stiffness and endothelial function, as well as blood pressure and heart rate, depend on the geomagnetic and, in most cases, weather conditions. The pulse wave velocity (PWV) was measured to characterize the arterial stiffness and was found to be the most sensitive to the effects of space weather parameters. The strength of the effect of geomagnetic activity was for the first time observed to depend on the configuration of terrestrial weather parameters. A linear correlation between the K index of geomagnetic activity and PWV was estimated at r =–0.44 (p = 0.0003), although the relationship was detectable exclusively in the case of certain terrestrial weather parameters. Endothelial dysfunction and the pulse-rate response to variations in geomagnetic activity implicated nitrogen monoxide in body adaptation to variations in geomagnetic activity.

The fate of the first publications by A.L. Chizhevsky that considered the influence of space weather on the dynamics of sociohistorical processes and on human collective behavior is discussed briefly. The scientist’s statistical data that indicate a correlation between certain characteristics of social processes and cosmophysical indices are noted to have been confirmed by independent Russian and foreign authors, and the hypothesis of the impact of solar activity on sociohistorical processes and the biosphere has passed the test of the latest biophysical and neurophysiological studies.

The temporal structure and dynamics of biological rhythms were formed in the course of evolution under the influence of environmental factors. Circadian rhythm as a central one in biological objects developed in response to daily luminosity and temperature rhythms related to rotation of the Earth. New causative factors that could be involved in this process and affect the entire spectrum of biological rhythms emerged with the advent of space research. The discovery of solar wind, interplanetary magnetic field, and Earth’s magnetosphere revealed similar periodicity of biological rhythms and magnetic factors which suggests possible participation of the latter in the formation of the former. Disturbances in magnetic rhythms may lead to desynchronization of biological processes by the adaptive stress mechanism as exemplified by circadian rhythm disorders in response to jetlag. This hypothesis forwarded by the authors in the 1990s was confirmed by further investigations including those reported by foreign researchers.

This work presents a review of studies of the Martian magnetic fields during the early Soviet missions to Mars in 1971–1974, which never approached Mars by closer than 1000 km before the experiment with the Magnetometer/Electronic Reflectometer (MAG/ER) on board the Mars Global Surveyor spacecraft, which could descend to altitudes of 80–100 km. At present, the experiment with the magnetometer (MAG) onboard the American MAVEN spacecraft adds new data, but the map of distribution of remnant magnetic fields of Mars and the picture of their interaction with the solar wind are already formed and, at its core, obviously, will not be revised. Thus, it would be very instructive to consider the following in detail: (a) what is already known regarding the features and distribution of remnant magnetic fields on Mars; (b) how they control the interaction of solar wind with a weakly magnetized planet (Mars); and (c) what is its distinction from another nonmagnetized planet (Venus).

Several problems can emerge in front of investigators, who take a detailed restoration of dependency. The key of them – is a mathematically rigorous formulation of the desired degree of details. Second in importance is the reliability problem of reproduction of these details. And the third problem is the evaluation of data collection efforts that will ensure the desired depending on the required details and results reliability. In this work the strict concept of spatial resolution of the locally linear algorithm of direct dependence recovery (DDR) is formulated mathematically. Such approach implies approximation of the system reaction (dependent variable) in the case of the assigned value of factors which only utilizes the data (precedents) from a spherical cluster surrounding those assigned value of factors. The concept of reliability of details is formalized through the noise attenuation coefficient. We derive a relationship between the size of the minimum required database, spatial resolution of the recovery algorithm, the number of influencing factors and the noise attenuation coefficient. Analytical findings are verified by numerical experiments. Maximum number of factors, functional dependence on which can be recovered via the database figuring in various helio-biological works published by many authors for several 10 of years, is estimated. It is shown that the minimum required size of the database depends on the number of influencing factors (dimension of space of the independent variable) as a power law. The analysis conducted in this study reveals that the majority of the dimensional potentials of helio-biological databases are significantly higher that dimensions, which are appear in the approaches of authors of these works.

