Equatorial vertical E × B drift velocities inferred from ionosonde measurements over Ouagadougou and the IRI-2007 vertical ion drift model

F-region vertical plasma drift velocities were deduced from the hourly hmF2 values acquired from ionogram data over a near dip equatorial station Ouagadougou (12.4°N, 358.5°E, dip angle 5.9°N) in Africa. Our results are compared against the global empirical model of Scherliess and Fejer (1999) incorporated in the IRI model (IRI-2007) for 1600 to 0800 LT from 1 year of data during sunspot maximum year of 1989 (yearly average solar flux intensity, F10.7 = 192) corresponding to the peak phase of solar cycle 22, under magnetically quiet conditions. The drifts are entirely downward between 2000 and 0500 LT bin for both techniques and the root mean square error (RMSE) between the modeled and the ionosonde vertical plasma drifts during these periods is 3.80, 4.37, and 4.74 m/s for June solstice, December solstice and equinox, respectively. Ouagadougou average vertical drifts show evening prereversal enhancement (PRE) velocity peaks (V_ZP) of about 16, 14, and 17 m/s in June solstice, December solstice, and equinox, respectively, at 1900–2000 LT; whereas global empirical model average drifts indicate V_ZP of approximately 33 m/s (June solstice), 29 m/s (December solstice), and 50 m/s (equinox) at 1800 LT. We find very weak and positive correlation (+0.10376) between modeled V_ZP versus F10.7, while ionosonde V_ZP against F10.7 gives worst and opposite correlation (−0.05799). The results also show that modeled V_ZP–Ap indicates good and positive correlation (+0.64289), but ionosonde V_ZP–Ap exhibits poor and negative correlation (−0.22477).     

Comparison of observed hmF2 and IRI 2007 model with M(3000)F2 estimation of hmF2 at low solar activity for an equatorial station

This is to investigate ways of improving the Equatorial F2-layer peak heights estimated from M(3000)F2 ionosonde data measured using the Ionospheric Prediction Service (IPS-42) sounder at Ouagadougou, Burkina Faso (Latitude +12.4°N, Longitude +1.5°W, Dip latitude +5.9°N) during a low solar activity year (1995). For this purpose, we have compared the observed h_mF2 (h_mF2_obs) deduced using an algorithm from scaled virtual heights of quiet day ionograms and the predicted h_mF2 values which is given by the IRI 2007 model (h_mF2_{IRI 2007}) with the ionosonde measured M(3000)F2 estimation of the h_mF2 values (h_mF2_est) respectively. The correlation coefficients R² for all the seasons were found to range from 0.259 to 0.692 for h_mF2_obs values, while it ranges from 0.551 to 0.875 for the h_mF2_{IRI 2007} values. During the nighttime, estimated h_mF2 (h_mF2_est) was found to be positively correlated with the h_mF2_obs values by the post-sunset peak representation which is also represented by the h_mF2_{IRI 2007} values. We also investigated the validity of the h_mF2_est values by finding the percentage deviations when compared with the h_mF2_obs and h_mF2_{IRI 2007}.     

Variations of radiation environment onboard the ISS in the year 2008

Using the data of high-sensitivity dosimetric units DB-8, variations of the radiation environment onboard the International Space Station (ISS) during the year 2008 are analyzed. Very low level of solar activity was observed throughout this time, and no proton events occurred. It is shown that the variations of the mean daily dose rate during this period were caused by variations in the height of the ISS flight.     

Investigation of the effectiveness of an algorithm of active magnetic damping

We consider the rapid rotation of a satellite equipped with an active magnetic attitude control system with the -Bdot algorithm designed to damp the initial angular velocity. The time-response of the algorithm is analytically studied as a function of orbit inclination.     

Observation of narrow energy spectrum electron flows on <Emphasis Type="Italic">the INTERBALL Tail Probe</Emphasis> and their possible relation with the spacecraft charging

The paper describes cases of observations of narrow energy spectrum electron flows up to 500 eV on the INTERBALL Tail Probe. About 30 events were registered in 1996 on the night side of the Earth predominantly in 03^h–06^h local time sector. Quasimonochromatic electrons (QME) were registered by all 8 spectrometer channels oriented along the spacecraft meridian with angles of the field of view centers relative to sunward direction from 11° to 169°. Quasimonochromatic electrons were observed simultaneously with large fluxes of high temperature magnetospheric electrons. The dependences of QME energy on both fluxes and energy of high-energy magnetospheric electrons were observed in every event. The ratio of full width at half height (FWHH) to mean energy of QME was ~20%. This electron component with quasimonochromatic energy probably was originated on the spacecraft surface. The registered energy of QME was apparently due to difference of potentials between spacecraft surface from which electron beam originated and the location of electron spectrometer.     

