Electrostatic units
The electrostatic system of units (CGS-ESU) is a system of units used to measure quantities of electric charge, electric current, and voltage within the centimeter–gram–second (or "CGS") system of metric units. In electrostatic units, electrical charge is defined by the force that it exerts on other charges.[1][2]
Although the CGS units have mostly been supplanted by the MKSA (meter–kilogram–second–ampere) or International System of Units (SI) units, the electrostatic units are still in occasional use in some applications, most notably in certain fields of physics such as in particle physics and astrophysics.
The main electrostatic units are:
- The statcoulomb, called the franklin or the "esu" for electric charge
- The statvolt for voltage
- The statampere for electric current.
The CGS-ESU units for magnetic quantities are seldom used,[3] and don't have special names. Sources tend to just use 'esu' or the derived unit expressed in terms of the CGS base units. For example, the unit for magnetic induction is g1/2/cm3/2, corresponding to ccgs gauss, and corresponding to ccgs × 10−4 tesla, where ccgs = c / (cm/s) = 29979245800 is the numeric part of speed of light c expressed in CGS units.[4][5]
References
- "Electrostatic unit of charge | unit of measurement". Encyclopedia Britannica. Retrieved 2018-03-27.
- Clarke, Richard. "Unit Systems in Electromagnetism". info.ee.surrey.ac.uk. Retrieved 2018-03-27.
- Slater, John C.; Frank, Nathaniel H. (2012). Electromagnetism. Dover. p. 208. ISBN 9780486150406. OCLC 868966382.
- Knoepfel, Heinz E. (2008). Magnetic Fields: A Comprehensive Theoretical Treatise for Practical Use. Wiley. p. 543. ISBN 9783527617425. OCLC 890041837.
- Cox, Arthur N., ed. (2015). Allen's Astrophysical Quantities. Springer. p. 24. ISBN 9781461211860. OCLC 905652263.