ALBERT

Description:    Nonlinear ion acoustic waves using a fluid model in cylindrical coordinates for the propagation parallel to the magnetic field are investigated in a low- β magnetized plasma. It is found that beside the existence of smooth regular solitons, cusp solitons also exist in plasmas when certain plasma conditions are satisfied. Characteristics of bipolar electric field solitary structures are also studied corresponding to the smooth regular solitons. Theoretical results agree with observations. Content Type Journal Article Pages 1-6 DOI 10.1007/s10894-011-9439-7 Authors M. N. S. Qureshi, Department of Physics, GC University, Lahore, 54000 Pakistan Jian Kui Shi, State Key Laboratory of Space Weather, CSSAR, Chinese Academy of Sciences, 100190 Beijing, China H. A. Shah, Department of Physics, GC University, Lahore, 54000 Pakistan Journal Journal of Fusion Energy Online ISSN 1572-9591 Print ISSN 0164-0313

Description:    The nitridation of SS304 surfaces is obtained by irradiating nitrogen ions from Amirkabir plasma focus device, which use multiple focus deposition shots at optimum distance 10 cm from the anode. The Vickers Micro-Hardness values are improved more than twice for the nitrided samples comparing to the nonnitrided ones. The X-ray diffraction (XRD) analysis is carried out in order to explore the phase changes in the near surface structure of the metals. The results of Scanning Electron Microscopy (SEM) indicate changes in surface morphology which are the emergence of smooth and uniform film on the surface of the nitrided metals. Content Type Journal Article Pages 1-4 DOI 10.1007/s10894-011-9440-1 Authors M. Afrashteh, Amirkabir University of Technology, Tehran, Iran M. Habibi, Amirkabir University of Technology, Tehran, Iran E. Heydari, Amirkabir University of Technology, Tehran, Iran Journal Journal of Fusion Energy Online ISSN 1572-9591 Print ISSN 0164-0313

Description:    Numerical experiments are carried out systematically to determine the argon soft X-Ray yield Y sxr for optimized argon plasma focus with storage energy E 0 from 1 kJ to 1 MJ. The ratio c = b/a, of outer to inner radii; and the operating voltage V 0 are kept constant. E 0 is varied by changing the capacitance C 0 . These numerical experiments were investigated on argon plasma focus at different operational gas pressures (0.41, 0.75, 1, 1.5, 2.5 and 3 Torr) for two different values of static inductance L 0 (270 and 10 nH). Scaling laws on argon soft X-Ray yield, in terms of storage energies E 0 , peak discharge current I peak and focus pinch current I pinch were found. It was found that the argon X-ray yields scale well with \text Y \text sxr = 8 ×10 - 11 \text I \text pinch 4.12 for the high inductance (270 nH) and \text Y \text sxr = 7 ×10 - 13 \text I \text pinch 4.94 for the low inductance (10 nH), (where yields are in joules and current in kilo amperes). While the soft X-ray yield scaling laws in terms of storage energies were found to be as \text Y \text sxr = 0.05 ×\text E 0 0.94 at energies in the 1–100 kJ region. The scaling ‘drops’ as E 0 is increased, and Y sxr scales as \text Y \text sxr = 1.01 ×\text E 0 0.33 at high energies towards 1 MJ for 10 nH at argon gas pressure of 1 Torr. The optimum efficiencies for SXR yield were found to be 0.00077% with a capacitor bank energy of 112.5 kJ for high inductance (270 nH) and 0.005% with a capacitor bank energy of 4.5 kJ for low inductance (10 nH). Therefore for larger devices, it may be necessary to operate at a higher voltage and use higher driver impedance to ensure increasing X-ray yield efficiency beyond the optimum values. As storage energy is changed the required electrode geometry for optimum yield is obtained and the resultant plasma pinch parameters are found. Required values of axial speed for argon soft X-ray emission were found to be in the range 11–14 cm/μs. Content Type Journal Article Pages 1-8 DOI 10.1007/s10894-011-9445-9 Authors M. Akel, Department of Physics, Atomic Energy Commission, P. O. Box 6091, Damascus, Syria S. Lee, Institute for Plasma Focus Studies, 32 Oakpark Drive, Chadstone, VIC 3148, Australia Journal Journal of Fusion Energy Online ISSN 1572-9591 Print ISSN 0164-0313

