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The articles mentioned in this Correction were published under category “Original Paper”. However, their correct category should be “Review Paper.”

[EN] There is an increasing interest to study the interactions between atmospheric electrical parameters and living organisms at multiple scales. So far, relatively few studies have been published that focus on possible biological effects of atmospheric electric and magnetic fields. To foster future work in this area of multidisciplinary research, here we present a glossary of relevant terms. Its main purpose is to facilitate the process of learning and communication among the different scientific disciplines working on this topic. While some definitions come from existing sources, other concepts have been re-defined to better reflect the existing and emerging scientific needs of this multidisciplinary and transdisciplinary area of research., This paper is based upon work from the COST Action "Atmospheric Electricity Network: coupling with the Earth System, climate and biological systems (ELECTRONET)," supported by COST (European Cooperation in Science and Technology). AO received funding from Poland Ministry of Science and Higher Education for statutory research of the Institute of Geophysics, Polish Academy of Sciences (Grant No 3841/E-41/S/2019).

Electric currents flowing in the global electric circuit are closed by ionospheric currents. A model for the distribution of the ionospheric potential which drives these currents is constructed. Only the internal electric fields and currents generated by thunderstorms are studied, and without any magnetospheric current sources or generators. The atmospheric conductivity profiles with altitude are empirically determined, and the topography of the Earth’s surface is taken into account. A two-dimensional approximation of the ionospheric conductor is based on high conductivities along the geomagnetic field; the Pedersen and Hall conductivity distributions are calculated using empirical models. The values of the potential in the E- and F-layers of the ionosphere are not varied along a magnetic field line in such a model and the electric field strength is only slightly varied because the segments of neighboring magnetic field lines are not strictly parallel. It is shown that the longitudinal and latitudinal components of the ionospheric electric field of the global electric circuit under typical conditions for July, under high solar activity, at the considered point in time, 19:00 UT, do not exceed $$9\,\upmu {\text{V/m}}$$ , and in the sunlit ionosphere they are less than $$2\,\upmu {\text{V/m}}$$ . The calculated maximum potential difference in the E- and F-layers is $$42\,{\text{V}}$$ ; the maximum of the potential occurs above African thunderstorms that are near the terminator at that time. A weak local maximum also exists above the thunderstorm area in Central America. The minimum potential occurs near midnight above the Himalayas. The potential has identical values at ionospheric conjugate points. The voltage increases to $$55\,{\text{V}}$$ at 23:00 UT and up to $$72\,{\text{V}}$$ at 06:00 UT, when local midnight comes, respectively, for the African and Central American thunderstorm areas. These voltages are about twice as large at solar minimum. With our more realistic ionospheric model, the electric fields are an order of magnitude smaller than those found in the well-known model of Roble and Hays (J Geophys Res 84(A12):7247–7256, 1979). Our simulations quantitatively support the traditional presentation of the ionosphere as an ideal conductor in models of the global electric circuit, so that our model can be used to investigate UT variations of the global electric circuit.

A mathematical model is constructed of the equatorial electrojets flowing in the ionosphere which are generated by thunderstorms occurring at low latitudes. We use the narrow definition of the global electric circuit (GEC) that includes only atmospheric and ionospheric electric fields and currents generated by thunderstorms, and ignores the contributions of all ionospheric and magnetospheric generators. The ionospheric currents which distribute charges from the thunderstorm areas to the fair weather parts of the Earth are largest in the vicinity of the geomagnetic equator. They form the specific electrojets discussed here which are in addition to the electrojets formed by the wind dynamo. A model of the ionospheric potential which drives these currents was developed earlier and this is suitably modified here. We use an empirical model of the diurnal variation of the number of lightning strikes to define the currents up to the ionosphere from the main thunderstorm areas. A two-dimensional approximation of the ionospheric conductor is based on its high conductivity along the magnetic field. The Pedersen and Hall conductivity distributions are calculated using empirical ionospheric models; the Pedersen and Hall conductances are calculated by integration along magnetic field lines and these are used in the 2-D model of the ionospheric conductor. The spatial distributions of the ionospheric electric fields and currents are obtained by numerical solution of the 2-D ionospheric current continuity equation. The positions and the directions of the electrojets are defined by the global distribution of the main thunderstorm areas, as well as of the ionospheric conductivity, and so they strongly vary with Universal Time. As far as the generation of the equatorial electrojets is concerned, the African and Asian thunderstorm areas are more effective than the American ones since they are closest to the geomagnetic equator. There are day-time electrojets, the strength of which may be up to 175 A, and night-time ones (of up to 60 A), while the total current flowing in the GEC is not larger than 1400 A at any moment of time in our model. Usually the electrojets are a few times weaker in the night-time ionosphere because of its smaller conductivity. The equatorial electrojets of the GEC thus produce magnetic perturbations on the ground, which are in the 0.1 nT range, while there are one hundred times stronger, wind dynamo-driven electrojets and other larger, space weather-associated magnetic perturbations. Nevertheless, using their specific features these magnetic perturbations could be measured, especially at the night-time geomagnetic equator when and where they are not so disguised by other ionospheric currents.

