Transfer of space science and technology: A third world point of view

In contrast to the more common discussions on the how, where and when of transfer of space science and technology, we open a general discussion on the consequences of the space era in the developing countries and draw attention to the fact that space science and technology create a scientific and economic dependence on the industrially developed countries. Recommendations are made to render the space programs more beneficial to the Third World. These include : formation of local groups of high level space scientists and experts; instead of sophisticated transferred technology the use of space technologies appropriate to local economic and social status; services to the poorest fraction of the population and educational programs that protect the indigenous cultures.     

Interplanetary medium – A dusty plasma

The average mass of dust per volume in space equals that of the solar wind so that the interplanetary medium should provide an obvious region to study dust plasma interactions. While dust collective behavior is typically not observed in the interplanetary medium, the dust component rather consists of isolated grains screened by and interacting with the plasma. Space measurements have revealed several phenomena possibly resulting from dust plasma interactions, but most of the dust plasma interactions are at present not quantified. Examples are the production of neutrals and pick-up ions from the dust, dust impact generated field variations at spacecraft and magnetic field variations possibly caused by solar wind interacting with dust trails. Since dust particles carry a surface charge, they are exposed to the Lorentz force in the interplanetary magnetic field and for grains of sub-micrometer sizes acceleration can be substantial.     

Chemical interactions of solar wind with cometary nuclei and comae

Solar wind particles, especially H, C, N, O, S, and P-ions, may undergo specific chemical reactions with gaseous or solid matter of comets when in the energy region of a few 10 to some eV. Each component of the solar wind, even if not chemically reactive itself, creates a multiplicity of energetic secondary particles by knock-on processes with the cometary matter. These are responsible for the majority of the so called “hot” chemical processes. Endothermic reactions with high activation energy and atom molecule interactions are possible and may add to the classical exothermic ion-molecule or radical reactions. Other sources of hot atoms or ions in comets are: cosmic rays, acceleration or pick-up processes and turbulences in comae and gas or dust tails, and photon absorption induced dissociation. The products of hot chemical reactions, short period comets experience on their orbits, add to those formed in the individual component ice or dust grains by strong fluxes of energetic particles in times prior to the accretion to a comet.     

Redefinition of the meteor storm from the point of view of spaceflight security

ZHR¹ is defined as number of meteoroids passing 1000 km² zenith area per hour which can produce craters no less than 1 cm in diameter on an aluminum material. The relationship between ZHR and ZHR¹ is deduced. We evaluate the strong meteor showers since 1990s by ZHR¹ instead of ZHR and find the Giacobinid (Draconid) shower in 1998 is much stronger than the Leonid shower in 1999, 2001 and 2002.     

一种基于地转风模型的平流层风场插值方法

平流层风场水平分量的数据精度和密度对高空气球实验的轨迹预测精度和飞行控制精度有着直接的影响。面向平流层风场,提出一种基于地转风模型的插值方法。该方法通过改进科里奥利频率公式,并用二维卷积计算地转风模型,提升了地转风模型的计算效率和低纬度地区风场精度,再用迭代二元线性回归和改进的自适应观测场偏差权重矩阵减小了观测误差对插值结果的影响。实验结果表明:所提插值方法能有效提升平流层风场插值计算速度,并对平流层风场水平分量的插值精度有显著提升。      

Configuration of the Uranus magnetosphere as seen from the point of view of the least energy criterion

The magnetic energy of idealized magnetospheric configurations has been investigated on the basis of the three-parameter family of 2D magnetospheres constructed in the author's earlier papers. The tilt angle λ can assume any value and the tail is characterized by the flux content Φ and the dimensionless parameter p. For fixed λ and Φ the value of p can be determined using the least energy criterion. The energetics of a configuration depends on the flux content in the tail. The results obtained in the 2D case can be translated to 3D. This enables to expect that the Uranian magnetosphere in the pole-on position will be axially symmetric when the flux in the tail is large. When the flux is small, then the neutral sheet will be a slightly bent surface.     

Observations of the interactions of heavy ions from Comet P/Giacobini-Zinner with the solar wind

During the encounter between the ICE spacecraft and Comet Giacobini-Zinner, intense fluxes of energetic heavy ions were observed at distances up to 4 × 10⁶ km from the comet. These ions were observed with steep energy spectra and highly anisotropic angular distributions, and are consistent with a composition comprising mainly ions from the water group. The flux versus time profiles have a general fall-off with increasing distance from the comet, but are modulated by both changes in the magnetic field direction and the solar wind velocity, the magnetic field variations being mainly responsible for variations on a time scale of minutes, and the solar wind velocity variations being responsible for much larger time-scale modulations, such as the inbound/outbound asymmetry of the intensity profile. In this paper we present correlated observations of heavy ions, the solar wind velocity and the magnetic field direction, and compare the observations of the ions with the theoretical predictions for their variations with distance from the comet, with the solar wind velocity and with the magnetic field direction.     

