INTERPLANETARY MAGNETIC FIELD AND AURORAL ZONES
INTERPLANETARY MAGNETIC FIELD AND AURORAL ZONES
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DOI：
10.1103/physrevlett.6.47
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发表时间：
1961-01-01
影响因子：
8.6
通讯作者：
DUNGEY, JW
中科院分区：
文献类型：
--
作者：
DUNGEY, JW
先锋五号发现了一个规则的行星际磁场，重新唤起了人们对霍伊尔的观点的兴趣，霍伊尔认为，主要的极光粒子在行星际磁场和地磁场结合的中性点加速。霍伊尔指出，极光的纬度取决于中性点离地球的距离，因此也就取决于观测到的行星际磁场强度。估计的粒子能量也是合理的。邓吉讨论了加速机制。这里概述了整个场的定性模型，并发现该模型被观测到的S&电流系统所证实。考虑一个行星际等离子体相对于地球运动的模型，这个“风”大约位于黄道平面上，而行星际磁场大致指向南方。没有行星际磁场的问题已经被几位作者研究过了，但是这个磁场的加入从根本上改变了这个问题。基本而棘手的问题是等离子体绕地球流动的问题。这个问题还没有解决，但将用流体磁学的物理图像来勾画。包含中性点的平面内的流动如图1所示。中性点附近的流动由存在于那里的强电流密度控制(3)。中性点之间的反向流动很重要；它必须绕地球流动，但以正常的空气动力学方式进行。为了简单起见，这里假设有一个稳定的层流，但应该指出的是，先驱者1号探测到的磁场变化很大。
The discovery'of a regular interplanetary mag-netic field by Pioneer V has reawakened interest in Hoyle's' suggestion thatthe primary auroral particles are accelerated at neutral points in the combination of an interplanetary field and the geomagnetic field. Hoyle pointed out that the latitude of the aurora would depend on the dis-tance of the neutral points from the earth and hence on theinterplanetary field strength in the observed sense. The estimated particle energy was also reasonable. Dungey'discusses the ac-celerating mechanism. Here a qualitativemodel of the whole field is outlined and is found to be confirmed by the observed S& current system. Consider a model with interplanetary plasma moving relative tothe earth, this" wind" lying approximately in the ecliptic plane, and an inter-planetary field pointing roughly southward. The problem with no interplanetary magnetic field has been studied by several authors, 4 but the inclusion of this field alters the problem radically. The basic and awkward problem is that of the flow of plasma round the earth. This has not been solved but will be sketched using the physi-cal picture of hydromagnetics. The flow in a plane containing the neutral points is shown in Fig. 1. The flow near the neutral points is con-trolled by the strong current density existing there (3). The reverse flow between theneutral points is important; it hasto flow round the earth, but does so in a normal aerodynamic way. A steady laminar flow will be assumed here for simplicity, but it should be noted that large var-iations of the field were detected by Pioneer I.