Excitation threshold and gyroharmonic suppression of artificial E region field‐aligned plasma density irregularities
Excitation threshold and gyroharmonic suppression of artificial E region field‐aligned plasma density irregularities
复制标题
人工 E 区场对准等离子体密度不规则性的激发阈值和回旋谐波抑制
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
M. McCarrick
中科院分区：
文献类型：
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作者：
D. Hysell;E. Nossa;M. McCarrick
利用HAARP设施沿着阿拉斯加的30 MHz相干散射雷达成像仪进行了电离层修改实验，以检查人工E区域场向等离子体密度不规则性（FAI）的特性。在一组实验中，RF发射功率逐渐变化，以确定不规则性产生的阈值电场。根据Thidé和Lundborg（1986）的全波形式，在99 km海拔高度和2.7 MHz加热频率下，确定阈值O模式峰值电场幅度为170-195 mV/m。在另一个实验中，逐渐改变抽运频率以研究在二次电子回旋谐波频率（2Ωe）附近频率处FAI的抑制。相干回波被发现在约2Ωe的40-50 kHz宽的非对称频带中的泵浦频率被抑制，但仅对于略微高于阈值驱动的不规则性。这些结果的理论背景。
Ionospheric modification experiments have been carried out using the HAARP facility along with a 30 MHz coherent scatter radar imager in Alaska to examine properties of artificial E region field‐aligned plasma density irregularities (FAIs). In one set of experiments, the RF emission power was varied gradually in order to determine the threshold electric field for irregularity generation. A threshold O mode peak electric field amplitude of 170–195 mV/m at an altitude of 99 km and a heating frequency of 2.7 MHz was identified based on the full‐wave formalism of Thidé and Lundborg (1986). In another, the pump frequency was varied gradually to investigate the suppression of the FAIs at frequencies near the second electron gyroharmonic frequency (2Ωe). Coherent echoes were found to be suppressed for pump frequencies in an asymmetric band 40–50 kHz wide around 2Ωe but only for irregularities driven marginally above threshold. Theoretical context for these results is provided.