摘要:

Collisions between cosmic‐ray protons and interstellar hydrogen nuclei will produce secondary electrons through the reaction chainThe production energy spectrum of these electrons has been calculated by means of a simplified version of the isobaric nucléon model of pion production. The resulting spectrum exhibits a broad maximum at a kinetic energy of about 25 Mev. It is shown that the high‐energy (E>1 gev) part of the spectrum will be of the same form as the cosmic‐ray spectrum if the total inelasticp‐pcross section remains essentially constant at high

ISSN:0148-0227    

DOI:10.1029/JZ068i015p04399

年代:1963

数据来源: WILEY

摘要:

The dynamic spectrums of whistlers excited by five nuclear explosions are found to be identical to those of natural whistlers observed within a few minutes of shot time. Two shots fired at the Nevada proving ground produced normal two‐hop whistlers at Stanford, 600 km to the west. Three shots fired over Johnston Island (about 14° geomagnetic latitude) produced one‐hop whistlers, some of which were received at northern hemisphere stations as far away as Stanford, 5100 km to the northeast. No whistlers were observed on Kauai, only 1200 km northeast of Johnston Island. Analysis shows that the magnetospheric paths of natural and explosion‐excited whistlers are essentially the same, and that these paths are fixed in the ionosphere and are not necessarily close to the impulse source or the receiver. From analysis of impulse‐whistler delays of shot Teak, it is deduced that the one‐hop whistler received at Stanford was excited by an impulse which first crossed the equator in the earth‐ionosphere wave guide before entering the whistler duct in the southern hemisphere, as suggested in the concept of the hybrid whistler. The recent high‐altitude shot Starfish Prime (July 9, 1962) was detonated at 400‐km altitude, but the dispersion of the source impulse was similar to that of ordinary lightning impulses. This result is interpreted to mean that the impulse was produced below the ionosphere, thus providing support for the Compton‐electron mechanism of impulse generation. The similarity between the natural and shot‐excited whistlers leads to the conclusion that shot‐excited whistlers cannot be used for the purpose of detect

ISSN:0148-0227    

DOI:10.1029/JZ068i015p04409

年代:1963

数据来源: WILEY

摘要:

Guiding‐center approximation for protons in the diamagnetic ring current is valid when two known conditions are satisfied. The critical energies, magnetic rigidities, and pitch angles in the geomagnetic field and the field of the ring current are studied, and the results are applied, as an example, to a model ring current belt proposed by Akasofu and Chapman. It is found that protons with energies 20–40 kev are most likely to be responsible for the belt. The lifetime of these protons in the ring current belt is estimated at 10 days, as observed on the magnetograms. The pp pulsations may, as it seems, be the cause of magnetic scattering of the ring current. This is suggested on the basis of the coincidence of commencements of pp pulsations observed by Troitskaya and the quicker increase of theHforce during the main phase at equatorial magnetic stati

ISSN:0148-0227    

DOI:10.1029/JZ068i015p04421

年代:1963

数据来源: WILEY

摘要:

We have investigated the role of plasma instabilities in the origin of a solar flare. Three types of stability problems are discussed: the magnetohydrodynamic instability of an infinitely conducting fluid, the instability due to the magnetic field gradients, and the finite conductivity instability. These instabilities are examined in a situation that occurs when two plasmas trapped in a pair of sunspot magnetic fields approach each other. The assumption of infinite conductivity gives rise to stable situations. The instability growth time in the magnetic field gradients that exist near sunspots is extremely large. The growth time for finite conductivity instability is of the order of a few seconds or minutes, and we therefore believe that the flare can be produced by finite conductivity instabilities in the solar atmosphere above a group of sunspots. Our analysis does not help explain the acceleration of charged particles to high energies; for this, the problem of acceleration must be considered separately.

