Coronal mass ejections (CMEs) are powerful events that send plasma from the Sun throughout the solar system. They create space weather at Earth, which impacts human technology, particularly in space. This project will improve our understanding of the structure of CMEs through numerical simulations and analysis of observations. The work supports an early career scientist. The research team will participate in public outreach efforts geared towards the general public, students, and teachers.<br/><br/>The project is a comprehensive analysis of the three-part structure of CMEs. It will combine multiple observations from NSF, NASA, and NOAA and numerical simulations. Three important science questions are addressed in order to better understand the CME structure and gain a general knowledge of the physical properties of the CME substructures: (1.) What is the CME structure observed in white-light coronagraphic images and where are the magnetic flux rope (MFR) and filament observed in coronagraphs? (a) In white-light coronagraphic images, does the bright core consist of the filament material, MFR structure, or both, and where is the bright core within the whole CME eruptive structure? (b) Are the observations of the filament and MFR in the low corona in EUV images consistent with the bright core and/or dark cavity in the middle and high corona in white-light images? (2.) Where is the CME trailing edge? Which signatures can be best used to identify the CME trailing edge in remote and in-situ observations and where is the CME trailing edge in white-light coronagraphic images? (3.) Can a consistent CME structure be identified in remote observation and in in-situ measurements? (a) Are the kinematics and evolution of the CME substructures (including the trailing edge) observed remotely consistent with those measured in situ? (b) Can the in-situ measurements be used to track back the CME substructures to the corona?<br/><br/>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.