Systems and methods are provided for monitoring a solid-liquid interface during a casting process. The systems and methods enable determination of the location of a solid-liquid interface during the casting process.
 This invention was made with U.S. Government support under National Renewable Energy Laboratory (NREL) Subcontract No. ZDO-2-30628-03 under Department of Energy (DOE) Contract No. DE-AC36-98GO10337, awarded by DOE. The U.S. Government has certain rights in this invention.