Numerical simulation of nonlinear ionization nonuniformities in nonequilibrium disk MHD generator

Journal Article · Sat Feb 01 04:00:00 EST 1997 · IEEE Transactions on Plasma Science

DOI:https://doi.org/10.1109/27.557481· OSTI ID:471119

Sokolov, A Yu; Kabashima, Shigeharu ^[1]

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1. Tokyo Inst. of Tech., Yokohama (Japan)

The formation and evolution of the ionization nonuniformities from initial disturbances of finite amplitude in the nonequilibrium Ar-Cs plasma in a disk magnetohydrodynamic (MHD) generator is studied by the numerical simulation. The simulations are carried out in the wide interval of electron temperatures corresponding to the region at which the seed partially ionizes, the region of the linear plasma stability at the fully ionized seed, and the region of the instability corresponding to the partial ionization of Ar at high electron temperatures. Initial disturbances of finite amplitude in electron temperature and density are introduced at the time t = 0 into the homogeneous plasma distribution, and the critical amplitudes determining the development of the instability are calculated. The initial disturbances are constructed using random functions with different spatial scales. The results are compared with the calculation of the critical amplitudes from the nonlinear theory of the plane ionization waves. It is found that at electron temperatures lower than 5,500 K, the temperature dependence of the critical amplitudes and the structure of the nonlinear waves agree well with the nonlinear theory. In the electron temperature region corresponding to the partial ionization of the nobel gas, the finite ionization rate of argon atoms is essential for analysis of the instability. In this region the margin of the plasma stability is wider than it is predicted by the nonlinear theory. The nonuniformity in the argon ion number density plays the dominating role in the instability development at high electron temperatures in comparison with the nonuniformity in T{sub e} in the initial disturbances.

• OSTI ID: 471119
• Journal Information: IEEE Transactions on Plasma Science, Journal Name: IEEE Transactions on Plasma Science Journal Issue: 1 Vol. 25; ISSN ITPSBD; ISSN 0093-3813
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
DISK MHD GENERATORS
ELECTRON DENSITY
ELECTRON TEMPERATURE
NON-EQUILIBRIUM PLASMA
NUMERICAL ANALYSIS
PLASMA SIMULATION
STABILITY
TEMPERATURE DEPENDENCE