  Coronal mass ejections (CMEs) are solar eruptions of plasma and magnetic
fields that significantly impact Space Weather, causing disruptions in
technological systems and potential damage to power grids when directed towards
Earth. Traditional coronagraphs along the Sun-Earth line struggle to precisely
track the early evolution of Earth-directed CMEs. Coronal dimmings, localized
reductions in extreme-ultraviolet (EUV) and soft X-ray emissions, are key
indicators of CMEs in the low corona, resulting from mass loss and expansion
during the eruption. This study introduces a novel method, DIRECD (Dimming
InfeRred Estimate of CME Direction), to estimate the early propagation
direction of CMEs based on the expansion of coronal dimmings. The approach
involves 3D simulations of CMEs using a geometric cone model, exploring
parameters like width, height, source location, and deflection from the radial
direction. The dominant direction of dimming evolution is then determined, and
an inverse problem is solved to reconstruct an ensemble of CME cones at various
heights, widths, and deflections. By comparing the CME orthogonal projections
onto the solar sphere with the dimming geometry, the 3D CME direction is
derived.Validated through case studies on October 1, 2011, and September 6,
2011, the DIRECD method reveals the early propagation directions of CMEs. The
CME on October 1, 2011, predominantly expands towards the South-East, while the
CME on September 6, 2011, inclines towards the North-West. These findings align
with previous studies using multi-viewpoint coronagraphic observations. The
study demonstrates the utility of coronal dimming information for early CME
direction estimation, providing valuable data for space weather forecasting and
mitigating potential adverse impacts on Earth before observation in
coronographs' field-of-view.
