IT has been widely accepted that plasma-sheet bubbles, defined by their reduced flux tube entropy and also known as bursty bulk flows, play a critical role in the earthward transport from the…

This is a $599,856.10 grant award to William Marsh Rice University, doing business as Rice University, by the National Aeronautics and Space Administration (NASA) Shared Services Center. The grant is for research to quantitatively understand the effects of plasma-sheet bubble injections in the near-Earth magnetosphere. The research aims to address specific questions related to the characteristics of plasma-sheet bubbles, their observable signatures, and the role of large-scale convection and meso-scale bubble injections in particle transport and energization in the inner magnetosphere. This grant does not have a set-aside designation. Rice University is a private research university known for its interdisciplinary research and collaboration with other institutions to advance scientific knowledge and develop innovative technologies.

IT has been widely accepted that plasma-sheet bubbles, defined by their reduced flux tube entropy and also known as bursty bulk flows, play a critical role in the earthward transport from the magnetotail. Although a majority of these meso-scale structures stop at ~10 RE in the nightside, injection events in the inner magnetosphere, some as deep as 3 RE, have also been discovered in the van allen probes (VAP) and MMS data. These deep injections often have complex and profound consequences, including ring current enhancement, radiation belt seed population injections, ULF buoyancy waves, plasmaspheric resonances excited by waves in the PI2 range, etc. We have recently developed a new and much improved version of the rice convection model, called RCM-i, which includes inertial effects. IT can produce braking oscillations in its treatment of particle injections, while maintaining the traditional RCM capabilities for including gradient-curvature drift transport of magnetospheric particles and high-resolution coupling to the ionosphere. Therefore, our group is uniquely positioned to use combined numerical simulation and spacecraft observations to understand how bubbles affect the plasma distribution deep in the inner magnetosphere. Science goals and objectives: the primary objective of our proposal is to quantitatively understand the effects of plasma-sheet bubble injections when they impinge the near-earth magnetosphere. We will address following specific questions: (1) what characteristics must plasma-sheet bubbles possess to produce the storm-time ring current, and is that distribution of bubbles consistent with plasma sheet data? (2) what are the observable signatures of bubble remnants in the storm-time ring current? (3) can the observed deep penetration of low-energy ions and energetic electrons be explained in terms of large-scale convection and meso-scale bubble injections? (4) what are the synergistic roles of bubble injections, gradient/curvature drift, and ULF buoyancy oscillations in particle transport and energization in inner magnetosphere?