Review on Recent Developments in Laser Driven Inertial Fusion

Discovery of the laser in 1960 hopes were based on using its very high energy concentration within very short pulses of time and very small volumes for energy generation from nuclear fusion as “Inertial Fusion Energy” (IFE), parallel to the efforts to produce energy from “Magnetic Confinement Fusion” (MCF), by burning deuterium-tritium (DT) in high temperature plasmas to helium. Over the years the fusion gain was increased by a number of magnitudes and has reached nearly break-even after numerous difficulties in physics and technology had been solved. After briefly summarizing laser driven IFE, we report how the recently developed lasers with pulses of petawatt power and picosecond duration may open new alternatives for IFE with the goal to possibly ignite solid or low compressed DT fuel thereby creating a simplified reactor scheme. Ultrahigh acceleration of plasma blocks after irradiation of picosecond (PS) laser pulses of around terawatt (TW) power in the range of 1020 cm/s2 was discovered by Sauerbrey (1996) as measured by Doppler effect where the laser intensity was up to about 1018 W/cm2. This is several orders of magnitude higher than acceleration by irradiation based on thermal interaction of lasers has produced

Fluorescence emission spectra of silver and silver/cobalt nanoparticles

AbstractVarious aqueous solutions of silver and silver/cobalt nanoparticles (Ag and Ag/Co NPs) were obtained, and their fluorescence emission spectra have been studied. First, colloidal Ag NPs were prepared by an electrochemical method under different time intervals and at different rotation speeds of rotating electrode. Next, in a reduction method, Ag/Co core–shell NPs were prepared, using Ag NPs as a core. The core–shell structure of Ag/Co NPs has been demonstrated by the Transmission Electron Micrograph (TEM) and X-Ray Diffraction (XRD) pattern. The fluorescence emission spectra of Ag and Ag/Co NPs, at different ranges of excitation wavelength, were investigated, which revealed two kinds of fluorescence emission peak. The shorter emission peak was fixed at about 485 (for Ag NPs) and 538 nm (for Ag/Co NPs). For both NPs, with an increase in excitation wavelength, the latter emission peak becomes red-shifted. The effect of duration time and rotation speed of the rotating electrode, in the electrochemical preparation of Ag NPs, on its fluorescence emission spectra, has also been investigated

Conductivity of the PGT Synthesized by the High Energy Ball Milling (HEBM)

Nanocrystalline Pb1−3x/2GdxTiO3 (where x=0.01) abbreviated as PGT has been synthesised by high energy ball milling at room temperature. Milling was continuous and X-ray analysis shows that single phase tetragonal structure of nanocrystalline PGT was formed after 15 h milling. The average crystallite size was found to be 17 nm. The frequency dependent ac conductivity of the PGT ceramic was studied in the range 100–525°C. Complex impedance analysis suggested the dielectric relaxation to be of non-Debye type. The activation energy was found to be 1.04 ev. The mechanism of charge transport in nanocrystalline PGT was successfully explained by correlated hopping model

Determination of Plasma Parameters as well as Electrons Distribution Function

Abstract In this research we determined the biasing effects on the plas ma electrons distribution function and plas ma displacement in a low beta, large aspect ratio and circular cross section tokamak. Fo r this purpose, a movable biasing system was designed, constructed, and installed, and then the positive voltage applied to an electrode inserted inside the tokamak limiter and the plasma current, part icle distribution function and also the plasma horizontal displacement in the absence and presence of the biasing based on the mult ipole mo ments technique were measured. Measurements result has shown a modification of plas ma confinement by decreasing the plasma displacement

Alteration of optical and morphological properties of polycarbonate illuminated by visible/IR laser beams

In this paper we investigate the effects of visible to near infrared (NIR) laser illumination on the optical transmission (OT) and morphological changes (MC) of thin, curved surfaces of polycarbonate (PC) as employed by industry. The second harmonic of Nd:YAG laser (532 nm) and two diode lasers (665 and 980 nm) were used as sources. We have shown that the morphological changes and optical transmission of the PC elements are influenced by visible to infrared coherent illumination. The morphological changes of the PC surfaces are determined using atomic force microscopy (AFM), demonstrating the appreciable changes caused by the shorter wavelengths (higher energy). When analyzing the OT spectra of PC thin films, a measurable decrease in the OT of the PC surfaces which were illuminated by 532, 665 and 980 nm, in particular 532 nm, for energy densities greater than 25 J/cm^2 can be seen

Edge Fluctuations, Disr uption and Limiter Biasing in the CT-6B Tokamak

Abstr act The MHD and electrostatic fluctuations have been investigated in the plasma boundary region of the CT-6B tokamak using an array of Mirnov coils and a movable isolated biasing limiter. In the normal and limiter biased discharges, formation of a disruption studied. The results shown that by changing the time of applying positive bias voltages the sudden disruption may be controlled. In addition, it is found that there is a coherency between fluctuation frequencies of poloidal magnetic field oscillations, plasma potential fluctuation and H emission fluctuation and suppression of fluctuations at the core and edge of plasma. Biasing operation at low plasma current <15 kA with hydrogen plasmas heated ohmically, shows different behavior with respect to higher plasma currents ~30 kA regime. Also, by applying positive bias voltage on plasma is seems effect on MHD mode behavior. MHD oscillation lead to disruption by changing bias application time has been done. In the sections to follow a description of the experiment, its findings and conclusion are presented. Descr iption of the exper iment The experiments were conducted on the ohmically heated iron core CT-6B tokamak, with a major radius R=0.45m and a minor radius a=0.125m defined by a fixed four-bloc