Both the correlation and coherency between the count rates of precipitated and trapped energetic (⪆40keV) electrons, as observed by a particle experiment aboard the ESRO 1A satellite at Northern high latitudes (5 L = 3.4) show similar, and other periodicities. These results are discussed in terms of O'Brien's ‘splash-catcher’ model and the Kennel-Petschek theory of whistlermode turbulence associated with a gyroresonance plasma instability.

This paper examines whether the Earth-ionosphere capacitor (EIC) model is correct, by comparing observed atmospheric electrical properties with those expected for a spherical capacitor, as defined in electrostatics. The comparisons suggest that the EIC concept cannot be reconciled with, and hence cannot account for, the observations, particularly the rapid reduction of the atmospheric electric field with height that is measured. This means that the spherical EIC concept is incorrect by being too simplistic; it is thus misleading. The reason for this flawed concept is simple: the model disregards the non-uniform conductivity of the atmosphere which requires the presence of a net positive charge in the lower atmosphere that equals in magnitude the Earth's negative charge. This positive charge shields the action of the Earth's negative charge from polarizing the ionosphere positively. Thus, the lower D region ionosphere remains electrically neutral, which makes the EIC concept inappropriate.

A fair-weather electric field has been observed near the Earth's surface for over two centuries. The field is sustained by charge generation in distant disturbed weather regions, through current flow in the global electric circuit. Conventionally, the fair-weather part of the global circuit has disregarded clouds, but extensive layer clouds, important to climate, are widespread globally. Such clouds are not electrically inert, becoming charged at their upper and lower horizontal boundaries from vertical current flow, in a new electrical regime—neither fair nor disturbed weather; hence it is described here as semi-fair weather . Calculations and measurements show the upper cloud boundary charge is usually positive, the cloud interior positive and the lower cloud boundary negative, with the upper charge density larger, but of the same magnitude (∼nC m −2 ) as cloud base. Globally, the total positive charge stored by layer clouds is approximately 10 5 C, which, combined with the positive charge in the atmospheric column above the cloud up to the ionosphere, balances the total negative surface charge of the fair-weather regions. Extensive layer clouds are, therefore, an intrinsic aspect of the global circuit, and the resulting natural charging of their cloud droplets is a fundamental atmospheric feature.

A model for the distribution of the ionospheric electric potential which drives the currents which close the global electric circuit is constructed. Only the internal electric fields and currents generated by thunderstorms are studied. The atmospheric conductivity profiles with altitude are empirically determined, and the topography of the Earth’s surface is taken into account. A two-dimensional approximation of the ionospheric conductor is based on large conductivities along the geomagnetic field; the Pedersen and Hall conductivity distributions are calculated using the empirical models IRI, MSIS and IGRF. The maximum calculated voltage difference in the ionosphere under typical conditions for July, under low solar activity, at 19:00 UT, is about 85 V. In our model the potential has identical values at ionospheric conjugate points. With our more realistic ionospheric model, the electric fields are found to be an order of magnitude smaller than those of the well-known model of Hays and Roble [9].

