The formation of small‐scale irregularities in the ionosphere
The formation of small‐scale irregularities in the ionosphere
复制标题
电离层小规模不规则现象的形成
DOI：
10.1029/ja073i005p01627
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发表时间：
1968
影响因子：
--
通讯作者：
G. Reid
中科院分区：
文献类型：
--
作者：
G. Reid
本文研究了几位作者以前讨论过的一种等离子体不稳定机制与电离层的相关性。对这种机制进行了线性化分析，它在几个方面与以前的处理方法不同，并且比实验室等离子体更直接地适用于电离层。研究发现，由于存在与潮汐发电机作用相当的稳定电场，电离层的发电区很可能不会随着电子浓度不规则的增长而变得不稳定，尺度从几十米到几公里不等。进一步提出，与较大尺度的发电区不规则性增长有关的空间电荷势可以沿着磁力线传导到F区，在赤道附近存在垂直电离梯度和在高磁纬度存在水平梯度的情况下，在F区产生不规则性。结果表明，这一理论似乎能够解释许多观测到的F区不规则性的特征，包括它们的日变化及其与磁扰动的关系，这种不规则性在高纬度是积极的，在倾角赤道附近是负的。讨论了这一机制与早期关于小尺度F区不规则性增长理论的关系。
This paper examines the relevance to the ionosphere of a certain plasma instability mechanism previously discussed by several authors. A linearized analysis of the mechanism is given that differs from earlier treatments in several respects and is more directly applicable to the ionosphere than to laboratory plasmas. It is found that the dynamo region of the ionosphere is likely to be unstable against the growth of irregularities in electron concentration with scale sizes in the range from a few tens of meters to a few kilometers, given the presence of steady electric fields comparable to those expected to be present from tidal dynamo action. It is further suggested that the space-charge potentials associated with the growth of the dynamo-region irregularities of larger scale size can be conducted up the magnetic field lines into the F region, generating irregularities there in the presence of a vertical gradient in ionization near the equator and in the presence of horizontal gradients at high magnetic latitudes. It is shown that this theory appears to be capable of explaining many of the observed features of F-region irregularities, including their diurnal variation and their correlation with magnetic disturbance, which is in a positive sense at high latitudes and in a negative sense in the vicinity of the dip equator. The relationship of the mechanism to earlier theories of the growth of small-scale F-region irregularities is discussed.