Macroscopic properties of liquids at very high temperature

Levitation of liquids heated by lasers has become a reference method for studies at temperatures above 2000°C. It has replaced older technologies which used refractory crucibles like tungsten, molybdenum or graphite. The levitation techniques overcome the problem of contamination of a reactive liquid by the container walls. Several groups around the world have adapted and upgraded these techniques to develop reference methods of thermophysical and spectroscopic measurements. Three techniques of levitating mm-sized liquid drops have emerged, enabling a wide range of applications from non-conducting materials to metals with potential applications to very high temperatures under controlled atmospheres. These are aerodynamic, electrostatic, and aero-electrostatic levitations amongst others. Current and challenging macroscopic property measurement methods with these techniques are reviewed.