摘要:

The dependence of the neutron monitor mass absorption coefficient on 11‐year changes in the primary cosmic‐ray spectrum was investigated for the monitors at Chicago, Illinois, and Climax, Colorado, using a modified single regression method. The analysis of hourly intensity and pressure values for 733 days at Chicago and 1000 days at Climax during the period 1954–1963 revealed no significant variation at either station. The mean value of the coefficient at Chicago is −0.938±0.007%/mm Hg; at Climax it is −1.010 ± 0.006%/mm Hg. This difference is significant and depends on the altitude characteristics of the nucleonic component. These results are compared with e

ISSN:0148-0227    

DOI:10.1029/JZ070i011p02469

年代:1965

数据来源: WILEY

摘要:

A diffusion model for the propagation of solar flare particles in interplanetary space is adopted. The irregularities in the magnetic field are assumed to act as a uniform distribution of scattering centers, and the regular part of the interplanetary field is taken to be either radial or homogeneous. A modified diffusion equation, involving a diffusion tensor, is considered. The resulting density is a function of the location of the flare on the surface of the sun. Under the same assumptions, a more rigorous approach is proposed through use of the Boltzmann equation. The solutions obtained suggest that the regular magnetic field leads to a transition (during the initial phase of the event) from a one‐dimensional to a three‐dimensional diffusion reg

ISSN:0148-0227    

DOI:10.1029/JZ070i011p02475

年代:1965

数据来源: WILEY

摘要:

Using a low energy electron detector on the low altitude, high latitude satellite Injun 3, large diurnal and latitudinal effects have been observed for 10‐kev electrons. It was found that intense fluxes of low energy electrons,J(Ee≥ 10 kev) ≥ 2.5 × 107electrons (cm2ster sec)−1, occur only during local night between 1700 and 0700 hours (magnetic local time) and that they occur only between 58° and 76° invariant latitude. These intense fluxes of low energy electrons occur predominantly during periods of high geomagnetic activity. It is also found that a large change in the slope of the electron energy spectrum is associated with the trapping boundary for 40‐kev electrons found at high latitudes during local night. This change is from a relatively hard spectrum inside the boundary to a very soft spectrum just outside the boundary. The intense fluxes of very soft electrons found beyond the 40‐kev trapping boundary at low altitudes are thought to be related to the intense fluxes of low energy electrons found by Gringauz and by Freeman at great distances on the night sid

ISSN:0148-0227    

DOI:10.1029/JZ070i011p02485

年代:1965

数据来源: WILEY

摘要:

Large‐scale electric potential fields in the magnetosphere are generally invoked in theories of the aurora. It is shown in the present article that irregular fluctuations of such fields cause a random radial motion of trapped energetic particles by violating the third adiabatic invariant. When the first and second invariants are conserved, any radial motion of the particles is associated with a corresponding energy change. Some particles move outward and others inward; but, if there is a source in the outer magnetosphere and a sink farther in, there will be a net inward transport and an associated net energy gain. This mechanism supplements that of particle transport by magnetic disturbances, which has already been discussed in the literature. The transport and acceleration of energetic particles by fluctuating electric potential fields have a formal similarity to the so‐called stochastic mode of acceleration in synchrocyclotrons. In the magnetosphere, the rate of displacement of trapped particles is found to depend on the spectral power density of the fluctuating electric fields at the azimuthal drift frequency and its harmonics. Which of these frequencies is most important depends on the spatial structure of the fluctuations. The observational data needed for numerical evaluation of the rate of transport are still lacking, but the formulas derived serve the purpose of indicating what properties of the fields are important and ought to be measured experimentally. The effects of magnetic time variations, which have been discussed in the literature under special assumptions, are considered in a more general way. A first‐order result is given, which applies not only to initial phases of magnetic storms but also to other types of magnetic time varia

ISSN:0148-0227    

DOI:10.1029/JZ070i011p02503

年代:1965

数据来源: WILEY

摘要:

