摘要:

Propagation characteristics of earthward streaming protons in the plasmasheet boundary layer are investigated in a model magnetosphere from the analysis of single particle trajectories. The phase space of initial proton distributions within the plasmasheet boundary layer out to 40 Earth radii (Re) can be separated into four major components. In a region outside the loss cone, protons with pitch angles less than about 2.6° can make it to the auroral zone at S3‐3 altitudes and below. Protons at all other pitch angles, with speeds greater than about 1100 km/s, reflect (or mirror) at high latitudes near the Earth and return tailward, often convecting toward the inner plasmasheet. Protons with velocities as high as 800 km/s, regardless of pitch angle, are found to mirror such that they are "trapped" in the ring current region of the magnetosphere. These results are dependent on the magnitude and direction of the convection electric field, such that during geomagnetic storms with higher convection electric fields, higher energies of the plasmasheet boundary layer protons would be expected to reach the low‐latitude portions of the ring cur

ISSN:0094-8276    

DOI:10.1029/GL013i001p00076

年代:1986

数据来源: WILEY

摘要:

The likely dimensions of an extended earth magnetotail are investigated by considering various published polar cap and magnetotail observations in light of recent knowledge about magnetosphere behavior under different interplanetary magnetic field conditions. It is argued that the magnetotail is highly‐time dependent. During southward field conditions the tail probably attains its maximum radius but is subject to "breaking off" via substorm associated reconnection events which temporarily deplete the flux and reduce the radius. During northward interplanetary conditions more field lines are apt to close near the earth leaving considerably less flux to form any extended tail. Using estimates for both the amount of open polar cap flux and the tail flux at 60 Re, we argue that at 200 Reeither the tail cross section is elongated in the equatorial plane or the average radius is not more than 25 R

ISSN:0094-8276    

DOI:10.1029/GL013i001p00080

年代:1986

数据来源: WILEY

ISSN:0094-8276    

DOI:10.1029/GL013i001p00084

年代:1986

数据来源: WILEY