The effect of local atmosphere status and space weather on the healthy volunteers and the patients suffering arterial hypertension (AH) is studied. The research group included 12 healthy volunteers and 15 patients suffering AH of 1–2 degree. In the period of 24-h electrocardiogram monitoring (ECG), all the patients suffering AH continued to take effective antihypertensive therapy individually prescribed. All the patients and volunteers had normal sinus rhythm without disorders in cardiac conduction pathways. The ECG monitoring covered the period from November 23, 2016 till March 29, 2017. During this period, 4 moderate and 11 minor magnetic storms occurred. The horizontal component of the magnetic field recorded ranged from 140 to 270 nT. We used multi-classifier algorithm based on the decision tree with parallel branching, which specially developed by the authors. Apart from the horizontal component of magnetic field, 6 basic characteristics of the local weather data were used as the predictors of the algorithm. The output of this algorithm is elementary statement of cause-consequence connection (insight). In the periods of weak frost and intense precipitations (snow or rain with snow), the combination of rather high horizontal component of the magnetic field with elevated atmospheric pressure and humidity resulted in abnormal RR, PR, and QT intervals of ECG.

In the present work four examinations (January, March, June, October 1991-1992) of the blood concentration of adrenal hormones (cortisol) and thyroid hormones (triiodothyronine (T3) and thyroxine T4) and their dependence on space and terrestrial weather parameters have been done for large groups of healthy inhabitants of high latitudes (Svalbard, the most northerly in the world year-round inhabited settlements). The aim of this study was to find the possible sensitivity of these biochemical parameters to variations of external natural factors at high latitudes in three independent groups of people living in this region (miners and people working underground (364 samples), the men working on the ground (274 samples) and women working on the ground (280 samples)). The obtained data indicate that the most expressed dependence of concentration of the three studied hormones is on the level of geomagnetic activity (GMA) - Kp, Ap, Kpmax - 3h. For two of the four seasons (June and October) with increasing levels of GMA a significant (p

Fifty-seven experiments have been conducted to monitor the minute indicators of heart rate at rest in 38 practically healthy individuals (9 men and 29 women) from 18 to 58 years old. The duration of each observation period is 60 to 200 min. We have measured the heart rate and the minute-averaged cardiac section durations reflecting the passage of electrical excitation over different parts of myocardium. A comparison of the dynamics of minute values of these physiological parameters with variations of the X and Z components of the geomagnetic field has shown that two-thirds of experiments revealed the synchronization of oscillations in the heart rate and variations in the components of the geomagnetic field. We have revealed both the matching of the observed periods of oscillations ranging between 4 and 30 min and an approximate synchronicity in the times of their appearance and disappearance.

A new approach to finding the dependence between heliophysical and meteorological factors and physiological parameters is considered that is based on the preliminary filtering of precedents (outliers). The sought-after dependence is masked by extraneous influences which cannot be taken into account. Therefore, the typically calculated correlation between the external-influence (x) and physiology (y) parameters is extremely low and does not allow their interdependence to be conclusively proved. A robust method for removing the precedents (outliers) from the database is proposed that is based on the intelligent sorting of the polynomial curves of possible dependences y(x), followed by filtering out the precedents which are far away from y(x) and optimizing the coefficient of nonlinear correlation between the regular, i.e., remaining, precedents. This optimization problem is shown to be a search for a maximum in the absence of the concept of gradient and requires the use of a genetic algorithm based on the Gray code. The relationships between the various medical and biological parameters and characteristics of the space and terrestrial weather are obtained and verified using the cross-validation method. It is proven that, by filtering out no more than 20% of precedents, it is possible to obtain a nonlinear correlation coefficient of no less than 0.5. A juxtaposition of the proposed method for filtering precedents (outliers) and the least-square method (LSM) for determining the optimal polynomial using multiple independent tests (Monte Carlo method) of models, which are as close as possible to real dependences, has shown that the LSM determination loses much in comparison to the proposed method.

