Why Do Active Regions Erupt? Modeling of Active Region from Pre-Eruptive to Eruptive Processes

University Of Alabama In Huntsville, Huntsville AL

Investigators

Abstract

Solar eruptions have significant impact on the near-Earth environment due to the enhanced flux of energetic particles bombarding the Earth and the embedded magnetic structures impacting the Earth's magnetosphere. This has serious consequences for our technological assets both in space and on the ground, including interruption of tele-communication, compromising the safety of astronauts, and damaging satellites and electric power grids. Therefore, focused investigations of solar eruptions and the associated magnetic field evolution of the solar corona have the potential to reveal the underlying physical mechanism(s) of the drivers of space weather at the Sun. This 3-year project is aimed at investigating the physical origins of solar eruptions at the Sun by means of data-driven, three-dimensional (3-D) numerical simulations. The project also has a strong educational component as it provides partial support for a Ph.D. student and a junior scientist at the University of Alabama in Huntsville. Thus, the research and EPO agenda of this project supports the Strategic Goals of the AGS Division in discovery, learning, diversity, and interdisciplinary research. This 3-year project is aimed at answering some of the fundamental questions concerning the physical origin and evolution of solar eruptions, which will expand the frontier of existing knowledge on the energy release during solar flares and Coronal Mass Ejections (CMEs) on the Sun and the associated reconfiguration of the solar corona. The underlying research objectives are: (i) understanding the fundamental active region (AR) eruptive physics; and, (ii) providing a practical tool as an initiation model for the development of a physics-based data-driven space weather prediction code. The research plan is to use the MHD-DARE model developed by the project team, together with observational data from the HMI and AIA instruments onboard the Solar Dynamics Observatory (SDO), to address the following science questions: (i) what are the basic characteristics of magnetic field configuration before a solar eruption?; (ii) how do photospheric surface motions, including shear, convergence and flux cancellation bring the initial emerged fields to such an unstable configuration?; (iii) what are the specific roles played by magnetic flux rope and magnetic reconnection in triggering solar eruptions?; (iv) can we understand the complexity of various flare/eruption process from topology and evolution of the magnetic field?; and, (v) how do solar eruptions leave imprints on the photospheric fields? These aspects of the AR development will be connected to the evolution of the coronal field long before and during a solar eruption, for which the project team will use the MHD-DARE model to carry out numerical simulations driven by the time-dependent vector magnetograms. Then, the simulation results will be analyzed to yield the evolution of the magnetic topology, electric currents, plasma flows, and Lorentz force to determine the primary triggering mechanisms of the solar eruption, and they will be compared with relevant solar observations. In addition, the project team plans to further improve the current model by including a realistic energy equation and a plasma configuration directly from the photosphere into the solar corona.