Description:    Compact toroidal configuration is of simpler construction than the conventional tokamak and has important advantages due to the novel physics properties of low aspect ratio. In this paper we are developing a numerical program to study the magnetic dynamo or relaxation of CT’s characterized by arbitrary tight aspect ratio. It is shown that the numerical method (Collocation Method), used here, works quite well to calculate numerically the lowest zero flux eigenvalues μ of Taylor’s relaxed plasma state equation ® Ñ   × ® B   = m ® B   for an axisymmetric tokamaks of circular cross section. An excellent fulfillment of the toroidal flux vanishing boundary condition \iint B Æ \text d r \text d z = 0 along the whole boundary for such tokamaks are achieved. Dependence of μ on the aspect ratio is also obtained. Several runs of the program for various wave numbers k showed that μ is very insensitive to the choice of k . Besides, the poloidal magnetic field topologies inside the tokamak are well represented. Content Type Journal Article Pages 1-6 DOI 10.1007/s10894-011-9434-z Authors Sh. M. Khalil, Faculty of Science, Physics Department, Princess Nora Bint Abdurrahman University, Riyadh, Kingdom of Saudi Arabia N. A. Alomayrah, Faculty of Science, Physics Department, Princess Nora Bint Abdurrahman University, Riyadh, Kingdom of Saudi Arabia R. A. Altuijri, Faculty of Science, Physics Department, Princess Nora Bint Abdurrahman University, Riyadh, Kingdom of Saudi Arabia Journal Journal of Fusion Energy Online ISSN 1572-9591 Print ISSN 0164-0313

Description:    High-current proton accelerators are being researched at Los Alamos National Laboratory and other laboratories for accelerator production of tritium, transmuting long-lived radioactive waste into shorter-lived products, converting excess plutonium, and producing energy. These technologies make use of spallation neutrons produced in ( p,xn ) and ( n,xn ) nuclear reactions on high-Z targets. Through ( p,xn ) and ( n,xn ) nuclear reactions, neutrons are produced and are moderated by heavy water. These moderated neutrons are subsequently captured on 3 He to produce tritium via the ( n,p ) reaction. Tritium self-sufficiency must be maintained for a commercial fusion power plant. Rubbia succeeded in a proposal of a full scale demonstration plant of the Energy Amplifier. This plant is to be known the accelerator-driven system (ADS). The ADS can be used for production of neutrons in spallation neutron source and they can act as an intense neutron source in accelerator-driven subcritical reactors, capable of incinerating nuclear waste and of producing energy. Thorium and Uranium are nuclear fuels and Lead, Bismuth, Tungsten are the target nuclei in these reactor systems. The spallation targets can be Pb, Bi, W, etc. isotopes and these target material can be liquid or solid. Naturally Lead includes the 204 Pb (%1.42), 206 Pb (%24.1), 207 Pb (%22.1) and 208 Pb (%52.3) isotopes. The design of ADS systems and also a fusion-fission hybrid reactor systems require the knowledge of a wide range of better data. In this study, by using Hartree–Fock method with an effective nucleon-nucleon Skyrme interactions rms nuclear charge radii, rms nuclear mass radii, rms nuclear proton, neutron radii and neutron skin thickness were calculated for the 204, 206, 208 Pb isotopes . The calculated results have been compared with those of the compiled experimental and theoretical values of other studies. Content Type Journal Article Pages 1-6 DOI 10.1007/s10894-011-9433-0 Authors E. Tel, Osmaniye Korkut Ata University, Faculty of Arts and Science, Osmaniye, Turkey A. Aydin, Department of Physics, Faculty of Arts and Sciences, Kirikkale University, Kirikkale, Turkey Journal Journal of Fusion Energy Online ISSN 1572-9591 Print ISSN 0164-0313

