An Efficient, Time‐Dependent High Speed Stream Model and Application to Solar Wind Forecasts

Predicting space weather effects of the solar wind requires knowing location and properties any embedded high speed streams (HSSs) or stream interactions regions (SIRs) that form as fast catches up to slow preceding wind. Additionally, this background affects evolution coronal mass ejections. We present Mostly Empirical Operation Wind with a High Speed Stream (MEOW-HiSS) model, which runs nearly instantaneously. This model is derived from magnetohydrodynamic (MHD) simulations an idealized HSS emanating circular hole. split MHD radial profiles into small well-described by simple functions (e.g., flat, linear, exponential, sinusoidal) can be constrained using values. then determine how region boundaries constraining values change CH area distance front. MEOW-HiSS only reproduce corresponding profile error less than 10% for most parameters. produces at subsequent times almost no loss in accuracy. compare results four observed situ 1 au. method determining inputs extreme ultra-violet images use these hindcast cases. find average accuracies 2.8 cm−3 number density (50% over full profile), 56.7 km/s velocity (10%), 2.2 nT absolute magnetic field (50%), 1.6 longitudinal 7 × 104 K temperature (50%).