Study of the influence of solar variability on a regional (Indian) climate: 1901–2007

We use Indian temperature data of more than 100 years to study the influence of solar activity on climate. We study the Sun–climate relationship by averaging solar and climate data at various time scales; decadal, solar activity and solar magnetic cycles. We also consider the minimum and maximum values of sunspot number (SSN) during each solar cycle. This parameter SSN is correlated better with Indian temperature when these data are averaged over solar magnetic polarity epochs (SSN maximum to maximum). Our results indicate that the solar variability may still be contributing to ongoing climate change and suggest for more investigations.     

The Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) for the Mars Express Mission

The general scientific objective of the ASPERA-3 experiment is to study the solar wind – atmosphere interaction and to characterize the plasma and neutral gas environment with within the space near Mars through the use of energetic neutral atom (ENA) imaging and measuring local ion and electron plasma. The ASPERA-3 instrument comprises four sensors: two ENA sensors, one electron spectrometer, and one ion spectrometer. The Neutral Particle Imager (NPI) provides measurements of the integral ENA flux (0.1–60 keV) with no mass and energy resolution, but high angular resolution. The measurement principle is based on registering products (secondary ions, sputtered neutrals, reflected neutrals) of the ENA interaction with a graphite-coated surface. The Neutral Particle Detector (NPD) provides measurements of the ENA flux, resolving velocity (the hydrogen energy range is 0.1–10 keV) and mass (H and O) with a coarse angular resolution. The measurement principle is based on the surface reflection technique. The Electron Spectrometer (ELS) is a standard top-hat electrostatic analyzer in a very compact design which covers the energy range 0.01–20 keV. These three sensors are located on a scanning platform which provides scanning through 180^∘ of rotation. The instrument also contains an ion mass analyzer (IMA). Mechanically IMA is a separate unit connected by a cable to the ASPERA-3 main unit. IMA provides ion measurements in the energy range 0.01–36 keV/charge for the main ion components H⁺, He⁺⁺, He⁺, O⁺, and the group of molecular ions 20–80 amu/q. ASPERA-3 also includes its own DC/DC converters and digital processing unit (DPU).     

Geotropic sensitivity of hornets.

Oriental Hornet workers, Vespa orientalis (Hymenoptera: Vespinae) were measured for their responses to changes in the direction of the gravitational field and this under both static and kinetic (centrifugal) conditions. The hornets can build a comb (oriented towards the gravitational force) when their multifaceted eyes are covered. Building activity is undertaken in the dark as well as by hornets that had been blinded or had eclosed in the dark and had never seen any light. If the frons plate of hornets is damaged, there is no or little building, and the comb direction is distorted. Hornets eclosing from and developing in combs subjected to centrifugal spinning build combs whose direction is affected both by rotation and by the resultant of the gravitational and centrifugal forces.     

Venera-15 and -16 spacecraft: Images and maps of Venus

The main purpose of the spacecraft Venera-15 and -16 was to radar map the north hemisphere of Venus. From October 1983 to July 1984, when this experiment was conducted, an area of 115 million km² was mapped. It stretches from the north pole to the latitude of 30°. The images (radar swathes) and height profiles of the whole surveyed territory were constructed.

At present mosaic maps of Venus were drawn by computer combining of individual swathes in a certain map projection. The height of the local topography was taken into consideration. Topographic maps of Venus were also drawn by interpolation of individual height profiles. They are the most detailed maps of Venus available.     

Optical observations of serendipitous EXOSAT sources in the Coma Cluster

A 7 hour observation of the central part of the Coma Cluster of galaxies has been performed with the EXOSAT LE telescopes and CMA detectors. Five serendipitous sources are detected within the inner 35 arcmin radius of the field. Optical spectroscopy demonstrates that at least three of these are background AGN not associated with the cluster. At the sensitivity level of the EXOSAT exposure, we would have expected to see only 0.01 background sources based on the Einstein Medium Sensitivity Survey. The EXOSAT and Einstein results may be reconciled if these AGN have a much softer average X-ray spectrum than previously assumed.