Theory of Kilometric Gradient-Drift Structures in the Daytime and Nightime Equatorial Electrojet

昼夜赤道电喷流中千米级梯度漂移结构理论

• 批准号: 9508552
• 负责人: Amitava Bhattacharjee
• 金额: $ 10.5万
• 依托单位: University of Iowa
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-01 至 1998-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9508552&HistoricalAwards=false
• 关键词: Theory; Kilometric; Gradient; Drift; Structures

This proposal includes a thorough exploration of the linear instability spectrum, using both eigenmode and initial-value methods, and the two dimensional turbulence that results from the nonlinear growth of these instabilities. The PI will use measured density and electric field profiles. He will attempt to clarify the role of short-wavelength instabilities in the presence of dominant kilometer-scale structures, the distinctions in turbulent characteristics between the upper electrojet in daytime as well as nighttime. Finally, he will ascertain (1) the role of velocity shear, much more effective in damping short-wavelength instabilities than long-wavelength ones, and (2) the self- regulatory role of velocity shear, not only driven by the ambient electric fields and neutral wind, but also possibly generated by a dynamo effect due to the turbulent Reynolds stress at short wavelengths.***

该建议包括对线性不稳定性谱的深入探索，使用特征模态和初始值方法，以及由这些不稳定性的非线性增长引起的二维湍流。PI将使用测量的密度和电场剖面。他将试图澄清短波长的不稳定性在千米尺度结构中所起的作用，以及白天和夜间上层电喷流湍流特性的区别。最后，他将确定(1)速度剪切的作用，它在抑制短波长的不稳定性方面比长波长的不稳定性更有效；(2)速度剪切的自我调节作用，它不仅由环境电场和中性风驱动，也可能由短波湍流雷诺应力引起的发电机效应产生***