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Energy losses during the magnetization process of soft magnetic laminations depend on the excitation waveform. Manufacturers of magnetic materials may not provide losses for different excitation waveforms. This may affect the accuracy of the predicted losses which are used to estimate the performance of electrical equipment during the predesign stage. Thus, a characterization tool which is capable of measuring hysteresis loops under controlled magnetization is required. Digital characterization systems available in literature use expensive commercial power amplifiers. In this work, a cost-effective power amplifier circuit is developed and interfaced with a LabVIEW program to characterize soft magnetic materials. The measurements for a sinusoidal excitation from the proposed setup are validated with those from a standard commercial measuring setup. The system is also used to measure hysteresis loops for arbitrary magnetization conditions (magnetic flux density ( $ {B}$ ) with harmonics). The proposed setup can operate over a frequency range 35–500 Hz. A small Epstein frame is also designed for measurements at higher frequencies (>200 and

Electrical discharge machining (EDM) is a non-conventional machining technique that requires pulse generators to create sparks between the tool and the workpiece. Classical texts describe only two types of EDM pulse generators (EPGs), although there are several different types. This work presents a classification and detailed comparative study of 13 important EPG topologies from the power electronics perspective. The operation of each topology is explained using simulation studies for EDM load with spark current of 10 A and pulse repetition frequency of 1 kHz. Control schemes of each topology are explained from the viewpoint of mechanical performance parameters, viz. material removal rate, surface finish, and tool electrode wear ratio. A general analytical methodology to compute efficiency based on machining duty is illustrated considering the existence of two distinct switching frequencies. Overall comparison between EPG topologies is presented considering control aspects, size, efficiency, voltage stresses and suitability for any required application. As an example, a case of investigation of cutting silicon ingots with wire EDM is considered and experimental results are provided for the same. This work can be used as a guideline to understand and develop EPG based on particular target specifications.

Pulse generators for wire electric discharge machining (WEDM) are derived from standard dc–dc converters. However, their design and analysis need to be done carefully by considering the pulsed nature of the load. In this article, these issues are discussed for a dual-converter-based topology considering the application of WEDM for slicing silicon ingots in the solar photovoltaic industry. It is shown that appropriate sizing can reduce the overall size of the pulse generator significantly. The efficiency computation procedure is outlined in detail as it is an important parameter, particularly when WEDM becomes a part of solar panel manufacturing chain. The present control scheme for the pulse generator yields around 31% efficiency. A new pulsed current reference scheme is proposed, which can improve the efficiency to 62%. Frequency-domain modeling is presented by considering distinct stages of operation of the pulsed load. The models are compared with the standard converters from which the topology is derived. This modeling method can be applied to other pulse generators as well. Hardware of the pulse generator is built with a maximum open-circuit voltage of 100 V, a maximum spark current of 10 A, and a pulse repetition frequency of 1 kHz. The novel control scheme is verified with experimental results.

With ever increasing penetration of inverter-interfaced generators and consequent reduction in available inertial reserve, traditional allowable delay in the provision of the primary frequency reserve will threaten the security of the future grids. However, droop control with fast-enough inertia-less generators can limit the post-contingency frequency excursion. To conform with the fast-enough reserve provision requirement in a reduced and varying-inertia system, an economical clearing of the reserve requires an allowable delay heuristic corresponding to the desired system frequency excursion characteristic; while alleviating the causality dilemma introduced by the unavailability of maximum delay heuristic itself before clearing. The proposed heuristic establishes a relationship among the system parameters, such as the aggregated system inertia, regulation factor, system frequency, desired frequency response, and allowable delay margin. The Pade approximation technique is utilized for deriving the transfer function of such a system, allowing calculation of the allowable delay with various damping ratios corresponding to the dominant poles. The impact of different Pade order on the determined heuristic is analyzed. The regulation factor of the generators is calculated based on the reserve bid volume to ensure proportional injection during contingencies. The impacts of regulation factor and associated delay on the frequency response are also studied.