The local magnetic field intensityBis often used as a coordinate for specifying position along a line of force in the earth's magnetic field. In this paper an alternate coordinate called χ is proposed to specify position along the line when dealing with trapped particles. The value of χ at any point is equal to (1 ‐B0/B)½, whereB0is the magnetic field strength at the equator of the line of force. The physical significance of χ is that a charged particle will mirror at a value of χ equal to the cosine of its pitch angle as it crosses the magnetic equator. It is shown thatj(μ0), the equatorial particle pitch angle distribution expressed as a function of pitch angle cosine, andJ(χ), the omnidirectional particle flux along the line of force expressed as a function of χ, are related by integral transformations. The properties of χ are such that near the magnetic equator χ increases almost linearly with latitude, whileBincreases fromB0as the latitude squared. Therefore χ is a more sensitive coordinate in the equatorial region thanB. A matrix approximation method, usually capable of a few per cent accuracy, is developed for transforming betweenj(μ0) andJ(x). An example of this matrix transformation scheme is presented, as well as several examples in whichj(μ0) andJ(χ) can be expressed in terms of known functions. Various other properties ofj(μ0),J(χ), and the coordinates χ

ISSN:0148-0227    

DOI:10.1029/JZ070i011p02517

年代:1965

数据来源: WILEY

摘要:

The effect of an electrostatic field on the mirror altitudes of charged particles is calculated under the assumption that the magnetic field lines are equipotentials and that the electric field drift velocities are small compared with the particle velocities. It is found that the effect of the electric field on the mirror altitudes of charged particles can be presented as a function of the geocentric distance of the particle in the equatorial plane independent of the explicit form of the electric field. The results of the computation are summarized in two graphs. It is also shown that the presence of a transverse electrostatic field does not affect the longitudinal invariant.

ISSN:0148-0227    

DOI:10.1029/JZ070i011p02529

年代:1965

数据来源: WILEY

摘要:

The geomagnetic solar quiet daily variation field,Sq, was studied separately for three longitudinal zones during each of three seasons using IGY data obtained at 69 stations. Equivalent external (overhead) and internal (induced within the earth) electric current systems responsible forSqvariations with respect to dip latitude were estimated by the method of spherical harmonic analysis in each zone for each season. Particularly interesting results are the large current intensity during equinoxes and the asymmetry between the northern and southern hemispheres for equinoctial months and even for the yearly average.

ISSN:0148-0227    

DOI:10.1029/JZ070i011p02535

年代:1965

数据来源: WILEY

摘要:

The geomagnetic lunar daily variation field,L, was studied using all available results of lunar analysis of geomagnetic data from a total of 37 stations. Equivalent external (overhead) and internal (induced within the earth) electric current systems responsible forLvariations with respect to dip latitude were estimated by the method of spherical harmonic analysis for each season. The external and internal current systems obtained for a mean lunation during the average solar activity period show more plausible current patterns with reasonable amount of total current intensities than any previously obtained.

ISSN:0148-0227    

DOI:10.1029/JZ070i011p02559

年代:1965

数据来源: WILEY

摘要:

Conjugate aspects of auroral zone electron precipitation are examined using data from ten simultaneous balloon flights of X‐ray detectors from Fairbanks, Alaska, and Macquarie Island, Australia, as well as riometer data from Kotzebue and College, Alaska. These results indicate a close correspondence, in similarity and simultaneity, in regions of near conjugacy over a wide range (Kp= 0+ to 60) of geophysical disturbance. Whereas gross features of activity remain intact, dissimilarities become quite evident at locations well removed from near conjugac

ISSN:0148-0227    

DOI:10.1029/JZ070i011p02579

年代:1965

数据来源: WILEY

摘要:

Simultaneous balloon observations of X‐ray pulsations in the 5–10 second range made from Fairbanks, Alaska, and Macquarie Island, Australia, showed no detailed correlation in time or amplitude. Observations in the northern hemisphere, with two balloon instruments separated by about 150 km in the east‐west direction, showed no obvious correlation, but when the separation was reduced to about 100 km in the north‐south direction, X‐ray pulsations showed in‐phase variations. Observations with two balloon instruments separated by 150 km in the east‐west direction showed time coincidences for about one‐third of the microbursts; the other two‐thirds were observed on one balloon or the other. From the small scale size of microburst electron precipitation it is suggested that magnetospheric plasma instabilities are responsible for the electron bombardment of the auroral zone atmosphere. Similar considerations are suggested for pulsating elect

ISSN:0148-0227    

DOI:10.1029/JZ070i011p02599

年代:1965

数据来源: WILEY