Collaborative Research: Ground-based Very Low Frequency (VLF) and High Frequency (HF) Measurements in Support of the VIPER Sounding Rocket Experiment

合作研究：支持 VIPER 探空火箭实验的地基甚低频 (VLF) 和高频 (HF) 测量

• 批准号: 1952498
• 负责人: Oleksiy Agapitov
• 金额: $ 12.12万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-15 至 2024-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1952498&HistoricalAwards=false
• 关键词: Collaborative; Research; Ground; based; Very; Collaborative; Research; Ground; based; Very

Radio emissions in the Very Low Frequency (VLF) range are known to propagate long distances bouncing between the surface of the Earth and the partially ionized layer of the upper atmosphere near 90 km in altitude called the D region. The D-region impacts long range radio communications between extremely low frequencies (ELF), used for long-range submarine communications, and high frequencies (HF), used by many critical communications systems. VLF emissions can also escape the ionospheric layer and propagate to much higher altitudes with denser plasma. VLF emissions of both natural and man-made origin can also cause wave-particle scattering in the magnetosphere resulting in particle precipitation in the ionosphere. VLF radio wave propagation and signal strength reduction has been challenging to model and observe, mostly due to the lack of continuous measurements in the D region and significant uncertainties in the knowledge of both plasma and neutral densities at these altitudes. In this project, an enhancement will be made to the existing VLF Trans-Ionospheric Propagation Experiment Rocket (VIPER) experiment, to launch from Wallops Island in July 2020. VIPER will provide important information about radio waves detected along its trajectory, enabling a determination of the VLF attenuation through the ionospheric D region. Specifically, this project will support the installation of ground-based VLF and HF receivers near the transmitter site to provide ground-truth measurements to compare to the rocket measurements. These ground measurements will constrain the ionospheric state and will enable an accurate assessment of the attenuation of the VLF wave as a function of altitude. This project will also support the education of a student at CU Boulder, the training of a postdoc at CU Boulder and a postdoc at UC Berkeley, enhancing their continuing educations and providing a unique opportunity to learn about the valuable work at Wallops Flight Facility.This collaborative effort with provide direct multi-point measurements of VLF wave amplitude and phase, referenced directly from the source transmitter. VIPER will measure the height-resolved amplitude and phase of the NAA (24.0 kHz) transmitter signal broadcast from Cutler, Maine, enabling a determination of the VLF attenuation through the collisional D-region ionosphere. VIPER will also measure the plasma density and HF signal amplitudes during the ionospheric traverse. Together with the rocket measurements, we will have VLF measurements at the transmitter; downrange on the ground; and downrange as an altitude profile from 60 to 150 km. These measurements will provide unprecedented insight into the attenuation of VLF waves by the collisional D-region plasma. In turn, this attenuation will yield insight into the effect of ground-based transmitter signals on the D-region ionosphere and their injection into the magnetosphere. The project also has the potential to make measurements of lightning sferics (on the ground) and whistlers (above the ionosphere), providing a broadband (DC to MHz) view of this attenuation. The lightning observations are a secondary goal and are not critical to the success of the VIPER project.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

已知非常低频率（VLF）范围内的无线电排放可以在地球表面和高度在90 km的高空中传播长距离在地球表面和部分离子化的层之间弹跳，称为D区域。 D-Region影响了许多关键通信系统使用的远程海底通信（ELF）（ELF）（ELF）（ELF）（ELF）（ELF）之间的远程无线电通信。 VLF排放还可以逃脱电离层层，并使用较密集的血浆传播到更高的高度。天然和人造起源的VLF排放也可能导致磁层中的波粒子散射，从而导致电离层的颗粒沉淀。 VLF无线电波的传播和信号强度的降低对于模型和观察的挑战是挑战，主要是由于在D区域缺乏连续测量以及在这些高度处的血浆和中性密度的知识中的明显不确定性。在该项目中，将对现有的VLF跨欧洲传播实验火箭（Viper）实验进行增强，以在2020年7月从沃洛普岛（Wallops Island）发射。Viper将提供有关沿其轨迹检测到的无线电波的重要信息，从而确定通过电离层D区域确定VLF衰减。具体而言，该项目将支持在发射机附近的地面VLF和HF接收器安装，以提供与火箭测量值相比的地面真相测量。这些地面测量将限制电离层状态，并能够准确评估VLF波的衰减作为高度的函数。该项目还将支持Cu Boulder的一名学生的教育，在Cu Boulder进行博士后的培训以及加州大学伯克利分校的博士后，增强了他们的持续教育，并提供了一个独特的机会，可以在Wallops Flight设施上学习有价值的工作。与VLF Wave Ampoint sournections的合作，直接介绍了VLF波动amplitude amplitude amplitude and transported tormented tormented tormented tormented。 Viper将测量从缅因州卡特勒（Cutler）广播的NAA（24.0 kHz）发射机信号的高度分辨振幅和相位，从而通过碰撞D-Grigion Ionosphere确定VLF衰减。毒蛇还将在电离层遍历期间测量血浆密度和HF信号振幅。 连同火箭测量值，我们将在发射机上进行VLF测量。在地面上;并作为60到150公里的海拔轮廓。这些测量结果将为碰撞D-Region等离子体对VLF波的衰减提供前所未有的见解。反过来，这种衰减将深入了解地面发射器信号对D区电离层的影响及其注射到磁层中。该项目还具有对闪电传奇（在地面上）和吹口哨（电离层上方）进行测量的潜力，从而提供了这种衰减的宽带（DC至MHz）。 闪电观察是次要目标，对于Viper项目的成功并不重要。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响评估标准来通过评估来支持的。