Although SI units are preferred in most publications, Gaussian and other units are still widely used in some fields, such as chapter 11-16 in Jackson 1999. One reason is:
Explicit factors of c appear in a natual manner in these units, making them more appropriate than SI units for relativistic phenomena.
Another reason is to make equations simpler, for example:
- Electromagnetic tensor:
(Gaussian, Heaviside-Lorentz, natural)
- Klein-Gordon equation:
(natural)
- Schrödinger equation for hydrogen atom:
(atomic)
Conversions between different unit systems can be found in many textbooks (e.g. appendix in Jackson 1999). However, I'd like to provide a more straight-forward method to make the process easy to understand.
Because of 2019 redefinition of the SI base units, the results here are different from other materials: there are uncertainties in most unit conversions between SI and Gaussian.
- 1. Methodology of Unit Conversion
- 2. CGS Units: ESU, EMU and Gaussian
- 3. Polarization and Magnetization
- 4. Natural Units
- 5. System-Independent Electromagnetic Equations
- 6. Magnetic Monopole
- 7. Atomic Units, Uncertainties and Correlation Coefficients
Appendix
- Physical Constants (CODATA 2018)
- Energy Conversions
- Non-SI Physical Units
- Imperial/US Units
- Chinese Units
- Magnetic B Field in SI, Gaussian and Natural Units
- Poynting Vector: System-Independent Form
- Dirac Quantization Condition