Conjugate features of magnetospheric electron dynamics observed at balloon altitudes

Analysis of recent observations (from balloons, spacecraft, and surface observatories) demonstrate regional, shell, and nearpoint conjugacy at L ～ 7 during precipitative events which were characterized by local acceleration as well as release of gradient-drifted electrons injected during substorms. A number of new features of magnetospheric dynamics relating to substorm development and sudden-commencement effects, have been brought to light which, though poorly understood at present, may prove of considerable importance and are worthy of further investigation.

1. During the initial period of instability in substorm evolution, preceding the slower magnetotail convective injection, precipitation of waves of electrons in rapid polewards motion exhibit L-shell conjugacy near midnight.
2. Transient, large scale expansions of the magnetospheric electron population accompanied by temporally imbedded substorms display large scale regional conjugacy and are simultaneously observed as similarly transient intensity dropouts at balloon altitudes.
3. Precipitation from gradient-drifting electrons in the dayside magnetosphere exhibits near point-conjugacy, at least down to the order of 50 km and quite probably less.

Similarly tight conjugacy applies to the release of electrons showing a specific local response to sudden commencements.

1. Analysis of the approach to and attainment of spectral equilibrium in the precipitation observed from drifting electrons may provide information about either, or both, the source spectrum at injection and the process of local release.
2. The specific precipitation effect sometimes observed at the time of an SC remains a rather puzzling feature, although it seems clear now that the acceleration and/or release process responsible is of a highly local nature and works selectively at small pitch angles well within the magnetospheric boundary. Coupling of the interplanetary shock with the magnetosphere must be an important aspect, but the details are not clear as yet.
3. On at least one occasion, a large part (perhaps all) of the magnetospheric electron population varied in a nearly synchronous manner in response to solar wind induced distortions during the variable compressive phase of a sudden commencement geomagnetic storm.

In the ongoing effort to identify and understand acceleration and release mechanisms involved in magnetospheric dynamics, balloon-borne experiments will continue to be useful, providing essential information presently unattainable by other means.     

Comparisons between primrose lake (54°N, 110°W) ROCOB winds (20–60 km) and Saskatoon (52°N, 107°W) M. F. radar winds (60–110 km): 1978–1982

The development of the new CIRA will require the combination of winds from many sources, e.g. rockets (ROCOB) up to ～60 km, and radar winds ～60–110 km. Difficulties are that such rocket data have larger errors at 60–65 km, and tidal effects may become significant. Radar data for 60–80 km may also have tidal contamination, due to ? 16h of data per day: from 80–110 km tidal corrections are usually reliable.Comparisons are made between the unique Saskatoon MF radar set, which is continuous from mid 1978–1983, and the ROCOB data from Primrose Lake, which is only 340 km northwest. While the agreement is satisfactory, special care is required when matching the two regions: particular problems are the low rocket sampling rate, and the unexpectedly large amplitude of the diurnal tide. Important differences from the zonal winds of CIRA-72 emerge, especially in winter months. Meridional cross-sections differ from previous data models in the extent of the summer equatorward flow.     

Shock acceleration of energetic particles in corotating interaction regions

A simple shock model for the acceleration of energetic particles in corotating interaction regions (CIR) in the solar wind is presented. Particles are accelerated at the forward and reverse shocks which bound the CIR by being compressed between the shock fronts and magnetic irregularities upstream from the shocks, or by being compressed between upstream irregularities and those downstream from the shocks. Particles also suffer adiabatic deceleration in the expanding solar wind, an effect not included in previous shock models for acceleration in CIR's. The model is able to account for the observed exponential spectra at earth, the observed behavior of the spectra with radial distance, the observed radial gradients in the intensity, and the observed differences in the intensity and spectra at the forward and reverse shocks.     

Effects of gravity perturbation on developing animal systems

Developing systems provide unique opportunities for analyzing the effects of microgravity on animals. Several unusual types of cells as well as various extraordinary cellular behavior patterns characterize the embryos of most animals. Those features have been exploited as test systems for space flight. The data from previous experiments are reviewed, and considerations for the design of future experiments are presented.     

Superlight rotating reflectors in space

There is a general possibility of creation in space of large controlled mirror reflectors for solar and electromagnetic radiation with specific mass order of 1 g m^?2 or less. Such reflectors may be used in space energetics for concentration of solar energy for its further conversion into microwave beam and transmission to the Earth. They can also be used to illuminate the Earth surface in a dark period with reflected sunlight, to control the weather, for research work and some other purposes. Such reflector is a good solar sail. The control of its orientation and position in space is performed using solar energy and light pressure without spending fuel delivered from the Earth. Its form is maintained by centrifugal forces and light pressure. The film strength permits concentrators with radii of several kilometres and nearly flat reflectors for lighting applications with radii of hundreds of metres. Large series of identical reflectors can be built in space using superthin film tape at assembly station. For a year more than a hundred reflectors with a diameter of 600 m can be assembled at such a station. The assembly station can be placed at the height of 1000 km. The reflectors transfer to synchronous or other orbit is performed using their sail-likeness. For realization of such reflectors one should solve a very difficult problem of superthin film mass production as well as assembly technology problems. Careful study and experimental checks of their lifetime should be also made.     

Airglow atmospheric imager on board the ‘IK-Bulgaria-1300’ satellite

This paper shows the possibilities of the optical scanning imager for investigation of the structure of the auroral, SAR and tropical arcs and in this way to study the particle precipitation, neutral winds across the magnetic equator, drifts, electric fields and the current systems in the ionosphere.     

The Effect of Pulse Shape and Duty Cycle on Laser Binary Communication Systems

The result of an investigation of the effects of pulse shape and duty cycle on the probability of error are presented for a pulse-gated binary modulation (PGBM) laser communication system when the background irradiance has the important Lorentzian spectral shape.     

Two-frequency radio occultation measurements with Venera-9 and Venera-10 orbiters

The experiment with two-frequency radio occultation measurements of the Venusian nightside ionosphere using the Venera-9 and 10 orbiters is described. The experiment is the first of a kind in which the radio link to one of the spacecraft is used to probe the ionosphere, while the other is measuring the variations in the integral electron number density along the path of radio ray propagation. The experiment has been designed to achieve the maximum possible accuracies in determining the parameters of the probed ionosphere using the bistatic two-frequency radio occultation method.     

Solar pulsations

Recent observational evidence on solar oscillations is reviewed; this evidence strongly favors the global interpretation for much of the observed spectrum. Implications of these observations for the study of the solar interior and atmosphere are discussed.This work was supported in part by the National Science Foundation and the Air Force Office of Scientific Research.