Simultaneous trapped electron and magnetic tail field observations

Abstract

Using data from the polar orbiting satellite 1963 38C, the behavior of the high‐latitude energetic (≥ 280 kev) electron trapping boundary, Λc, at 1100 km is presented for the period March 15 through June 3, 1964. A sudden collapse of Λc to lower latitudes during the onset of magnetic storms, as indicated by Kp and Dst, is found to be a characteristic feature of the low‐altitude trapped electron population. Details of this behavior are presented and discussed. In addition, during this time period, the NASA IMP 1 satellite sampled field characteristics in the geomagnetic tail. Correlated observations of the simultaneously observed behavior during magnetic disturbances of the 1100‐km trapped electron population and of the field strength in the tail are presented. In three cases there is agreement and in one case disagreement with the latitude decreases that are predicted with an extended geomagnetic tail configuration. These results are considered to be direct evidence of the important influence exerted by the geomagnetic tail field in governing not only the quiet‐time trapped particle distribution, but also the behavior of the trapped particle population during magnetic storms.

The acceleration and precipitation of Van Allen outer zone energetic electrons

“…Other correlated magnetospheric phencmena include (1) inward notion of plasma pause (Carpenter, 1966), (2) radial motion of plasma sheet (Vasyliunas, 1968), (3)emission of magnetic micropulsations (McPherron, 1967), (4)energetic electron precipitation, (5) emission of VLF noise (flMrozumi, 1965) and (6) collapse of high-latitude trapping boundary (Williams and Ness, 1966).…”

The Configuration of the Geomagnetic Field

“…Behannon and Ness (1966) used a boundary crossing anomalously close to the tail axis and a flux conservation argument to suggest the flux enhancement. Ness and Williams (1966), Williams and Ness (1966) ;t # figure 15 (Fairfield and Ness, 1970) presents distributions similar to Figure 14 only for the solar magnetospheric Z component of the field. There is no variation of Z sm corresponding to that for F in Figure 14.…”

Substorm aspects of magnetic pulsations

“…This shift is more important when the frequency shift of the IPDP is larger (see Table II). Lacourly and Gendrin (1967) have studied in more detail this movement of the trapping boundary with the help of the 1963-38 C satellite data, published by Williams and Ness (1966). On Figure 14, one sees that at each time that the trapping boundary is moving inwards (or that its invariant latitude at 1000 km is decreasing) there exists at least an IPDP observed at the Kerguelen station.…”

“…But no specific relation between this southward direction and the and occurrence of IPDP's at Kerguelen. The first and third lines are taken from the work of Williams and Ness (1966). Distinction is made between 'pronounced' IPDP's (~) of which the final frequency is greater than 1 Hz, and the less pronounced IPDP's (~').…”