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Particle-in-Cell (PIC) simulation is a powerful and extensively used tool for plasma studies. We have recently developed our own PIC code at IHPC. In the code, we have implemented both explicit and implicit algorithms1 for Maxwell solver. The explicit scheme is efficient for short simulations, while the implicit scheme is more superior in term of numerical noise suppression. This allows us to choose...
The purpose of this study is to develop scaling relations for material erosion with respect to electrical current for aluminum and titanium. Experiments were performed with a source capable of generating short pulses (approx. 100 μs) with up to 20kA currents across a small gap between sample pieces. The amount of damage on the experimental coupons was significant and visible even with a low magnification...
Microplasmas in liquid with microsecond and nanosecond duration are generated by the application of fast rise time voltage pulses to a micro-tipped-electrode immersed in the liquid with single and double spark gap switching respectively. T h e time dependent light emission occurring during the microplasmas generation in liquid with different energy inputs are investigated in this research. Salt water...
Exact solutions for the equations that predict the flow and state of plasmas are few and limited to very simple problems, and so computer aided solutions are important to study more interesting and complex plasmas. Verification problems are important for comparison with computed models to demonstrate that computational methods are implemented correctly. When exact solutions are unavailable, it is...
Multipactor (MP) is known as the avalanche growth of the number of secondary electrons emitted from a solid surface in the presence of RF field under vacuum conditions. It may occur in various RF and microwave systems usually substantially impairing their performance. Therefore, theoretical and experimental studies of MP aimed at finding methods of its suppression are extremely important. In this...
Micro-plasma high-pressure spark gaps have been investigated for the generation of ultra wideband (UWB) microwave pulses. Such micro-plasma spark gaps are characterized by sub-ns current rise-times and high peak power output in short impulses. A repetition rate of 1 MHz is demonstrated by a single micro-plasma spark gap at the Pohang Accelerator Laboratory, Pohang, South Korea. For the MHz repetition...
Pulsed Power has been applied to foods for the extraction of vegetable juice and sterilization of foods. The juice from sugar beet increased with pulsed electric fields1. Since the aging of Japan's population is advancing, the softening of foods becomes important to keep the quality of life.
Application of dielectric barrier discharges for wound and disease therapies–plasma medicine–is one of the fastest-growing fields in non-thermal, low temperature plasma research. It remains unclear of how particles and fields produced by the plasma source induce changes internally within the cell. This effort aims to elucidate the effect of an atmospheric pressure plasma on internal properties of...
Particle-in-cell simulation package VORPAL, developed by the Tech-X Corporation, is used to simulate laboratory experiments investigating RF plasma sheaths. Experimental procedures on scaled down RF antenna systems at ORNL have been created to provide diagnostics of the nonlinear RF sheath that is formed over antenna, enabling spatial and temporal resolution of fields within the sheath. The primary...
Breast cancer now has very high incidence and death rate among women. Chemotherapy plays a vital role in breast cancer treatment. However, problems brought by chemotherapy are not neglectable. One of the major problems in human cancer treatment is the chemotherapeutic resistance, which possibly leads to the failure of the treatment. Another is the adverse effects induced by chemotherapy, including...
Pulsed electromagnetic field (PEF) has shown to induce positive effects on plant cells and tissues, to lead faster growth in stem and root, and result in increased production. However little is known about the effect of nanosecond pulse electric field (nsPEF) on plant seeds and only the model plant Arabidopsis thaliana was given a try. In contrast with the growth inhibiting effect of plasma membrane...
Intense nanoseconds pulsed electric field (nsPEF) is a novel physical stress to organisms, and has been reported to induce various unique responses to mammalian cells, such as bleb formation, phosphatidylserine externalization, increase in calcium ion concentration1, as well as increase in membrane permeabilization. The primary biological effect of nsPEF depends on the pulse parameters such as pulse...
PrismSPECT is a collisional-radiative spectral analysis code designed to simulate the atomic and radiative properties of LTE and non-LTE plasmas over a wide range of conditions. For a grid of user-specified plasma conditions, PrismSPECT computes spectral properties (emission and absorption), ionization fractions, atomic level populations, and line intensity ratios by solving either time-dependent...
Short-wavelength radiation sources are indispensible tools in advancing science and technology. Extending these sources to shorter wavelengths requires improved undulator performance, especially at short periods. Present undulator designs, superconducting and permanent magnet, have shortcomings as the period is decreased. In addition, they require complex systems, cryogenics and/or mechanical gap...
Propagation process of the laser absorption wave was introduced by analysis of one dimensional steady state flow with heat interaction. The shock wave is sufficiently strong so that the shocked heated gas is hot enough to begin absorbing the laser irradiation. This is an analog of the chemical detonation wave that can be viewed as a shock followed by a strong deflagration. However, the velocity given...
In order to serve several experiments simultaneously, the Project X1 requires a programmable chopping system to deflect bunches from the initially 162.5MHz CWH-beam. A helical 200 Ohm deflector is proposed, which needs a ±500V variable pulse length driver with ∼1ns rise/fall time at an average repetition rate of 33MHz. The SLAC Hybrid MOSFET/driver Switch Modules (HSMs) have demonstrated 1ns switching...
Over the past 10 years Extreme Ultraviolet Lithography (EUVL) sources based on 13.5nm emission from Sn plasmas have been investigated. Sn plasmas produce strong resonant emission due to 4d–4f, 4p–4d and 4d–5p transitions around 13.5 nm, which overlap in adjacent ion stages to yield an intense unresolved transition array (UTA). The UTA consists of hundreds of thousands of near-degenerate resonance...
When plasmas are instantaneously created around an electromagnetic wave, frequency of the wave up-converted to the frequency, which depends on the plasma frequency. This phenomenon is called as the flash-ionization predicted by S. C. Wilks et. al. [1]. The theory requires not only the plasma creation in time much shorter than an oscillation period of the electromagnetic wave but also plasma length...
Perfluorooctane sulfonic acid (PFOS: C7F15SO3H) is an excellent surface-active agent and has been widely used in various applications. However, PFOS is a bioaccumulating substance and has toxic effects on the human body. We recently found that plasma generated in gas bubbles can decompose PFOS very efficiently and rapidly [1]. During the PFOS decomposition process using plasma, perfluorocarboxylic...
We present results of an experimental study aimed at producing a compact Marx generator consisting of three to six stages in series. A continuous plasma column is used to trigger simultaneously each element of the generator. This plasma channel is created by the filamentation of an intense femtosecond laser pulse (200–250 mJ, 700 fs @ 800 nm) from a Ti: Sapphire chirped pulse amplification laser chain...
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