Based on the results of 4-year observations of daily variations in blood pressure (BP) and heart rate (HR) in seven healthy volunteers, two distinct types of reaction of physiological indicators (PIs) to changes in meteorological parameters (first and foremost, atmospheric temperature T atm) are revealed. The first type is a monotonic (but nonuniform with respect to speed) decrease in systolic BP with increasing temperature, which is most pronounced for T atm < −5°C and T atm > 15°C, with a weaker reaction of diastolic BP and no reaction of HR (in four volunteers). The second type is a two-phase nonmonotonic dependence of BP indicators on T atm, which coincides with the first type in the range T atm < −5°C and is characterized by a positive correlation of BP and HR indicators with T atm for T atm > −5°C (in two volunteers). The physiological mechanisms that can provide the observed compensatory-adaptive reactions of healthy individuals to atmospheric factors in different temperature ranges are analyzed in detail. It has been shown that the revealed regularities can explain the results obtained by the authors in earlier studies.

As follows from the statement of the Third Official Solar Cycle 24 Prediction Panel created by the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Administration (NOAA), and the International Space Environment Service (ISES) based on the results of an analysis of many solar cycle 24 predictions, there has been no consensus on the amplitude and time of the maximum. There are two different scenarios: 90 units and August 2012 or 140 units and October 2011. The aim of our study is to revise the solar cycle 24 predictions by a comparative analysis of data obtained by three different methods: the singular spectral method, the nonlinear neural-based method, and the precursor method. As a precursor for solar cycle 24, we used the dynamics of the solar magnetic fields forming solar spots with Wolf numbers Rz. According to the prediction on the basis of the neural-based approach, it was established that the maximum of solar cycle 24 is expected to be 70. The precursor method predicted 50 units for the amplitude and April of 2012 for the time of the maximum. In view of the fact that the data used in the precursor method were averaged over 4.4 years, the amplitude of the maximum can be 20–30% larger (i.e., around 60–70 units), which is close to the values predicted by the neural-based method. The protracted minimum of solar cycle 23 and predicted low values of the maximum of solar cycle 24 are reminiscent of the historical Dalton minimum.

Long series of daily measurements of the vascular tone parameters, such as blood pressure (BP), pulse wave velocity (PWV), and endothelial function (EF), have been performed on one volunteer for three years. The Tonocard device, which was designed for this experiment, is used. To analyze the sensitivity these parameters to geomagnetic and meteorological factors, two independent approaches have been used. One of them is based on traditional methods of mathematical statistics; the other is based on pattern-recognition theory. The results obtained using these methods are in very good agreement, both qualitatively and quantitatively. It has been found that the volunteer’s systolic blood pressure (SBP), PWV, and EF were substantially affected by a complex of meteorological factors. Sensitivity to geomagnetic activity has been found only for the PWV. It is suggested that a decrease in the elasticity of vessel walls, which is reflected by this indicator, is a more pronounced and specific human reaction to geomagnetic disturbances than regular BP changes.

The influence of weather factors (atmospheric pressure and temperature) and the geomagnetic activity on the development of severe cardiological pathologies has been studied using the daily data from two Moscow clinics, accumulated over a period of 12 and 7 years. It was shown that the most biotropic factors are variations of atmospheric temperature. The relative contribution of the geomagnetic activity to the development of diseases is only 20%; however, its action is combined with the effect of ordinary weather because both these factors affect the vascular tonus of humans.

We present here an overview of the results of Russian investigations of planetary atmospheres in 2003–2006 prepared by the Commission on Planetary Atmospheres of the National Geophysical Committee for the National Report on Meteorology and Atmospheric Sciences to the 24th General Assembly of the International Union of Geodesy and Geophysics (Perugia, June 2–13, 2007).