In this paper we present the capability of a new network of field mill sensors to monitor the atmospheric electric field at various locations in South America; we also show some early results. The main objective of the new network is to obtain the characteristic Universal Time diurnal curve of the atmospheric electric field in fair weather, known as the Carnegie curve. The Carnegie curve is closely related to the current sources flowing in the Global Atmospheric Electric Circuit so that another goal is the study of this relationship on various time scales (transient/monthly/seasonal/annual). Also, by operating this new network, we may also study departures of the Carnegie curve from its long term average value related to various solar, geophysical and atmospheric phenomena such as the solar cycle, solar flares and energetic charged particles, galactic cosmic rays, seismic activity and specific meteorological events. We then expect to have a better understanding of the influence of these phenomena on the Global Atmospheric Electric Circuit and its time-varying behavior. Fil: Tacza, J.. Universidade Presbiteriana Mackenzie. Escola de Engenharia. Centro de Radio Astronomia E Astrofisica; Brasil Fil: Raulin, J. P. . Universidade Presbiteriana Mackenzie. Escola de Engenharia. Centro de Radio Astronomia E Astrofisica; Brasil Fil: Macotela, E.. Universidade Presbiteriana Mackenzie. Escola de Engenharia. Centro de Radio Astronomia E Astrofisica; Brasil Fil: Norabuena, E.. Instituto Geofísico del Perú; Perú Fil: Fernandez, German Enzo Leonel. Consejo Nacional de Investigaciones Cientí­ficas y Técnicas. Centro Científico Tecnológico San Juan. Complejo Astronómico "El Leoncito"; Argentina Fil: Correia, E.. Universidade Presbiteriana Mackenzie. Escola de Engenharia. Centro de Radio Astronomia E Astrofisica; Brasil. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil Fil: Rycroft, E.. CAESAR Consultancy; Reino Unido Fil: Harrison, R. G.. University of Reading. Department of Meteorology; Estados Unidos

Here, we consider a topic which is absolutely central to the successful operation of all satellites and spacecraft, namely the basic principles and fundamental concepts of visible light in particular and of electromagnetic radiation in general. Both the wavelike nature of light (the speed of light being 300,000 km/s through free space) and its particle-like nature (as photons) are considered. We introduce its wave properties which explain the phenomena of reflection, refraction, diffraction, interference, polarization, and the Doppler effect. The photon properties explain blackbody radiation, continuous spectra, emission spectra, absorption spectra, and the photoelectric effect. We mention how electromagnetic radiation is used actively for radio communications with Earth-orbiting satellites and passively for remote sensing investigations not only of the atmospheres of the Earth and other planets but also of distant stars and the structure of Universe. M.J. Rycroft Cambridge Atmospheric and Space Activities and Research (CAESAR) Consultancy, 35 Millington Road, Cambridge, CB3 9HW, UK e-mail: michaelrycroft@btinternet.com J.N. Pelton, S. Madry, S. Camacho-Lara (eds.), Handbook of Satellite Applications, DOI 10.1007/978-1-4419-7671-0_38, # Springer Science+Business Media New York 2013 667

[1] We use VLF electromagnetic wave data measured by the DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) satellite at an altitude of about 700 km to check for the presence of statistically significant changes of natural wave intensity (due to signals from lightning) related to preseismic activity. All the relevant data acquired by DEMETER during almost 6.5 years of the mission have been analyzed using a robust two-step data-processing schema. This enables us to compare data from the vicinity of about 8400 earthquakes with an unperturbed background distribution based on data collected during the whole DEMETER mission and to evaluate the statistical significance of the observed effects. We confirm previously reported results of a small but statistically significant decrease of the wave intensity (by ∼2 dB) at frequencies of about 1.7 kHz. The effect is observed for a few hours before the times of the main shocks; it occurs during the night. The effect is stronger between March and August, at higher latitudes and for the positions of hypocenters below the sea. We suggest an explanation based on changed properties of the lower boundary of the ionosphere, which leads to a decrease of the intensity of lightning-generated whistlers observed at the spacecraft altitude. This effect might result from a lowering of the ionosphere associated with an increase in the electrical conductivity of the lower troposphere due to an additional ionization of air molecules at the Earth's surface prior to earthquakes.