Wire Electric Discharge Machining (WEDM) is being explored as an efficient alternative for cutting silicon wafers for photovoltaics. This is because WEDM results in lesser kerf loss as compared to traditional abrasive cutting techniques. While the commercially available WED machines are developed for cutting metals, it is necessary to develop a customized WEDM for cutting semiconductor materials such as silicon. To this end, this paper discusses design aspects of a miniature WED machine (of size 1200 × 600 × 600 mm) customized for cutting of silicon. Design and topology of pulse generator are also presented here. Voltage and current waveforms while cutting silicon are compared with those obtained while cutting steel. It is seen that there are significant differences in the two, such as the spark current is more pulsating in cutting silicon than that in cutting steel. Such observations point out some fundamental differences in the nature of sparking while cutting semiconductors vis-a-vis metals, which could be attributed to difference in their physical properties.

Multi-Wire EDM (MWEDM) is being investigated for cutting silicon wafers from ingots in solar industry and IC manufacturing industry. However, practical realization of MWEDM is limited by the forces exerted on the wires. This paper explains nature of forces in case of MWEDM for slicing of silicon ingots, which is distinct from the case of single wire EDM for metal cutting. In particular, the material properties of semiconductor are different from those of the metals and the geometry of the problem is also different. It is shown that the wires in MWEDM exert forces on each other, in addition to those exerted by the workpiece on wires. Quantification of dominant electromagnetic forces is done by analytical means and the results are validated by Finite Element Analysis (FEA) for the cases of 5-wire EDM and 10-wire EDM. Experimentally determined material properties and spark current profiles are used as input to FEA. An algorithm has been developed to calculate the required wire tension considering number of wires, radius of wires, spark current, and wafer thickness. Validation of the algorithm is provided by comparing the results with the experimental data for 40-wire EDM published earlier.

Aim of the study: to analyze the results of performing retrograde perfusion of the pulmonary artery during an open thromboembolectomy from the pulmonary artery. Materials and methods: the experience of performing retrograde perfusion of the pulmonary artery in 10 patients operated in our clinic for massive pulmonary embolism is presented. Retrograde perfusion was performed after the stage of embolectomy from the pulmonary artery. For the latter, we used a disposable cardioplegic solution delivery system and 2 cardioplegic pumps of the heart-lung machine: the first for taking blood perfusate from the oxygenator, the second for supplying the combined solution. The blood perfusate and solution were mixed in a 3:1 ratio and injected selectively into the orifices of the pulmonary veins under a pressure of up to 20 mm Hg. (volume perfusion rate 200-250 ml/min) for 4 minutes. Results: despite the initial severity of the patients' condition, as well as the amount of surgical intervention performed, the hospital survival rate was 100%. Along with this, we did not note the development of specific complications, as well as the aggravation of the course of the intraoperative and early postoperative periods. Conclusion: retrograde pulmonary artery perfusion is a very encouraging and promising technique that provides effective and safe removal of small thromboembolism from the peripheral parts of the pulmonary arterial bed, as well as preventing the development of residual pulmonary hypertension as a result of developing intraoperative air embolism.

Magnetic properties of electrical steels exhibit a strong sensitivity to mechanical stress; this phenomenon is known as magneto-elastic coupling. Mechanical stress affects microstructural features of soft magnetic materials, which in turn leads to a change in their magnetic characteristics. Therefore, the magneto-elastic coupling in these materials needs to be studied and modeled accurately. This paper is devoted to the development of an analytical magneto-elastic hysteresis model. A recently proposed analytical hysteresis model based on Kadar product approach is modified to model the magnetoelastic effects using a multi-scale approach. The proposed model is validated using the quasi-static hysteresis loops measured for a non-oriented (NO) material (M235-35A) subjected to uni-axial compressive stress and tensile stress. The proposed formalism is applicable to model the reversible effects of stress (in elastic range) and it offers a closed form equation. A stress-dependent coercive parameter is introduced in this equation using a simple numerical procedure. Thus the model can be implemented easily in circuit and field analyses.