Investigations of the effect of geomagnetic activity factors on the cardiac rhythm regulation and arterial pressure of cosmonauts during the expeditions onboard the Soyuz spacecraft, and the MIR and ISS orbital space stations was carried out for various durations of flight in weightlessness and, under control. Groups of cosmonauts were inspected under flight conditions outside the geomagnetic disturbances and in ground preflight conditions, during disturbances without them. The presence of specific effect of geomagnetic disturbances on the system of vegetative regulation of blood circulation of cosmonauts during the flight was demonstrated for the first time. The response of cosmonauts’ cardiac rhythm on the magnetic storm is definitely revealed; however, it depends on the initial functional background and, in particular, on the state of mechanisms of vegetative regulation (the duration of flight and adaptation to it).

This article reviews our understanding of the ionospheres in the solar system. It provides some basic information on the sources and sinks of the ionospheric plasma, its dynamics, the energetics and the coupling to the neutral atmosphere. Ionospheres in the solar system are reviewed and comparative ionospheric topics are discussed.

Space weather hazards have been well-studied during the past few decades, mainly in connection with effects on technical systems. The biological effects of solar and geomagnetic activity have been largely ignored because the amplitudes of the electromagnetic fields (EMF) are small, typically one to several hundreds of nanoteslas. This is much weaker than electromagnetic noise of anthropogenic origin and about 10 orders of magnitude less than the characteristic energies of biochemical reactions. During the past 20 years, however, more careful consideration has been given to possible nonthermal mechanisms of interaction of biological systems with weak (

Rhythms of heliogeomagnetic activity and their dynamics in the solar activity (SA) cycles are analyzed. Heliogeomagnetic rhythms are the mixture of a periodic signal and noise component, which differs from a periodic signal by a substantial suddenness. Therefore, the filtering methods optimized for smoothness were used to analyze these rhythms and to separate rhythm periodic components. Short-period rhythms of the Kp index of geomagnetic activity and Wolf numbers (W) have been revealed. The rhythm dynamics in SA cycles has been indicated. Clearly defined near-seven-day, semi-seven-day, and other components, which are harmonics of the solar rotation period, are present in the rhythms of the Kp index in contrast to W. A comparison of the Kp and Dst rhythms indicates that the seasonal and annual variations in these indices are substantially similar. It has been indicated that the rhythms of heliogeomagnetic activity could be the external synchronizers of biological rhythms, having integrated into the endogenous temporal structure of these rhythms in the process of evolution, and that the dependence of the population macroparameters on W is much weaker than on Kp.

Analysis of ambulance calls in Moscow during 1979–1981 reporting myocardial infarction (85 700 events), sudden death (71 700 events), and hypertension crises (165 500 events) shows the presence of clear seasonal variations with a deep summer minimum and a winter maximum. The same trend was upon analysis of monthly data on infarction mortality in Bulgaria over 15 years (1970–1985). One of the biotropic factors influencing the human cardiovascular system can be geomagnetic pulsations Pc1, agreeing in frequency with cardiac rhythms. In the seasonal trend, Pc1 have maximum intensity in winter. The comparison of data on ambulance calls in Moscow with the Pc1 observation data catalog revealed that, on ∼70% of days, an abnormally large number of myocardial infarction calls was accompanied by the presence of Pc1; their concurrence was half again the chance expectation. Besides, it was determined that the biotropic influence of magnetic storms in winter was much higher than in summer. One of the plausible reasons of the winter infarction maximum could be seasonal variations in the production of the pineal hormone melatonin, which destabilized the organism and increased its sensitivity to geomagnetic disturbances attended by Pc1.