This paper gives a resume of the papers written in English which (a) describe some of the recording instruments in use at the Nagycenk Observatory (NCK) since the International Geophysical Year (IGY 1957–1958) and up to the present time, (b) summarise the most important and different types of observations associated with thunderstorms which have been made there, and (c) discuss their various geophysical interpretations. The paper describes the main results which have been obtained in four areas of thunderstorm associated atmospheric and geospace science within the context of Earth system science. These relate to the following parameters of atmospheric electricity: the vertical electric potential gradient just above the Earth’s surface and the air–Earth current as well as the point discharge current, Schumann resonance (SR) signals of the Earth-ionosphere cavity at 8, 14 and 20 Hz, transient luminous events (TLEs), and some aspects of the behaviour of the ionosphere. Deductions from these data sets are concerned with the global lightning activity and the conductivity of the air, with diurnal, seasonal, annual and long-term variations of the SR amplitudes and resonant frequencies in terms of migrating thunderstorm centres, with transient SR excitations and with sprites and other TLEs, and with ionospheric disturbances. The paper closes with some thoughts on future research directions based on the observations at NCK and Sopron and the results achieved since the IGY.

An apparent discrepancy is pointed out - at all heights, and by up to an order of magnitude - between the height profiles of atmospheric conductivity derived at AC using ELF propagation studies, especially from information on Schumann resonance of the Earth-ionosphere cavity, and using a model of the DC global atmospheric electric circuit. This serious issue is resolved by creating a hybrid profile of these two mid-latitude profiles, the first of which refers to conditions by day and the second by night. This hybrid profile is thus a first order attempt to represent globally averaged conditions. Close to the Earth’s surface, where the resistance of the atmosphere is largest, the properties of the DC global model exert the greatest influence, whereas in the middle atmosphere, at heights between 40 and 100 km, full wave computations show that the AC results are the more crucial. The globally averaged hybrid profile presented here has some limitations, and the physical reasons for these are addressed. They are due to the presence of aerosol particles of ice and/or of meteoric material which reduce the ionospheric D-region conductivity by an order of magnitude over only ~2 km of height, thereby causing ledges of ionisation. In the context of the globally averaged profile, published observations of the ionospheric effects of the giant gamma-ray flare from SGR 1806-20 (a neutron star having an enormously large magnetic field) occurring at 21:30 U.T. on December 27, 2004, are briefly discussed.

The global atmospheric electric circuit is driven by thunderstorms and electrified rain/shower clouds and is also influenced by energetic charged particles from space. The global circuit maintains the ionosphere as an equipotential at~+250 kV with respect to the good conducting Earth (both land and oceans). Its "load"is the fair weather atmosphere and semi-fair weather atmosphere at large distances from the disturbed weather "generator"regions. The main solar-terrestrial (or space weather) influence on the global circuit arises from spatially and temporally varying fluxes of galactic cosmic rays (GCRs) and energetic electrons precipitating from the magnetosphere. All components of the circuit exhibit much variability in both space and time. Global circuit variations between solar maximum and solar minimum are considered together with Forbush decrease and solar flare effects. The variability in ion concentration and vertical current flow are considered in terms of radiative effects in the troposphere, through infra-red absorption, and cloud effects, in particular possible cloud microphysical effects from charging at layer cloud edges. The paper identifies future research areas in relation to Task Group 4 of the Climate and Weather of the Sun-Earth System (CAWSES-II) programme. © 2012 Elsevier Ltd.

We illustrate how coupling could occur between surface air and clouds via the global electric circuit – through Atmospheric Lithosphere–Ionosphere Charge Exchange (ALICE) processes – in an attempt to develop a physical understanding of the possible relationships between earthquakes and clouds.

We propose a mechanism to explain suggested links between seismic activity and ionospheric changes detected overhead. Specifically, we explain changes in the natural extremely low-frequency (ELF) radio noise recently observed in the topside ionosphere aboard the DEMETER satellite at night, before major earthquakes. Our mechanism utilises increased electrical conductivity of surface layer air before a major earthquake, which reduces the surface-ionosphere electrical resistance. This increases the vertical fair weather current, and (to maintain continuity of electron flow) lowers the ionosphere. Magnitudes of crucial parameters are estimated and found to be consistent with observations. Natural variability in ionospheric and atmospheric electrical properties is evaluated, and may be overcome using a hybrid detection approach. Suggested experiments to investigate the mechanism involve measuring the cut-off frequency of ELF "tweeks", the amplitude and phase of very low frequency radio waves in the Earth-ionosphere waveguide, or medium frequency radar, incoherent scatter or rocket studies of the lower ionospheric electron density. © 2009 Elsevier Ltd.

