GEM: The Competition Between Waves and Field Line Scattering in Driving Relativistic Electron Precipitation and the Resulting Atmospheric Effects

GEM：波与场线散射在驱动相对论性电子沉淀中的竞争以及由此产生的大气效应

• 批准号: 2247265
• 负责人: Luisa Capannolo
• 金额: $ 60万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2247265&HistoricalAwards=false
• 关键词: GEM; Competition; Between; Waves; Field

Electron precipitation into the Earth’s atmosphere is typically driven by plasma waves excited in the magnetosphere or by scattering due to the curvature of magnetic field lines (also known as current sheet scattering, CSS). As a result, the radiation space environment can undergo a significant loss and its energy is directly deposited into the atmosphere. This proposal aims to assess the respective role of waves and field line scattering in the relativistic electron precipitation and to evaluate its effects on the Earth’s atmosphere. The PI is an early career female scientist who will be mentored by a female faculty and a senior female scientist. Graduate and undergraduate students will be supported.This project focuses on relativistic electron precipitation (REP) and addresses the following science questions (SQ): SQ1. What are the properties of wave-driven REP compared to CSS-driven REP? SQ2. What is the relative contribution of wave-driven REP and CSS-driven REP to the total REP? SQ3. What are the effects of REP on the atmosphere (e.g., ozone depletion, conductivity change)? This builds on preliminary work showing that the observed precipitation profiles at low-Earth-orbit differ depending on the associated driver. REP events will be collected from a decade of observations, which we will use as inputs to the Whole Atmospheric Community Climate Model (WACCM) to estimate the resulting atmospheric effects. The work will quantify if, where, and under what geomagnetic conditions CSS is more efficient in causing electron precipitation than waves. This result will be useful to radiation belt models that currently do not typically consider CSS. Similarly, the team will obtain the distribution of REP and its contribution from waves. With such information, they will infer the magnetospheric regions where pitch-angle scattering from wave-particle interactions is more favorable for relativistic electrons. Finally, WACCM simulations will provide an estimate of the ozone depletion caused specifically by relativistic electrons in the latitude and longitude where they occur most often, contributing toward how the local REP contribution should be considered in large scale atmospheric models.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.

地球大气层中的电子沉淀通常是由磁层中激发的等离子体波或由于磁场线的曲率引起的散射（也称为电流片散射，CSS）驱动的。因此，辐射空间环境可能遭受重大损失，其能量直接沉积在大气层中。该建议旨在评估波和场线散射在相对论电子沉淀中的各自作用，并评估其对地球大气的影响。PI是一名职业生涯早期的女科学家，将由一名女教师和一名高级女科学家指导。研究生和本科生将得到资助。这个项目的重点是相对论电子沉淀（REP）和解决以下科学问题（SQ）：SQ1。与CSS驱动的REP相比，波浪驱动的REP有哪些特性？SQ2。波浪驱动的REP和CSS驱动的REP对总REP的相对贡献是多少？SQ3。REP对大气的影响是什么（例如，臭氧消耗、导电性变化）？这是以初步工作为基础的，初步工作表明，在低地球轨道观测到的降水概况因相关驱动因素而异。REP事件将从十年的观测中收集，我们将使用这些事件作为全大气社区气候模型（WACCM）的输入，以估计由此产生的大气影响。这项工作将量化CSS是否、在哪里以及在什么样的地磁条件下比波更有效地引起电子沉淀。这一结果将是有用的辐射带模型，目前通常不考虑CSS。同样，该团队将获得REP的分布及其对波浪的贡献。有了这些信息，他们将推断磁层区域，在那里波粒相互作用的俯仰角散射更有利于相对论电子。最后，WACCM模拟将提供一个臭氧消耗的估计，特别是相对论电子在纬度和经度，他们最经常发生，有助于如何当地REP的贡献应考虑在大规模大气模型。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。