In an open system, system resources are managed by the contributors themselves. Because the participation needs to be voluntary and contributors true utility will remain unmonitored, proper communication among the participants is essential. In the discussed common-pool resource (CPR) problem, all the members need not be contributors, but the non-excludable component of the resource is required to be multiplied with each of the member's rivalrous component, and all these products are needed to be summed up to calculate the overall resource requirement. This characteristic applies to a typical power system optimization problem, where, if a customer group installs a common dynamic voltage restorer, voltage improvement can be treated as non-excludable quantity, while the peak load of individual customers can be treated as rivalrous quantity. In this work, we consider, the participants sharing the CPR contribute to form an open system to capitalize on ‘economy of scale’, while discouraging the unilateral free-riding benefit. Considering the benefit and average production cost curve represented by piecewise linear functions we have shown that the utility function is convex. Furthermore, for the given problem, we have numerically calculated the utility distribution scheme by solving an optimization problem.

Modelling hysteresis behaviour is an essential task in transient analysis of electrical machines. A curve fitting approach based on isoparametric elements is proposed in this work. A hysteresis loop is split into sub-curves and each sub-curve has been modelled in terms of a second degree polynomial using three data points. Thus the model requires few data points to model a complete loop. The model equations can be easily derived using predefined shape functions of an isoparametric element without using any curve fitting algorithms. The proposed approach has been applied to model hysteresis data of two different materials, namely, grain-oriented (GO) laminations and soft magnetic composites (SMC). Symmetrical minor loops of GO materials with magnetization along any arbitrary direction are modelled for the first time. The calculated results are in close agreement with measured values. Compared to existing methods, the proposed technique in this paper is simple to understand and computationally efficient.

The axial magnetic field (AMF)-type contact is utilized in vacuum interrupters (VIs) due to its effectiveness in current interruption. This paper deals with the study of the eddy current phenomenon occurring in the AMF VIs. The residual AMF beyond current zero is directly the result of eddy currents in the contact plate and, thus, is dependent on the contact plate geometry. Considering that the contact plate is analogous to a disk winding, an analytical formulation is developed to compute the eddy current decay constant as a function of contact plate parameters. The analytical predictions are verified using finite-element method (FEM) simulations of the step response of a circular plate placed in a uniform magnetic field. A linear relationship is established between the contact plate parameters and the eddy current decay constant. The analytical formulation is then used to predict the residual flux decay constant in the context of AMF contact model simulations. A coil-type AMF contact is analyzed using FEM simulations, and parametric studies are carried out to study the effect of the contact opening velocity and radial slots on distribution of the contact gap AMF. The results reported in this work will enable VI engineers to improve the contact design by better control of contact plate parameters.

The effects of mechanical stress on static and dynamic (frequency-dependence) magnetic behaviors of soft magnetic materials have to be modeled. A scalar static magneto-elastic hysteresis model is proposed which combines a simplified version of a multi-scale approach and the Jiles-Atherton (JA) model. The magneto-elastic hysteresis model is extended to include dynamic losses using the field separation approach. The effect of stress on dynamic loss components, particularly on the excess loss, is approximated using an exponential function. The model is validated with measured dynamic hysteresis loops over a frequency range of up to 1 kHz and uniaxial mechanical loading up to 50 MPa (both compressive and tensile stresses). The proposed model still preserves its simplicity and inverse form representation, which makes it quite amenable to numerical implementations. The approach can be applied to model magneto-elastic effects in the elastic range.

