Spatiotemporal Relationships of the Groove Belts,Coronal Structures,and Rift Zones of Venus

Solar System Research - We have analyzed the spatial and age relationships of volcano-tectonic units that have developed on the surface of Venus: groove belts, coronae, and rift zones. Most of the...     

A phase-space boundary integration of the Vlasov equation for collisionless one-dimensional stellar systems

The evolution of one dimensional (stratified) self-gravitating systems of stars with constant phase-space density (water bag model) is investigated by following the motion of the boundary curves defining the systems. The results are compared with those obtained by sheet-model computer experiments and good agreement is found. New aspects of the evolution, revealed by the present method, are discussed.     

Long term storage of relativistic particles in the solar corona

A model is presented which shows that large numbers of energetic electrons (0.3-> 10 MeV) and protons (1–30 MeV) can be stored in the solar corona at altitudes around 3 × 10⁵ km for periods in excess of 5 days. Specific reference is made to the time period July 6–16 1968 as an excellent example of energetic solar particle storage. Time histories of interplanetary charged particle intensities observed by the IMP-4 and Pioneer 8 satellites are used to substantiate this contention. Detailed reference is also made to solar X-ray, optical and radio data obtained during the period in question, in addition to interplanetary magnetometer data. This model provides a unique solution to many hitherto unexplained solar particle events, and can also account for the lack of prompt particle emission from certain large solar flares recorded in the past.     

Eclipse of radio emission on 7 March, 1970 at 10 cm wavelength from the active region associated with McMath plage 10 618

Radio emission of 10 cm from the whole disk was monitored during the eclipse of 7 March, 1970 by the Aerospace San Fernando Observatory and AFCRL Sagamore Hill Solar Radio Observatory. For both, the active region associated with sunspot 17 774, McMath region 10 618, was occulted. At Sagamore Hill the entire region was occulted. At SFO only the southern half of the sunspot group and the hydrogen plage southeast of the group was occulted. This region produced an importance class 1N flare and 10 cm burst beginning at 1601 UT and was enhanced about 15 flux units above the mean value of 190 units at onset.The Sagamore Hill data indicate the region was about 3.8 and contributed about 0.21 of the total radiation from the disk. The SFO data gave about 5.4 for the size of the southern half of the region and showed that about 0.20 of the total radiation came from there. Radiation came primarily from the hydrogen plage southeast of the major spot of the group. The hydrogen plage northwest of the group did not contribute significantly. Although the small flare occurred in this region, it did not contribute more than 0.04 of the total (0.20 of the active region) at occultation of region 10 618.     

Fine structure in the inner corona observed at the 1970 eclipse

On the slit spectrogram obtained at the 1970 eclipse in Mexico, the intensities of four coronal lines (Nixiii 5116, Fexiv 5303, Fex 6374, and Nixv 6702) and the continuum were measured as a function of distance along the slit. It is found that there exist a lot of fine fluctuations both in the lines and in the continuum intensities superposed on a large scale formation. The correspondence of such fluctuations between the continuum and the lines is good, with the exception of the line 6374 which shows a peculiar fluctuation. It is shown that the intensities of the three lines 5116, 5303, and 6702 seem to be proportional to the square of the continuum intensity while the 6374 line intensity may be proportional to the fourth power or more.     

The termination of the solar wind

It has previously been suggested that the solar wind might terminate at distances of 5 AU to 20 AU from the Sun, and that the solar wind might be drastically slowed down by charge exchange and photoionization of interstellar hydrogen atoms which approach the Sun. However, recent satellite measurements of resonantly scattered Lyman alpha radiation, together with pulsar dispersion and Faraday rotation measures, imply very small values for the interstellar hydrogen density (0.05 cm⁻³) and magnetic field strength (3 μG). As a result, the solar wind is not expected to be slowed down by more than about 30% inside the termination distance, which is expected to be about 100 AU.     

High-resolution measurements of photosphere and sunspot velocity and magnetic fields using a narrow-band birefringent filter

Modifications to a Zeiss 1/4 Å filter are described which allow high spatial resolution observations of the line-of-sight velocities and magnetic fields in the photosphere and in sunspots. First results show: (1) the granular velocity field to be very strong; differences in upward motions in the granules and downward motions in between are as much as 6 km/sec; (2) the Evershed effect in sunspots to originate primarily in the dark regions between bright penumbral filaments.