International audience; Mini arrays are commonly used for infrasonic and seismic studies. Here we report for the first time the detection and mapping of distant lightning discharges in the sky with a mini array. The array has a baseline to wavelength ratio ∼4.2·10-2 to record very low frequency electromagnetic waves from 2 to 18 kHz. It is found that the mini array detects ∼69 lightning pulses per second from cloud-to-ground and in-cloud discharges, even though the parent thunderstorms are ∼900-1100 km away and a rigorous selection criterion based on the quality of the wavefront across the array is used. In particular, lightning pulses that exhibit a clockwise phase progression are found at larger elevation angles in the sky as the result of a birefringent subionospheric wave propagation attributed to ordinary and extraordinary waves. These results imply that long range lightning detection networks might benefit from an exploration of the wave propagation conditions with mini arrays.

In the field of Atmospheric Physics, the recent half century was characterized by the development of Dynamical Meteorology, along with its applications in weather forecasting and climate science for the troposphere and stratosphere (the altitude range from about 0 to 50 km). This process was stimulated by the use of comprehensive numerical models combined with new measurement and data assimilation techniques. Exploration of the upper atmosphere (at altitudes above about 120 km) and space was mainly fostered by many dedicated satellites and by novel ground-based instruments. The atmospheric layer between these two heights, nowadays known as the mesosphere/lower thermosphere (MLT, from 50 to 120 km), received comparatively little attention. Although being interesting in its own right because of various fluid dynamical and other physical curiosities, it is only in recent years that the MLT region has become to be recognized as the missing piece in the jigsaw puzzle that connects weather and climate to processes occurring in the upper atmosphere and space. The proper physical description of the MLT region is particularly challenging because it requires the combination of different physical disciplines. The knowledge acquired and the methods used in Meteorology have to be extended by concepts that have been developed for the particular processes operating in the MLT and the upper atmosphere. Amongst those challenges, we mention the proper description of the following

A description is given of the global atmospheric electric circuit operating between the Earth’s surface and the ionosphere. Attention is drawn to the huge range of horizontal and vertical spatial scales, ranging from 10−9 m to 1012 m, concerned with the many important processes at work. A similarly enormous range of time scales is involved from 10−6 s to 109 s, in the physical effects and different phenomena that need to be considered. The current flowing in the global circuit is generated by disturbed weather such as thunderstorms and electrified rain/shower clouds, mostly occurring over the Earth’s land surface. The profile of electrical conductivity up through the atmosphere, determined mainly by galactic cosmic ray ionization, is a crucial parameter of the circuit. Model simulation results on the variation of the ionospheric potential, ∼250 kV positive with respect to the Earth’s potential, following lightning discharges and sprites are summarized. Experimental results comparing global circuit variations with the neutron rate recorded at Climax, Colorado, are then discussed. Within the return (load) part of the circuit in the fair weather regions remote from the generators, charge layers exist on the upper and lower edges of extensive layer clouds; new experimental evidence for these charge layers is also reviewed. Finally, some directions for future research in the subject are suggested.

Our colleague A. P. Nickolaenko has pointed out an unfortunate, and obvious, misprint in our paper. The error is in line 5 of page 12 showing values for s0, which corresponds to the value of the surface conductivity in units of S/m. These values should not be negative.

We study theoretically the propagation of lower-hybrid resonance (LHR) waves in the auroral ionospheric plasma. The ray-tracing technique is used to study the properties of LHR wave propagation with account of a large-scale inhomogeneity both along and across the geomagnetic field. It is shown that wave refraction in such an inhomogeneous medium can result in direct transformation of LHR waves whose wave normals make large angles with the geomagnetic field into whistler-mode waves, whose wave vectors are close to the geomagnetic-field direction and which can therefore pass through the ionosphere to the ground. The parameters of LHR waves which can thus be transformed into whistler-mode waves are found. The transformation process considered can be important for interpreting ground-based observations of ELF waves.