This study uses electrical characterization of sparks to advance the understanding of complex mechanism involved in wire electrical discharge machining (WEDM) of photovoltaic grade silicon. Specifically, WED machining of silicon is compared with that of steel as a base, with two approaches of experimentation — (a) one factor at a time (OFAT) and (b) design of experiments (DoE). The responses are measured in terms of four pulse parameters — maximum current I max , maximum voltage V max , average voltage V avg , pulse energy E p ; and three summary statistics. It was evident that the current required for steel workpiece is more by ≈ 10–15 A than that for silicon, whereas the spark voltage is more by ≈ 10 V for silicon than that for steel. Analysis of variance (ANOVA) showed that, current setting primarily affects the mean of I max , V avg , E p and the effect is > 60 % for both silicon and steel. Moreover, quantitative effect of input factors on the pulse-to-pulse variation was also obtained for the first time. The pulse-to-pulse variation in V avg for silicon is influenced by several parameters: current, pulse period, ON-time, and wire speed (cumulative effect ≈ 55 % ), whereas that for steel only current setting influences and the effect is > 51 % . The role of workpiece thickness (height of cut) has not been studied in detail in the available literature and is important for slicing cylindrical ingots as the length of cut changes continuously while slicing the cylindrical ingots. Therefore, the effect of workpiece thickness was studied, especially from perspective of the current and voltage pulse parameters during slicing. For silicon, an increase in workpiece thickness results in an increase in V avg , and a decrease in I max , whereas for steel, such effect was not seen. The equivalent circuit of spark as observed from the pulse generator showed that besides electrical conductivity of the materials, the junction between spark plasma and silicon plays a dominant role in deciding the current drawn by the spark-erosion process.

Precise localization of partial discharge (PD) inside a power transformer winding is a challenging task. Previously, researchers have used internal calibration or reference signals to locate the PD source. The location of any arbitrary (test) PD source is ascertained from the maximum correlation between reference and test signals. However, in practical transformer windings, internal tappings or design details are usually unavailable to generate reference signals. The proposed work employs terminal measurements to construct a physically realizable ladder network. Simulated responses obtained from the ladder network for signals of known pulse-widths at all locations are used as reference data. The terminal responses of the test PD signals are obtained from a laboratory-scale winding by applying signals of arbitrary pulse-widths and shapes at various locations. The PD test signals are generated using a function generator, a PD calibrator, and real discharges. To predict the location of the PD source, the simulated reference data are then correlated with the test data. The position corresponding to the maximum correlation indicates the PD location. The proposed methodology is verified using experimental investigations carried out on two different laboratory-scale transformer windings.

Background Traumatic Brain Injury (TBI) is one of the most common surgical emergencies in service hospitals of India. Computed tomography (CT) has been a consistent and reliable technique for detecting intracranial hemorrhages but is limited by its non-availability in most service hospitals. Therefore the need for a cheaper, portable and easily available option required to be explored. The aim of this study was to determine the sensitivity, specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) of Near Infra Red Spectroscopy (NIRS) against the gold standard of NCCT head. Methods An observational, prospective study was conducted in 100 patients of closed head injury, attending the emergency department or surgical OPD of a service zonal hospital with NIRS. All these patients were subsequently subjected to NCCT head. Sensitivity, specificity, and positive and negative predictive values of NIRS were calculated. The study was conducted from Oct 2010 to Jul 2012. Results All the 100 patients were evaluated with NIRS and subsequently subjected to NCCT head. The results were compiled and statistical analysis of the same was conducted. The data revealed a sensitivity of 58.46%, a specificity of 42.86%, a positive predictive value of 65.52% and a negative predictive value of 35.71%. Conclusion Near Infra Red Spectroscopy (NIRS) is a good screening tool for prediction of intra cerebral haemorrhage in the field and even intensive care units. This was the first study of its kind in the Indian subcontinent and the results suggest that NIRS is a good device to predict intracranial subdural and epidural haematomas. It is however not superior to computer tomography and magnetic resonance imaging.

Advancements of power electronic technologies result in significant improvement in efficiency of power delivery to applications that consume or feed electrical energy to a grid. A transformer is an integral part of the power delivery process. Transformers used for power delivery must be efficient, compact and of low cost, and more importantly, they should be compatible with the connected source such as a power inverter. For a desired power density, the transformer design involves optimization of its electrical and magnetic circuits permitted by the thermal limits of core and copper. The limit of the magnetic circuit is indirectly linked to the winding design. Better use of core influences the design of the electrical circuit as well. Therefore, proper choice of core material and geometry is very important design consideration. This article reviews the domain of soft magnetic materials suitable for handling large electrical power from grid frequency to high-frequency applications. The paper covers different examples and elaborates the role of a transformer for one specific application. Review of transformer design considerations used in different applications, which are categorized based on their load characteristics, is a novelty of this work.

