Normal spectral emissivity of stable and undercooled liquid silicon using electromagnetic levitation in a dc magnetic field

Normal spectral emissivity of a stable and undercooled liquid (1660–1790 K) was determined for wavelengths of 780–920 nm using direct measurement of radiance of statically electromagnetically levitated liquid silicon: a dc magnetic field suppressed surface oscillation and the transitional motion of the silicon droplet. A spectrometer used for spectral radiance measurement was calibrated using a quasi-blackbody with a copper metal fixed point. The emissivity shows weak negative wavelength dependence, and negligible temperature dependence. The wavelength dependence of the normal spectral emissivity is expressible using the Drude free electron model