Pub Date : 2019-06-01DOI: 10.1109/PPPS34859.2019.9009718
J. Leckbee, S. Simpson, D. Ziska, B. Bui
High voltage vacuum systems with stringent vacuum requirements are often designed with ceramic insulators which have low flashover strength. In this paper, we report on experimental results comparing pulsed high voltage flashover of Rexolite®(cross-linked polystyrene), a pulsed power industry standard vacuum insulator, to Kel-F® (polyclorotrifluoroethylene), a plastic with significantly lower vacuum outgassing. Our results show similar surface flashover results with the two materials, with both exhibiting large spread in flashover electric field. The average electric field for flashover of each material agree well with predictions based on previously published results.
{"title":"Vacuum Insulator Flashover of Ultra High Vacuum Compatible Insulators","authors":"J. Leckbee, S. Simpson, D. Ziska, B. Bui","doi":"10.1109/PPPS34859.2019.9009718","DOIUrl":"https://doi.org/10.1109/PPPS34859.2019.9009718","url":null,"abstract":"High voltage vacuum systems with stringent vacuum requirements are often designed with ceramic insulators which have low flashover strength. In this paper, we report on experimental results comparing pulsed high voltage flashover of Rexolite®(cross-linked polystyrene), a pulsed power industry standard vacuum insulator, to Kel-F® (polyclorotrifluoroethylene), a plastic with significantly lower vacuum outgassing. Our results show similar surface flashover results with the two materials, with both exhibiting large spread in flashover electric field. The average electric field for flashover of each material agree well with predictions based on previously published results.","PeriodicalId":103240,"journal":{"name":"2019 IEEE Pulsed Power & Plasma Science (PPPS)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126022203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/PPPS34859.2019.9009698
H. Porteanu, I. Stefanović, M. Klute, R. Brinkmann, P. Awakowicz, W. Heinrich
Plasma jets belong to the category remote plasma. This means that the discharge conditions and the chemical effect on samples can be tuned separately, this being a big advantage compared to standard low-pressure reactors. The inductive coupling brings the advantage of a pure and dense plasma. The microwave excitation allows furthermore miniaturization and generation of low temperature plasmas. The present paper shows the state of the art of the research on such sources, demonstrating their work up to atmospheric pressure.
{"title":"Inductively Coupled Plasma at Atmospheric Pressure, a Challenge for Miniature Devices","authors":"H. Porteanu, I. Stefanović, M. Klute, R. Brinkmann, P. Awakowicz, W. Heinrich","doi":"10.1109/PPPS34859.2019.9009698","DOIUrl":"https://doi.org/10.1109/PPPS34859.2019.9009698","url":null,"abstract":"Plasma jets belong to the category remote plasma. This means that the discharge conditions and the chemical effect on samples can be tuned separately, this being a big advantage compared to standard low-pressure reactors. The inductive coupling brings the advantage of a pure and dense plasma. The microwave excitation allows furthermore miniaturization and generation of low temperature plasmas. The present paper shows the state of the art of the research on such sources, demonstrating their work up to atmospheric pressure.","PeriodicalId":103240,"journal":{"name":"2019 IEEE Pulsed Power & Plasma Science (PPPS)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117342503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/PPPS34859.2019.9009759
C. Harjes, J. C. Pouncey, Lisa Fisher, J. Lehr, E. Savrun, J. Neely
In large machines, such as accelerators and high power microwave systems, it is common to implement pulsed power technology. Pulsed power attempts to deliver large amounts of power in a short amount of time. This is done by storing high voltage and delivering that energy to the desired load quickly through switches. To ensure that the energy is delivered to the desired load it is necessary to use insulators to separate conductors having different potentials. The insulators function is crucial in the success or failure of the system and because of this, much research has been done in the materials, geometries, and sizes of insulators. A common mean of failure for these insulators is surface flashover. Surface flashover occurs when the electric field becomes strong enough to accelerate electrons along the surface of the insulator to a point where an arc is created between conductors of different potentials. The machine is therefore limited to the amount of voltage it can sustain and the amount of power it can deliver. By making modifications to the insulator, improvements in sustained electric field has been documented. This paper attempts to further investigate the different methods used to increase the sustained electric field to improve the function of the system.
