Further observational support for the limited-latitude magnetodisc model of the outer Jovian magnetosphere

The distinction between the magnetic anomaly model of the outer Jovian magnetosphere (Dessler and Vasyliunas, 1979; Vasyliunas and Dessler, 1981) and the magnetodisc model (as, for example, discussed most recently by Goertz (1981)) is reviewed, and a further observational comparison of the two models is pointed out. The comparison involves the latitudinal variation of the intensity of energetic charged particles confined near the magnetic equatorial plane. Because of this confinement, there should be a direct relationship between the maximum latitude excursion (relative to the magnetic equatorial plane) made by a spacecraft during one 10-hour planetary rotation period and the ratio of the maximum intensity observed in the manetic equatorial plane to the minimum intensity observed off the equator. Thus if the maximum latitude excursion is large, the minimum between two maxima should be quite deep. If the maximum latitude excursion is known, a scale height for the energetic particle confinement can be estimated from observed maximum-to-minimum ratios. The two magnetospheric models (magnetic anomaly and magnetodisc) in general predict different maximum latitude excursions. For the outbound passes of Voyagers 1 and 2, these predictions are combined with observations of energetic particle intensities (Krimigis et al, 1979a, b) to calculate the confinement scale heights for the energetic particles. For the magnetodisc model, the scale height is generally less than 2 R/sub J/ and is a weakly decreasing function of r, in excellent quantitative agreement with the scale height derived from a combination of simple MHD theory and a magnetic field model based on Pioneer 10 out bound magnetic field measurements (Goertz, 1976). The magnetic anomaly model, on the other hand, yields a scale height which apparently increases to large values at large radial distances