AGS-PRF: Probing the Relationship Between Radiation Belt Electron Precipitation and Electromagnetic Ion Cyclotron (EMIC) Waves

AGS-PRF：探讨辐射带电子沉淀与电磁离子回旋（EMIC）波之间的关系

• 批准号: 1524755
• 负责人: Lauren Blum
• 金额: $ 8.6万
• 依托单位: Blum Lauren W
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-01 至 2018-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1524755&HistoricalAwards=false
• 关键词: AGS; PRF; Probing; Relationship; Between

Just as in the ocean and the atmosphere, waves exist in space plasmas. In these plasmas, where collisions between charged particles are rare, energy can be transferred to a charged particle from a plasma wave (analogous to a surfer on an ocean wave). As a result, plasma waves are a major means of transferring energy from one charged particle population to another, and for energizing a small portion of the population to very high energies. There are many types of plasma waves. Microphysics tells us that plasma waves, called electromagnetic ion cyclotron waves (EMIC), are able to scatter electrons formerly trapped in the radiation belts into the atmosphere where they are lost. However, the relative importance of EMIC waves to the global variability of the radiation belts has been a subject of intense scientific debate for the past 50 years. The main goal of the research is to resolve this debate by combining multi-point conjugate measurements of particles and fields in space with electron precipitation. The capability for making these measurements was recently expanded by the Van Allen Probes and BARREL balloons missions. The grant will support the further training and development of a promising female early-career scientist. The resulting global maps of relativistic electron precipitation will be useful to the broader space physics and aeronomy communities, to researchers studying the chemistry of the middle atmosphere, and for space environment applications, such as active mitigation techniques for both natural and artificial radiation in space.To address the open questions raised above, the methodology is to construct large-scale maps of plasma and wave fields in space and correlated maps of high-energy electrons precipitating into the atmosphere from multiple satellites both at high- and low-Earth orbit. At issue is how long radiation belt electrons actually travel through regions occupied by EMIC waves as they move along closed drift path in the radiation belts. The longer they interact with the EMIC waves the more likely they will be scattered out of their closed drift paths and be lost. If the waves exist only in limited regions that are sparsely distributed throughout the radiation belts, or turn on and off rapidly, their cumulative effects may be insignificant. Comparing these maps not only provides information about the global distribution of plasma waves but also about whether the relationships between the mapped quantities are consistent with EMIC waves. Even if these maps are not consistent with EMIC wave interactions with the energetic particles and cold plasmas, they provide clues to, and place constraints on, other mechanisms..

就像在海洋和大气中一样，波也存在于太空等离子体中。在这些等离子体中，带电粒子之间很少发生碰撞，能量可以从等离子体波传递给带电粒子（类似于海浪上的冲浪者）。因此，等离子体波是将能量从一个带电粒子群转移到另一个带电粒子群的主要手段，也是将一小部分带电粒子群激发到非常高的能量的主要手段。等离子体波有很多种。微物理学告诉我们，等离子体波，称为电磁离子回旋波（EMIC），能够将以前困在辐射带中的电子散射到大气中，在那里它们丢失了。然而，在过去的50年里，源波对辐射带的全球变率的相对重要性一直是一个激烈的科学争论的主题。本研究的主要目标是通过结合粒子和空间场的多点共轭测量与电子沉淀来解决这一争论。最近，范艾伦探测器和BARREL气球任务扩大了进行这些测量的能力。这笔拨款将支持一位有前途的早期职业女性科学家的进一步培训和发展。由此产生的相对论性电子沉降全球图将有助于更广泛的空间物理学和航空学界、研究中层大气化学的研究人员以及空间环境应用，例如空间自然辐射和人工辐射的主动减缓技术。为了解决上述悬而未决的问题，方法是构建空间等离子体和波场的大比例图，以及从高、低地球轨道的多颗卫星上沉降到大气中的高能电子的相关图。问题是，当辐射带中的电子沿着封闭的漂移路径移动时，辐射带电子实际上在被电磁波占据的区域中行进了多长时间。它们与主位波相互作用的时间越长，它们就越有可能从封闭的漂移路径中散射出去并丢失。如果引力波只存在于整个辐射带中稀疏分布的有限区域，或者迅速开启和关闭，则它们的累积效应可能微不足道。比较这些图不仅提供了关于等离子体波的全球分布的信息，而且还提供了映射量之间的关系是否与主位波一致的信息。即使这些地图与高能粒子和冷等离子体的主位波相互作用不一致，它们也为其他机制提供了线索，并对其施加了限制。