Triggered Auroral Kilometric Radiation

触发极光千米辐射

• 批准号: 9312013
• 负责人: Wynne Calvert
• 金额: $ 3万
• 依托单位: University of Iowa
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-02-01 至 1995-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9312013&HistoricalAwards=false
• 关键词: Triggered; Auroral; Kilometric; Radiation

9312013 Calvert Auroral electron precipitation is hypothesized to result from electron pitch-angle scattering by the cyclotron maser instability during the generation of auroral kilometric radiation (AKR). The AKR consists of intense, primarily extraordinary-mode waves originating on auroral magnetic field lines at geocentric altitudes of 1.3 to 3.3 earth radii. Comprising up to one percent of the total power of the aurora the AKR is now widely believed to be generated by the cyclotron maser instability which results from the doppler-shifted, cyclotron-resonant, pitch-angle scattering of energetic electrons into the loss cone. Critical to this new theory of the aurora is explaining the observed triggering of the AKR by radio waves from the sun, since that phenomenon clearly confirms the new theory. The proposed work is to study this triggering, believed to be caused by enhanced local precipitation in ambient density minima and the consequent creation of density depletions in which radio lasing can occur. Such radio lasing consists of closed-loop wave feedback oscillations caused by wave reflections at the source, exactly analogous to those of conventional optical lasers and likewise producing nearly-perfect discrete, coherent, and monochromatic emissions. ***

9312013卡尔弗特极光电子沉淀被假设是由于电子俯仰角散射的回旋脉泽不稳定性在极光千米辐射（AKR）的产生。 AKR由强烈的，主要是起源于地心高度极光磁场线的异常模式波组成 1.3到3.3地球半径。 AKR占极光总能量的1%，现在人们普遍认为它是由回旋脉泽不稳定性产生的，这种不稳定性是由高能电子进入损耗锥的多普勒频移、回旋共振、俯仰角散射引起的。 对这个新的极光理论来说，关键是解释观测到的来自太阳的无线电波触发AKR，因为这种现象清楚地证实了新的理论。 拟议的工作是研究这种触发，认为是由增强的局部降水在环境密度最小值和随之产生的密度耗尽，其中可以发生无线电激光。 这种无线电激光由源处的波反射引起的闭环波反馈振荡组成，完全类似于传统的光学激光器，同样产生近乎完美的离散，相干和单色发射。 ***