The efficiency of energetic electron cyclotron acceleration in the Earth’s magnetosphere in different regimes of electron resonant interaction with parallel propagating whistler mode waves of variable frequency, specifically, with chorus ELF-VLF emissions, is considered. The regime of stochastic acceleration, typical of the interaction between particles and noise-like emissions, and particle acceleration in the regime of nonlinear trapping by a quasimonochromatic wave field are discussed. The specific feature of the latter regime consists in its non-diffuse character, i.e., the definite sign of the energy variation depending on the frequency variation in the wave packet. The trapped electron energy becomes higher if frequency increases within an element, which is typical of chorus emissions. For the parameters typical of chorus emissions (the amplitude of a wave magnetic field B ∼ = 102 nT, the initial frequency ω ∼ 0.3ω H , and the frequency variation &Dω ∼ 0.15ω H , where ω H is the electron gyrofrequency), the energy increase during one act of such an interaction at L = 4−5 exceeds the rms variation in the energy of untrapped electron (during stochastic acceleration) by one-two orders of magnitude. The estimates indicate that a considerable fraction (several tens of percent) of the chorus element energy can be absorbed by electrons accelerated in the trapping regime during a single hop.

Acceleration of relativistic electrons in an inhomogeneous geomagnetic field during their resonant interaction with longitudinally propagating whistler-mode waves of varying frequency has been considered. Specific features of acceleration of electrons trapped by the wave field have been studied. Previous estimates of the efficiency of such acceleration have been generalized with regard to relativistic effects, and the simple formula for energy gain in a wide range of initial energies has been obtained. It has been indicated that the energy gain during a single interaction between electron and a whistler-mode wave packet, with typical parameters of an element of chorus emissions in the Earth’s magnetosphere, can reach several keV. The conditions of this acceleration mechanism realization are discussed. Specifically, it has been found that, in the case of chorus emissions in the Earth’s magnetosphere, this mechanism can be effective for electrons with perpendicular energies several times as high as such an energy of electrons generating chorus.

The possibility that conditions on the Sun and in the Earth's magneto- sphere can affect human health at the Earth's surface has been debated for many decades. This work reviews the research undertaken in the field of heliobiology, focusing on the effect of variations of geomagnetic activity on human cardiovascular health. Data from previous research are analysed for their statistical significance, resulting in support for some studies and the undermining of others. Three con- clusions are that geomagnetic effects are more pronounced at higher magnetic lat- itudes, that extremely high as well as extremely low values of geomagnetic activity seem to have adverse health effects and that a subset of the population (10-15%) is predisposed to adverse health due to geomagnetic variations. The reported health effects of anthropogenic sources of electric and magnetic fields are also briefly dis- cussed, as research performed in this area could help to explain the results from studies into natural electric and magnetic field interactions with the human

This paper addresses, with examples, the essential need to devise important scientific research questions in order to set the objectives of space missions. However, the crucial objective of the human race is to survive the numerous hazards, both natural and anthropogenic, which may be expected to occur on Earth during the 21st century. With some experts believing that human civilisation may not survive to the end of the century, the main goals for space exploration should first be the preservation of planet Earth as a human habitat and, second, for human beings to settle in another haven, e.g. to colonise Mars. Treating this as an insurance policy, the annual premium for which could be around $16 billion, a globally cooperative plan should now be prepared and agreed. The fundamental message of this article echoes Zubrin's belief that, in order to survive, humanity must become a spacefaring species.

Space physics is a young discipline in Turkey. Since 1970 various national near-Earth space research activities and several international collaborations have been conducted in Turkey and some of these are continuing. In May 2004 a four-week Graduate Course on “Space and Atmospheric Physics I and II” was held at the Tubitak Feza Gursey Institute in Istanbul, Turkey. This paper explains the background behind this initiative, and gives an introduction to the topics that were covered during the course, especially emphasizing how solar-terrestrial physics is applied to space weather. During the course the students, in parallel with the lectures delivered, performed projects based on the curriculum, and using information available on the Internet and in the literature. A resume of their results concerning the well-known “space weather” event at the end of 2003 is given.

Electrical processes coupling the atmosphere and ionosphere differ from all other such processes, because both DC and AC effects operate at (almost) the speed of light. Electrostatic and/or electromagnetic field changes in different parts of the global atmospheric electrical circuit, which cause these “teleconnections”, arise from thunderstorms, lightning and sprites and, at higher latitudes, from the precipitation of Van Allen belt energetic electrons and interactions of the solar wind with the magnetosphere. Some observational, theoretical and modelling studies of interest are outlined.

