The equilibrium magnetic field is written [5,14] [see Equation (2.130)]
where is a convenient scale magnetic field-strength,
Equilibrium Magnetic Field
is the safety-factor profile. [See Equation (2.128).]
Here, and are dimensionless functions.
It follows from Equations (14.1)–(14.5), (14.17), and (14.18) that
The equilibrium poloidal magnetic flux (divided by ),
where, by convention,
. [Note that
is equivalent to the quantity defined in Equation (2.130).] The normalized poloidal magnetic
, is defined such that
. In general,
. Finally, if
. Thus, is the safety-factor of the magnetic flux-surface that encloses 95% of the poloidal magnetic flux enclosed by
the last closed magnetic flux-surface.