The analysis of 85,800 events (1979–1981) of Moscow ambulance calls, related to the myocardial infarction (MI), demonstrates a seasonal variation with the profound summer minima and winter maxima. Similar results were obtained by analyzing the 25-year (1970–1995) statistical monthly data on the death from infarction in Bulgaria. The estimated high correlation coefficient (0.84) between Moscow and Bulgarian data suggests a common reason. There is a great number of clinical and statistical studies confirming that the MI number rises during geomagnetic disturbances, which have a maximum of occurrence near equinox, not in winter. In order to explain this contradiction we suggest that one of the critical additional factors, which affect a human cardiovascular system, could be geomagnetic Pc1 pulsations at frequencies comparable with the human heart beat rate. The MI variations as well as the Pc1 pulsations exhibit a summer minimum. The comparative analysis of the Moscow ambulance MI data and Pc1 pulsations recorded at the geophysical observatory in Borok is presented. It is shown that in about 70% of the days when an anomalously great number of ambulance calls (AMI) has been registered Pc1 pulsations have been recorded. In the winter season the probability of the simultaneous AMI and Pc1 occurrence was 1.5 times larger than their accidental coincidence. Moreover, it was found that the effects of magnetic storms and Pc1 in AMI were much higher in winter than in summer. We suggest that the seasonal variation of the production of the pineal hormone melatonin leads to a winter instability in the human organisms and increases the sensitivity of the patient to the “negative” influence of Pc1 geomagnetic pulsations in winter.

The effects of zero magnetic field conditions on cardiovascular system of healthy adults have been studied. In order to generate zero magnetic field, the facility for magnetic fields modeling "ARFA" has been used. Parameters of the capillary blood flow, blood pressure, and the electrocardiogram (ECG) monitoring were measured during the study. All subjects were tested twice: in zero magnetic field and, for comparison, in sham condition. The obtained results during 60 minutes of zero magnetic field exposure demonstrate a clear effect on cardiovascular system and microcirculation. The results of our experiments can be used in studies of long-term stay in hypo-magnetic conditions during interplanetary missions.

Using data from a radio occultation experiment onboard the Mars Global Surveyor spacecraft, altitude variations of the scale height of the neutral atmosphere in the northern and southern hemispheres of Mars are analyzed. The averaged altitude gradient of temperature for neutrals in the thermosphere is estimated. The revealed variations of the scale height of the neutral atmosphere at zenith angles of less than 82° indicate that the near polar atmosphere is not isothermal at altitudes of 125–145 km, which experimentally confirms predictions of models of the Martian atmosphere. It is shown that when one approaches the terminator the near polar atmosphere is cooled and the effects of variation of the solar zenith angle modulate the local time effects in both hemispheres.

The strongest crustal magnetic fields at Mars are located in certain regions in the Southern hemisphere and lead to the formation of large-scale mini-magnetospheres. In the Northern hemisphere, the crustal fields are rather weak and usually do not prevent direct interaction between the SW and an ionosphere/atmosphere. Exceptions occur in the isolated mini-magnetospheres formed by the crustal anomalies. Electron density profiles derived from radio occultation data obtained by the Radio Science Mars Global Surveyor (MGS) experiment have been compared with the crustal magnetic fields measured by the MGS Magnetometer/Electron reflectometer (MAG/ER) experiment. The effective scale-height of the electron density for two altitude ranges, 145–165 km and 165–185 km have been derived for each of the profiles studied. For the regions outside of the mini-magnetospheres the thermal pressure of the ionospheric plasma for the altitude range 145–185 km has been derived. The pressure balance in the high latitude ionosphere at Mars has been studied. In the Northern hemisphere average pressure at the altitude 160 km p 160 is practically independent of SZA. In the Northern hemisphere B 2 /8π can exceed p 160 in half the cases at altitudes 170–180 km, and magnetic forces can drive effective convection. In large scale mini-magnetospheres in the Southern hemisphere the ratio H 145–165 / H 165–185 on average, larger and more variable than in the Northern hemisphere. This suggests that plasma convection at altitudes above 165 km is effective. Within the Martian mini-magnetospheres plasma convection has to be primarily a drift of charged particles across the strong crustal magnetic fields and in this regard Martian mini-magnetospheres are similar to the terrestrial magnetosphere.

