CEDAR: Understanding the Loss of Energetic Electrons from the Radiation Belts Using Remote Sensing with Multi-point Riometer Measurements and Satellite In Situ Measurements

研究人员将结合现场卫星数据使用多点里程计测量，以更好地了解高能电子从磁层起源向电离层沉淀的情况。在10‘S千电子伏特(Kev)范围内的高能电子沉淀到高D区和低E区电离层，并负责增强电离。同样的粒子群在内部磁层中很重要，因为它提供了一个波源，并在辐射带中充当相对论电子的种子群。对等离子体群和波的现场观测通常局限于单个点，这使得时间和空间分析变得复杂。此外，卫星飞行任务的寿命往往被限制在几年之内，这使得无法推断磁层条件和太阳周期相关性的长期气候学。电离层等离子体状况的多点遥感可以提供电离层和磁层状况的全球视角，并且可以在时间尺度上审查磁层和电离层现象之间的耦合，以便进行全面的统计分析。研究人员将用卫星测量的降水通量相互校准里氏流量计，并比较赤道平面上捕获的电子数量的变化。与现场观测的降水通量相比，将显示哪些能量电子可以用测力计测量，并有助于绘制降水的纬度和磁性当地时间(MLT)分布图。该团队还将研究降水如何依赖于太阳风条件和地磁指数。与被困人口相比，来自卫星的测量将量化大气损失与被困外边界和向外输送的损失的比例。与沉淀高能电子通量相关的长期里程测量仪测量，未来可以作为磁层波活动的替代。电子沉淀还可以改变电离层的电导率，从而影响磁层-电离层的耦合。这项研究通过展示对电离层降水的遥感如何帮助科学家了解磁层和辐射带的过程来支持范艾伦探测器任务。这项研究的结果将促进对磁层-电离层耦合的了解，这对于提供更好的E区电离层电导估计是重要的。此外，在10‘S的KeV范围内的高能电子作为相对论电子的种子种群，这可能会损坏卫星系统和硬件。此外，高能电子的沉淀直接影响高层大气化学，代表了太阳和磁层活动以及气候之间的联系。

The investigators will use multi-point riometer measurements in conjunction with in-situ satellite data, to improve understanding of the precipitation of energetic electrons into the ionosphere from their magnetospheric origins. Energetic electrons in the 10's of kilo-electron volt (KeV) range precipitate to the upper D- and lower E region ionosphere, and are responsible for enhanced ionization. This same particle population is important in the inner magnetosphere, as it provides a source of waves, and acts as a seed population for relativistic electrons in the radiation belts. In situ observations of plasma populations and waves are usually limited to a single point, which complicates temporal and spatial analysis. Also, the lifespan of satellite missions is often limited to several years, which does not allow the inference of long-term climatology of magnetospheric conditions and solar cycle dependencies. Multi-point remote sensing of the ionospheric plasma conditions can provide a global view of the ionospheric and magnetospheric conditions, and the coupling between magnetospheric and ionospheric phenomena can be examined on time-scales that allow comprehensive statistical analysis. The investigators will inter-calibrate riometers with satellite measurements of precipitating fluxes and also compare to variations in the trapped electron population in the equatorial plane. Comparison with in-situ observations of precipitating fluxes will show which energy electrons can be measured by riometers and allow development of maps of latitudinal and magnetic local time (MLT) distributions of precipitation. The team will also study how precipitation depends on the solar wind conditions and geomagnetic indexes. Comparison with trapped population measurements from satellites will quantify the fraction of the loss to the atmosphere vs loss to the outer boundary of trapping and the outward transport. Long-term riometer measurements, which are correlated with fluxes of precipitating energetic electrons, can be used in the future as a proxy for magnetospheric wave activity. Electron precipitation can also modify ionospheric conductivity, which will influence magnetosphere-ionosphere coupling. This study supports the Van Allen Probe mission by demonstrating how remote sensing of ionospheric precipitation can help scientists understand processes in the magnetosphere and radiation belts. The results of the study will advance knowledge of magnetosphere-ionosphere coupling, which is important to provide better quality conductance estimates in the E-region ionosphere. Additionally, the energetic electrons in the 10's of keV range act as a seed population for relativistic electrons, which may damage satellite systems and hardware. In addition, the precipitation of energetic electrons directly influences the upper atmospheric chemistry, and represents a link between solar and magnetospheric activity, and climate.