Time-Dependent Connectivity Mapping of the Solar Magnetic Field

The ambient solar magnetic field plays a key role in heliophysics in general and in space weather in particular. nbsp;It is especially important for the propagation of solar energetic particles (SEPs), guiding them along the magnetic field from their generation near the Sun to locations in the heliosphere. nbsp;Solar Particle Events (SPEs), arising from SEPs produced by solar eruptions, represent a significant hazard for humans and technological infrastructure. nbsp;Providing longer range (2-3 day) forecasts of SPEs and/or all-clear periods is highly desirable but difficult to achieve, because a forecast must occur prior to the start of the eruption. nbsp;Given a flare/CME forecast, a major source of uncertainty in SPEs is the magnetic connectivity. nbsp;The goal of nbsp;our project is to develop CORHEL-E (CORHEL with Evolution). nbsp;CORHEL-E will provide time-dependent coronal and solar wind solutions, driven by evolving boundary conditions provided by photospheric flux transport models. nbsp;In phase I of our project, we will demonstrate time-dependent estimates of magnetic connectivity of Earth for specific time periods, using ensembles of solutions to assess variability and uncertainty. nbsp;At the completion of phase II, we will provide CORHEL-E to the CCMC, capable of running continuously. nbsp;Given a flare/eruption forecast from a threatening active region, CORHEL-E will allow the user to assess the regional connectivity and likelihood that SEPs can reach Earth or other heliospheric locations of interest. nbsp;Using STAT, an eruption can actually be simulated and particle fluxes predicted. nbsp;Longer term, our vision for an operational capability is a near-real time model of the solar corona and inner heliosphere, updated with new magnetic (and other) observations as they become available. nbsp;CMEs would be initiated in the model after being observed, and then be simulated as part of the continuous solution. nbsp;The development of CORHEL-E is a crucial next step towards this goal.