Amongst the great variety of heavy particles present in the galactic and solar cosmic ray spectra, hydrogen and helium nuclei are significantly more abundant than all other heavier ions and, as such, represent a major radiation hazard to humans in space. Experimental data have suggested that differences in relative biological effectiveness (RBE) exist between the two species at the same value of linear energy transfer (LET). This has consequences for heavily ionising radiation protection procedures, which currently still assume a simple dependence of radiation quality on LET. By analysing the secondary electron (δ-ray) emission spectra of protons and α particles, in terms of the spatial characteristics of energy deposition in cellular targets and the likelihood of complex lesion formation, a numerical quantity representing biological effectiveness is generated. When expressed relative to a reference radiation, this quantity is found to differ for protons and α particles of the same LET, demonstrating not only the ion-specific nature of RBE but also the inadequacy of specifying radiation quality as a function of LET only. Such a method for numerically assessing radiation quality may have implications for procedures for heavy ion protection in space at low doses and for understanding the initial mechanisms of radiation action.

This paper outlines the way in which the ESF Scientific Network “Space Processes and Electrical Changes Influencing Atmospheric Layers” (SPECIAL) came into being, and how the ideas involved have evolved via discussions in the network. Both the organisational structure and some scientific themes are covered to assist readers of this SPECIAL special issue of the Journal of Atmospheric and Solar–Terrestrial Physics.

The purpose of this paper is to model numerically the ionisation created in the mesosphere above a strong horizontal (cloud-to-cloud) lightning discharge, and thus to understand better the formation of elves and related columniform (spatially structured) sprites. Such ionisation depends upon height, via the ratio of the VLF/LF wave electric field (radiated by the current in the discharge) to the atmospheric neutral density. The simulation shows local maxima on the order of 10 km apart due to the interference between direct waves radiated by the discharge current, waves reflected by the ground and waves reflected by the ionosphere. Parametric studies are carried out varying the frequency, amplitude, height, length and duration of the current. For waves ⩾30 kHz generated by a current ⩾50 kA , localised peaks of electron density occur from 75 to 85km altitude, particularly for discharges longer than 15 km. From such peaks, time-varying “stalactites” on the bottom of the ionosphere, streamers could develop and propagate downwards. These could become columniform sprites in the presence of the quasi-electrostatic field due to the negative charge remaining in the thundercloud after a positive cloud-to-ground discharge.

It has recently been suggested that successive intense lightning-electromagnetic pulse (EMP) events could cause significant large-scale changes to the properties of the nighttime lower ionosphere. In order to examine this quantitatively, data on lightning detected over the United States are combined with the output from a simulation code. During the course of a night strong lightning-EMP events can lead to significant (∼100% or even greater) increases in the electron density of the lower ionosphere, with the largest increases at ∼90 km altitude. Regions with significant decreases in electron density are also possible. It is shown that changes in the electron temperature of the lower ionosphere are unlikely to be significant. The time required to produce large-scale changes of ionospheric electron density above an active thunderstorm may explain the observation of a thunderstorm “modification time” before red sprite activity is initiated.

This paper introduces the topic of space techniquesfor environmental risks. It does this by giving someexamples of the damage and havoc wrought in recent tragic events –mudslides, floods, cyclones, earthquakes and theChernobyl disaster. It introduces the concept ofa Geographic Information System where informationderived from remote sensing observations made fromspace is combined with other types of informationand processed in a computer.

We review the theory, as well as satellite and ground-based data testifying to the high efficiency of parametric interactions of whistler mode waves and lower-hybrid resonance (LHR) and ion-acoustic or ion-cyclotron waves. Some applications of the parametric effects to diagnostics of the ionosphere and the magnetosphere are discussed.