The processes of inception, growth, and propagation of Partial Discharge (PD) along the dielectric are complicated. Their analysis requires a thorough understanding of underlying physics. A software simulation tool has been developed to study typical PD processes. The simulator generates pulses of varying amplitudes, shapes and time of occurrence of pulses observed in practice using National Instruments LabVIEW software as a base platform. The rise time of PD pulses plays an important role in the characterization of PD. The rise time formulation has been attempted based on the approach using the dipole moment development and law of conservation of energy. PD phenomenon is usually studied with the assumption of an air-filled void being energized by parallel plate/ coaxial cylinder electrode configuration. An SF 6 -filled spherical void inside a dielectric between two coaxial cylinder electrode plates is used as another configuration. Phase-resolved partial discharge (PRPD) pattern and the characteristics of PD pulses simulated are in agreement with results reported in literature. The contribution of this paper is versatility of the simulator for detailed study and comprehensive analysis of PD without the use of high voltage (HV) setup.

International audience; The presence of mechanical stress significantly affects the performance of electrical machines, particularly in terms of permeability and losses of core materials. A precise modeling of electrical machines requires to consider such magneto-elastic couplings. An efficient approach needs a constitutive model to predict magneto-elastic hysteretic characteristics and its implementation into numerical analyses. However, it is a challenging task for engineers and researchers due to computational time and convergence issues. This paper deals with an approach to model the magneto-elastic behavior of electrical steels using complex permeability. The complex permeability function is used in this work for the first time in the literature to model the effects of stress. The proposed model is quite amenable to numerical analyses and it reduces computational time significantly. Although, the proposed approach is applicable to steady state or cyclic fields and it considers only reversible effects of stress. It provides an alternative way to consider magneto-elastic coupled behavior in numerical analysis of electrical devices involving magnetic materials. Computed results are in good agreement with measured ones with a maximum error of 2.5% for different stress levels and frequencies.

Supercapacitors complement the limitations of battery storage technologies, and therefore, a battery-supercapacitor hybrid storage device (HSS) has established as a viable option for mitigating the renewable energy variability. For optimal sizing of both batteries and supercapacitors, batteries are treated as low-frequency variation mitigation device and supercapacitors as high-frequency variation mitigation device. However, the maximum amount of current injected or extracted from the battery for a given capacity rating is limited, failing which, supercapacitors would replace batteries to mitigate low-frequency variability. Both slow and fast varying components are defined respecting a cutoff frequency, and in this problem, the objective is to minimize the annualized cost of HSS with optimal cut-off frequency. The sizing of the HSS should also minimize the variability for a given statistical significance. The cut-off frequency is iterated over the solution space using mode pursuing sampling method to obtain the optima. The proposed method is illustrated with a sample dataset and results are discussed. Additionally, an additional problem where the frequency of operation of the supercapacitors is limited to two hours to limit the self-discharge rate of the supercapacitors is also discussed.

Electrical Discharge Machining (EDM) is a manufacturing process in which erosion takes place due to sparking between a workpiece and a tool electrode. The EDM circuit consists of DC-DC converters, the EDM load and an interfacing circuit to regulate the machining. The DC-DC converter topologies are modified to suit requirements of the EDM load. Such modifications along with the nature of load and the interfacing circuit, give rise to issues specific to the EDM power supplies. For a particular topology with two DC-DC converters, such issues in modelling and control of the converters are addressed in this work. A new methodology to determine sizing of passive components is discussed. Pulsed current reference scheme is also illustrated, which can improve input to the EDM load efficiency by more than 30%.

