Chemically Reactive Species In Liquids Generated By Atmospheric-Pressure Plasmas And Their Roles In Plasma Medicine

8th International Conference on Atomic and Molecular Data and Their Applications, ICAMDATA 2012; Gaithersburg, MD; United States; 30 September 2012 through 4 October 2012Satoshi Hamaguchi, AIP Conference Proceedings 1545, 214 (2013) https://doi.org/10.1063/1.4815857This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in AIP Conference Proceedings 1545, 214 (2013) and may be found at https://doi.org/10.1063/1.4815857

Ion temperature gradient driven turbulence in the weak density gradient limit

The anomalous heat transport arising from the ion temperature gradient driven mode or ηi-mode turbulence is extended to the range of the weak density gradient limit (ηi = Ln/ L T→ ∞ ), which is appropriate for H-mode dishcarges. It is shown that the anomalous ion heat conductivity χi with L n→ ∞ scales as χi = g(ρs/ LT) (cTi/eB) exp( - βσ) with σ = (T e/Ti) (LT/Ls), β≃4, and g≃1. This χi scaling is the natural extension for high ηi of the scaling of χi for K = (T i/Te) (1 + ηi) ≲ 4 obtained [Phys. Fluids B 2, 1833 (1990)] from analytical and numerical studies. © 1990 American Institute of Physics.Satoshi Hamaguchi and Wendell Horton, Physics of Fluids B: Plasma Physics 2, 3040 (1990) https://doi.org/10.1063/1.85937

Molecular-dynamics simulations of organic polymer etching by hydrocarbon beams

Molecular-dynamics simulations of hydrocarbon beam injections into a poly (1,4-phenylene) substrate surface are carried out with the use of classical potential functions for covalent bonds of carbon and hydrogen atoms. Van der Waals interactions among carbon atoms are also taken into account. In the low injection energy (50 eV) regime, we have observed that injected carbon atoms tend to be deposited on the surface, whereas hydrogen atoms tend to chemically break carbon bonds in the substrate. With the combination of chemical effects by hydrogen with large momenta carried by the injected carbon atoms, hydrogen-rich carbon clusters can etch organic polymer surfaces with relatively high efficiency. Implications of our simulation results on etching processes of low-dielectric-constant organic polymers by hydrogen-nitrogen plasmas are also discussed. © 2004 American Institute of Physics.H. Yamada et al., Journal of Applied Physics 96, 6147 (2004) https://doi.org/10.1063/1.180890

Nonlinear evolution of the m=1 internal kink mode in the presence of magnetohydrodynamic turbulence

The nonlinear evolution of the m=1 internal kink mode is studied numerically in a setting where the tokamak core plasma is surrounded by a turbulent region with low magnetic shear. As a starting point we choose configurations with three nearby q=1 surfaces where triple tearing modes (TTMs) with high poloidal mode numbers m are unstable. While the amplitudes are still small, the fast growing high-m TTMs enhance the growth of the m=1 instability. This is interpreted as a fast sawtooth trigger mechanism. The TTMs lead to a partial collapse, leaving behind a turbulent belt with q ~= 1 around the unreconnected core plasma. Although, full reconnection can occur if the core displacement grows large enough, it is shown that the turbulence may actively prevent further reconnection. This is qualitatively similar to experimentally observed partial sawtooth crashes with post-cursor oscillations due to a saturated internal kink.Comment: 14 pages, 13 figure

A Test for Light Gravitino Scenario at the LHC

Supersymmetric (SUSY) standard models in which the lightest SUSY particle (LSP) is an ultralight gravitino (m_{3/2}=O(1) eV) are very attractive, since they are free from the cosmological gravitino problems. If the neutralino is the next lightest SUSY particle (NLSP), it decays into a photon and the gravitino in collider experiments. We propose a simple test for the lightness of gravitino at the LHC.Comment: 9 pages, 2 figure

Effects of excitation voltage pulse shape on the characteristics of atmospheric-pressure nanosecond discharges

The characteristics of atmospheric-pressure microdischarges excited by nanosecond high-voltage pulses are investigated in helium-nitrogen mixtures, as a function of the parameters of the excitation voltage pulses. In particular, cases of single-pulse excitation as well as unipolar and bipolar double-pulse excitation are studied, at different pulse durations, voltage amplitudes, and delay times (for the case of double-pulse excitation). Our investigations are carried out with a particle-simulation code that also comprises the treatment of the VUV resonance radiation in the plasma. The simulations allow gaining insight into the plasma dynamics during and after the excitation pulse, the development and the decay of charged particle density profiles and fluxes. We find a strong dependence of the electron density of the plasma (measured at the end of the excitation pulse) on the electrical input energy into the plasma and a weak influence of the shape of the excitation pulse at the same input energy

Quantum cascade laser absorption spectroscopy with the amplitude-to-time conversion technique for atmospheric-pressure plasmas

Yumii, T., Kimura, N., and Hamaguchi, S., Journal of Applied Physics 113(21), 213101 (2013) http://doi.org/10.1063/1.480826