{"title":"Insulator Technologies to Achieve Maximum Electric Field Holdoff","authors":"C. Harjes, J. C. Pouncey, Lisa Fisher, J. Lehr, E. Savrun, J. Neely","doi":"10.1109/PPPS34859.2019.9009759","DOIUrl":"https://doi.org/10.1109/PPPS34859.2019.9009759","url":null,"abstract":"In large machines, such as accelerators and high power microwave systems, it is common to implement pulsed power technology. Pulsed power attempts to deliver large amounts of power in a short amount of time. This is done by storing high voltage and delivering that energy to the desired load quickly through switches. To ensure that the energy is delivered to the desired load it is necessary to use insulators to separate conductors having different potentials. The insulators function is crucial in the success or failure of the system and because of this, much research has been done in the materials, geometries, and sizes of insulators. A common mean of failure for these insulators is surface flashover. Surface flashover occurs when the electric field becomes strong enough to accelerate electrons along the surface of the insulator to a point where an arc is created between conductors of different potentials. The machine is therefore limited to the amount of voltage it can sustain and the amount of power it can deliver. By making modifications to the insulator, improvements in sustained electric field has been documented. This paper attempts to further investigate the different methods used to increase the sustained electric field to improve the function of the system.","PeriodicalId":103240,"journal":{"name":"2019 IEEE Pulsed Power & Plasma Science (PPPS)","volume":"67 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133602419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/PPPS34859.2019.9009968
H. Truong, K. Hogge, M. Misch, J. Smith, M. Garcia, E. Ormond, M. Parrales
The United States initiated the Subcritical Experiment (SCE) program to support a stockpile stewardship mission shortly after the 1992 moratorium on underground nuclear testing was established. Many SCE's are conducted at the Nevada National Security Site (NNSS) in Nevada. Cygnus is a high energy radiation generating device (RGD) located and operated at the NNSS and is a primary diagnostic for the SCE program. This analysis methodology will provide a standard to trouble shoot results of individual Cygnus shots, and also to monitor long term Cygnus performance. Accordingly, this type of extensive analysis will contribute to optimized Cygnus performance on SCEs. The Cygnus Dual Beam Radiographic Facility consists of two identical radiographic sources, Cygnus 1 and Cygnus 2. From creation of the high power V-I drive to energy transport and X-ray conversion at the rod-pinch diode, the Cygnus machines utilize the following components: oil-filled Marx generator, water-filled pulse-forming line (PFL), water-filled coaxial transmission line (CTL), three-cell vacuum induction voltage adder (IVA), and rod-pinch diode. The diode pulse has the following electrical specifications: 2.25 MV, 60 kA, 60 ns. Each source has the following X-ray specifications: 1 mm diameter, 4 rad at 1 m, and 50 ns radiation pulse. SCE's are both single-event and high-value, therefore a high level of performance in reliability and reproducibility are key issues of Cygnus. Prior to executing such a SCE, there are a formidable number of shots (e.g. each of the two Cygnus RGD's charging and discharging properly into the rod-pinch diode load) that must be executed to determine reliability and reproducibility of the Cygnus RGD's. For every shot on Cygnus, voltages and currents along the machine are recorded and analyzed. In this paper we summarize attributes of the voltage and current waveforms at different locations using distribution plots. These distribution plots are used to quantify the reliability and reproducibility for Cygnus.
