Key points are not available for this paper at this time.
From March 22 to May 26, 1964, during orbits 30 through 47, the IMP 1 satellite was located within the earth's magnetic tail, and measurements of the imbedded neutral sheet were possible. Forty-two observations of magnetic field reversals accompanied by a decrease in the field magnitude were detected. Of these, 38 are identified as crossings of a well-developed magnetic neutral sheet or current sheet. The relatively thin neutral sheet lies within a broad region of magnetic field depression and plasma enhancement, or ‘plasma sheet.’ The neutral sheet frequently appears to be moving relative to the satellite with a maximum velocity of a few kilometers per second, and on many orbits multiple crossings occur. The formation of the sheet appears to begin near the magnetic equatorial plane at a geocentric distance of 10±3 RE. The sheet thickness appears to be larger close to the earth and the dawn side of the tail and smaller farther away and toward the noon-midnight meridian. At its thinnest region the sheet appears to be about 500 km thick and about 5000 km at the thickest part. The normal component of magnetic field within the sheet appears from these measurements to be 1–4 gammas toward the dawn side of the tail and less than 1 gamma near the noon-midnight meridian plane. Thus the IMP 1 results favor those models of the tail field topology in which merging of field lines occurs across the imbedded neutral sheet.
Speiser et al. (Sun,) studied this question.