Particle transfer in multiregions

Asymptotic calculations for reflection and transmission coefficients for particles incident on an inhomogeneous plane parallel medium are performed. The medium is assumed to consist of several different optically thick homogeneous layers. Functional relations between the reflection and transmission coefficients for the sublayers are obtained. The invariant embedding concepts are used to calculate the albedo for sublayers. Numerical calculations and comparisons are performed.     

Study on the onsets of solar energetic electron events

Fine time resolution observations of the angular distributions of the intensities of energetic electrons (220 ≤ E _e ≤ 500 keV) by the IMP-7 and 8 spacecraft during the onsets of solar electron events and the technique of mapping the solar wind to the solar corona have been incorporated in this work in order to obtain the large-angle scattering distance of these particles under different configurations of the large scale structure of the interplanetary medium. It is found that in the presence of stream-stream interaction regions with compressed magnetic fields beyong 1 AU, the large-angle scattering is determined by the distance along the streamlines from the spacecraft to their intersection by a faster solar wind stream. In cases of diverging magnetic fields the estimated large-angle scattering distance exceeds 1 AU.     

Observation of the flare of 12 June 1982 by Norikura coronagraph and Hinotori

Flare activity was observed near the limb with two coronagraphs at the Norikura Solar Observatory and the Soft X-ray Crystal Spectrometer (SOX) aboard HINOTORI. A prominence activation occurred and then Hα brightenings were seen on the disk near the prominence. The prominence became very bright and its electron density increased to 10^12.8 cm^?3 in 1/2 hour. Loop prominence systems appeared above the Hα brightenings about half an hour after the onset of the flare, and were observed in the coronal lines CaXV 5694Å, FeXIV 5303Å, and FeX 6374Å. Shifted and asymmetric profiles of the emission line of 5303Å were sometimes observed, and turbulent phenomena occurred even in the thermal phase. The energy release site of the flare at the onset would be lower than 20 000 km above the solar limb.     

General aspects of hard X-ray flares observed by Hinotori: Gradual burst and impulsive burst

We survey here the observational results on five gradual and four impulsive type events from the hard X-ray imaging (SXT) and spectrometer (HXM) instruments on the Hinotori satellite. A set of differences are clearly recognized between the gradual and impulsive type bursts. These are: (1) Hard X-ray images show the existence of a large coronal source for each gradual burst and a wide variety of source structures for impulsive bursts. (2) The source heights of the impulsive bursts appear to be low. (3) All gradual bursts show power-law spectra while impulsive bursts show exponential thermal spectra at least before the maximum phase. (4) Energy-dependent peak delays are observed only in gradual bursts. From these differences we suggest that two different acceleration and emission mechanisms are involved with these two kinds of hard X-ray bursts.     

The occurrence frequency of white-light flares

We derive an occurrence frequency for white-light flares (WLF) of 15.5 ± 4.5 yr^?1 during a 2.6 year period following the maximum of solar cycle 21. This compares with a frequency 5–6 yr^?1 derived by McIntosh and Donnelly (1972) during solar cycle 20. We find that the higher frequency of the more recently observed WLFs is due to the availability of patrol data at shorter wavelengths (λ ? 4000 Å), where the contrast of the flare emission is increased; the improved contrast has allowed less energetic (and hence more frequently occurring) events to be classified as WLFs. We find that sufficient conditions for the occurrence of a WLF are: active region magnetic class = delta; sunspot penumbra class = K, with spot group area ≥ 500 millionths of the solar hemisphere; 1–8 Å X-ray burst class ≥ X2.     

The GLE-associated flare of 21 August, 1979

We use a variety of ground-based and satellite measurements to identify the source of the ground level event (GLE) beginning near 06∶30 UT on 21 August, 1979 as the 2B flare with maximum at ～06∶15 UT in McMath region 16218. This flare differed from previous GLE-associated flares in that it lacked a prominent impulsive phase, having a peak ～9 GHz burst flux density of only 27 sfu and a ?20 keV peak hard X-ray flux of ?3 × 10^-6 ergs cm^-2s^-1. Also, McMath 16218 was magnetically less complex than the active regions in which previous cosmic-ray flares have occurred, containing essentially only a single sunspot with a rudimentary penumbra. The flare was associated with a high speed (?700 km s^-1) mass ejection observed by the NRL white light coronagraph aboard P78-1 and a shock accelerated (SA) event observed by the low frequency radio astronomy experiment on ISEE-3.     

An imaging spectrometric observatory for spacelab

The capability to measure nearly simultaneously the entire spectrum of atmospheric emission from the extreme ultraviolet to the near infrared, with relatively high spectral resolution and high sensitivity, while also obtaining global and altitude coverage, would provide a database from which significant advances could be made in our current understanding of the atmosphere and its processes. The large payload capacity of the shuttle orbiter offers the first opportunity to put such instrumentation into space. The Imaging Spectrometric Observatory (ISO) comprises an array of five spectrometers designed to make full use of the shuttle as an observing platform for remote sensing of the atmosphere. ISO covers the wavelength range 300–12000 Å at 2–7 Å resolution. Use of area array detectors (intensified-CCD's) permits simultaneous measurements of ～1000 Å at a time. The instrument is capable of scanning the entire wavelength range in less than 20 s, or dwelling on weaker features for longer periods of time. The detectors are two dimensional and permit spectral imaging in one direction and spatial imaging in the other. The spatial imaging and spatial scanning features permit measurement of altitude profiles, or mapping of strongly spatially varying features such as aurorae. The instrument is designed to allow versatility. The various functions are programmable and software controlled. The key subsystems are modular for convenient replacement or upgrading. It is anticipated that the instrument will have applications not only in the area of atmospheric science, but also in studies of the ionosphere and magnetosphere, and in support of active experiments to be performed in space.     

Discovery of a flare star near Sirius

The discovery of a flare star (R.A. (1950)=6^h43^m6^s.07, Decl.(1950)=?16°45′24″) located about 6 arc min south of Sirius is reported. During photometric observations on the night of 13 January, 1982, using the 102 cm telescope at Kavalur, India, the star was seen to brighten by 2.55 mag. inV band over a duration of about 200 s. Observations on this object for a duration of about 10.5 hr spread over seven more nights indicate the star to be variable. The results of these observations are presented.     

Cosmic-ray antimatter: A primary origin hypothesis

We examine the possibility that the observed cosmic-ray protons are of primary extragalactic origin. The present \(\bar p\) data are consistent with a primary extragalactic component having \(\bar p\) /p?3.2±0.7 x 10^-4 independent of energy. Following the suggestion that most extragalactic cosmic rays are from active galaxies, we propose that most of the observed \(\bar p\) 's are alos from the same sites. This would imply the possibility of destroying the corresponding \(\bar \alpha \) 'sat the source, thus leading to a flux ratio \(\bar \alpha \) /α< \(\bar p\) /p. We further predict an estimate for \(\bar \alpha \) α～10^-5, within the range of future cosmic-ray detectors. the cosmological implications of this proposal are discussed.