Use of a pressless multianvil high-pressure split-sphere apparatus to measure the silicate melt viscosity

The possibility of using a pressless multianvil high-pressure split-sphere apparatus to measure the viscosity of silicate melts was studied experimentally using as an example diopside melt (CaMgSi$_2$O$_6$) at a pressure of 4.0 GPa and a temperature of 1800$^\circ$C. The viscosity was calculated by the Stokes formula. The measurement error of the melt viscosity was estimated by the falling ball method. Prospects for using devices of this type to estimate the viscosity of silicate melts at high pressures and temperatures are shown.