This grant is for partial support of a project selected and funded under the 2012 NASA-NSF partnership for Space Weather Modeling Collaborations. The project is a collaborative effort, led by UC Berkeley and with participation also from Stanford University and Lockheed-Martin. The objective is to develop a data-driven Coronal Global Evolution Model (CGEM) to use observations of the evolving photospheric magnetic field to drive a time-dependent model of the coronal magnetic field, with the aims of both understanding how solar eruptive events work and predicting such events. The model's Earth-facing hemisphere will be driven using electric fields derived from the observed evolution of photospheric line-of-sight magnetic fields and electric currents. Far-side data inputs will be from an existing flux transport code, combined with helioseismological far-side observations of new active regions, with empirical parameterizations of orientation and flux. Because this model includes large-scale coronal electric currents, it is a substantial improvement over existing real-time global coronal models, which assume potential fields. Data products available from the model include: 1) the evolving photospheric electric field, Poynting flux, and helicity flux; 2) estimates of coronal free energy and non-potential geometry and topology; 3) initial and time-dependent boundary conditions for MHD modeling of active regions; and 4) time-dependent boundary conditions and flux tube expansion factors for MHD and empirical solar wind models.
When completed, the CGEM Model will be delivered to the Community Coordinated Modeling Center (CCMC) for global runs on demand at moderate resolution for use by the general science community. Modules used to derive surface electric fields from magnetic evolution will be run continuously at lower resolution at the Stanford/Lockheed Joint Science Operations Center (JSOC) for general use by the scientific community. As the JSOC serves as the main repository and distribution node for data from the Solar Dynamics Observatory satellite mission, CGEM output will be readily available to members of the solar-physics and space-weather communities as a tool for both scientific research and space weather applications. The build-up and release of magnetic free energy in the corona is one the most important manifestations of solar eruptive activity, and the model will improve the forecast of these events, which is highly relevant to National space weather goals.
