Stimulation of plasma waves in the magnetosphere using satellite JIKIKEN (EXOS-B)

The stimulated plasma wave experiment (SPW) has been successfully carried out in the plasmasphere and the magnetosphere along the JIKIKEN (EXOS-B) satellite orbit where the plasma parameters indicate wide variety of the combination of the electron number density, ranging from 1/cc to 10⁴/cc, and the electron cyclotron frequency, ranging from 6 kHz to 200 kHz.The upper hybrid resonances F_UHR usually persists for long periods up to 125 msec and the electron cyclotron resonances nF_H are stimulated at frequencies with the very high harmonic number n; sometimes, the nF_H resonance takes place for n=47.All the features of the resonances including F_On reflect the characteristics of the magnetospheric plasma that contains the energetic and non-Maxwellian components of the particles. The measurement of the plasma resonance contributes to the detection of the local electron density and the magnetic field intensity. The mode of the propagating radio waves is also determined being compared with the observed local plasma resonance frequency F_p.     

Expressions in Closed Form for the Angular Accuracy of a Scanning Radar

Closed-form expressions are given for the standard deviation of the error in estimating angle (usually azimuth) in a scanning radar. The formulas apply to Swerling's lower bound and to the error using a pulse-to-pulse two-pole filter. They apply to non-fluctuating and Swerling II targets and hold for all signal-to-noise ratios. Comparison with graphical results in the literature shows that the average deviation obtained using the formulas is less than 4 percent.     

Genetic response of bacterial spores to very heavy ions.

Using spores of two Bacillus subtilis strains differing in repair capacity, we have studied repair and mutation induction in the spores after irradiation with very heavy ions up to uranium with specific particle energies up to 18.6 MeV/u. The results indicate that repair and mutation induction after heavy ion irradiation are closely related to each other and that both phenomena strongly depend on the atomic number and specific energy of the ions. The effects are discussed in comparison with results obtained after X-irradiation.     

Perspectives of auroral X-ray measurements in the 1980s

The measurement of auroral X-rays with balloon-borne instruments is an efficient means to study the behaviour of electrons with energies above about 30 keV in the magnetosphere during disturbed periods. Possibilities will be discussed to continue such measurements in the 1980's. It will be pointed out, what kind of investigations may be performed. Recently developed payloads will be described that can be used as a basis for further technical developments. Satellite projects scheduled for the 1980's will be presented that are suited for coordinated X-ray measurements.     

Comparative neutral composition instrumentation and new results

Composition and gas density measurement at all altitudes in the atmospheres of earth and other planets are made by mass spectrometers. Because of the impartiality and large dynamic range they are particularly favored for exploratory missions. Measurements of trace constituents, inert gases and height profiles, especially below clouds, are objectives where mass spectrometry is most useful. Significant advances have been made in recent years in development of light weight automated instruments. Experiments conducted in rarified atmospheres have been more successful or results were less controversial than in attempts to analyze high pressure atmospheres. Gas sampling and conditioning techniques are highly specific because of measurement environments and engineering constraints on the mission, and are usually the most critical elements in the experiment. Chemical sample enrichment and scrubbing for noble gas enhancement are additional sample conditioning techniques now employed. Dynamic range of more than 10⁸ is achievable. Reliable measurements of complex organic or chemically active trace constituents with mixing ratios of less than 10^?9 still require significant instrument development particularly where weight, power and sampling time are severely restricted. Adaptation of familiar and proven laboratory techniques for flight instruments is usually not straightforward and practical.     

Radio aurora magnetic and streaming aspect sensitivities on 6 simultaneous links at 50 MHz

During August 1981, a 50 MHz c.w. radar system was operated in central Canada to measure auroral scatter amplitudes and Doppler spectra from a scattering region centered near 66° magnetic invariant latitude (L ≈ 6.0). Narrow beams from 3 transmitters, differing in frequency by 1 KHz, were directed to cover a common volume of the ionosphere over a ground location at 56.3°N, 103.5°W. The scattered signals were received on narrow beam antennas at two receiving sites, and recorded in analog form on magnetic tape under the control of an AIM65 microcomputer. The analog tapes were digitized later and FFT-processed to obtain Doppler spectra and amplitudes.The 6 transmission paths were designed to provide several magnetic aspect angles varying by 1.5°-7° from perpendicularity with the earth's field B and two streaming aspect angles differing by ～38°. The objective was to employ controlled geometric factors to study the functional dependency of signal amplitudes and Doppler shifts on magnetic and streaming aspect angles. Several hundred hours of excellent data were obtained in continuous operation during the month of August 1981. Preliminary results will be reported.     

Perspectives for Strategic Analysis in Advancing Ocean Technology

There is a growing need for the scientist, engineer, and administrator to better understand the kinds of overall, across-the-board planning problems involved in the development of off-shore coastal areas. A recommended approach is to use systems analysis techniques. Principles will be set forth on maintaining and improving the quality of the ocean environment, with considerations of cost in so doing. Each proponent of an aspect of ocean technology usually believes that his field must be greatly enlarged in the near future. Along with these advances there is the likelihood of unnecessary social costs emanating from undesirable modifications of the environment. In making the analysis, an early step is to identify specific needs and appropriate roles. A next step is to lay out alternatives for achieving objectives both within a given organization and external to it. The alternatives may be appraised through their costs and benefits. But how do you make choices between goals when resources are limited? How can we gather the data, accomplish the evaluation, and do the planning that will make rational choices possible? This paper elucidates the problems involved in these kinds of questions and suggests methodology that might lead toward solutions.     

Latitudinal structure of the solar wind and interplanetary magnetic field

A review is given of both observational and theoretical results concerning the latitudinal structure of the solar wind and interplanetary magnetic field. Observations are reported on the solar wind plasma and magnetic fields, obtained both from direct satellite measurements and indirect methods, such as the observation of comet tails, radio scintillations, the study of the polar geomagnetic field and the semi-annual variation of geomagnetic activity. Results of theoretical work, both on three-dimensional modelling of the solar wind and on gas-magnetic field interactions in the solar corona are summarized. Finally, an attempt is made to compare available observations and theories. This points to the open questions which, to be settled, will need direct observations of plasma and magnetic field at high heliographic latitudes.     

Wide angle X-ray optics for use in astronomy

Recently there was a suggestion in the literature to apply the principle of the lobster-eye to X-ray astronomy imaging (J.R.P. Angel, Ap. J. 233, 364, 1979). Our own suggestion for a wide angle X-ray telescope made earlier (W.K.H. Schmidt, Nucl. Instr. Meth.127, 285, 1975) is very similar to the above one. It consists of one or two sets of plane mirrors used in a grazing incidence configuration. The advantages of this type of X-ray optics over other systems for particular astronomical observations will be discussed.     

Radiation protection problems for the space station and approaches to their mitigation.

With the advent of a permanent manned space station the longstanding problems of radiation protection in manned spaceflight have acquired an immediacy. This paper endeavors to emphasize the gaps of our knowledge which must be closed for effective radiation protection. The information that is required includes the accurate determination of the exposure inside the space station to the various components of tile ionizing radiation, the evaluation of the biological importance of the different radiation qualities and the depth dose distribution of the less penetrating component. There is also the possibility of an interaction with weightlessness. It is necessary to establish adequate radiation protection standards and a system of dosimetric surveillance. There is a need for studies of possible methods of hardening selective shielding of the space station. Spaceflight experiments, which might contribute to the solution of some of these problems are discussed.