ameneh kargarian

This article aims to design and construct a plasma generation device using the surface dielectric barrier discharge method (SDBD) on a laboratory scale to produce a stable and uniform atmospheric pressure plasma layer. For this purpose, a copper electrode with a thickness of 100 microns with a comb- like structure was designed and constructed for this system, and a mica sheet with a thickness of 0.5 mm and dimensions of 10 × 10 cm was built to make the dielectric. According to the experimental data and analytical calculations of the constructed SDBD system in working conditions of 3 kV voltage and 12.5 kHz frequency, the consumption power of this system is calculated at 50 watts. Due to the production of stable and uniform plasma created on the dielectric surface and the measured power consumption, this system will be able to be used in various sciences and industries, including surface processing industries.

The stable and uniform non-thermal plasma in atmospheric pressure produced by the surface dielectric barrier discharge (SDBD) device can be used in various industrial applications. Investigation of the electrical properties, especially the measurement of the power consumption of this device, is significant because of the cost-effectiveness importance of its uses in industries. In this paper, the power consumption of the SDBD system with two different structures has been investigated. For this purpose, two SDBD systems with the same material and dimensions of electrodes and dielectric and two different structures comb and mesh electrodes were designed and constructed. After that, under the same conditions, the power consumption of both systems was measured and compared using the monitoring capacitor method. The purpose of this study is to choose the appropriate structure for the electrode in designing of the SDBD device for various industrial applications.

In this paper, using 2D PIC simulation, the electron acceleration in the bubble regime has been investigated in the interaction of a short high-power laser pulse with an underdense plasma with a density ramp. Due to the laser pondermotive force, a plasma wave and its corresponding electric field are formed in the plasma. The electrons injected in the focusing and acceleration region of the plasma wave field can get energy from the wave and are accelerated to high energies of the Giga-electron-Volt range. The simulation results show that with increasing the plasma density gradient, the phase speed of the generated plasma wave increases, and the corresponding wavelength decreases. This causes the displacement of the plasma wave focusing and acceleration region and ultimately increases the acceleration length in the acceleration process. Considering a laser pulse with dimensionless intensity amplitude , pulse duration , and plasma with density ramp length ,the plasma wave accelerating electric field with amplitude was generated. The results of this work can be crucial in choosing an appropriate plasma profile to design the laser-plasma accelerator system for obtaining the Giga-electron-Volt energy gain in a short time.

Higher worldwide research activities in the fields of nuclear fusion energy indicate the importance of developing such technology in Iran as well. On the other hand, the ambiguity regarding the justification and priority of investing in each of the methods of nuclear fusion is a universal challenge that is altimatlly common among nuclear fusion experts Iran too. The present research is aiming at presenting a coherent investigation that can be based on analytical and comparative analysis to achieve a rational prioritization among different methods of nuclear fusion. In this article, different nuclear fusion options are prioritized, using the experts’opinions through Analytic Hierarchy Process (AHP); free from any personal judgments and influences. Furthermore, through Delphi method, 19 quality criteria related to different methods of nuclear fusion were classified based on mathematical logic, and based on the degree of importance and screenings, 13 criteria were finally selected. Then, using hierarchical analysis method and also through Expert Choice software, pairwise comparisons between criteria were performed to determine their coefficient of importance. In addition, pairwise comparisons were made between each of the criteria for each of the fusion methods. Finally, the strategic practical prioritization of three different nuclear fusion methods was quantitatively achieved as 0.415, 0.379, and 0.207, respectivly; for Iran.

Investigation of plasma heating is of crucial importance because of its extensive applications including plasma preheating in inertial confinement fusion and magnetic confinement fusion. By propagation of a high-power ultra-short laser pulse through the underdense plasma, the plasma wave is excited in the longitudinal direction behind the laser pulse due to the laser pondermotive force. The laser energy is transferred to the plasma environment via the laser plasma interaction with the particles, so leading to plasma heating. By increasing the laser intensity or plasma density, the wave-breaking phenomenon occurs. The maximum plasma heating occurs in the wave-breaking amplitude. In this paper, the effects of applying a homogenous magnetic field on the plasma wave excited by the propagation of high-power ultra-short laser pulse in the plasma in the amplitudes below the wave-breaking amplitude is investigated, using the 2D PIC simulation method. The results show that the application of this field causes the excited wave to distort and break due to the phase-mixing phenomenon. Moreover, the simulation results show that by applying an inhomogeneous magnetic field, the wave-breaking effects appear sooner than the homogenous one. Therefore, in the moderate laser intensities and low plasma densities, it is possible to gain the maximum heating of plasma by applying the homogenous and inhomogeneous magnetic fields.

The plasma wave acceleration of electron in the bubble regime is investigated in a new configuration containing a planar wiggler. The space-charge field of the laser-created ion channel can focuse and stabilize the electron trajectory to guide it toward the acceleration region. The high-gradient plasma wave field can resonantly accelerate the trapped electron to higher energies in the presence of a planar wiggler compensating the electron dephasing. The results show that in the lower plasma wave amplitudes the planar wiggler plays a more significant role on the electron energy enhancement. The increment of the electron energy in this configuration isvalidated using a three-dimension single-particle code. The energy gain of electrondependency on the planar wiggler, ion channel field, plasma wave angle and amplitude as well as the initial energy of electron has been investigated. The results of paper will be of importance in the optimization of electron energy and improving the quality of the accelerated electrons in the plasma wakefield accelerators.