Formation design for interplanetary shock imaging interferometric array

Continuous monitoring of interplanetary coronal mass ejections (CMEs) plays a vital role in modelling of CME heliospheric propagation and improving space weather prediction, which remains a significant challenge due to the lack of effective observations. The type II radio bursts produced by CME-driven interplanetary shocks provide an opportunity for us to imaging the CMEs and their shocks through interferometry technology. This paper proposes a concept for the program of CME/shock imaging through low-frequency radio interferometry based on satellite formation. The formation consists of one mother satellite and seven daughter satellites, forming an interferometric array with the equivalent aperture size of 100 km to conduct three-dimensional tomography of CME/shock at 0.1 MHz ∼ 30 MHz. Two types of satellite formations, including a linear formation and a coplanar formation, are designed to provide different options of baseline distributions. Then, the fuel budgets for formation deployment and maintenance are analyzed. Besides, GNSS (Global Navigation Satellite System) differential positioning is discussed for relative measurement between the mother and daughter satellites. Finally, imaging simulations are performed to demonstrate the imaging performances of the interferometric array. The proposed interferometric formation will furnish essential insights into the Earth-directed CME propagation and provide critical and unprecedented observation data for space weather forecasting.