Control of the edge plasma modes by hot limiter biasing in the IR-T1 tokamak

Tokamak plasma modes were analyzed using the Fast Fourier Transform (FFT) in presence of hot limiter biasing system in the IR-T1 Tokamak. Fourier analysis is reliable technique for mode detection in tokamaks. For this purpose we used a poloidal array of Mirnov coils and hot limiter biasing system. After Fourier analysis of Mirnov coils data in presence of hot biased limiter, Power Spectral Density (PSD) diagram was plotted. PSD describes how the power of a signal is distributed with frequency. In this contribution we also determined edge safety factor and safety factor from Fourier based derived mode numbers q = m/n. We obtained the maximum MHD activity using power spectrum at the frequency 33 kHz. Also the edge safety factor was determined less than 3, and the values of obtained safety factor from the mode numbers are between 2 ≤ q ≤ 5. Results show that hot limiter biasing can be used for increasing the plasma safety factor.Моды плазмы токамака анализировались с использованием быстрого преобразования Фурье (БПФ) при наличии системы подачи напряжения на горячий лимитер в токамаке IR-T1. Использовалась полоидальная схема расположения катушек Мирнова. С помощью Фурье-анализа данных катушек Мирнова была построена диаграмма спектральной плотности мощности (СПМ), описывающая распределение мощности сигнала с частотой. Были определены величины q на краю плазмы и по данным Фурье-анализа (как отношение мод: q=m/n). Максимум активности МГД оказался на частоте 33 кГц; на краю величина q≤ 3, а найденная из номеров гармоник − 2 ≤ q ≤ 5. Результаты показали, что подача напряжения на лимитер может использоваться для увеличения плазменного коэффициента надежности.Моди плазми токамака аналізувалися з використанням швидкого перетворення Фур'є (ШПФ) за наявності системи подачі напруги на гарячий лімітер у токамаці IR-T1. Використовувалась полоїдальна схема розміщення котушок Мірнова. За допомогою Фур'є-аналізу даних з котушок Мірнова була побудована діаграма спектральної щільності потужності (СЩП), яка описує розподіл потужності сигналу з частотою. Були визначені величини q на краю плазми і по даним Фур'є-аналізу (як відношення мод: q = m/n). Максимум активності МГД виявився на частоті 33 кГц; на краю величина q ≤ 3, а знайдена з номерів гармонік – 2 ≤ q ≤ 5. Результати показали, що подача напруги на лімітер може використовуватися для збільшення плазмового коефіцієнта надійності

Cotton in the new millennium: advances, economics, perceptions and problems

Cotton is the most significant natural fibre and has been a preferred choice of the textile industry and consumers since the industrial revolution began. The share of man-made fibres, both regenerated and synthetic fibres, has grown considerably in recent times but cotton production has also been on the rise and accounts for about half of the fibres used for apparel and textile goods. To cotton’s advantage, the premium attached to the presence of cotton fibre and the general positive consumer perception is well established, however, compared to commodity man-made fibres and high performance fibres, cotton has limitations in terms of its mechanical properties but can help to overcome moisture management issues that arise with performance apparel during active wear. This issue of Textile Progress aims to: i. Report on advances in cotton cultivation and processing as well as improvements to conventional cotton cultivation and ginning. The processing of cotton in the textile industry from fibre to finished fabric, cotton and its blends, and their applications in technical textiles are also covered. ii. Explore the economic impact of cotton in different parts of the world including an overview of global cotton trade. iii. Examine the environmental perception of cotton fibre and efforts in organic and genetically-modified (GM) cotton production. The topic of naturally-coloured cotton, post-consumer waste is covered and the environmental impacts of cotton cultivation and processing are discussed. Hazardous effects of cultivation, such as the extensive use of pesticides, insecticides and irrigation with fresh water, and consequences of the use of GM cotton and cotton fibres in general on the climate are summarised and the effects of cotton processing on workers are addressed. The potential hazards during cotton cultivation, processing and use are also included. iv. Examine how the properties of cotton textiles can be enhanced, for example, by improving wrinkle recovery and reducing the flammability of cotton fibre

Plasma Internal Inductance in Presence of Toroidal Field Ripple of Tokamak

Abstract In this research we investigated the effects of toroidal field ripple of tokamak on the plasma internal inductance. For this purpose, array of magnetic probes and also a diamagnetic loop with its compensation coil were designed, constructed, and installed on outer surface of the IR-T1 tokamak. A mplitude of the TF ripple is obtained 0.01, and also the effect of the TF ripple on the plasma internal inductance was discussed. In the high field side region of tokamak chamber, the TF ripple effect is increasing of the plasma internal inductance, whereas the low field side has inverse situation