megabar

Megabar is a non-SI unit of pressure equal to one million bars. Since 1 bar equals 100,000 pascals, 1 megabar equals 10^11 pascals, or 100 gigapascals. The megabar is primarily used in high-pressure physics and materials science, where pressures reach the upper end of static and dynamic compression. It appears in discussions of diamond anvil cell experiments, shock compression, and planetary science, where pressures inside large planets or during core formation are relevant. In modern literature, gigapascals are more common, and megabar usage is largely historical or specialized.

Common abbreviations include Mbar (or MBAR). The unit is non-SI; the pascal remains the SI unit for pressure in most scientific contexts. Conversions: 1 GPa = 0.01 MBAR; 1 MPa = 1e-5 MBAR; 1 bar = 1e-6 MBAR. Therefore, 1 MBAR = 100 GPa.