Dipole Measurements of Waves in the Ionosphere
Dipole Measurements of Waves in the Ionosphere
复制标题
电离层波的偶极子测量
DOI：
10.1007/3-540-33203-0_7
复制
发表时间：
2006
期刊：
影响因子：
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通讯作者：
H. G. James
中科院分区：
文献类型：
--
作者：
H. G. James
摘要通过对俄狄浦斯C(OC)两点传播实验数据的分析，验证了磁等离子体中分布偶极子天线的理论。电离层中电磁信号在1公里范围内的传输已被用来证实冷磁等离子体中波的发射、传播和探测理论。来自OC研究结果的对偶极理论的证实和洞察导致了对一些更古老的数据的回归，这些数据可以用它们来解释。利用互易原理对偶极子有效长度的概念进行了定量的重新检验。研究发现，以前对电磁哨子模传播的测量结果与用真空偶极子理论中的经典互易定义所预测的结果相似。相比之下，OC的调查发现，在哨子模共振锥附近传播的电磁场可以是偶极子物理长度的数倍。这一发现对解释射电发射极光嘶嘶声的测量强度以及其来源的性质具有重要意义。由于电离层内在下斜共振锥或上斜共振锥附近的传播实验产生了极强的透射率，因此在解释相应频域中等离子体波现象的强度时必须谨慎地选择LEF。
AbstractThe theory of distributed dipole antennas in magnetoplasmas has been tested through the analysis of the data from the two-point propagation experiment OEDIPUS C (OC). The transmission of electromagnetic signals over a 1-km distance in the ionosphere has been used to substantiate the theory of emission, propagation and detection of waves in a cold magnetoplasma. Confirmations and insights about the dipole theory arising from the OC research results have occasioned a return to some older data that can be profitably interpreted with them. The concept of dipole effective lengthLeffhas been re-examined quantitatively with the help of the reciprocity principle. It is found that previous measurements of electromagnetic whistler-mode propagation giveLeffvalues similar to those predicted using a classic reciprocity definition brought over from the vacuum dipole theory. In contrast, OC investigations found thatLeffcan be many times the dipole physical length for propagation near the whistler-mode resonance cone. The finding has important consequences for the interpretation of the measured strength of the radio emission auroral hiss and, by extension, the nature of its source. Since intra-ionospheric experiments on propagation near either the lower- or the upper-oblique-resonance cone produced extremely strong transmission, theLeffapplied to the interpretation of the strength of plasma-wave phenomena in the corresponding frequency domains must be chosen with care.