Collaborative Research: The Collective Wedgelet Formation of the Substorm Current Wedge--The Role of Different Plasma Populations and Insights from a Fully Coupled Geospace Model

The magnetosphere is the region that surrounds the Earth, which is carved out by its magnetic field as it deflects the supersonic solar wind plasma around it. The solar wind is a major energy source for the magnetosphere that can lead to complex dynamics. One such dynamic is the magnetospheric substorm, a major system reconfiguration that results in an energy release in Earth's magnetosphere-ionosphere system. During a substorm, a large-scale current system is observed known as the substorm current wedge (SCW). This project's focus is to better understand the physical process that leads to the SCW. Another example of the complex behavior observed in the magnetosphere is the presence of sporadic fast flows, known as bursty bulk flows (BBFs). This project seeks to investigate if there is any connection between the formation of the SCW and BBFs. The project's successful outcome will lead to a better understanding of the Earth's magnetosphere and current systems. This project will support two early-career scientists. Results of the study will be conveyed to the public (including K-12 students) via education and public outreach eWorts in both the PI and Co-I's institutes, which will enhance public interest in space science. The research focuses on the substorm current wedge (SCW), which plays a crucial role in the energy release process within Earth's magnetosphere-ionosphere system. This research aims to explore the causes behind this asymmetry and investigate the validity of the collective wedgelet formation of a SCW. Specifically, the team suggested to answer the following questions: Q1. Do the thermal pressure asymmetries around DFBs result from an interplay between the meso and global scales? Q2. Which plasma populations contributed to the pressure asymmetry within the dipolarization front layer? Q3. Are the collective eWects of wedgelets consistent with a substorm current wedge? The team will use the Multiscale Atmosphere-Geospace Environment (MAGE) model, inertialized Rice Convection Model (RCM-I) numerical simulation, and THEMIS observations to achieve the science goals. The outcome of our studies will provide constructive information on the physics of the inner magnetosphere dipolarization process and advance our understanding of the nature of substorm current wedge formation. 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.