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

进入地球大气层的电子沉淀通常是由磁层中激发的等离子体波驱动的，或者是由磁力线弯曲引起的散射(也称为电流片散射，CS)驱动的。因此，辐射空间环境可能遭受重大损失，其能量直接沉积到大气中。这一建议的目的是评估波和场线散射在相对论电子降水中的各自作用，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，将由一名女性教职员工和一名资深女科学家指导。这个项目的重点是相对论电子沉淀(REP)，并回答以下科学问题(SQ)：SQ1。与CSS驱动的REP相比，波驱动的REP有哪些特性？SQ2.波驱动的代表和css驱动的代表在总代表中的相对贡献是多少？SQ3.REP对大气有什么影响(例如，臭氧消耗、电导率变化)？这是建立在初步工作的基础上的，该工作表明，在近地轨道观测到的降水分布因相关的驱动力而不同。REP事件将从十年的观测中收集，我们将使用这些事件作为整个大气社区气候模式(WACCM)的输入，以估计由此产生的大气影响。这项工作将量化是否、在哪里以及在什么地磁条件下，css在引起电子沉淀方面比波更有效。这一结果对于当前通常不考虑css的辐射皮带模型将很有用。同样，团队将从Waves获得代表的分布及其贡献。有了这样的信息，他们将推断出磁层区域，在那里波-粒子相互作用的俯仰角散射更有利于相对论电子。最后，WACCM模拟将提供对出现最频繁的纬度和经度的相对论电子具体造成的臭氧消耗的估计，有助于如何在大尺度大气模式中考虑本地REP贡献。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.