Controlling and mitigating plasma disruptions are a matter of serious concern for tokamak operation since they can cause serious damage to the machine. Dedicated experiments on disruption mitigation have been carried out in ADITYA (R = 75 cm, a = 25 cm), an Ohmically heated circular limiter tokamak. A rapid growth of magneto hydrodynamic (MHD) modes is found to be the major cause of disruptions in ADITYA tokamak. Stimulated disruptions induced by hydrogen gas puffing are successfully mitigated through stabilization of these MHD modes by applying a biased-electrode placed inside the last-closed flux surface prior to the gas injection. However, as biased electrodes cannot be placed inside the plasma in bigger tokamaks, the application of ion-cyclotron waves (ICWs) prior to disruption has been successfully attempted to mitigate disruptions through stabilization of MHD modes in ADITYA tokamak. The amplitude of MHD modes (m/n = 3/1, 2/1) is significantly reduced upon the application of ICW prior to disruption, and the stimulated disruptions are successfully mitigated by preventing the growth and overlapping of these MHD modes. These experimental results demonstrate that MHD driven disruptions may be mitigated due to stabilization of m = 2 modes by ponderomotive force of the IC waves.

A methodology to evaluate the anisotropy of magnetic properties of grain-oriented steel sheets is presented. The approach is based on the orientation distribution function (ODF) theory. The existence of sheet symmetry and orthorhombic symmetry of body-centered cubic iron crystal is discussed with ODF. As a result, in order to characterize the magnetic properties, it is sufficient to carry out measurements for three directions, since the evaluated property is directly related to the magnetocrystalline anisotropy. The presented approach may be a useful tool for the designers of magnetic circuits in electrical machines.

This publisher’s note corrects the author list in J. Opt. Soc. Am. A 37, 680 (2020).JOAOD60740-323210.1364/JOSAA.381365

Recently, many techniques have been employed to solve inverse scattering problems by exploiting the sparsity of the scatterer in the wavelet basis. In this paper, we propose an iteratively reweighted norm regularization scheme within the settings of the Born iterative method (BIM) to effectively leverage the sparsity of the wavelet coefficients. This “iteratively reweighted minimization” method is then used along with norm minimization in order to achieve solutions that are not over-smoothened at the discontinuities. The proposed method is an expansion of a well-known joint norm minimization technique. The advantage offered by the algorithm is that the reconstruction is now independent of the initial choice of weights. This technique accounts for the fact that sparsity is concentrated more in the detail wavelet coefficients rather than their coarse counterpart. The effectiveness of the method is demonstrated using several 2D inverse scattering examples by employing it in each iteration of the BIM.

Renewable energy (RE) resources are non-dispatchable due to their intermittent nature, and battery storage devices (BSDs) play an important role to overcome their inherent variability. Therefore, for optimal operability, BSDs must be appropriately sized. Historical RE generation data can be used for sizing, with the objective to minimize the annualized planning cost. Application of high and low pass filters about a given cut-off frequency on the frequency spectrum of the historical generation data, calculated using discrete Fourier transform approach, segregate the fast and slowly varying components. The proposed methodology is based on ${3} {\sigma }$ principle and will ensure minimum injection of RE-generation variability into the grid for day-ahead scheduling with both fast and slowly varying components. The analysis shows that the batteries with the minimum unit capacity cost to throughput ratio provide minimum annualized planning cost for both slow and fast varying components. Determination of sizing of BSDs for a given cut-off frequency is numerically “costly” and to obtain the optimal cut-off frequency, a derivative-free mode-pursuing sampling method is applied. Exponential reduction in the daily injection of variability with increasing statistical significance in sizing is observed. Impact of unit-capacity cost to throughput-ratio on the sizing of BSDs is also studied.

