摘要:

The time history of the intensity of several solar cosmic ray events can be interpreted in terms of a unified interplanetary diffusion model which assumes that the diffusion coefficientD=Mrβ, whereris the heliocentric radial distance andMandβare parameters, which may be dependent on particle energyE. The model is particularly successful in accounting for the decay phases. For the September 28, 1961, eventMvaries asE0.33, and, assuming spherical geometry,βis equal to 1 for 55

ISSN:0148-0227    

DOI:10.1029/JZ070i013p02943

年代:1965

数据来源: WILEY

摘要:

Emission at 2800 Mc/s (λ = 10.7 cm) has been examined for 164 solar flare events in 1957–1961 that displayed type II and/or type IV emission at meter wavelengths. Characteristics of the centimeter bursts are presented and discussed in relation to the meter bursts, flares, the magnetic class of the associated sunspots, ionospheric disturbances (SWF), and geomagnetic and solar proton (PCA) effects. No centimeter bursts were detected for 13% of the events; bursts with an impulsive profile were observed for 82% of the events. Of the impulsive bursts, 74% reached maximum quickly, displaying a simple, narrow burst profile (average half‐width 1.8 minutes); the rest had complex profiles containing a predominant broad component (average half‐width 17 minutes). The narrow profile bursts are considered to beMtype, and the broad profile bursts to evidence type IVμemission. The majority of the narrow profile centimeter bursts corresponded to events in which only a type II burst was observed at the meter wavelengths. When type IV bursts were observed at the meter wavelengths, narrow profile centimeter bursts were seen in 43% of the cases and broad profile bursts in 57%. A strong association with magnetically complex sunspots, flares of importance ≥2+, SWF of importance ≥3−, geomagnetic storms, and PCA was found for only those events in which the centimeter burst had a broad profile. It is concluded that the peak intensity and the half‐width of the burst profile at 2800 Mc/s enable solar events with a significant association with geomagnetic and PCA activity t

ISSN:0148-0227    

DOI:10.1029/JZ070i013p02961

年代:1965

数据来源: WILEY

摘要:

A flare plasma cloud model is proposed which has a characteristic magnetic field asymmetry that develops as a natural consequence of the interaction between the expanding solar plasma region and the spiral magnetic field set up by the solar wind. It is a basic characteristic that leads to an understanding of various solar‐terrestrial relationships, such as observed asymmetries in polar cap absorptions and Forbush decreases. These events show pronounced differences, depending on whether the associated flares are east or west. Both a large increase in absorption at the time of storm sudden commencement and a large Forbush decrease are caused almost exclusively by eastern and central flares but not by western flares. The ‘east‐west’ differences require an asymmetrical trapping of solar protons and an asymmetrical field configuration relative to the sun‐e

ISSN:0148-0227    

DOI:10.1029/JZ070i013p02977

年代:1965

数据来源: WILEY

摘要:

Extensive measurements of the magnetic field of the earth at distances greater than approximately 7Re(earth radii) have been performed by the Imp 1 satellite. These magnetic field measurements began on November 27, 1963, and ended on May 30, 1964. During this six‐month interval the apogee‐earth‐sun angle in solar ecliptic coordinates decreased from 336° to 156°. The apogee of the satellite was 31.7Re, and the range of the magnetometers was between 0.25 and 300γ. This paper is concerned principally with the topology of the magnetic field within the magnetosphere and the position of both its boundary and the detached collisionless bow shock wave. The geomagnetic field is observed to trail out far behind the earth in the antisolar direction, thus forming amagnetic tail. Magnetic field strengths of approximately 10 to 30 γ are observed out to satellite apogee. The diameter of the magnetosphere at a distance of 30Rebehind the earth is found to be approximately 40Re. The direction of the field is parallel to the earth‐sun line and in the antisolar direction below the solar magnetospheric equatorial plane and in the solar direction above this plane. A neutral surface separating antisolar directed fields in the southern hemisphere from solar directed fields in the northern hemisphere has been detected over a large area. This experimental result suggests the development of quantitative theories explaining the aurora, gegenschein, day‐night asymmetry, and formation of the radiation belts. On the basis of a preliminary review of the data, it appears that the geomagnetic field trails out far behind the earth following the flow field of the solar plasma to a distance far beyond the orbit of the moon. No termination of the magnetic tail is detected or suggested by the data. Thus the earth can be compared to the nucleus of a comet, the radiation belts and co‐rotating magnetosphere being the coma and the magnetic tail being th

ISSN:0148-0227    

DOI:10.1029/JZ070i013p02989

年代:1965

数据来源: WILEY

摘要:

The results of an investigation of the characteristics of flux and density fields generated by the isotropic injection of bound particles into the gravitational field of a finite attractive center are presented in this paper. It is found that both flux and density maximums occur; that the density maximum always lies outside the flux maximum; and that the extremum values, for the distances of the flux and density maximums of bound particles from the attractive center, are 3/2 and 2 radii of the finite center, respectively. When distances are measured in units of the center radius, and speeds in units of the ‘escape velocity’ from the surface of the center, several interesting relationships between the characteristics of surviving orbits can be easily developed and displayed, including the fraction of injected particles that falls into surviving orbits as a function of the location of the point of injection and the magnitude of the injection veloc

ISSN:0148-0227    

DOI:10.1029/JZ070i013p03007

年代:1965

数据来源: WILEY

摘要:

Using data from the polar orbiting satellite 1963 38C, we have obtained the diurnal variation of trapped electrons of energiesEe≥280 kev and ≥1.2 Mev during magnetic quiet. This diurnal variation is measured as a latitude shift for constant electron intensity and is obtained as a function of invariant magnetic latitude. All the data were obtained for dipole orientations within ±12° from the normal to the earth‐sun line and for satellite positions within 8° of the noon‐midnight meridian. Assuming conservation of the adiabatic invariants as these trapped electrons drift in the magnetosphere, it has been possible to obtain a nightside magnetic field configuration that fits the observed diurnal variations. A dayside configuration that agrees with experimental observations was used. The nightside configuration so determined displays an extended field line geometry and a current sheet in the magnetic equatorial plane. The field due to this current sheet is found to range from 20 to 40 gammas adjacent to the sheet, depending upon the radial extent of the sheet. A field line configuration in the noon‐midnight meridian is presented. The nightside trapping boundary as defined by field line closure was found to occur at 1100 km at 67°, in agreement with observed boundaries at 1100 km of ∼67° for both ≥40‐ and ≥280‐kev electrons. The situation on the dayside is di

ISSN:0148-0227    

DOI:10.1029/JZ070i013p03017

年代:1965

数据来源: WILEY

摘要:

Particle detectors on board the Alouette 1 satellite at an altitude of 1000 km occasionally detect electron fluxes at latitudes above the region where the boundary of the outer Van Allen radiation zone normally occurs. The latitude profiles of the electron fluxes are usually in the form of a fairly narrow spike, and some of the events have extremely high intensities; directional intensities of electrons above 40 kev approaching 109cm−2sec−1 ster−1have been observed. The high latitude electron fluxes are found preferentially on the night side of the earth on lines of force which presumably connect to the ‘tail’ of the magnetosphere and at times when enhanced electron fluxes are observed in the outer radiation zone. It is suggested that electrons generated in the tail of the magnetosphere may form an important source of electrons for the outer radia

ISSN:0148-0227    

DOI:10.1029/JZ070i013p03031

年代:1965

数据来源: WILEY

摘要:

The Lockheed‐Aerospace P11 satellite (1964‐45A) launched into a polar eccentric orbit on August 15, 1964, included in its payload a VLF electric field experiment supplied by TRW Space Technology Laboratories. Measurements in the frequency range 1.7 to 14.5 kc/s reveal that the indicated background rarely falls below 10−3volt/m and that sustained field enhancements withE≃ 20–100 mv/m are generally detected in regions where energetic electrons are precipitated from the Van Allen belts. The experiment is described; some early results are presented; and an interpretation in terms of electrostatic ion waves is given. The possibility that large‐amplitude ion waves cause diffusion acrossLshells and magnetospheric electron acceleration is als

ISSN:0148-0227    

DOI:10.1029/JZ070i013p03045

年代:1965

数据来源: WILEY

摘要:

An electrodynamic heating mechanism is proposed to account for the precipitation of kilovolt energy electrons during an auroral disturbance. It is shown that given the existence of an electric field transverse to the geomagnetic field caused by space charges in the magnetosphere, currents will flow along the magnetic field connecting the space charges to the conducting ionosphere. It is shown that the longitudinal current deduced from magnetic observations can be of sufficient intensity to become unstable, resulting in growing ion acoustic waves. In the nonlinear limit these waves tend to inhibit current flows in a collisionless plasma and transform the ordered flow energy into turbulent energy, thus resulting in extreme electrodynamic heating of the electrons. The flow of these ‘hot’ electrons down the geomagnetic field lines is believed to be responsible for the bright aurora and accompanying ionospheric absorpt

ISSN:0148-0227    

DOI:10.1029/JZ070i013p03061

年代:1965

数据来源: WILEY

摘要:

A quasilinear diffusion equation for particles interacting with transverse waves propagating along a homogenous magnetic field is constructed to study the effect of resonant magnetic‐moment‐violating interactions. It appears that quite anisotropic flat‐helix particle distributions can result from such interac

ISSN:0148-0227    

DOI:10.1029/JZ070i013p03075

年代:1965

数据来源: WILEY