Energy is a central concept in physics. Thus I was particularly drawn to this new book by an author who, in the last 30 years, has written 20 books, half of which have the word ‘‘energy’’ or ‘‘energetics’’ in their titles. Vaclav Smil, a Distinguished Professor at the University of Manitoba in Canada, has written on energy in the environmental context broadly, and specifically on agriculture, the biosphere and biomass, and in the developing world and China. Here, with erudite quotations Professor Smil provides an excellent, balanced overview of both the sources and the uses—by the human species—of different forms of energy on our planet. The fundamental aim of this book is ‘‘to produce a comprehensive, systematic, revealing (and hence interdisciplinary and quantitative) treatment of all major aspects of energy in nature and society’’. This most ambitious aim is definitely achieved by the analyses and syntheses presented. The first two chapters adopt a historical and physics approach to the concept of energetics, contrasting quantities such as power, or energy flow (in W or J/s), power density or rate of energy flow per unit area (in W/m), and specific energy or energy intensity (in J/kg). The conversions between different forms of energy—chemical, electrical, electromagnetic, gravitational, kinetic, nuclear and thermal—are explained. This discussion is highly relevant in the light of today’s discussions on biofuels. Energy fluxes are explored, ranging from that due to solar radiation (peaking at a wavelength of *500 nm) to terrestrial radiation (peaking at 10 lm), meridional heat transport in the ocean, tornadoes, geothermal processes, volcanoes and earthquakes. That ‘‘sets the stage for reviewing both the bioenergetic fundamentals and the specific and ecosystemic peculiarities of the plant and animal kingdoms’’. Chapter 3 is on photosynthesis, the bioenergetics of primary production in bacteria or green plants. Phototrophs are organisms which obtain energy from sunlight for the synthesis of organic compounds. They require oxygen in the atmosphere to remove carbon dioxide from the atmosphere, i.e. in order to assimilate (or ‘‘fix’’) carbon. The complicated enzymatic chemical reactions of ‘‘net primary productivity’’ are explained. Trees store *20 MJ/kg

Following some lightning flashes from energetic thunderclouds, blue jets and red sprites are observed in the atmosphere above the cloud and into the ionosphere. In order to understand the physical processes leading to these and associated phenomena, both the temporal and spatial evolution of the electric (and magnetic) fields due to the thundercloud and the lightning discharge are modelled. These numerical simulations are carried out either using a quasi-electrostatic code or an electromagnetic code, with appropriate boundary conditions and grids. The redistribution of electric charge and the electromagnetic pulse due to the lightning, can accelerate electrons, which collide with neutrals and ions, heating them, and also ionising the atmosphere. Runaway electrons and/or electrical breakdown of the atmosphere can also occur. The first and second positive bands of molecular nitrogen are excited appreciably if sufficient energy is produced. The situation is strongly nonlinear. The results (see also Cho and Rycroft, this issue) show the temporal and spatial development of (a) the electric field divided by the neutral gas density, and (b) the energy density of optical emissions (up to 10 13 photons m −3 s −1 ). They show that energy propagates up to the ionosphere in 0.3 ms, at the speed of light. A ring of optical emissions is created, the outer rim of which propagates horizontally in the ionosphere at an altitude ∼ 90 km, reaching a radial distance of 280 km in a further 0.7 ms. At the same time, the intense electric field at > 07 km altitude above the thundercloud creates a much enhanced ( ∼ 10 3 ×) electron density (with a radius up to 25 km) which lasts for several ms. This heated region modifies the amplitude and phase characteristics of VLF radio waves propagating in the Earth-ionosphere waveguide.

Computersimulations are carried out to study the ‘sprite’ onset mechanism. Both electrostatic and electromagnetic codes are developed to calculate the electric field structure and optical emission intensity between the top of the thundercloud and the ionosphere. The optical emission is composed of two structures. One peaks at 70 km height and its lateral dimension is 50–60 km; the other peaks at 90 km height and the lateral dimension extends beyond 200 km. It is found that the nitrogen first positive band, which has a red colour, dominates over the nitrogen second positive band except at the bottom of the optical emission. The upper part of the optical emission is caused by a horizontally travelling electromagnetic pulse induced by a lightning discharge current. The lower structure is caused by electrostatic effects induced by the unneutralized charge left after the lightning discharge current flows. The electromagnetic codes developed can simulate the self-consistent response of the upper atmosphere to the lightning discharge current. The electrostatic treatment can predict only the optical emission at heights less than ∼80 km. The optical emission intensity has a strong nonlinear dependence on the electric field strength through the enhanced electron density, and is increased for a long discharge path, a large current, and a short pulse. Also, the higher the lightning discharge is initiated, the brighter the optical emission is, because the electrostatic field is stronger for high altitude lightning.