Equatorial current sheet in the magnetosphere
Equatorial current sheet in the magnetosphere
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磁层中的赤道电流片
DOI：
10.1029/ja077i031p06093
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发表时间：
1972
影响因子：
--
通讯作者：
M. Sugiura
中科院分区：
文献类型：
--
作者：
M. Sugiura
从OGO 3号和5号卫星推算的ΔB分布表明，等离子体层内赤道地区存在较大的场低压。该−ΔB区域的存在是通过证明由ΔB(Kp=2-3)ΔB(Kp=0-1)导出的−ΔB的等高线具有与ΔB等高线相似的特征来确定的，从而排除了所讨论的ΔB分布可能源于用于计算ΔB的参考场中的误差或轨道确定中的系统误差。在ΔB分布的基础上，证明了通常认为的静止时间环电流是赤道片电流，它是中性片电流在磁层尾部的延伸。等离子体层内大场降低的主要来源是一群能量在0.1-1 Mev的质子，最初是由Davis和Williamson(1963)和Davis(1965)在探测器12、14和15上探测到的。Frank(1967,1971)在Ogo 3上广泛测量的低能质子是等离子体顶层附近和之外的电流的主要来源。尽管电流的来源与在这两个不同能量范围内发现质子的工作人员有关，但将片状电流划分为两个独立的电流带是武断的，而且是不可取的，除非未来的实验表明有必要这样划分。目前已有的磁场数据与从尾部到2.5Re的片状电流是一致的。从磁层粒子动力学的观点来看，包含所有能量的赤道带电粒子片可能是一个比等离子体片和等离子体层的传统概念更有用的概念。
The ΔB distribution deduced from the Ogo 3 and 5 satellites shows large field depressions in the equatorial region inside the plasmasphere. The existence of this −ΔB region is established by demonstrating that contours of differential ΔB, derived by ΔB (Kp = 2–3) − ΔB (Kp = 0–1), have characteristics similar to those of ΔB contours, and thus the possibility is eliminated that the ΔB distribution in question may have arisen from errors in the reference fields used to calculate ΔB or systematic errors in the orbit determination. On the basis of the ΔB distribution it is shown that what is usually considered the quiet-time ring current is an equatorial sheet current that is an extension of the neutral sheet current in the magnetospheric tail. The primary source of the large field reductions inside the plasmasphere is a population of protons with energies of 0.1–1 Mev initially detected by Davis and Williamson (1963) and Davis (1965) on Explorer 12, 14, and 15. Low-energy protons extensively measured on Ogo 3 by Frank (1967, 1971) are primarily responsible for the current near and outside the plasmapause. Although the sources of the current are identified with the workers who discovered protons in these two different energy ranges, the division of the sheet current into two separate current belts is arbitrary and inadvisable unless future experiments indicate the necessity for such a division. The presently available magnetic-field data are concordant with a sheet current continuous from the tail to 2.5 RE. It is suggested that from the standpoint of particle dynamics in the magnetosphere an equatorial charged-particle sheet including all energies may be a more useful concept than the conventional concepts of the plasma sheet and the plasmasphere.