ONLINE FOOD DELIVERY SYSTEM is a website designed primarily for use in the food delivery industry. This system will allow hotels and restaurants to increase scope of business by reducing the labor cost involved. The system also allows to quickly and easily managing an online menu which customers can browse and use to place or ders with just few clicks. Restaurant employees then use these orders through an easy to navigate graphical interface for efficient processing. Our proposed system is an online food ordering system that enables ease for the customers. It overcomes the disa dvantages of the traditional queuing system. https://www.ijiert.org/paper-details?paper_id=141268

The SWASTIK type radial magnetic field (RMF) contact design is widely used in vacuum interrupters. The mutually perpendicular petal limbs are a unique feature of this contact design. The focus of this work is to relate the Lorentz force acting on the arc with petal dimensions through closed-form expressions. Considering the petal limbs as equivalent to finite current carrying conductors, analytical equations are derived to compute the magnetic flux density at any point in space. The results are verified by using finite-element method (FEM) simulations of rail electrodes. The expressions are then used to compute the Lorentz force on the arc in SWASTIK contacts. The analytical predictions are compared with three-dimensional FEM simulations of a CAD model of the contacts. Applicability of the analytical results is investigated in the context of parametric variation of the radius, length and position of the arc and temporal variation of the contact current. The present work can be used in the first iteration of contact petal design. It is also applicable for the design of rail gun geometries.

Ion cyclotron resonance heating (ICRH) data acquisition control system (DAC) system for 100 kW, 45.6 MHz has been designed for RF ICRH system. This system is used for control and monitoring for 2, 20, and 100 kW RF amplifier stages, respectively. ICRH system consists of different power supplies for each RF amplifier stages. PLC-based DAC has been used for various power supplies monitor, control, and interlocks. Acquired data has been stored in MDSPLUS tree in binary format with defined signal list. Python is an open source scripting language which has been used for core development of software system. Python is very popular programming language for embedded as well as high-level programming. MDSPLUS is an open source package used for data archival and visualization. It is data archival and analysis tools used in various fusion experiments for data logging and visualization with configuration. It has standard developed program interface available with most of the popular languages like Fortan, C++, Python, Java, MATLAB, and IDL for graphical display of data and browsing. The paper introduces the interface of Python-based API for integration of Python and MDSPLUS for ICRH DAC software. Module allows user to read/write data directly in binary tree of MDSPLUS hierarchy. Java-based jScope tool is a part of MDSPLUS database which is used for data visualization.

High-power radio frequency (RF) heating system in the frequency range of ion cyclotron range of frequencies (ICRF) on tokamak needs a mechanism for matching impedance seen by the antenna in presence of plasma to the generator output impedance for maximum transfer of RF power to the plasma with minimum reflections to avoid damage to the generator. The impedance of the antenna is strongly dependent on edge plasma parameters and the impedance sometimes changes as fast as 10−4 s, while the RF generators used can deliver full power only into constant load impedance. Hence, the matching system with dynamic response in between generator and antenna is very much essential for high power ICRF experiments when the plasma is of longer duration with variable load impedance. For ICRF system on SST-1 tokamak, two automatic matching systems are employed each for one transmission line, which consists of motorized stub tuners and phase shifters to match the antenna impedance in the time scale of 120 ms. As a part of initial testing, online impedance matching system is tested with individual transmission lines and then both the lines are matched simultaneously on a variable dummy load which simulates the plasma load. In order to deliver power to both the lines from a single RF generator, hybrid coupler is used which also protects RF generator from reflections up to certain extent. However for hybrid coupler has to work properly and both the lines should see same load impedance. The automatic matching system is installed on tokamak state super-conducting tokamak (SST-1) and is tested up to 140 kW power in the vacuum vessel of the tokamak. Here we present the details of the online matching system and its testing results. The significant result is that we could match the variable load impedance with the generator impedance within 120 ms by suitably adjusting the step counts of the motor controller.

Plasma heating with the fast magnetosonic waves in the ion cyclotron range of frequencies (ICRF) is one of the auxiliary heating schemes of Aditya tokamak. Numerical simulation of second-harmonic resonance heating scenarios in low-temperature, low-density Aditya plasma has been carried out for fast magnetosonic wave absorption in ICRF range, using full-wave ion cyclotron heating code TORIC combined with Fokker–Planck quasilinear solver SSFPQL and the results are explained. In such low-temperature, low-density plasma, ion absorption for second-harmonic resonance heating is less but significant amount of direct electron heating is observed.