HF‐induced airglow at magnetic zenith: Thermal and parametric instabilities near electron gyroharmonics
HF‐induced airglow at magnetic zenith: Thermal and parametric instabilities near electron gyroharmonics
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磁天顶处的高频感应气辉：电子陀螺谐波附近的热和参数不稳定性
DOI：
10.1029/2005gl023864
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发表时间：
2005
影响因子：
5.2
通讯作者：
W. J. Burke
中科院分区：
文献类型：
--
作者：
E. Mishin;M. Kosch;T. Pedersen;W. J. Burke
我们分析了高频有源极光研究计划(HAARP)设施中强无线电波诱导的气辉，以获得第二和第三电子回旋谐波(FC)附近的泵浦频率f0。在f0∼2FC加热过程中通过减弱电离层的双共振时，气辉强度突然上升，并在连续四个脉冲中保持升高。在此期间，热不稳定性和参数不稳定性并存。随后，热参数不稳定性受到阻碍。二次回旋谐振区附近的加热效果归因于二次回旋谐振区附近的特殊色散特性。这些观测表明，当局域等离子体和二次回旋谐波频率匹配时，朗缪尔波参与了回旋加速。对于f0∼3fc，由于回旋加速的抑制和参数衰变不稳定性，气辉终止。
We analyze airglow induced by intense radio waves at the High‐frequency Active Auroral Research Program (HAARP) facility for pump frequencies f0 near the second and third electron gyroharmonic (fc). While passing through the double resonance in the weakening ionosphere during heating at f0 ∼ 2fc, airglow intensities rose abruptly and remained elevated during four consecutive pulses. During this period both the thermal and parametric instabilities coexisted. Subsequently, the thermal parametric instability was hampered. The effectiveness of heating near the second gyroharmonic is ascribed to specific dispersion characteristics near the double resonance. The observations suggest that Langmuir waves participate in cyclotron acceleration when the local plasma and second gyroharmonic frequencies match. With f0 ∼ 3fc the airglow terminated due to the suppression of cyclotron acceleration and parametric decay instability.