{"title":"Analysis of Cygnus Electrical Signals","authors":"H. Truong, K. Hogge, M. Misch, J. Smith, M. Garcia, E. Ormond, M. Parrales","doi":"10.1109/PPPS34859.2019.9009968","DOIUrl":"https://doi.org/10.1109/PPPS34859.2019.9009968","url":null,"abstract":"The United States initiated the Subcritical Experiment (SCE) program to support a stockpile stewardship mission shortly after the 1992 moratorium on underground nuclear testing was established. Many SCE's are conducted at the Nevada National Security Site (NNSS) in Nevada. Cygnus is a high energy radiation generating device (RGD) located and operated at the NNSS and is a primary diagnostic for the SCE program. This analysis methodology will provide a standard to trouble shoot results of individual Cygnus shots, and also to monitor long term Cygnus performance. Accordingly, this type of extensive analysis will contribute to optimized Cygnus performance on SCEs. The Cygnus Dual Beam Radiographic Facility consists of two identical radiographic sources, Cygnus 1 and Cygnus 2. From creation of the high power V-I drive to energy transport and X-ray conversion at the rod-pinch diode, the Cygnus machines utilize the following components: oil-filled Marx generator, water-filled pulse-forming line (PFL), water-filled coaxial transmission line (CTL), three-cell vacuum induction voltage adder (IVA), and rod-pinch diode. The diode pulse has the following electrical specifications: 2.25 MV, 60 kA, 60 ns. Each source has the following X-ray specifications: 1 mm diameter, 4 rad at 1 m, and 50 ns radiation pulse. SCE's are both single-event and high-value, therefore a high level of performance in reliability and reproducibility are key issues of Cygnus. Prior to executing such a SCE, there are a formidable number of shots (e.g. each of the two Cygnus RGD's charging and discharging properly into the rod-pinch diode load) that must be executed to determine reliability and reproducibility of the Cygnus RGD's. For every shot on Cygnus, voltages and currents along the machine are recorded and analyzed. In this paper we summarize attributes of the voltage and current waveforms at different locations using distribution plots. These distribution plots are used to quantify the reliability and reproducibility for Cygnus.","PeriodicalId":103240,"journal":{"name":"2019 IEEE Pulsed Power & Plasma Science (PPPS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130347228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/PPPS34859.2019.9009985
S. Simpson, R. Goeke, P. Miller, K. Coombes, K. DeZetter, O. Johns, J. Leckbee, D. Nielsen, M. Sceiford
Next generation pulsed power (NGPP) machines and accelerators require a better understanding of the materials used within the vacuum vessels to achieve lower base pressures (P << 10−5 Torr) and reduce the overall contaminant inventory while incorporating various dielectric materials which tend to be unfavorable for ultra-high vacuum (UHV) applications. By improving the baseline vacuum, it may be possible to delay the onset of impedance collapse, reduce current loss on multi-mega Amp devices, or improve the lifetime of thermionic cathodes, etc [3]. In this study, we examine the vacuum outgassing rate of Rexolite® (cross-linked polystyrene) and Kel-F® (polychlorotrifluoroethylene) as candidate materials for vacuum insulators [1]. These values are then incorporated into boundary conditions for molecular flow simulations using COMSOL Multiphysics® and used to predict the performance of a prototypical pulsed power system designed for 10−8 Torr operations.
{"title":"Vacuum Outgassing Study of Candidate Materials for Next Generation Pulsed Power and Accelerators: Improving the Boundary Conditions for Molecular Flow Simulations","authors":"S. Simpson, R. Goeke, P. Miller, K. Coombes, K. DeZetter, O. Johns, J. Leckbee, D. Nielsen, M. Sceiford","doi":"10.1109/PPPS34859.2019.9009985","DOIUrl":"https://doi.org/10.1109/PPPS34859.2019.9009985","url":null,"abstract":"Next generation pulsed power (NGPP) machines and accelerators require a better understanding of the materials used within the vacuum vessels to achieve lower base pressures (P << 10−5 Torr) and reduce the overall contaminant inventory while incorporating various dielectric materials which tend to be unfavorable for ultra-high vacuum (UHV) applications. By improving the baseline vacuum, it may be possible to delay the onset of impedance collapse, reduce current loss on multi-mega Amp devices, or improve the lifetime of thermionic cathodes, etc [3]. In this study, we examine the vacuum outgassing rate of Rexolite® (cross-linked polystyrene) and Kel-F® (polychlorotrifluoroethylene) as candidate materials for vacuum insulators [1]. These values are then incorporated into boundary conditions for molecular flow simulations using COMSOL Multiphysics® and used to predict the performance of a prototypical pulsed power system designed for 10−8 Torr operations.","PeriodicalId":103240,"journal":{"name":"2019 IEEE Pulsed Power & Plasma Science (PPPS)","volume":"49 3-4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116651062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/PPPS34859.2019.9009870
G. Komarzyniec, H. Stryczewska, P. Krupski
Designing power supply systems for arc plasma reactors is a complex and multi-threaded problem. Proper plasma parameters are often determined not only by electrical parameters, but also by the structural and material parameters of the power supplies. Four different types of power supply systems designed to supply a plasma reactor with a gliding arc discharge were subjected to comparative analysis. The obtained characteristics of plasma reactor operation gave information about the differences in its operation and allowed to specify the parameters of power supply systems to which special attention should be paid when it is necessary to obtain plasma with strictly specified parameters.