Description:    A new design of Langmuir Probe (LP) used for diagnosing plasma in Tokamak has been reported in this work. The thermal state of LP is given by finite element analysis and an explanation of temperature variation based on the changes in heat flux are presented. The evaluation of thermal contact resistance at the interface of different materials are presented. A effective analytical method based on numerical calculation and experimental investigation has been developed for studying the heat transfer capability of LP. This method, is able to predict the inner thermal state of LP, thereby leading to optimize the design of LP. Excellent agreement between simulated results and calculated results figured out by ANSYS and experimental data, indicated the validity of this model. These results obtained are useful for developing the high-performance LP. Content Type Journal Article Pages 1-5 DOI 10.1007/s10894-011-9437-9 Authors Tao Wang, National Key Laboratory of Science and Technology on Nano/Micro Fabrication Technology, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, 800 Dong Chuan Road, Minhang Dist., Shanghai, 200240 China Lieming Yao, School of Physics Electronics, University of Electronic Science and Technology of China, 4 North Jianshe Road, Chengdu, 610054 China Yong Zhou, National Key Laboratory of Science and Technology on Nano/Micro Fabrication Technology, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, 800 Dong Chuan Road, Minhang Dist., Shanghai, 200240 China Shengmei Yan, The Institute of Optics And Electronics, The Chinese Academy of Sciences, Chengdu, 610209 China Journal Journal of Fusion Energy Online ISSN 1572-9591 Print ISSN 0164-0313

Description:    A 3.3 kJ Mather type dense plasma focus device is used to generate a pulsed argon ion beam of 100 KeV in this work. Hydrogenated amorphous silicon (a-Si:H) film prepared by plasma enhanced chemical vapor deposition (PECVD) on c-Si substrate was irradiated with the argon ion beam produced by this dense plasma focus device. The effects of exposure to a single, 5 and 10 shots of dense plasma focus argon ion beam irradiation on the surface morphology, crystallinity and chemical bonding properties of the a-Si:H films were studied using Field Emission Scanning Electron Microscope (FESEM), X-ray Diffraction (XRD), Raman scattering and Fourier Transform Infrared (FTIR) spectroscopy, respectively. Formation of nano-crystalline silicon phase along with increase in structural order and hydrogen content in the film structure has been observed when the a-Si:H film was irradiated with a single shot of dense plasma focus argon ion beam. Exposure to 5 and 10 shots of the dense plasma focus argon ion beam irradiation reduced the hydrogen content resulting in a decrease in crystallinity and structural order in the film structure. Content Type Journal Article Pages 1-8 DOI 10.1007/s10894-011-9435-y Authors S. K. Ngoi, Plasma Research Laboratory, Plasma Technology Research Center, Physics Department, University of Malaya, 50603 Kuala Lumpur, Malaysia S. L. Yap, Plasma Research Laboratory, Plasma Technology Research Center, Physics Department, University of Malaya, 50603 Kuala Lumpur, Malaysia B. T. Goh, Solid State Research Laboratory, Low Dimensional Materials Research Center, Physics Department, University of Malaya, 50603 Kuala Lumpur, Malaysia R. Ritikos, Solid State Research Laboratory, Low Dimensional Materials Research Center, Physics Department, University of Malaya, 50603 Kuala Lumpur, Malaysia S. A. Rahman, Solid State Research Laboratory, Low Dimensional Materials Research Center, Physics Department, University of Malaya, 50603 Kuala Lumpur, Malaysia C. S. Wong, Plasma Research Laboratory, Plasma Technology Research Center, Physics Department, University of Malaya, 50603 Kuala Lumpur, Malaysia Journal Journal of Fusion Energy Online ISSN 1572-9591 Print ISSN 0164-0313

