S15-1
Atomic and radiation processes of multiple charged ions and their applications
多価電離イオンの原子過程と輻射の物理と応用の展開	 
Akira Sasaki
佐々木明
Kansai Photon Science Institute, Japan Atomic Energy Agency
8-1-7 Umemidai, Kizugawa-shi, Kyoto 619-0215, Japan
原子力機構 関西光科学研究所 〒619-0215 京都府木津川市梅美台8-1-7

Atomic and radiation processes of multiple
charged ions have been attracted attention.
Spectroscopy of the emission from high-Z ions has
been used as a useful diagnosing tool of the plasmas.
In the magnetic fusion plasmas, the radiation loss
from impurity ions are interested. In the indirectdriven inertial fusion, high-Z ions are used toconvert the energy of the laser to x-rays by to
implode the target. Recently, EUV emission at
λ=13.5nm using tin plasmas has been investigated,
toward its application to microlithography.
6 papers will be presented in this symposium,including the spectroscopy of tungsten ions inmagnetic fusion plasmas and collisional radiative(CR) modeling, atomic emission using the electron
beam ion trap (EBIT), radiation hydrodynamics
simulation of the laser produced plasmas, andinvestigation of the plasma EUV source.
The emission spectra from tungsten ions arecomplex, especially in the case of N-shell ions at
low temperature (≈1keV). Recently, computational
atomic codes have enabled us to develop collisionalradiative (CR) model of such complex ions andallow us to calculate the emission spectra. Inexperiments, in the magnetic fusion devices, spectrafrom uniform and quasi-stationary plasma can beobserved. Using EBIT, emission spectra from eachcharge state of tungsten ions can be observed
separately, using which the emission lines observedin the fusion plasmas can be identified. By
comparing calculations with experimental spectra,
the atomic model is validated.
Figure 1 shows the mean charge of tungsten
plasma as an example. At high temperature(Te≈3keV) where Ni-like tungsten is dominant,results from different calculations agree well eachother, which are also consistent with experiments.
In contrast, at lower temperatures, disagreement
between calculations is seen, and calculated mean
charge is higher than experiment [4]. This suggeststhat accuracy of the atomic data especiallycollisional cross sections need improvement.
In laser produced plasmas, the radiationtransport determines their temporal and spatial
characteristics, which also decides the conversion
efficiency of the EUV source. Accurate opacity data
is required, and also novel methods to calculate
frequency and angle dependent radiation transport,
which is computationally intensive, are demanded.
With further experimental and theoreticalinvestigation of atomic and radiation processes inplasmas the model will be more useful for fusion
and a variety of applications, and will also become
useful in astrophysics.

Fig.1. Mean charge of tungsten at ne=1014/cm3. Lines
are calculated result from this work (thick solid line)[1], from ref. 2 (thick dotted line), and from the codes
presented at the NLTE7 kinetics workshop [3]. Squares
show the result from the measurement at LHD.
References[1] A. Sasaki and I. Murakami: J. Phys. B96 (2014)
175701.
[2] T. Pütterich, et al.: Plasma Phys. Control. Fusion.
50 (2008) 085016.
[3] H.-K. Chung, et al.: High Energy Density Phys. 9(2013) 645.
[4] I. Murakami et al., IAEA 25th Fusion Energy
Conference (Oct.12-18, 2014, St. Petersburg、Russia),
EX/P6-28.