{"title":"The Influence of the Architecture of the Power System on the Operational Parameters of the Glidarc Plasma Reactor","authors":"G. Komarzyniec, H. Stryczewska, P. Krupski","doi":"10.1109/PPPS34859.2019.9009870","DOIUrl":"https://doi.org/10.1109/PPPS34859.2019.9009870","url":null,"abstract":"Designing power supply systems for arc plasma reactors is a complex and multi-threaded problem. Proper plasma parameters are often determined not only by electrical parameters, but also by the structural and material parameters of the power supplies. Four different types of power supply systems designed to supply a plasma reactor with a gliding arc discharge were subjected to comparative analysis. The obtained characteristics of plasma reactor operation gave information about the differences in its operation and allowed to specify the parameters of power supply systems to which special attention should be paid when it is necessary to obtain plasma with strictly specified parameters.","PeriodicalId":103240,"journal":{"name":"2019 IEEE Pulsed Power & Plasma Science (PPPS)","volume":"177 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116845493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/PPPS34859.2019.9009664
E. Ormond, M. Parrales, Michael R. Garcia, John R. Smith, P. H. Amos, K. Hogge, M. Misch, Mohammed Mohammed, H. Truong
The Cygnus Dual Beam Radiographic Facility consists of two identical radiographic sources each with a dose rating of 4-rad at 1 m, and a 1-mm diameter spot size. The development of the rod pinch diode was responsible for the ability to meet these criteria1. The rod pinch diode in a Cygnus machine uses a 0.75-mm diameter, tapered tip, tungsten anode rod extended through a 9-mm diameter, aluminum cathode aperture. When properly configured, the electron beam born off the aperture edge can self-insulate and pinch onto the tip of the rod creating an intense, small x-ray source. The Cygnus sources are utilized as the primary diagnostic on Subcritical Experiments that are single-shot, high-value events. The system timing on Cygnus will be evaluated as related to the following system elements: HV trigger generator, Marx, pulse forming line and rod pinch diode. Spare trigger generators will also be included in this evaluation.
{"title":"Cygnus System Timing","authors":"E. Ormond, M. Parrales, Michael R. Garcia, John R. Smith, P. H. Amos, K. Hogge, M. Misch, Mohammed Mohammed, H. Truong","doi":"10.1109/PPPS34859.2019.9009664","DOIUrl":"https://doi.org/10.1109/PPPS34859.2019.9009664","url":null,"abstract":"The Cygnus Dual Beam Radiographic Facility consists of two identical radiographic sources each with a dose rating of 4-rad at 1 m, and a 1-mm diameter spot size. The development of the rod pinch diode was responsible for the ability to meet these criteria1. The rod pinch diode in a Cygnus machine uses a 0.75-mm diameter, tapered tip, tungsten anode rod extended through a 9-mm diameter, aluminum cathode aperture. When properly configured, the electron beam born off the aperture edge can self-insulate and pinch onto the tip of the rod creating an intense, small x-ray source. The Cygnus sources are utilized as the primary diagnostic on Subcritical Experiments that are single-shot, high-value events. The system timing on Cygnus will be evaluated as related to the following system elements: HV trigger generator, Marx, pulse forming line and rod pinch diode. Spare trigger generators will also be included in this evaluation.","PeriodicalId":103240,"journal":{"name":"2019 IEEE Pulsed Power & Plasma Science (PPPS)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128133907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/PPPS34859.2019.9009714
G. S. Jaar, R. K. Appartaim
Emission spectra from a microsecond x-pinch were studied in the soft x-ray region which give information about the radiating hot spot plasma. The spectra were collected using a flat crystal spectrometer from aluminum and molybdenum in a 2×25 µm wire x-pinch configuration. We present results that show aluminum reaching the hydrogen-like state and molybdenum reaching the neon-like charge state, from which relevant plasma parameters are determined. We also present the results of a load optimization study for an x-pinch driven by a 350-kA microsecond generator. A scan of the configuration space across material, thickness, and number of wires was performed to determine which parameter combination creates the best total x-ray yield for use in radiography and backlighting. The configuration assessment was conducted using x-ray imaging, Si photodiodes, and diamond radiation detectors.