Alignment of serial epidemiological, physiological, including electrocardiographic data with variations in galactic cosmic rays, geomagnetic activity, and atmospheric pressure suggests the possibility of links among these physical environmental variations and health risks, such as myocardial infarctions and ischemic strokes, among others. An increase in the incidence of myocardial infarction in association with magnetic storms, reported by several investigators from Russia, Israel, Italy and Mexico, accounts in Minnesota for a 5% ( 220 cases / year ) increase in mortality during years of maximal solar activity by comparison with years of minimal solar activity. Magnetic storms are also found to decrease heart rate variability (HRV), indicating a possible mechanism since a reduced HRV is a prognostic factor for coronary artery disease and myocardial infarction. Longitudinal electrocardiographic monitoring for a week or much longer spans in different geographic locations, notably in the auroral oval, further suggests that the decrease in HRV affects spectral regions other than that around 3.6 s (0.15– 0.40 Hz ), reportedly associated with the parasympathetic nervous system. Differences in some associations are observed from solar cycle to solar cycle, and as a function of solar cycle stage, a finding resolving controversies. Coordinated physiological and physical monitoring, the scope of an international project on the Biosphere and the Cosmos, seeks reference values for a better understanding of environmental effects on human health and for testing the merit of space weather reports that could prompt countermeasures in space and on earth. Physiological data being collected systematically worldwide and morbidity/mortality statistics from causes such as myocardial infarction and stroke constitute invaluable data bases for assessing changes within the physiological range, for detecting environmental effects and for recognizing endogenous as well as exogenous disease-risk syndromes. Timely and timed intervention may then be instituted to lower risk, in preference to exclusive current focus on treating overt disease. These chronodiagnostics are particularly important for those venturing into regions away from hospitals, such as astronauts in space.

Magnetic storm modulates morphological and functional state of the heart and the related systems. Changes in cardiomyocyte ultrastructure induced by changes in geomagnetic activity were studied in experiments on rabbits. We describe a possible mechanism underlying changes in cardiac activity in intact animals induced by geomagnetic perturbations. The most pronounced alterations of cardiomyocyte ultrastructure were observed during the major phase of magnetic storm.

The slopes of the electron density profiles obtained by radio occultation experiments at Mars revealed different variations with solar zenith angle in comparison with behavior of the electron density profiles in the magnetic field free ionosphere of Venus. The results obtained by the Mars-Global-Surveyor (MGS) spacecraft show the existence of highly variable and very localized magnetic fields of crustal origin at Mars. Addressing the difference between the ionosphere at Venus and Mars, the scale heights of electron density profiles obtained by radio occultation methods onboard Mariner 9 and Viking 1 are analyzed at altitudes higher than the topside boundary of the photoequlibrium region in the magnetic field-free ionosphere. The local increase of the mean scale height in the altitude region 180–250 km is assumed to be either an effect of a nonhorizontal magnetic field associated with the magnetic anomalies or diffusive equilibrium in the magnetic field free ionosphere. The areas where the scale height of electron density profile is increased in comparison with average one have been selected. The angle between the magnetic field measured by MGS MAG/ER at altitudes 120–250 km and local zenith direction is investigated throughout these selected areas.

The Mars Global Surveyor mission has revealed that localized crustal paleomagnetic anomalies are a common feature of the Southern Hemisphere of Mars. The magnetometer measured small-scale magnetic fields associated with many individual magnetic anomalies have magnitudes ranging from hundreds to thousands nT at altitude above 120 km. That makes Mars globally different from both Venus and Earth. The data collected by Lunar Prospector near the Moon were interpreted as evidence that above regions of inferred strong surface magnetic fields on the Moon the SW flow is deflected, and a small-scale mini-magnetosphere exists under some circumstances. With a factor of 100 stronger magnetic fields at Mars and a lower SW dynamic pressure, those conditions offer the opportunity for a larger size of small `magnetospheres' which can be formed by the crustal magnetic fields. Outside the regions of the magnetic anomalies, the SW/Mars interaction is Venus-like. Thus, at Mars the distinguishing feature of the magnetic field pile-up boundary most likely varies from Venus-like to Earth-like above the crustal magnetic field regions. The observational data regarding the IMF pile-up regions near Venus and the Earth are initially reviewed. As long as the SW/Mars interaction remains like that at Venus, the IMF penetrates deep into the Martian ionosphere under the `overpressure' conditions. Results of numerical simulations and theoretical expectations regarding the temporal evolution of the IMF inside the Venus ionosphere and appearance of superthermal electrons are also reviewed and assessed.

