Lifetime migration in Indonesia based on 1971 and 1980 census data

Internal migration trends in Indonesia are reviewed using 1971 and 1980 census data. The author notes that although migration in 1971 was primarily to Jakarta and Lampung, by 1980 it was more diversified, with significant migration to some of the outer islands. The importance of the national transmigration program is noted.     

The acceleration of minor ion species in the solar wind

This paper provides a comprehensive analysis of the dynamics of the flow of minor ion species in the solar wind under the combined influences of gravity, Coulomb friction (with protons), rotational forces (arising from the Sun's rotation and the interplanetary spiral magnetic field) and wave forces (induced in the minor ion flow by Alfvén waves propagating in the solar wind). It is assumed that the solar wind can be considered as a proton-electron plasma which is, to a first approximation, unaffected by the presence of minor ions. In the dense hot region near the Sun Coulomb friction accelerates minor ions outwards against the gravitational force, part of which is cancelled by the charge-separation electric field. Once the initial acceleration has been achieved, wave and rotational forces assist Coulomb friction in further increasing the minor ion speed so that it becomes comparable with, or perhaps even exceeds, the solar wind speed. A characteristic feature of the non-resonant wave force is that it tends to bring the minor ion flow into an equilibrium where the radial speed matches the Alfvén speed relative to the solar wind speed, whereas Coulomb friction and rotational forces tend to bring the flow into an equilibrium where the radial speed of the minor ions equals the solar wind speed. Therefore, provided that there is sufficient wave energy and Coulomb friction is weak, the minor ion speed can be trapped between these two speeds. This inteststing result is in qualitative agreement with observational findings to the effect that the differential flow speed between helium ions and protons is controlled by the ratio of the solar wind expansion time to the ion-proton collision time. If the thermal speeds of the protons and minor ions are small compared to the Alfvén speed, two stable equilibrium speeds can exist because the rapid decrease in the Coulomb cross-section with increasing differential flow speed allows the non-resonant wave force to balance Coulomb friction at more than one ion speed. However, it must be emphasized that resonant wave acceleration and/or strong ion partial pressure gradients are required to achieve radial speeds of minor ions in excess of the proton speed, since, as is shown in Section 4, the non-resonant wave acceleration on protons and minor ions are identical when their radial speeds are the same, with the result that, in the solar wind, non-resonant wave acceleration tends (asymptotically) to equalize minor ion and proton speeds.     

Radar observations of asteroid 1580 Betulia

Radar observations of the asteroid 1580 Betulia, made at a wavelength of 12.6 cm, show a mean radar cross section of 2.2 ± 0.8 km² and a total spectral bandwidth of 26.5 ± 1.5 Hz. Combining our bandwidth measurements with the optically determined rotation period sets a lower limit to the asteroid's radius of 2.9 ± 0.2 km.     

On the influence of mass loss and convective overshooting on the evolution of massive stars

Evolution of massive stars losing mass with the rateM H L/V C is computed (for =1,2,7). It is shown that observed mass loss rates correspond to 0.3 and, therefore, mass loss by stellar wind cannot play any significant role in the evolution of normal massive stars. However, for several types of massive stars (WR, OH/IR, X-ray sources) enhanced mass loss explains their peculiar features. Computations of evolutionary sequences of massive stars with convective overshooting taken into account (as a formal increase of the convective core) show that a significant broadening of the hydrogen-burning band in the H-R diagram may be obtained.     

A remote unmanned ELF/VLF goniometer receiver in Antarctica

In March 1977 an unmanned ELF/VLF goniometer receiving station was deployed on the Antarctic plateau 110 km south south west of the British Antarctic Survey base at Halley. A UHF Telemetry link enabled the ELF and VLF signals to be monitored and recorded at Halley, simultaneously with data from an identical ELF/VLF receiver at Halley. The remote station was designed for unattended operation with a wind driven generator to recharge its battery. Design considerations and problems encountered are discussed and some preliminary results are presented.     

