Fig. 1. Schematic of the internal structure of the Walker-type LVP module.

Fig. 2. Configurations of BDD cell assemblies using (a) Mo and (b) TiC as the electrode, and (c) a Ca-doped ZrO₂ sleeve as the heating insulation for ultrahigh-temperature experiments. These cell assemblies are modified from those presented in Ref. 4.

Fig. 3. Time–voltage relationship in phase angle control mode.

Fig. 4. Schematics of the 2D axisymmetric model (a) and the 3D model without (b) and with (c) the thermocouple (TC). The grids indicate the meshes. The red dots indicate the center positions of the heaters.

Fig. 5. Temperature–power relationship for the high-pressure-temperature experiments at 7.9 MN (∼28 GPa). The solid lines represent linear extrapolations of the temperature–heating power relationship within the effective temperature range of the D-type thermocouple, and the thick dashed lines represent data extrapolated using a cubic polynomial. The diamond symbols mark the maximum power and estimated temperature for each experiment.

Fig. 6. (a) and (b) BSE images of recovered samples from runs JLUC308 and JLUC272, respectively. (c) and (d) Magnified images of the areas inside the yellow frames in the central parts of the samples from runs JLUC308 and JLUC272, respectively. The main component of melts 1 and 2 are respectively Mg/Si/Al-rich and Zr-rich quenched crystals from melts.

Fig. 7. Time–temperature relationship calculated by different models at an equivalent voltage of 3.69 V.

Fig. 8. (a) Calculated temperature difference vs temperature from different models. (b) and (c) Calculated temperature difference vs temperature and load, respectively, from the 3D&AC model.

Fig. 9. Relationships between heating power and temperature obtained from finite element analysis of runs JLUC306, JLUC272, JLUC337, and JLUC419. Once the temperature exceeds 2600 K, the thermocouple starts reacting with other components, and the thermoelectric potential signals gradually become distorted. Below this temperature, the simulated values show good consistency with the experimental results.

Fig. 10. Temperature contour maps obtained from (a) the 3D axisymmetric model and (b) the model with thermocouple (b). These maps were generated by mirroring and rotating the initial model. The nodal temperatures at the centers of the heaters are indicated by the small circles.

Fig. 11. (a) Relationship between temperature and Y coordinate. The radial direction is designated as the X axis and the axial direction as the Y axis, as shown in Fig. 10(b). The inset is an isothermal contour map of the model with thermocouple. (b) Relationship between temperature and X coordinate.