Magnetospheric electron densities inferred from upper‐hybrid band emissions
Magnetospheric electron densities inferred from upper‐hybrid band emissions
复制标题
DOI：
10.1029/2004gl020847
复制
发表时间：
2004-10
影响因子：
5.2
通讯作者：
Robert F. Benson;P. Webb;James L. Green;Leonard N. Garcia;B. Reinisch
中科院分区：
文献类型：
--
作者：
Robert F. Benson;P. Webb;James L. Green;Leonard N. Garcia;B. Reinisch
当电子等离子体频率fpe（∝Ne1/2）大于电子回旋频率fce时，磁层电子密度Ne通常可以从被动无线电波动态谱中得到不到百分之几的结果。这一结论是基于在等离子体顶附近的IMAGE卫星上的无线电等离子体成像仪（RPI）的交错主动和被动观测得出的。Ne的测定是基于强窄带发射的频率限制，确定为上混合带。下限用fpe表示，上限用上混合频率fuh = (fpe2 + fce2)1/2表示。这些频率限制和大的发射幅度，通常比背景高20 dB或更多，表明强Z模波，而不是准热波动，是发射源。
The magnetospheric electron density Ne can often be obtained to within a few percent from passive radio‐wave dynamic spectra when the electron plasma frequency fpe (∝ Ne1/2) is greater than the electron cyclotron frequency fce. This conclusion is based on interleaved active and passive observations from the Radio Plasma Imager (RPI) on the IMAGE satellite in the vicinity of the plasmapause. The Ne determinations are based on the frequency limits of an intense narrowband emission identified as the upper‐hybrid band. The lower limit is identified with fpe and the upper limit with the upper‐hybrid frequency fuh = (fpe2 + fce2)1/2. These frequency limits and the large amplitude of the emission, typically 20 dB or more above background, suggest strong Z‐mode waves, rather than quasi‐thermal fluctuations, as the emission source.