On the correlation of the solar wind observed at the L5 point and at the Earth

The L5 point is a promising location for forecasting co-rotating high-speed streams in the solar wind arriving at the Earth. We correlated the solar wind data obtained by the Nozomi spacecraft in interplanetary space and by the Advanced Composition Explorer (ACE) at the L1 point, and found that the correlation is significantly improved from that of the 27-day recurrence of ACE data. Based on the correlation between the two spacecraft observations, we estimated the correlation of the solar wind velocity between the L5 point and at the Earth, and found that the correlation coefficient was about 0.78 in late 1999, while that of the 27-day recurrence was 0.51. Eighty-eight percent of the velocity difference falls within 100 km/s between the L5 point and the Earth. This demonstrates the potential capability of solar wind monitoring at the L5 point to forecast the geomagnetic disturbances 4.5 days in advance.     

Establishing satellite data bases in developing countries: A critical view

Remote sensing is a data gathering and analysis technique that offers the possibility of natural resource evaluation. Countries that have not yet evaluated their main resources owing to the lack of basic knoweldge of their territory, are attracted by the idea of rapidly creating data banks through the use of remote sensing. While such a technique offers advantages over traditional means of data acquisition, it requires special systems and methods of analysis that are not particularly easy to assimilate. The building of data bases is taken here as the framework for analyzing some problems confronted by developing countries when trying to incorporate the techniques of teledetection.     

Propagation of non-linear ion-sound pulses in dusty plasma waveguides

There are a lot of objects in space associated with dusty plasma inclusions. Such inclusions may bear a prolonged shape and behave as waveguides for ion-sound waves. In the case of space plasmas, the dust particles can possess both negative charge, due to electron attachment, and positive one, due to photoionization. In this paper the propagation of linear and non-linear ion-sound wave pulses in the dusty plasma waveguides, possessing positive charge, is studied. It has been demonstrated that non-linear dynamics of baseband pulse propagation in plasma waveguide possesses essentially non-solitonic behavior. Namely, propagation of a long ion-sound pulse leads to an excitation of a shock-like wave but not a stable localized nonlinear pulse. Also, when a Korteveg–de Vries (KdV) soliton is incident onto the dusty plasma waveguide, some part of the soliton energy is captured by the waveguide and transformed into a multi-pulse structure. Additionally, an interaction of dusty plasma inclusions with KdV soliton can lead to the occurrence of transverse instabilities of the soliton and its eventual destruction.     

A different view of the ionospheric winter anomaly

The Winter Anomaly (WA) is an ionospheric phenomenon, particularly related to the F2-layer, that is classically defined as the situation in which the ionization level during winter is higher than during summer for a certain location. This situation is anomalous because it contradicts what would be naturally expected with summer’s ionization levels higher than winter ones. This phenomenon has been a matter of study since the early decades of the XX century.This contribution tackles the study of the WA based on long time series (up to two solar cycles) of Total Electron Content (TEC) measurements over a globally distributed network of stations. The work done relies on a threefold strategy including: a classical approach based on the comparison of the winter and summer maximum TEC values, that confirmed the results previously documented; an intermediate approach with maximum TEC values modelled as linear functions of the solar radiation level, that allowed to identify stations where the WA is likely to be observed (and at what solar radiation level) and where is not; a final original approach where the maximum TEC values are modelled using Chapman’s function for the seasonal variations, linear regressions for the solar activity dependence and the introduction of site and month dependent equivalent ionization coefficients for the remaining effects. The main conclusions are that the coefficients for winter months seem to depend mainly on geomagnetic latitude, to increase towards high latitudes and to be asymmetric between hemisphere. In accordance to these findings, the occurrences of WA effects would be regulated by proper combinations of these three effects.     

