In this study, a newly-constructed plasma focus (PF) device ODAK-3K is introduced to the literatu... more In this study, a newly-constructed plasma focus (PF) device ODAK-3K is introduced to the literature and some results of first fusion research realized in this device are reported. The device has a maximal energy input of 3 kJ and is used for both plasma and D–D reaction explorations. Experiments with deuterium have shown that peak current of Ipeak=39 kA flows between the
ABSTRACT Two distinct Josephson junctions (JJs) connected with a constant coupling resistance Rcp... more ABSTRACT Two distinct Josephson junctions (JJs) connected with a constant coupling resistance Rcp are theoretically considered to investigate the overall dynamics below and above the critical current Ic. The circuit model of the device is driven by two DC current sources, I1 and I2. Each junction is characterized by a nonlinear resistive–capacitive junction (NRCSJ). Having constructed the circuit model, time-dependent simulations are carried out for a variety of control parameter sets. Common techniques such as bifurcation diagrams, two-dimensional attractors and Lyapunov exponents are applied for the determination of chaotic as well as periodic dynamics of the superconducting junction devices. According to the findings, two states (namely superconducting and ordinary conducting) are determined as functions of the source currents. The chaotic current which flows through Rcp exhibits a very rich behavior depending on the source currents I1 and I2 and junction capacitances C1 and C2. The device characteristics are summarized by a number of three-dimensional phase diagrams in the parameter space. In addition, for certain parameters, hyper-chaotic cases with two positive Lyapunov exponents are encountered. In contrast to earlier studies claiming the need for a sinusoidal feeding current for generating a chaotic signal, our circuitry can easily generate one via a DC source.
As a macroscopic quantum system, superconducting junction devices are considered both analyticall... more As a macroscopic quantum system, superconducting junction devices are considered both analytically and numerically with the help of the Schrödinger wave equation. Considering the Cooper pair wave function psi in a time-dependent nature, the Hamiltonian of the system is constructed. The phase difference theta is assumed to be a unique independent variable of the superconducting junction in order to evaluate the characteristics of the system. The probability rho(theta) and super current j(theta) densities are determined for different applied voltages V. It is observed that both the amplitude and the period of the wave function psi(theta) have indicated different behaviors as functions of theta for various cases of V. Similarly, rho and j reflect drastic changes. It is shown that numerical results are in good agreement with the analytic results. Our results indicate consistency with some earlier experimental studies for different superconducting devices.
An innovative axial-field permanent magnet generator (AFPMG) with multiple stators and double rot... more An innovative axial-field permanent magnet generator (AFPMG) with multiple stators and double rotors is designed and the structural and electromagnetic features are investigated. This generator has two permanent magnet (PM) rotors at the left - and right-hand sides of a double-sided stator. In order to get benefit from the magnetic flux produced at the outer parts of the generator, two other stators are also positioned near the PM rotors. AFPMG is mainly considered for wind energy applications and it has three phases. The electromagnetic features are characterized by finite element method (FEM) and the transient solutions are analyzed based on a proposed equivalent magnetic circuit model using three phases of induced emf at the coils having two different geometries. New AFPMG generates 80V at each phase for a constant velocity of 125 rpm and it has an efficient dynamics with low cogging torque values.
Abstract Current harmonics of the permanent magnet synchronous motors (PMSMs) varies with the sha... more Abstract Current harmonics of the permanent magnet synchronous motors (PMSMs) varies with the shaft structures. These harmonics produce additional loses at both windings and the core of a PMSM and increase the temperature inside the machine. Such a temperature ...
In this study, a newly-constructed plasma focus (PF) device ODAK-3K is introduced to the literatu... more In this study, a newly-constructed plasma focus (PF) device ODAK-3K is introduced to the literature and some results of first fusion research realized in this device are reported. The device has a maximal energy input of 3 kJ and is used for both plasma and D–D reaction explorations. Experiments with deuterium have shown that peak current of Ipeak=39 kA flows between the
ABSTRACT Two distinct Josephson junctions (JJs) connected with a constant coupling resistance Rcp... more ABSTRACT Two distinct Josephson junctions (JJs) connected with a constant coupling resistance Rcp are theoretically considered to investigate the overall dynamics below and above the critical current Ic. The circuit model of the device is driven by two DC current sources, I1 and I2. Each junction is characterized by a nonlinear resistive–capacitive junction (NRCSJ). Having constructed the circuit model, time-dependent simulations are carried out for a variety of control parameter sets. Common techniques such as bifurcation diagrams, two-dimensional attractors and Lyapunov exponents are applied for the determination of chaotic as well as periodic dynamics of the superconducting junction devices. According to the findings, two states (namely superconducting and ordinary conducting) are determined as functions of the source currents. The chaotic current which flows through Rcp exhibits a very rich behavior depending on the source currents I1 and I2 and junction capacitances C1 and C2. The device characteristics are summarized by a number of three-dimensional phase diagrams in the parameter space. In addition, for certain parameters, hyper-chaotic cases with two positive Lyapunov exponents are encountered. In contrast to earlier studies claiming the need for a sinusoidal feeding current for generating a chaotic signal, our circuitry can easily generate one via a DC source.
As a macroscopic quantum system, superconducting junction devices are considered both analyticall... more As a macroscopic quantum system, superconducting junction devices are considered both analytically and numerically with the help of the Schrödinger wave equation. Considering the Cooper pair wave function psi in a time-dependent nature, the Hamiltonian of the system is constructed. The phase difference theta is assumed to be a unique independent variable of the superconducting junction in order to evaluate the characteristics of the system. The probability rho(theta) and super current j(theta) densities are determined for different applied voltages V. It is observed that both the amplitude and the period of the wave function psi(theta) have indicated different behaviors as functions of theta for various cases of V. Similarly, rho and j reflect drastic changes. It is shown that numerical results are in good agreement with the analytic results. Our results indicate consistency with some earlier experimental studies for different superconducting devices.
An innovative axial-field permanent magnet generator (AFPMG) with multiple stators and double rot... more An innovative axial-field permanent magnet generator (AFPMG) with multiple stators and double rotors is designed and the structural and electromagnetic features are investigated. This generator has two permanent magnet (PM) rotors at the left - and right-hand sides of a double-sided stator. In order to get benefit from the magnetic flux produced at the outer parts of the generator, two other stators are also positioned near the PM rotors. AFPMG is mainly considered for wind energy applications and it has three phases. The electromagnetic features are characterized by finite element method (FEM) and the transient solutions are analyzed based on a proposed equivalent magnetic circuit model using three phases of induced emf at the coils having two different geometries. New AFPMG generates 80V at each phase for a constant velocity of 125 rpm and it has an efficient dynamics with low cogging torque values.
Abstract Current harmonics of the permanent magnet synchronous motors (PMSMs) varies with the sha... more Abstract Current harmonics of the permanent magnet synchronous motors (PMSMs) varies with the shaft structures. These harmonics produce additional loses at both windings and the core of a PMSM and increase the temperature inside the machine. Such a temperature ...
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