A cosmochemical view of cosmic rays and solar particles

The composition of cosmic rays and solar particles is reviewed with emphasis on the question of whether they are representative samples of Galactic and solar matter. The composition of solar particles changes with energy and from flare to flare. A strong excess of heavy elements at energies below a few MeV/nuc decreases with energy, and at energies above 15 MeV/nuc the composition of solar particles resembles that of galactic cosmic rays somewhat better than that of the solar atmosphere. The elements Ne through Pb have remarkably similar abundances in cosmic ray sources and in the matter of the solar system. The lighter elements are depleted in cosmic rays, whereas U and Th may be enriched or not, depending on whether the meteoritic or solar abundance of Th is used. Two prototype sources of cosmic rays are considered: gas with solar system composition but enriched in elements with Z > 8 during acceleration and emission (by analogy with solar particle emission), and highly evolved matter enriched in r-process elements such as U, Th and transuranic elements. The energy-dependence of cosmic ray composition suggests that both sources may contribute at different energies.Miller Institute Professor, 1972–73.     

Calculation of Probability of Detection with Target Scintillation

This paper presents a computational method for the calculation of probability of detection using measured radar target cross-section data. The described method can also be used for probability of detection calculations when the radar target cross section follows a specified probability density function. Using the computational procedure of the paper, a number of curves are generated which can be used for probability of detection calculations with exponential and Gaussian radar target cross-section distributions. The results obtained using theoretical distributions are compared with the corresponding results using actual target cross-section measurements. The results of computer runs are compared to the corresponding values in the literature where available.     

Identifications of some highly-ionized iron and nickel lines in the 200–400 Å region of the solar spectrum

A number of previously unclassified multiplets of Fexiv, xiii, xii, and xi produced by transitions of the type 3s ²3p ⁿ -3s3p ⁿ⁺¹ are identified in the XUV spectrum of the Sun. The iron lines account for most of the previously unidentified strong lines between 330 and 370 Å. Solar observations of especial value for the investigation of the 300–400 Å region were the slitless spectroheliograms of September 22, 1968 (Purcell and Tousey, 1969) and November 4, 1969 (Tousey, 1971) — on which the image of a flare was recorded. Other solar identifications in the same spectral region include the resonance lines of Nixvii and Nixviii, and one 3p-3d multiplet of Fexiii. The solar blend at 417 Å involving the Fexv inter-combination line and Sxiv is resolved.     

Electronically Tracking Antenna System for Satellite Reception

This correspondence describes a novel electronically tracking antenna system for satellite reception in the VHF range. The "hedgehog" antenna consists of several antennas directed in different directions to cover the whole sky. An electronic switch, controlled by the satellite receiver, connects the receiver to the antenna from which the desired satellite signal is obtained. This system is especially suitable for unmanned reliable receiving stations if an antenna gain of the order of 10 dB is enough.     

An Aspect of Determining the Range of Radar Detection

The determination of the range of radar is carried out according to statistical methods which are not always immediate. For this reason, a parametrical method is proposed which condenses the elements necessary for this calculation in the form of three abaci. Furthermore, a general formula condenses this result, and the formula is extended to the other transmission systems.     

A Concept of Position Fixing by a Passive Mode Navigation Satellite System

A position fix in a passive mode using satellites usually necessitates an expensive computer or lengthy hand calculation. This is the largest drawback of passive navigation and it would be more desirable if the user could find his position by a mere glance at a chart and table, as one uses Loran. The first step toward this goal is to use a synchronous satellite because it simplifies the problem. The next step is to find the position of the user by a Loran type of chart, which is universal, and correct this apparent position by looking at a special table which is made according to the amount of perturbation of both the satellite and the user's position. An example of the position fix along the route between Yokohama to Hawaii is shown. The concept can be extended to orbiting satellites due to the rules which govern the motion of satellites, if the fix accuracy is in the order of 2 to 5 miles. This method should be more accurate than the common sextant and more practical due to the fact that the satellite can be used at any time and in any weather. As a total system, it will be better than Omega because it could provide additional navigation information such as communication or traffic control by using satellites.     

Comments on Stabilization of a Satellite

An expression is derived for the cost resultingfrom the stabilization of a satellite using aspecific optimal control (SOC). An exampleis given in which the optimal and SOC yieldvirtually identical costs.     

Solar Gamma-Ray Spectroscopy

Interactions of ions accelerated in solar flares produce gamma-ray lines and continuum and neutrons. These emissions contain a rich set of observables that provides information about both the accelerated ions and the environment where the ions are transported and interact. Ion interactions with the various nuclei present in the ambient medium produce gamma-ray lines at unique energies. How abundance information is extracted from the measurements is discussed and results from analyses of a number of solar flares are presented. The analyses indicate that the composition of the ambient gas where the ions interact (typically at chromospheric densities) is different from that of the photosphere and more like the composition of the corona, exhibiting low-FIP elemental enhancements that may vary from flare to flare. Evidence for increased Ne/O and the photospheric ³He abundance is also discussed.