摘要:

The intensities of electrons as measured with the SUI satellite Injun 1 during its deepest penetrations into the earth's inner radiation zone are reported for the period July 16 to August 10, 1961. The unidirectional intensity of electrons of energy greater than 40 kev was 5×106electrons/cm2sec ster in a direction perpendicular to B atL= 1.22 in the magnetic equatorial plane. The corresponding omnidirectional intensity is estimated to be 1×107/cm2sec. No temporal variations greater than the experimental uncertainty of 30 per cent were found in this region during the period of observation of this repor

ISSN:0148-0227    

DOI:10.1029/JZ068i005p01203

年代:1963

数据来源: WILEY

摘要:

Recent measurements by earth satellites provide conclusive evidence that the magnetosphere of the earth is distorted by the solar wind, as has been predicted on theoretical grounds for some time. In the work reported here motions of charged particles trapped in the distorted magnetosphere were computed by using, as a model of the magnetosphere, the field of a weak magnetic dipole in the presence of a strong magnetic dipole. Drift paths through this field were calculated both for particles whose motion is confined to the magnetic equatorial plane and for particles mirroring at low altitudes. The paths of particles of various energies moving in the magnetic equatorial plane under the combined influences of field gradient‐induced drift and field rotation were also calculated. It was found that, in the model used, the field rotation energizes trapped particles on the morning side and de‐energizes them on the evening side of the earth. It is suggested that this effect must occur in any realistic model of the distorted magnetosphere and that it may play a role in the accumulation of the energetic particles that constitute the Van Allen zo

ISSN:0148-0227    

DOI:10.1029/JZ068i005p01209

年代:1963

数据来源: WILEY

摘要:

Neutron detectors consisting of B10F3proportional counters and Li6I(Eu) scintillation counters, surrounded by varying amounts of moderating material, have been flown above the atmosphere in a number of vehicles. The shape of the neutron energy spectrum given by Hess, Canfield, and Lingenfelter has been verified within experimental limitations, and the flux of neutrons at 650‐km altitude and 36.5°N geomagnetic latitude has been determined to be 0.28±30 per cent neutrons per cm2sec, whereas at 320‐km altitude and 8.7°S the flux is 012±40 per cent neutrons per cm2sec. This flux determination gives an absolute neutron flux a factor of 3 lower than previously reported determi

ISSN:0148-0227    

DOI:10.1029/JZ068i005p01221

年代:1963

数据来源: WILEY

摘要:

The modulation of a spirmmg search coil signal by time‐variant magnetic fields is discussed. For typical spacecraft usage, dipolar inhomogeneity produces a trivial signal. The primary contributions to the signal arise from the coil spin and field time variance. Variations in the scalar value of the field produce both amplitude and phase modulation. In a base field like the earth's with superimposed fluctuations, amplitude modulation from Alfvén waves is usually trivial. The amplitude power spectrum depends on both the spin rate of the spacecraft and the Fourier decomposed frequencies of the fluctuations. Where frequencies near the spin are encountered, spectral inversion can result from what becomes effectively the mixing of two carrier signals. The results of the previous paper of this series are discussed under these conditions, the latter of which is essentially removal of the restriction (∂H/

ISSN:0148-0227    

DOI:10.1029/JZ068i005p01229

年代:1963

数据来源: WILEY

摘要:

The procedure for analysis of fluctuation phenomena in the geomagnetic field, reported in part 1, is extended to study finite disturbances in amplitude and direction at distances of 12.3–14.6 earth radii on the sunlit hemisphere of the magnetopause (magnetospheric‐interplanetary transition region). The appearance of large and small excursions in both field amplitude and direction suggests a highly stirred or turbulent plasma of β ∼1 in this region of space on the day of this flight. The directional changes are generally reversals in polarity and precede the most extreme pulses. The data are characterized by many finite‐amplitude pulses suggestive of collisionless waves such as might typify the microstructure of a shocked region in the collisionless domain. These pulses have crests of extreme sharpness, suggesting the possibility of radiative dissipation. Moreover, the front‐back asymmetry, together with satellite pulse structure, is consistent with damping by either the mechanism of Gardner and others or that of Petschek. Power spectrums of both longitudinal and transverse excitation have been computed. The longitudinal (compressive) energy density is generally ∼10−9erg/cm3; the transverse energy density is ∼10−10erg/cm3. The longitudinal half‐power frequency increases from 2 to 4 rad/sec in traversing outward through this segment of the field. The large depression in power and the arithmetic mean field values for the greatest distance suggest a geomagnetic or interaction termination at 14.6 Re. Arguments are given to show that, within the scope of this experiment, the planar or two‐dimensional view of these phenomena do not qualitatively modify the observations. The results, regarding both the macroscopic and microscopic character, are discussed extensively in part 4 of this series. In the discussion of power spectrums the assumption ∂H/∂t≪ ωH(the unimportance of folded contributions) is adhered to and forms the framework for certain

ISSN:0148-0227    

DOI:10.1029/JZ068i005p01233

年代:1963

数据来源: WILEY

摘要:

The fine‐scale structure of the magnetic field data given in part 3 is examined. The front slopes of the large pulses generally rise to peak value in about 1 second. The rear elopes apparently decay exponentially, often with a satellite structure having a period about one‐sixth that of a medium fixed with respect to the magnetometer, suggesting strong Doppler shifting. Thus, the assumption of a Larmorlike periodicity for these satellite pulses indicates an Alfvén Mach 6 velocity away from the spacecraft. The large pulses (hyperwaves) also appear to be consistent with collisionless, finite‐amplitude hydromagnetic pulses. The slope asymmetry is in qualitative accord with theoretical views, i.e., an anisotropic plasma pressure and/or first‐order dissipation and relaxation.The power spectrums for neitherH⊥nor ψ* are Kolmogoroffian. TheH⊥spectrums are generally compatible with a two‐step process; ψ* (vorticity) spectrums have increasing power density with wave number. Velocity bounds provide a scale size for both the hyperwaves and the eddy distribution. The condition ∂H/∂t«ωH, as discussed at length in part 2 of this series, necessarily forms the basis for certain of the conclusions drawn, especially those just enumerated.The steeply peaked pulse profile implies large crest electric fields due to the Hall effect. Acceleration of charged particles is suggested and is in consonance with a cosmic‐ray view of this region of space on Pioneer 4 and the theory of Morawetz. The conclusion that the pulses are primarily magnetoacoustic with a preponderance of propagation vectors directed earthward is in keeping with the conclusion in part 1 that the hydromagnetic excitation mechanism was a source function of large scale with respect to the magnetosphere.The existence of a copious supply of field reversals always followed by a pulse lends support to a model in which hypersonic gas bubbles are propagating into the vestigial field, inertial reaction creating the pulse and a condition of minimum field potential energy being achieved by twisting of tubes of force on the upstream boundary (magnetopause model).An alternative model implies a large bowlike shock wave, the shock microstructure being fine‐scale collisionless pulse phenomena like those suggested in the type of wave studied by Davis, Lüst, and Schlüter. This last model, however, requires the generation of an exotic ad hoc mechanism to provide plasma instability leading to the X‐type nulls often associated with the waves.The termination of activity at about 14 Re would suggest magnetic termination on the leading edge of the macroscopic shock. The identical termination distance on Pioneer 4 with cosmic‐ray pulses seen as far into the field as 10 Re where the dipole magnitude becomes appreciable favors the magnetopause model over any simple struct

ISSN:0148-0227    

DOI:10.1029/JZ068i005p01265

年代:1963

数据来源: WILEY

摘要:

The magnetic field of the earth is assumed compressed by an incident stream of ionized particles from the sun. A time‐dependent magnetic and electric field is propagated as part of this interaction. A simplified model, a mirror dipole moving in space but of constant magnetic moment, is chosen to calculate the manner in which this electric field will compress and possibly accelerate ions already trapped in the earth's magnetosphere. This model would tend to dump radiation from the terrestrial belts into the atmosphere. For geometrical reasons the effects might be most pronounced in early morning and late evenin

ISSN:0148-0227    

DOI:10.1029/JZ068i005p01295

年代:1963

数据来源: WILEY

摘要:

It has been suggested that auroral backscattering of radio waves in the frequency range 100–800 Mc/s is a consequence of the joint action of turbulence and the earth's magnetic field, which was assumed to produce small‐scale elongated irregularities of ionization lined up with the earth's field. In the present work we investigate solutions of the equation for diffusion and transport of ionization in a weakly ionized turbulent plasma in the presence of a magnetic ffeld. Because of space charge effects, the problem is nonlinear in the ionization densityn(x,t). We show that in the linearized approximation the effect of the magnetic field on turbulence does not lead to irregularities of a scale sufficiently small to explain the observed data. Nonlinear effects may play a role and are being investigated. Preliminary results show that they are indeed capable of increasing density gradients in irregularities of sufficient amplit

ISSN:0148-0227    

DOI:10.1029/JZ068i005p01303

年代:1963

数据来源: WILEY

摘要:

A dilute ionized gas is considered, for which electronion collisions can be neglected and which deviates from thermal equilibrium by having an ion temperatureT4different from the electron temperatureTe. These conditions apply to the ionosphere in theFlayer and above. Methods are reviewed for treating statistical mechanics at thermal equilibrium and the Boltzmann equation for general problems. The electron‐electron, electronion, and ion‐ion pair correlation functions are derived for generalTeT4, and an arbitrary time‐independent magnetic field. The total cross section for scattering of an electromagnetic wave from such a gas is derived for generalTeT4. The results are shown to agree with the integral of the theoretical frequency spectrum derived previously by a number of authors. For long wavelength andT4Te≪1 the cross section is proportional toT4Te. The sources of error for an incorrect result stated by Renau are ex

ISSN:0148-0227    

DOI:10.1029/JZ068i005p01321

年代:1963

数据来源: WILEY

摘要:

During the night of July 27–28, 1962, a zenith night airglow photometer recorded intense flashes of the 0–0 band of the first negative system of N2+caused by lightning strokes in an electrical storm some 60 km distant. The peak intensity of the brightest flash was about 50 rayleighs above the background of 28 rayleighs for the 3914 A emission in the airglow above China L

ISSN:0148-0227    

DOI:10.1029/JZ068i005p01335

年代:1963

数据来源: WILEY