A new approach to solar wind monitoring

The monitoring of solar wind parameters is a key problem of the space weather program. We are presenting a new solution of plasma parameter determination suitable for small and fast solar wind monitors. The first version will be launched during the SPECTR-R project into a highly elongated orbit with apogee ∼350,000 km. The method is based on simultaneous measurements of the total ion flux and ion integral energy spectrum by six identical Faraday cups. Three of them are dedicated to determination of the ion flow direction, the other three (equipped with control grids supplied by a retarding potential) are used for determination of the density, temperature, and speed of the plasma flow. The version under development is primarily designed for the measurements in the solar wind and tail magnetosheath, thus for velocities range from 270 to 750 km/s, temperatures from 1 to 30 eV, and densities up to 200 cm⁻³. However, the instrument design can be simply modified for measurements in other regions with a substantial portion of low-energy plasma as a subsolar magnetosheath, cusp or low-latitude boundary layer. Testing of the engineering model shows that the proposed method can provide reliable plasma parameters with a high time resolution (up to 8 Hz). The paper presents not only the method and its technical realization but it documents all advantages and peculiarities of the suggested approach.     

A polytropic model for the solar wind

The solar wind fills the heliosphere and is the background medium in which coronal mass ejections propagate. A realistic modelling of the solar wind is therefore essential for space weather research and for reliable predictions. Although the solar wind is highly anisotropic, magnetohydrodynamic (MHD) models are able to reproduce the global, average solar wind characteristics rather well. The modern computer power makes it possible to perform full three dimensional (3D) simulations in domains extending beyond the Earth’s orbit, to include observationally driven boundary conditions, and to implement even more realistic physics in the equations. In general, MHD models for the solar wind often make use of additional source and sink terms in order to mimic the observed solar wind parameters and/or they hide the not-explicitly modelled physical processes in a reduced or variable adiabatic index. Even the models that try to take as much as possible physics into account, still need additional source terms and fine tuning of the parameters in order to produce realistic results. In this paper we present a new and simple polytropic model for the solar wind, incorporating data from the ACE spacecraft to set the model parameters. This approach allows to reproduce the different types of solar wind, where the simulated plasma variables are in good correspondence with the observed solar wind plasma near 1 AU.     

A solar wind driven model of geosynchronous plasma moments

We describe a tabular specification model of the density and temperature of ions and electrons at geosynchronous orbit as a function of magnetic local time and solar wind parameters. This model can be used to provide boundary conditions for numerical ring current models. Unlike previous specification models of geosynchronous plasma moments, this model is parameterized by upstream solar wind conditions. We find that solar wind parameters are a better predictor of geosynchronous ion density than magnetospheric indices, and as upstream parameters they are often more appropriate as model inputs since they causally precede the model outputs. Of the upstream parameters that were tested, the best predictors of geosynchronous conditions were the solar wind flow pressure and the magnitude and Z-component of the interplanetary magnetic field.     

Solar wind low-energy energetic ion enhancements: A tool to forecast large geomagnetic storms

Predicting the occurrence of large geomagnetic storms more than an hour in advance is an important, yet difficult task. Energetic ion data show enhancements in flux that herald the approach of interplanetary shocks, usually for many hours before the shock arrival. We present a technique for predicting large geomagnetic storms (Kp  7) following the arrival of interplanetary shocks at 1 AU, using low-energy energetic ions (47–65 keV) and solar wind data measured at the L1 libration point. It is based on a study of the relationship between energetic ion enhancements (EIEs) and large geomagnetic storms by Smith et al. [Smith, Z., Murtagh, W., Smithtro, C. Relationship between solar wind low-energy energetic ion enhancements and large geomagnetic storms. J. Geophys. Res. 109, A01110, 2004. doi:10.1029/ 2003JA010044] using data in the rise and maximum of solar cycle 23 (February 1998–December 2000). An excellent correlation was found between storms with Kp  7 and the peak flux of large energetic ion enhancements that almost always (93% of time in our time period) accompany the arrival of interplanetary shocks at L1. However, as there are many more large EIEs than large geomagnetic storms, other characteristics were investigated to help determine which EIEs are likely to be followed by large storms. An additional parameter, the magnitude of the post-shock total magnetic field at the L1 Lagrangian point, is introduced here. This improves the identification of the EIEs that are likely to be followed by large storms. A forecasting technique is developed and tested on the time period of the original study (the training data set). The lead times, defined as the times from the arrival of the shock to the start of the 3-h interval of maximum Kp, are also presented. They range from minutes to more than a day; the average for large storms is 7 h. These times do not include the extra warning time given when the EI flux cross the high thresholds ahead of the shock. Because the data-stream used in the original study is no longer available, we extended the original study (1998–2000) to 2001, in order to: (a) investigate EIEs in 2001; (b) present a validation of the technique on an independent data set; (c) compare the results based on the original (P1) energy channel to those of the replacement (P1′) and (d), determine new EIE thresholds for forecasting geomagnetic storms using P1′ data. The verification of this P1′ training data set is also presented, together with lead times.     

