Three-dimensional global simulation of interplanetary coronal mass ejection propagation from the Sun to the heliosphere: Solar event of 12 May 1997

A newly developed hybrid code, HAFv.2+3DMHD, that combines two simulation codes, Hakamada‐Akasofu‐Fry code version 2 (HAFv.2) and a fully three‐dimensional (3‐D), time‐dependent MHD simulation code, is used to study the global interplanetary coronal mass ejection (ICME) from the 12 May 1997 solar event. The solar wind structure is first simulated from the photosphere (1 solar radius, Rs) out to 2.5 Rs. The first step is derived from daily solar magnetograms. The HAFv.2 code is then used from 2.5 Rs to provide input at 18 Rs (0.08 AU) for the three‐dimensional MHD code that calculates the evolution of solar wind plasma and interplanetary magnetic field beyond this distance into the heliosphere. A dynamic disturbance, mimicking the flare's energy output from the 12 May 1997 solar event, is then delivered to this quiescent nonuniform heliospheric structure to model the evolution and interplanetary propagation of the ICME (including its shock). We compare the derived ICME velocity and number density with the Wind spacecraft observations near Earth. We integrate the line‐of‐sight density in the plane of sky to compare with the white light brightness data observed by the Large‐Angle Spectrometric Coronograph (LASCO) instrument on SOHO. This simulation will provide a tool to link the general cases of ICME at 1 AU to their solar sources, as well as to identify the possible origins of shock formation due to CMEs and CME/corotating interaction region interactions. In the case of complex or interacting ejecta, model interpretation is often required to accurately determine the solar sources of the ejecta at 1 AU. Because this newly developed model is performed using 3‐D MHD, its results can be extended to simulate coronal and heliospheric observations, including the ambient medium's nonuniformity provided by the HAFv.2 model, from the recently launched Solar Terrestrial Relations Observatory (STEREO) mission.