n e τ
transp
imp calculated from the ADAS database. Similar dependencies, but for Ne, are
shown in Fig. 2.16. As one can see from Figs. 2.15 and 2.16, in both cases E
imp
ion ~ few
keV if the impurity ion confinement is good n e τ
transp
imp ∼10
10 s Á cm
À3
. The estimate
E
imp
ion ∼ few keV is consistent with the experimental and computational results from
Refs. [80, 81], where the so-called impurity “radiation potential” (having the physical meaning somewhat similar to E
imp
ion ) was introduced.
Fig. 2.15 Dependence of W
rad
imp (a) and E
imp
ion (b) for N on electron temperature for the electron
density n e ¼ 10
14
cm
À3 and different values of n e τ
transp
imp for 10
10
, 10
9
, and 10
8 s cm
À3
, calculated
from the ADAS database
Fig. 2.16 Dependence of W
rad
imp (a) and E
imp
ion (b) for Ne on electron temperature for the electron
density n e ¼ 10
14
cm
À3 and different values of n e τ
transp
imp for 10
10
, 10
9
, and 10
8 s cm
À3
, calculated
from the ADAS database
42
2 Atomic Physics Relevant to Fusion Plasmas