In this paper a possibility to find out some effect of dipole-like intrinsic magnetic field on the plasma scale height at altitudes 180–240 km in the Martian ionosphere, that is above the topside boundary of the chemically controlled region predicted by existing models of the magnetic field-free ionosphere, is examined. It is assumed that the effect could be detected if the relationship between plasma and neutral atmosphere scale heights which is expected under the photochemical equilibrium conditions in the multicomponent atmosphere remains valid at altitude region 180–240 km. The plasma scale heights assessed from the data collected during the Mariner 9 and Viking 1 sessions are statistically analyzed and its trends with the solar zenith angle and F10.7 flux are evaluated. A half of statistically averaged scale height presented as a function of the solar zenith angle (SZA) and F10.7 flux is compared with the neutral atmosphere scale heights, calculated from the model of Izakov and Roste (1996) for the corresponding SZA and F10.7 fluxes. Since the conditions for the radio occultation experiments during the Mariner 9 and Viking 1 sessions are different a ratio of assessed plasma scale height to the appropriate neutral atmosphere scale height suits better for comparison than the average scale heights itself does. Employing such ratios the effect of dust content within the lower atmosphere on the thermal balance within the topside atmosphere at altitude 180–200 km is estimated.

This paper contains anecdotes concerning Konstantin Iosifovich Gringauz, his life, character, and scientific results. His transmitter-antenna system on Sputnik 1 announced the opening of the space era, and his scientific results, obtained during a period of 35 years, made a significant contribution to space physics.

The accuracy of estimates of electron impact ionization which are based on the gasdynamic model of the solar wind interaction with Venus is discussed. Employing the hybrid simulations and in situ data on electron temperature or electron fluxes the electron impact ionization is reevaluated. The electron impact ionization rate estimated in this paper is typically 4–8 times less than the value derived from the gasdynamic model Zhang et al. [1993]. During solar maximum the photoionization rate is typically greater than the electron impact ionization rate.

In biology, circadian rhythms with a period of one cycle in 20–28 h are known to be ubiquitous and partly endogenous. Rhythms with a frequency lower than one cycle per day are called 'infradian rhythms'. Among them are components with one cycle in about 3.5, 7, 14 and 28 days, the multiseptans, which, like the circadians, must be regarded as a general characteristic of life: they characterize unicells as well as much more differentiated organisms. We hypothesize that heliogeophysical factors other than the solar visible light, held responsible for the evolution of circadian periodicity, underlie the infradian rhythms of biosystems. The periodicities in the solar wind and variations in the interplanetary magnetic field (IMF) which are associated with the solar rotation are very similar in length to the biological periodicities. We investigate the temporal relations of variations in solar activity and in biological systems to test associations between events in the IMF, in geomagnetic disturbance, in myocardial infarction and in physiology. By cross-spectral analysis, we also find relations at certain frequencies between changes in human physiology on the one hand, and (1) the vertical component of the induction vector of the IMF, Bz, and (2) a global index of geomagnetic disturbance, Kp, on the other hand. We wish to stimulate interest in these periodicities of both biological systems and geophysical endpoints among physicists and biologists alike, so that problems relevant to clinicians and other biologists, including evolutionists, are eventually solved by their cooperation with the geophysical community.