Description:    Among many facilities in the field of nuclear fusion devices, inertial electrostatic confinement (IECF) device has the specific character of tendency to generate fusion products continuously. Besides the distinctive characteristics, it has become an outstanding focus of interest for many scientists because of several applications such as the ability of performing hydrogen boron fusion. This paper summarizes primary results of the design and construction of the first Iranian IECF device (IR-IECF). It consists of 13.5 cm diameter stainless steel cathode, 41 cm diameter anode with a 60 cm diameter and 60 cm height vacuum chamber. The outcomes of neutron detection represent more than 10 7 neutron/s at the maximum biased voltage of −140 kV and 70 mA current with deuterium operational filling gas in the steady state regime. Content Type Journal Article Pages 1-3 DOI 10.1007/s10894-011-9438-8 Authors V. Damideh, CCF (Combinatorial Confinement Fusion) Group, Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute AEOI, 14399-51113, Tehran, Iran A. Sadighzadeh, CCF (Combinatorial Confinement Fusion) Group, Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute AEOI, 14399-51113, Tehran, Iran A. Koohi, CCF (Combinatorial Confinement Fusion) Group, Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute AEOI, 14399-51113, Tehran, Iran A. Aslezaeem, CCF (Combinatorial Confinement Fusion) Group, Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute AEOI, 14399-51113, Tehran, Iran A. Heidarnia, CCF (Combinatorial Confinement Fusion) Group, Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute AEOI, 14399-51113, Tehran, Iran N. Abdollahi, CCF (Combinatorial Confinement Fusion) Group, Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute AEOI, 14399-51113, Tehran, Iran F. Abbasi Davani, Radiation Application Department, Shahid Beheshti University, Tehran, Iran R. Damideh, CCF (Combinatorial Confinement Fusion) Group, Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute AEOI, 14399-51113, Tehran, Iran Journal Journal of Fusion Energy Online ISSN 1572-9591 Print ISSN 0164-0313

Description:    In this work, we report the effect of growth temperature (room temperature, 150, 200 and 250°C) during the deposition of tantalum nitride thin films by a reactive planar DC magnetron sputtering system on the steel substrates, in a constant nitrogen partial pressure of 15% has been studied. The X-ray spectrum of deposited tantalum nitride films indicated an increasing in intensity of sharp peak of hexagonal TaN and was evidence of grain growth at higher temperatures. By increasing temperature the streaks’ directions, observed from AFM micrographs, were varied. Content Type Journal Article Pages 1-5 DOI 10.1007/s10894-011-9431-2 Authors M. R. Hantehzadeh, Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran S. H. Mortazavi, Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran S. Faryadras, Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran M. Ghoranneviss, Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran Journal Journal of Fusion Energy Online ISSN 1572-9591 Print ISSN 0164-0313

Description:    This study focuses on the crystallographic defects introduced by neutron irradiation and the resulting changes of the superconducting properties in the high temperature superconductor YBa 2 Cu 3 O 7-δ . This material is considered to be most promising for magnet systems in future fusion reactors. Two different bulk samples, pure non-doped YBa 2 Cu 3 O 7-δ (YBCO) and multi-seed YBa 2 Cu 3 O 7-δ doped by platinum (MS2F) were studied prior to and after irradiation in the TRIGA MARK II reactor in Vienna. Neutron irradiation is responsible for a significant enhancement of the critical current densities as well as for a reduction in critical temperature. The accumulation of small open volume defects (〈0.5 nm) partially causes those changes. These defects were studied by positron annihilation lifetime spectroscopy at room temperature. A high concentration of Cu–O di-vacancies was found in both samples, which increased with neutron fluence. The defect concentration was significantly reduced after a heat treatment. Content Type Journal Article Pages 1-7 DOI 10.1007/s10894-011-9436-x Authors J. Veterníková, Department of Nuclear Physics and Technology, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovičova 3, 812 19 Bratislava, Slovak Republic M. Chudý, Vienna University of Technology—Atominstitut, Stadionallee 2, 1020 Vienna, Austria V. Slugeň, Department of Nuclear Physics and Technology, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovičova 3, 812 19 Bratislava, Slovak Republic M. Eisterer, Vienna University of Technology—Atominstitut, Stadionallee 2, 1020 Vienna, Austria H. W. Weber, Vienna University of Technology—Atominstitut, Stadionallee 2, 1020 Vienna, Austria S. Sojak, Department of Nuclear Physics and Technology, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovičova 3, 812 19 Bratislava, Slovak Republic M. Petriska, Department of Nuclear Physics and Technology, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovičova 3, 812 19 Bratislava, Slovak Republic R. Hinca, Department of Nuclear Physics and Technology, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovičova 3, 812 19 Bratislava, Slovak Republic J. Degmová, Department of Nuclear Physics and Technology, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovičova 3, 812 19 Bratislava, Slovak Republic V. Sabelová, Department of Nuclear Physics and Technology, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovičova 3, 812 19 Bratislava, Slovak Republic Journal Journal of Fusion Energy Online ISSN 1572-9591 Print ISSN 0164-0313