高頻主動式極光研究項目(英語:High Frequency Active Auroral Research Program,常縮寫為HAARP),是一個由美國空軍、美國海軍、國防高等研究計劃署及阿拉斯加大學所共同合作的電離層研究計劃。[1][2]HAARP計劃在阿拉斯加加科納(英語:Gakona, Alaska)設有一個由美國空軍負責管理的研究設施,被稱為HAARP研究站(HAARP Research Station)。
NRL Scientists Produce Densest Artificial Ionospheric Plasma Clouds Using HAARP (新聞稿). U.S. Naval Research Lab. 2013-02-25 [5 April 2013]. (原始內容存檔於2013-03-02). Using the 3.6-megawatt high-frequency (HF) HAARP transmitter, the plasma clouds, or balls of plasma, are being studied for use as artificial mirrors at altitudes 50 kilometers below the natural ionosphere and are to be used for reflection of HF radar and communications signals. Past attempts to produce electron density enhancements have yielded densities of 4×10⁵ electrons per cubic centimeter (cm³) using HF radio transmissions near the second, third, and fourth harmonics of the electron cyclotron frequency. This frequency near 1.44 MHz is the rate that electrons gyrate around the Earth's magnetic field. The NRL group succeeded in producing artificial plasma clouds with densities exceeding 9×10⁵ electrons cm³ using HAARP transmission at the sixth harmonic of the electron cyclotron frequency.
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