megaampere

Megaampere (symbol MA) is a unit of electric current equal to one million amperes (10^6 A). It represents the application of the SI prefix mega to the ampere and is used in contexts where extremely large currents are involved.

In normal electrical practice, currents are far smaller, typically ranging from fractions of an ampere to tens of kiloamperes in large power systems. Megaampere-scale currents appear in specialized domains such as pulsed power systems, large electromagnets, and certain scientific facilities. Applications include magnetic confinement fusion devices (tokamaks and stellarators), where large currents are driven through magnet circuits to generate strong magnetic fields; particle accelerators and beamlines that require high-current magnet circuits; and pulsed power experiments like Z-pinch or railgun research, which involve short-duration, high-current pulses reaching multi-megaampere levels.

Measurement of MA-level currents requires dedicated instrumentation, including high-current transformers and resistive shunts, designed to withstand rapid transients and significant magnetic forces. Such systems also pose substantial safety and engineering challenges due to intense magnetic fields, heat, and mechanical stresses.

Relation to other units: 1 MA equals 1000 kA and 1,000,000 A. The megampere term is therefore used primarily in research, large-scale experimental facilities, and certain specialized industrial applications where currents far exceed conventional engineering thresholds occur.