Physics-Based Forecasting of Tomorrow's Solar Wind at 1 AU

Abstract

Inspired by the concept of relativity of simultaneity used in the theory of special relativity, a new approach is proposed to simulate future solar wind conditions at any point in the inner solar system. An important distinctive feature of the proposed approach is that the simulation in the solar corona is driven by hourly updated solar magnetograms and is continuously simulated in nearly real time. The model for the inner heliosphere is based on time transformation to a boosted frame of reverence (or spacetime coordinate system) in which the current state of the solar wind at the solar corona -- inner heliosphere boundary and future states of the solar wind are simultaneous. The predictive capability for tomorrow's parameters of the ambient solar wind at 1 AU is achieved by simulating them simultaneously with the current observations of the solar magnetic field, the time offset being due to the use of boosted frame. We derive the modified governing equations for both hydrodynamics and magnetohydrodynamics and present a new numerical algorithm that solves the modified governing equations. The proposed method enables an efficient numerical implementation and thus a significantly longer forecast time than traditional solution methods. In the numerical test for transient propagation, the boosted solution for the CME-driven shock arrival at 1AU is 16 hours ahead of the solution at the solar corona -- inner heliosphere boundary.