Thermal balance of the mid-latitude F2-region at night

The thermal balance of the plasma in the night-time mid-latitude F2-region is examined using solutions of the steady-state O⁺ and electron heat balance equations. The required concentrations and field-aligned velocities are obtained from a simultaneous solution of the time-dependent O⁺ continuity and momentum equations.The results demonstrate the systematic trend for the O⁺ temperature to be 10–20 K greater than the electron temperature during the night at around 300 km, as observed at St. Santin by Bauer and Mazaudier. It is shown that frictional heating between the O⁺ and neutral gases is the cause of the O⁺ temperature being greater than the electron temperature; the greater the importance of frictional heating in the thermal balance the greater is the difference in the O⁺ and electron temperatures. A study is made of the roles played in the thermal balance of the plasma by the thermal conductivity of the O⁺ and electron gases; collisional heat transfer between O⁺ electrons and neutrals; frictional heating between the O⁺ and neutral gases; and advection and convection due to field-aligned O⁺ and electron motions. The results of the study show that, at around 300 km, electron cooling by excitation of the fine structure of the ground state of atomic oxygen plays a major role in the thermal balance of the electrons and, since the temperature of the ions is little affected by this electron cooling process, in determining the difference between the ion and electron temperatures.     

Influences of the interplanetary magnetic field on the auroral dynamics

This paper reports the study concerning the latitudinal dispalacement of the auroral oval as a function of the northward orientation of the B_z-component IMF and the relation between southward B_z and the auroral dynamics in the night sector.     

Long term modulation of cosmic rays and inferable electromagnetic state in solar modulating region

It is demonstrated that the long term variation in cosmic ray intensity I(t) can be described by an integral equation,

$\text{I(t)=I}{}_{\mathrm{\infty }}\text{?}\text{∫}\text{0}\text{∞}\text{f(τ)S(t?τ)}\text{d}\text{τ}$

, which is derived from a generalization of Simpson's coasting solar wind model. A source function S(t?τ) is given by some appropriate solar activity index at a time t?τ(τ ? 0) and the characteristic functionf(τ)(?0 forτ ? 0) expresses the time dependence of the efficiency of the intensity depression due to solar disturbances represented by S(t ?τ) when the disturbances generated at the solar surface propagate through the modulating region with the solar wind. It is demonstrated further that the equation can be derived from the general diffusion-convection theory on some assumptions, and as a result, the source and characteristic functions can be related to diffusion coefficient and its transition in space. Assuming the sunspot number R (or two activity indices including R) as the source function, the characteristic function f(τ) [or f(τ)'s] is obtained with data of the cosmic ray intensity extended over several decades. Based on the theory, one can obtain from f(τ) the following physical quantities in space, such as the transition and life time of solar disturbances, the boundary of the modulating region, and the radial and time dependences of the diffusion coefficient, radial density gradient and modulated intensity of cosmic rays. Results deduced from the present analysis are consistent with those obtained directly or indirectly by space observations.     

Origin of framboidal pyrite in clayey Holocene sediments and in Jurassic black shale in the northwestern part of the Barents Sea

Framboidal pyrite is identified in clayey Holocene sediments in the northwestern part of the Barents Sea, and also in clasts of black Jurassic (?) shale within these sediments. Two types of framboidal pyrite are distinguished. Framboids in the Holocene sediments lack a matrix between the microcrystals whereas the Jurassic specimens have a matrix. In contrast to the rest of the clastic sedimentary material in the area, the framboidal pyrite in the Holocene sediments is not reworked from the underlying Mesozoic rocks, but has formed recently. In some Holocene sediments the microcrystals are well organized and crystal-like faces are developed. The framboidal texture is probably a result of pyrite crystallization. The matrix is concluded to be due to diagenetic alteration and is not a primary feature of the framboidal pyrite.