... written2.1
It is conventional to take account of the negative charge of electrons by making the electron gyrofrequency ${\mit\Omega}_e$ negative. This approach is implicit in formulae such as Equation (2.52). 
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
... particles.4.1
In general, this is not true. Atomic or nuclear processes operating in a plasma can give rise to local sources and sinks of particles of various species. However, if a plasma is sufficiently hot to be completely ionized, but still cold enough to prevent nuclear reactions from occurring, then such sources and sinks are usually negligible. 
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
...solar!rotation8.1
To an observer orbiting with the Earth, the rotation period appears to be about 27 days. 
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.