Gamma-ray blazars: The view from AGILE

During the first 3 years of operation the Gamma-Ray Imaging Detector onboard the AGILE satellite detected several blazars in a high γ-ray activity: 3C 279, 3C 454.3, PKS 1510-089, S5 0716+714, 3C 273, W Comae, Mrk 421, PKS 0537-441 and 4C +21.35. Thanks to the rapid dissemination of our alerts, we were able to obtain multiwavelength data from other observatories such as Spitzer, Swift, RXTE, Suzaku, INTEGRAL, MAGIC, VERITAS, and ARGO as well as radio-to-optical coverage by means of the GASP Project of the WEBT and the REM Telescope. This large multifrequency coverage gave us the opportunity to study the variability correlations between the emission at different frequencies and to obtain simultaneous Spectral Energy Distributions of these sources from radio to γ-ray energy bands, investigating the different mechanisms responsible for their emission and uncovering in some cases a more complex behavior with respect to the standard models. We present a review of the most interesting AGILE results on these γ-ray blazars and their multifrequency data.     

Introduction to planetary electrodynamics: A view of electric fields,currents and related magnetic fields

The environment surrounding a planet is composed of plasma, ionized gases and a neutral atmosphere that are continuously under the influence of solar effects. The complex dynamical interactions among these media and the generated electric fields create complicated interrelated current systems in the magnetosphere, ionosphere and atmosphere of the planets. Electric fields, currents and the related magnetic disturbances constitute the planetary electrodynamics scenario that will be considered in this tutorial. Beside providing a comprehensive and integrated view of the planetary electrodynamics, this tutorial intends to introduce the necessary theoretical background to understand the physical processes involved and particularly, to discuss some topics in which the authors are currently focussing their interests: Sun–Earth electrodynamical coupling, numerical simulations, plasmaspheric electron content variability, atmospheric electrical discharges, and the effects of intense magnetic storms at the Earth’s surface and in the magnetic anomaly region. New results on these subjects are also presented. A deeper and broader comprehension of this complex scenario involving multidisciplinary investigations will certainly bring several implications in the observational, theoretical, computational and technological developments, with repercussions in biological and medical sciences.     

A global view of tidal temperature perturbations above the mesopause: Preliminary model/observation intercomparison

Migrating and nonmigrating diurnal tides in the temperature data from the satellite borne, Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) experiment are compared to model predictions from the Thermosphere Ionosphere Mesosphere Electrodynamics General Circulation Model (TIME-GCM) and from the Global Scale Wave Model (GSWM). The comparative model/observation analysis is performed between 75–120 km altitude and at 7.5°N. The results suggest that interactions between quasi-stationary planetary waves and radiative and latent heat forced tidal components may play an important role in generating the thermal tidal structure above the mesopause though more extended model studies are necessary.     

A VLBI search for pulsar wind nebulae in supernovae

We examine recent supernovae which have been observed with very-long-baseline interferometry in order to detect or limit the emission from a possible compact remnant of the explosion. Such a remnant could be a neutron star, generating a pulsar wind nebula, or a black hole with an accretion disk and jets. Four supernovae, and also more than a dozen supernovae or their young remnants in M82, have structure sufficiently resolved to allow useful conclusions as to the strength of the emission from such young neutron stars or black holes. We recently discovered a compact component in the center of SN 1986J’s shell with a spectral luminosity at 15 GHz 200 times that of the Crab Nebula. This is most likely the compact remnant of the explosion, the first and only one found in any modern supernova. For other modern supernovae, the upper limits on the radio spectral luminosities of such young compact remnants range from 180 times that of the Crab Nebula for SN 1979C in M100 in the Virgo cluster to 0.001 times that of the Crab Nebula for SN 1987A in the Large Magellanic Cloud.     

The ultraviolet view of the Magellanic Clouds from GALEX: A first look at the LMC source catalog

The Galaxy Evolution Exporer (GALEX) has performed unprecedented imaging surveys of the Magellanic Clouds (MC) and their surrounding areas including the Magellanic Bridge (MB) in near-UV (NUV, 1771-2831 Å) and far-UV (FUV, 1344-1786 Å) bands at 5^″$5^{″}$ resolution. Substantially more area was covered in the NUV than FUV, particularly in the bright central regions, because of the GALEX FUV detector failure. The 5σ$\sigma$ depth of the NUV imaging varies between 20.8 and 22.7 (ABmag). Such imaging provides the first sensitive view of the entire content of hot stars in the Magellanic System, revealing the presence of young populations even in sites with extremely low star-formation rate surface density like the MB, owing to high sensitivity of the UV data to hot stars and the dark sky at these wavelengths.