
326 Compact Plasma and Focused Ion Beams
has been compared with standard-model energy distribution functions of
the same mean energy given by [4]
fE
mE
E
m
m
m
m
mean
mm
m
() exp
()
()
()
()
/
//
Γ
Γ
Γ
Γ
52
32
52
32
32
52 32
/
/
/
/
EE
mean
m
,
(21.1)
where Γ is the complete gamma function and m is an integer 1 and 2. m = 1
corresponds to Maxwellian, f
M
and m = 2 corresponds to Druyvesteyn, f
D
.
The comparison shows that the population of low- and high-energy tail ions
are decient in the IED as compared to f
M
and f
D
. The ions posses medium
energy, and the distribution is largely monoenergetic with a smaller energy
spread of ~5 eV.
Unlike RF plasmas, microwave plasmas ...