Plasma Species
The plasma is assumed to consist of three (charged) species; namely, electrons (
), majority ions (
), and impurity ions
(
). The charges of the three species are
,
, and
, respectively, where
is the magnitude of the electron charge.
Quasi-neutrality [1] demands that
![$\displaystyle n_e= n_i+ Z_I\,n_I,$](img4678.png) |
(A.1) |
where
is the species-
number density. Here,
is the flux-surface label introduced in Section 14.2.
Let
![$\displaystyle \alpha_I(r) =\frac{Z_I\,(Z_{\rm eff}-1)}{Z_I-Z_{\rm eff}},$](img4679.png) |
(A.2) |
where
![$\displaystyle Z_{\rm eff}(r) = \frac{n_i+Z_I^{\,2}\,n_I}{n_e}$](img4680.png) |
(A.3) |
is the effective ion charge number. (See Section 1.6.) It follows that
Finally, let
Note that
.