Stimulated electromagnetic emissions during pump frequency sweep through fourth electron cyclotron harmonic
Stimulated electromagnetic emissions during pump frequency sweep through fourth electron cyclotron harmonic
复制标题
通过第四电子回旋加速器谐波进行泵频率扫描期间的受激电磁发射
DOI：
10.1029/2001ja005082
复制
发表时间：
2002
影响因子：
--
通讯作者：
E. Sergeev
中科院分区：
文献类型：
--
作者：
T. Carozzi;B. Thidé;S. Grach;T. Leyser;M. Holz;G. Komrakov;V. Frolov;E. Sergeev
[1]使用计算机控制的发射机信号，在大约以电子回旋频率的四次谐波为中心的60 kHz宽频带内，扫描了入射到电离层的高功率高频无线电波的频率。因此，可以以前所未有的分辨率、速度和电离层稳定性来测量经过预处理后的受激电磁发射(SEE)的频谱行为。基于实验数据的局域电子回旋频率估计的比较揭示了某些下移极大值模型与经验的广义上移极大值(BUM)特征公式ΔfBUM=f0−nFce之间的差异。在标称燃烧截止频率以下发现了与燃烧有关的微弱排放。最后，我们观察到，根据泵浦频率扫描是上升还是下降，某些SEE分量的强度不同。
[1] The frequency of a high-power HF radio wave incident on the ionosphere was swept, using a computer-controlled transmitter signal, in <10 s within a 60-kHz-wide frequency band approximately centered on the fourth harmonic of the electron cyclotron frequency. Measurements of the spectral behavior of stimulated electromagnetic emissions (SEE) across this harmonic after preconditioning could thereby be made with unprecedented resolution, speed, and ionospheric stability. Comparison of local electron cyclotron frequency estimations based on the experimental data reveals discrepancies between certain downshifted maximum models and the empirical broad upshifted maximum (BUM) feature formula ΔfBUM = f0 − nfce. Weak emissions related to the BUM were discovered below the nominal BUM cutoff frequency. Finally, we observed that the intensity of certain SEE components differed depending on the whether the pump frequency sweep was ascending or descending.