The objective of our proposal is to understand the dynamics of waves generated in the multi-scale boundary layers of magnetic reconnection (electron and ION diffusion regions, separatrices, inflow and…

This federal contract award was issued by the Shared Services Center, a civilian federal agency, to Southwest Research Institute (SwRI) to conduct research on the dynamics of waves generated in the multi-scale boundary layers of magnetic reconnection. The $520,528.06 grant will fund SwRI's investigation into whether and how waves influence the magnetic reconnection process, as well as how wave observations can reconstruct the reconnection geometry and evolution. SwRI will use a combination of in-situ Magnetospheric Multiscale (MMS) mission data, particle-in-cell simulations, and analytical studies to address these research questions. The award is not associated with a set-aside program and is part of SwRI's broader portfolio of federal contract and grant awards supporting scientific research for government agencies like NASA, the Department of Energy, and the Nuclear Regulatory Commission.

The objective of our proposal is to understand the dynamics of waves generated in the multi-scale boundary layers of magnetic reconnection (electron and ION diffusion regions, separatrices, inflow and exhaust regions) and the roles and effects of these dynamics on the magnetic reconnection process. The intrinsic multi-scale structure of reconnection including inflow, exhaust, and diffusion regions drives various wave modes. Those waves in the reconnection site, in particular, in the electron diffusion region, can provide anomalous resistivity, which could be a crucial ingredient in triggering reconnection. Previous simulations and spacecraft observations indicated that electron/ION distributions and plasma parameters vary not only in terms of the spatial location in reconnection topology but also the temporal phase of reconnection processes. The recently-launched MMS spacecraft, providing detailed high-resolution particle and field data at and near the nightside (symmetric) and dayside (asymmetric) reconnection sites, have shown that particle distributions are highly structured and, accordingly, localized waves are often observed. Such deformations in the distribution functions can supply free energy for waves. In turn, particle distributions alter by generating waves and/or interacting with waves. Therefore, waves together with particle distributions can represent both spatial locations in reconnection geometry and temporal phases of the reconnection process. However, we have not yet developed a complete context of those waves in association with the spatiotemporal variations of reconnection processes. Here, we plan to investigate the following scientific questions via our project. (Q1) whether or not and by what means are waves responsible for reconnection? (Q2) what are generation mechanisms and properties of waves in the multi-scale reconnection site? (Q3) can wave observations reconstruct the reconnection geometry and the evolutionary phases? By answering Q1-3, we will address the impact and roles of waves in the reconnection processes and how waves enable US to construct the full context of reconnection topology and evolution. To answer these questions, we will use combined methodologies using in-situ MMS data and both explicit/implicit particle-in- cell (PIC) codes supported by analytic studies. Field data (EDP, FGM, and SCM) will be analyzed to investigate wave modes and properties, which will be compared with the simulation results. Particle distribution functions and moment data (FPI) will be analyzed for the comparison with simulations as well as used for the input parameters of simulations. Explicit PIC, which most appropriately resolve electron scale waves, and the kinetic theory with MMS data as initial conditions will enable US to sort out wave modes and generation mechanisms, and track down wave-particle interactions and saturations, in particular in the electron diffusion region. Implicit PIC will be used to investigate the relationship among the electron/ION scale waves, particle distributions, and spatial and temporal variations of reconnection process according to different reconnection topology (e.g., with/without a guide field). By synthesizing MMS observations, simulations, and theoretical studies, we will tackle a long-standing question in reconnection discipline, whether or not and how effectively waves influence (trigger/modulate) reconnection processes, and answer how the particle and wave data can be used for mapping the MMS location or trajectory within the reconnection region. Our program is key to understanding reconnection, one of most fundamental processes that occur both within the heliosphere and throughout the universe (DSG #4), which is directly relevant to the goals of MMS mission. This program will also improve our understanding of the dynamics and coupling of earth's magnetosphere, ionosphere, and atmosphere and their response to solar and terrestrial inputs (DSG #2).