23P162R
Numerical Analysis for Low-Temperature and Dense Plasma Generation using
Pulsed Power Discharge Devices
数値解析によるパルスパワー放電装置を用いた低温高密度プラズマ生成の検討	 
Takashi Kikuchi1), Toru Sasaki1), Nob. Harada1), Weihua Jiang2), and Akira Tokuchi2) 3)
菊池崇志, 佐々木徹，原田信弘，江	  偉華，徳地	  明
1)

Department of Electrical Engineering, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, 940-2188,
Japan
長岡技術科学大学・電気系	  〒940-2188	  新潟県長岡市上富岡町1603-1
2)

Extreme Energy-Density Research Institute, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka,940-2188, Japan
長岡技術科学大学・極限エネルギー密度工学研究センター	  〒940-2188	  新潟県長岡市上富岡町1603-13)

Pulsed Power Japan Laboratory Ltd., 4-5-2, Nomura, Kusatsu, 525-0027, Japan
株式会社パルスパワー技術研究所	  〒525-0027	  滋賀県草津市野村4-5-2	 

To investigate properties of low-temperature and dense plasma for the inertial confinement fusion, thenumerical simulation of time-dependent one-dimensional thermal diffusion is carried out in the compact
pulsed power discharge device. The simulation result is useful to understand the thermodynamic
phenomena during the discharge in comparison with the experimental result. Using an intense pulsed
power generator "ETIGO-II", it is expected that the properties of dense plasma is investigated during theshort time duration such as the implosion dynamics of inertial confinement fusion pellet.

1. Introduction
Property data of low-temperature and dense
plasma are important to understand implosion
dynamics in a fuel pellet of inertial confinement
fusion (ICF) [1]. Because the phase of the fuelpellet changes from a solid to plasma due toirradiation of energy drivers.
In this study, we numerically investigate togenerate the low-temperature and dense plasma
by using pulsed power discharge devices toobtain the properties of low-temperature anddense plasmas.
2. Numerical Simulation for Foam/Plasma
Generated by Compact Pulsed Power Discharge
Time-dependent
one-dimensional
thermaldiffusion equation with cylindrical symmetry
configuration is numerically solved to simulate thelow-temperature and dense plasma generation in thecompact pulsed power discharge experiment [2].
The computational box is shown in Fig.1. In thisapparatus, a foamed copper is used as a sample, andis surrounded with a hollow sapphire capillary.
Table I shows the material parameters for numericalsimulation. The initial temperature is set as 300 K.
The input energy is given by the corresponding
experimental data [2]. The density of the foamed
copper in the hollow capillary is 0.032 times thesolid density. In this setup, the fluid dynamics ofthe sample plasma is limited by the capillary. For
this reason, we only calculate the thermodynamics
in the foam/plasma without the fluid phenomena ofplasma.

Fig.1. Computational box for
one-dimensional thermal diffusion
cylindrical symmetry configuration

time-dependentequation with

Table I. Material parameters for calculation

Copper Region:
Thermal Conductivity
Specific Heat
Solid Density
Sapphire Region:
Thermal Conductivity
Specific Heat
Solid Density

κ(T) [3,4] W/m K
Cv(T) [5,6] J/kg K
8920 kg/m3
42 W/m K
750 J/kg K
3970 kg/m3

volumetric dense plasma generation is expected,
even in the short pulse duration. For example, it isestimated that the foamed copper of φ20 mm x 100
mm with 0.032 times the solid density can beablated in the nominal parameter operation of thevoltage and current.

Fig.2.
Calculation
resultof
time-dependent
one-dimensional thermal diffusion equation withcylindrical symmetry configuration in regions of foamed
copper and sapphire capillary

The conventional thermal property data of copperin solid, liquid, and gas phases are given by Refs.
[3-6]. Since the sample is a foamed material, weassumed that the skin effect can be ignored. As aresult, the discharge current distribution is assumed
as uniform in the copper region.
Figure 2 shows the numerical simulation result oftime-dependent thermal diffusion in the copper
foam and the sapphire capillary regions. The
numerical simulation confirmed that the sample isachieved to the temperature generating plasma. The
result indicates that the temperature at the interface
between the copper foam and the sapphire capillary
is diffused, and the temperature around the edge ofcopper region is reduced due to the difference of theheat capacities.
The result can be compared with theexperimental result to understand the phenomena in
the capillary during the discharge.
3. Dense Plasma Generation using Intense
Pulsed Power Device
As mentioned in previous section, the compact
pulsed power discharge device is useful tool togenerate the low-temperature and dense plasma
condition. Although typical implosion time for ICF
is in several-10 ns [7], the discharge time driven by
the compact pulsed power device is not suitable toobserve the fast phenomena during the implosion.
The nominal parameters of the intense pulsed
power generator "ETIGO-II" [8] (see Fig.3) are 1
MV- 1MA - 50 ns (FWHM) in the current condition.
Using this intense pulsed power device, theFig.3. Intense pulsed power generator "ETIGO-II" atExtreme Energy-Density Research Institute in Nagaoka
University of Technology

4. Conclusions
To investigate the low-temperature and dense
plasma for the inertial fusion energy output, thenumerical simulation of time-dependent thermal
diffusion was carried out in the compact pulsed
power discharge device. The simulation result isuseful to understand the thermodynamics
phenomena during the discharge. Using the intense
pulsed power generator "ETIGO-II", we will
investigate the properties of dense plasma during
the short time duration in comparison with theimplosion dynamics of ICF pellet.
References[1] S. Atzeni and J. Meyer-ter-Vehn: The Physics ofInertial Fusion (Oxford, New York, 2004).
[2] Y. Amano, Y. Miki, T. Takahashi, T. Sasaki, T.
Kikuchi, and Nob. Harada: in this proceeding,
24P123-P.
[3] C.Y. Ho, R.W. Powell, and P.E. Liley: JPCRD 1(1972) 279 (See p.54 for Cu).
[4] C.Y. Ho, R.W. Powell, and P.E. Liley: JPCRD 3(1974) 1.
[5] NIST Standard Reference Database Number 69.
[6] M.W. Chase: J. Phys. Chem. Ref. Data 9 (1998) 1.
[7] T. Kikuchi, T. Someya, and S. Kawata: IEEJ Trans.
FM 125 (2005) 515.
[8] W. Jiang, et al.: Jpn. J. Appl. Phys. 32 (1993) L752.