Science goals and objectives the overarching goal of this proposal is to understand the characteristics of the ionospheric currents of reconnection-generated fast flows that cause either global…

This is a $643,295.44 grant awarded by the National Aeronautics and Space Administration (NASA) to the University of California, Los Angeles (UCLA) for research on the characteristics of ionospheric currents related to magnetospheric reconnection and substorm events. The overarching goal is to improve understanding of the relationship between fast plasma flows in the magnetosphere and the corresponding responses in the ionosphere, including equivalent ionospheric currents and field-aligned currents.

The research will leverage data from NASA's THEMIS, Van Allen Probes, and Magnetospheric Multiscale missions, as well as a neural network model of ionospheric currents developed by the research team. The work directly supports Goal 2 of NASA's Heliophysics Decadal Survey to determine the dynamics and coupling of Earth's magnetosphere, ionosphere, and atmosphere. The grant has a period of performance through July 2023 and does not have a set-aside designation. UCLA is the prime grantee, with the State of California Controller's Office serving as the parent organization.

Science goals and objectives the overarching goal of this proposal is to understand the characteristics of the ionospheric currents of reconnection-generated fast flows that cause either global substorms, or localized pseudo breakups. Specifically, we aim to quantitatively assess both the localized and global responses of equivalent ionospheric currents (eics) and field aligned currents (facs) to different types of fast flows: with or without global substorms; with dipolarization fronts or slowed flows in the breaking region. The specific science questions that will be addressed are: 1. What are the typical characteristics of the ionospheric response of eics and facs to different types of fast flows? A. How do the ionospheric currents vary in latitude, local time, intensity with different flows? B. Under what conditions do current vortices appear and where do these vortices appear with respect to the harang discontinuity? 2. What are the typical characteristics of different types of fast flows? A. Do the flux transport rate and entropy of flows determine whether a global substorm can be triggered? B. Are the changes in the lobe magnetic field strength and open lobe magnetic flux different for different types of flows? 3. What are the potential physical quantities that determine whether a fast flow will trigger a global substorm or a localized pseudo breakup? Methodology the proposed project will combine the field and particle data of fast flows observed by NASA s themis, van allen probe (VAP) and MMS; ionospheric eics and current amplitudes (i.e., a proxy for the facs) obtained from the SEC methods; and a neural network model of the ionospheric currents to address the above important science questions. More specifically, 1. Using existing lists of fast flows and substorm onsets generated by our team [CHU ET AL., JGR, 2015], we will categories fast flows with and without global substorms; fast flows with dipolarization front, and slowed flows in the breaking region. 2. Using the high spatiotemporal resolution data of eics obtained from the spherical elementary current system (SEC) method by our team [weygand ET AL., JGR, 2011], we will develop a neural network (NN) model of the ionospheric currents which provides full local time coverage. This model resolves the problem that periodically no data are available on the nightside when the magnetometers are located at other local times, and greatly increases the number of conjunctions with satellites. 3. Using the modeled ionospheric current data, we will construct the characteristics of the ionospheric response to different categories of fast flows. 4. For different categories of fast flows, we will study the characteristics of these flows (entropy and flux transport rate) and the magnetospheric response (change in the lobe magnetic field and amount of flux released by the tail reconnection). Relevance to the decadal survey goals and the h-SR program our proposed project directly addresses the most important questions in magnetospheric reconnection, which is currently one of NASA s highest priorities. The proposed research is highly relevant to goal 2 from the heliophysics decadal survey, which is to determine the dynamics and coupling of earth s magnetosphere, ionosphere, and atmosphere and their response to solar and terrestrial inputs . The proposed project perfectly fits the scope of heliophysics SR program.