The bow shock is one of the most important plasma regions in the global interaction between the solar wind and the Earth's magnetosphere. Satellite observations have shown that pressure pulses with spatial and temporal bursts are frequently present in the foreshock region of the quasi-parallel shock. These transient variations have been found to further transmit through the magnetosheath and interact with the dayside magnetopause and magnetosphere, causing irregularities in the magnetospheric field and current system. Recent observations indicate that the structure of the bow shock and its associated waves are highly three-dimensional (3-D), and more and more new multi-dimensional phenomena are being discovered in the bow shock-magnetosheath-magnetosphere system. Very few 3-D kinetic calculations of the bow shock have been conducted so far. The importance of the 3-D structure of the bow shock transients in the global interaction makes it necessary and timely to perform investigations of the bow shock using a 3-D global model. Due to the crucial roles of ion kinetic effects in the bow shock transients, a systematic 3-D global hybrid simulation, with massively parallel computations, will be performed to study the kinetic structure of the bow shock and its interaction with the dayside magnetosphere. The 3-D hybrid code has been developed on the basis of a highly successful 2-D code. In the simulation, the bow shock, magnetosheath, and magnetopause form by the self-consistent interaction between the solar wind and the geomagnetic field. The primary tasks are: (1) determination of the 3-D structure and ion particle signature of the curved bow shock, including the quasi-parallel and quasi-perpendicular shocks, (2) the generation of foreshock pressure pulses and bow shock transients by ion kinetic effects and their transmission through the magnetosheath, and (3) determination of the relationship between the bow shock and the observed cusp energetic ions.
The study will not only contribute to our understanding of the fundamental physics of the coupling between the solar wind and magnetosphere, but the success in the 3-D kinetic global modeling efforts will also have broader applications in other topics of magnetospheric, astrophysical, and laboratory plasma physics. The simulation, which can track the effects of geo-effective perturbations self-consistently, will help to distinguish the spatial and temporal effects in satellite observations. The study will include a graduate student at Auburn University, and it will also contribute to the National Science Foundation (NSF)'s goal of developing and maintaining cutting edge national computing and information infrastructure for research and education.