The assumptions and peculiarities of the numerical codes, as well as the spatial resolution of the gas-dynamical and hybrid simulations which are available at present are discussed. As found the present day estimates of O+ ion production rates which can effect the bow shock geometry as intensively as observed by Pioneer-Venus-Orbiter are controversial. The disagreement of the gas-dynamical simulations by Breus et al. (Planet. Space Sci. 40, 131–138, 1992) and Stahara and Spreiter (Venus and Mars: Atmospheres, Ionospheres and Solar Wind Interactions, Geophysical Monograph 66, p. 345. AGU, 1992) is a result of different numerical implementation of the flow tangency condition which does not permit the specification of the equation of state p = p(ϱ) at the impenetrable obstacle. The numerical code by Breus et al. uses the reflection procedure for the implementation of the flow tangency condition and is insensitive to the equation of state at the obstacle surface. The reflection procedure does not employ explicitly the boundary conditions at the obstacle which the Stahara and Spreiter code does. As a result Stahara and Spreiter's (Venus and Mars: Atmoshheres, Ionospheres and Solar Wind Interactions, Geophysical Monograph 66, p. 345. AGU, 1992) simulation is in agreement with observations only in the case of an unreasonable value of the electron impact ionization: in several times of the photoionization within the magnetic barrier at Venus. Breus et al. (Planet. Space Sci. 40, 131–138, 1992) agree well with observations if the electron impact ionization is 60–70% of the photoionization there. Brecht and Ferrante (J. geophys. Res. 96, 11209–11220, 1991) simulated an insignificant effect of the magnetic barrier on the shock geometry. However this simulation is unable to estimate the O+ ionization rate to fit the hybrid model with observations. The cells employed by Moore et al. (J. geophys. Res. 96, 7779–7791, 1991) are larger than the thickness of the magnetic barrier region estimated from the magnetometer data by Zhang et al. (J. geophys. Res. 96, 11145–11153, 1991). Thus Moore et al. cannot simulate the magnetic barrier region properly and their prediction of an insignificant effect of the mass-loading under any expectable O+ ion production rate should be revised.

On the Mars-94 mission a long wavelength radar will be deployed on the orbiter for the purpose of probing the surface and sub-surface layers of the planet as well as the top-side of the Martian ionosphere. The radar will permit the study of the structure and electrophysical characteristics of the planetary regolith. The specific goal is to determine the extent and depth of permafrost layers thought to exist. The altitude distribution, the zenith angle variations and the solar wind dependence of the ionospheric electron density will be determined with the same radar for the purpose of assessing the influence of the planetary atmosphere and weak intrinsic and/or induced magnetic fields on the interaction between the planet and the solar wind.

The purpose of this paper is to examine the effects of a horizontal magnetic field and of horizontal transport of plasma on the vertical electron density profile in the Martian ionosphere. A two-dimensional magnetohydrodynamic model for the steady state Martian ionosphere is presented. The model takes into account the basic reactions involving O+, O2+, and CO2+ ions and vertical plasma transport as well as horizontal plasma transport along the hypothesized magnetic field lines. The good agreement between model predictions and experimental electron density radio occultation profiles supports the hypothesis of an intrinsic magnetic field of Mars.

One striking observation made during the Phobos -2 mission concerns the existence of a welldefined plasma boundary where the solar wind proton flux terminates. Different mechanisms have been proposed to explain this interesting new feature. In the present study, we explore the possible influence of charge exchange on the loss of solar wind protons in the Martian exosphere as the reason of such a composition boundary. Unlike the cometary interaction, the charge exchange process is effective only in the vicinity of the subsolar point of the Martian “magnetopause” where the streamlines cross the dense neutral atmosphere. The most recent model of the Martian upper atmosphere and the flow field obtained by numerical simulation are used to provide the basis for such a scenario.

This paper is Part of the review concerning the influence of weak electromagnetic fields on humans and animals under real and experimental conditions. It shows that participation of melatonin in the mechanism of such influence is responsible for desynchronization of circadian rhythms. Interestingly, preventive treatment with melatonin helps to eliminate negative impacts of the Earth's weather on patients with hypertensive disease.