Collaborative Research: GEM--How Upstream Solar Wind Conditions Determine the Properties of the Foreshock Backstreaming Ions

合作研究：GEM——上游太阳风条件如何决定前震回流离子的特性

• 批准号: 2420710
• 负责人: Kun Zhang
• 金额: $ 27.11万
• 依托单位: University of California-Los Angeles
• 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: 2023-10-01 至 2026-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2420710&HistoricalAwards=false
• 关键词: Collaborative; Research; GEM; How; Upstream; Collaborative; Research; GEM; How; Upstream

The interaction of the solar wind and the Earth's magnetic field created a collisionless shock called a bow shock in front of the Earth's magnetosphere. The incident particles can be accelerated and reflected at the bow shock, resulting in their counter-streaming along field lines and interacting with the local plasma. Earth's bow shock is a natural laboratory to study the complex interactions between the incident solar wind and the counter-streaming foreshock populations. This study aims to build a predictive model of the foreshock backstreaming ions, which can be integrated into a space weather prediction model to help accurately forecast and mitigate space weather hazards. An early-career female scientist leads this project and involves the participation of multiple early-career scientists. The related science materials will be presented to k-12 students, parents, and the general public audience through various outreach events to promote STEM education.This study focuses on the foreshock ion properties and addresses the following questions: (1) What are the properties of the freshly reflected ions near the bow shock, including reflection rate, velocity, perpendicular and parallel temperatures and Velocity Distribution Function (VDF) types (e.g., field-aligned beam, ring distributions, etc), as a function of upstream solar wind conditions (e.g., speed, interplanetary magnetic field (IMF), Mach number, beta, etc) and shock normal angles? (2) How do the properties of the freshly reflected ions evolve spatially and temporally as they travel away from the bow shock as suggested by global simulations? (3) Can the obtained properties be explained by existing acceleration and reflection theories, such as adiabatic and specular reflections? The project combines analysis of satellite measurements and numerical simulations to reveal how the ion distributions are determined by the upstream solar wind conditions. This project will improve our understanding of the properties of the bow shock reflected ions and the related reflection, acceleration, and scattering processes.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.

太阳风与地球磁场的相互作用产生了无碰撞冲击，称为地球磁层前的弓形冲击。 入射颗粒可以在弓形冲击下加速并反射，从而导致它们沿场线进行反流并与局部血浆相互作用。 地球的弓箭是一家天然实验室，可研究太阳风与反流式前置种群之间的复杂相互作用。 这项研究旨在建立前换货回离子的预测模型，该模型可以集成到太空天气预测模型中，以帮助准确预测和减轻太空天气危害。 一位早期的女科学家领导该项目，并涉及多个早期职业科学家的参与。 相关的科学材料将通过各种宣传活动向K-12学生，父母和公众受众介绍，以促进STEM教育。本研究重点介绍了前瞻性离子的特性，并解决了以下问题：（1）新鲜反射离子在弓箭震动附近的属性是什么，包括重新质量，速度，速度，速度和平行性的频繁和velocity和Velocity（Velocely fiqu）（VELOCTICE（VELOCE）（VELOCE）（VELOCTICE（VELOCE）（VELOCE）（VELOCE）（VELOCE）（VELOCE）（VELOCE）（VELOCE）（VELOCE））与上游太阳风条件（例如，速度，行星际磁场（IMF），MACH数，Beta等）和冲击正常角度的函数（例如，速度，速度，行星际磁场（IMF）和休克正常角度？ （2）正如全球模拟所建议的那样，新鲜反射离子的特性如何在空间和时间上发展？ （3）是否可以通过现有的加速和反射理论（例如绝热和镜面反射）来解释所获得的属性？ 该项目结合了对卫星测量值和数值模拟的分析，以揭示离子分布如何由上游太阳风条件决定。 该项目将提高我们对弓休克反射离子的特性以及相关的反射，加速和散射过程的理解。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛的影响来评估的评估值得支持的。