ISSN:0148-0227    

DOI:10.1029/JZ068i015p04429

年代:1963

数据来源: WILEY

摘要:

We examine the nature of the distortion of the earths magnetic field in the radiation belt regions for the combination of two external sources of the distortion, the ring current and the solar plasma flow. The distortion is expressed by diagrams showing the location of two points on the distorted lines of force, the radial distance re of a point at which the line of force crosses the equator and its anchoring latitude ϕ (orL= 1/cos2ϕ) on the earth's surface. The γe‐ ϕ (or γe‐L) diagrams thus constructed are of use in a study of the deformations of the outer radiation belt. It is suggested that the lowering of the boundary.Lvalue of the outer belt, observed by the Injun 1 satellite during magnetic storms, is due to the growth of the ring current embedded within the ou

ISSN:0148-0227    

DOI:10.1029/JZ068i015p04437

年代:1963

数据来源: WILEY

摘要:

The relationship between the local (K) and planetary (Kp) magnetic activity and the occurrence of visual auroras inside the auroral zone is investigated. The visual aurora above geomagnetic latitude 80° is found to be negatively correlated with theKandKpmagnetic indexes, whereas nearer to the auroral zone the correlation is positive. The relationship in the region 75–80° latitude is more complicated and of a transitional nat

ISSN:0148-0227    

DOI:10.1029/JZ068i015p04447

年代:1963

数据来源: WILEY

摘要:

Time sequences of lightning photographs were taken at a range of about 100 meters, covering fields of about 10 by 15 meters. Film frames were exposed for 2 μ sec at intervals of about 100 μsec. Analysis of these records has yielded accurate determination of the lightning channel diameter, changes in brightness with time, and changes in the geometry of the channel within individual return strokes and from stroke to stroke within a single flash. Three films successfully exposed show that the diameter of the stroke is typically from 30 to 120 mm, that the stroke brightness usually decreases monotonically from a time within 50 μsec of its onset (but may fluctuate in brightness in some cases). Within a single stroke the shape of the channel ordinarily remains constant, but changes do occur from stroke to stroke within a single fla

ISSN:0148-0227    

DOI:10.1029/JZ068i015p04455

年代:1963

数据来源: WILEY

摘要:

The effect of electric fields on the supercooling of water drops was studied by a special experimental technique which permitted the observation of the action on water drops of a dc electric field of 1 to 30 kv/cm. These experiments, documented by a motion picture film, showed that freezing could be initiated in the water drops at a temperature which was only a few degrees below 0°C by applying external electric fields which had field strengths of several kilovolts per centimeter. It was found that the electrofreezing effect was not due to an orientation of water molecules in the water sample, nor was it due to participate matter produced by sparks or corona discharges since no such discharges took place during the experiments. It was found that the effect was a consequence of the movement of the drop in the electric field along a solid surface. It was concluded from the experiments (1) that an external electric field is able to activate the ice‐micleability of a solid surface and (2) that the characteristics of the effect make it very unlikely that freezing can be initiated by electric fields in atmospheric clouds since the solid surfaces with which the drops have to be in contact during their deformation are not present in mature thunderstorm clou

ISSN:0148-0227    

DOI:10.1029/JZ068i015p04463

年代:1963

数据来源: WILEY

摘要:

Perhaps fools venture where angels fear to tread. Thus, despite Pruppacher's [1963] proper reluctance at attempting to interpret the processes underlying his excellent observations, I cannot resist the temptation to speculate, since such speculation may assist future workers in understanding and further investigating the phenomenon.

ISSN:0148-0227    

DOI:10.1029/JZ068i015p04475

年代:1963

数据来源: WILEY

摘要:

Raindrops were collected from within or near the bases of orographic shower‐producing clouds in Hawaii as an exploratory effort to test some laboratory work and to learn in what way, if any, the isotope concentration might be used as an indicator of the nature of the processes of drop growth in the trade‐wind clouds. Much of the data reveal an inverse relation of deuterium and drop size. Alternative ways of explaining these data are briefly explored in terms of differences in the heights of the cloud tops, in the deuterium within them, and in the time required for drops to equilibrate as they fall through the clouds. It is concluded that the deuterium data given here are not useful as indicators of the processes of raindrop growth in Hawaiian orographic clouds. However, a study of these data, and of the relevant weather conditions obtaining when the raindrops were sampled, has led to specific suggestions for the altering of drop‐sampling procedures so as to make future measurements useful in testing certain models of raindrop g

ISSN:0148-0227    

DOI:10.1029/JZ068i015p04477

年代:1963

数据来源: WILEY