{"title":"X-ray Spectroscopy and Total Yield Measurements on a Microsecond X-Pinch","authors":"G. S. Jaar, R. K. Appartaim","doi":"10.1109/PPPS34859.2019.9009714","DOIUrl":"https://doi.org/10.1109/PPPS34859.2019.9009714","url":null,"abstract":"Emission spectra from a microsecond x-pinch were studied in the soft x-ray region which give information about the radiating hot spot plasma. The spectra were collected using a flat crystal spectrometer from aluminum and molybdenum in a 2×25 µm wire x-pinch configuration. We present results that show aluminum reaching the hydrogen-like state and molybdenum reaching the neon-like charge state, from which relevant plasma parameters are determined. We also present the results of a load optimization study for an x-pinch driven by a 350-kA microsecond generator. A scan of the configuration space across material, thickness, and number of wires was performed to determine which parameter combination creates the best total x-ray yield for use in radiography and backlighting. The configuration assessment was conducted using x-ray imaging, Si photodiodes, and diamond radiation detectors.","PeriodicalId":103240,"journal":{"name":"2019 IEEE Pulsed Power & Plasma Science (PPPS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128440302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/PPPS34859.2019.9009612
H. Polat, D. Ceylan, O. Keysan
The utilization of external field windings in electromagnetic launchers provides an additional electromagnetic field between the rails of an electromagnetic launcher which increases the Lorentz force acting on the armature in the acceleration direction. However, additional magnetic field created by the conventional copper windings are very limited due to their low maximum current carrying capability. Therefore, using high temperature superconductors (HTS) with a current carrying capability up to 100 A/mm2 for the external coils can be used to increase the magnetic field density between rails. This paper presents an optimization study for the design of two external coils with rectangular tape YBCO superconducting wire. The HTS coils are proposed to increase the efficiency of a 3 meter long launcher with 25 mm x 20 mm rectangular bore caliber. The optimization parameters are selected as the magnitude of the DC coil current, the coil position, the number of turns of the coil, and the number of coil layers. Also, the objective function of the optimization is the electromagnetic force acting on the armature, which is dependent of the rail current and B field on the armature. During the operation of the launcher and the external coils, it is critical to prevent quenching of the HTS coils due to the perpendicular and tangential magnetic field on the coils, temperature and current density of the coils. In order to estimate the quench and calculate the objective function, finite element analysis (FEA) is used in 2D. Real coded genetic algorithm (RCGA) is also used as optimization method. The results of the optimization study shows that HTS coil augmentation is feasible for small caliber railguns. The HTS coil position is limited by cryogenic chamber and rail containment dimensions. The maximum coil current is determined by the self field due to cancellation B field generated by the rails and the coils. For 500 kA rail current the force acting on the armature increases from 55 kN to 70 kN with and increase rate of 26%, a muzzle velocity increase from 1650 m/s to 1900 m/s with an increase rate of 12% and a muzzle energy increase from 160 kJ to 210 kJ with and increase rate of 25% when external HTS coil augmentation is used.
{"title":"Utilization and Optimization of Superconducting Coil Parameters in Electromagnetic Launcher Systems","authors":"H. Polat, D. Ceylan, O. Keysan","doi":"10.1109/PPPS34859.2019.9009612","DOIUrl":"https://doi.org/10.1109/PPPS34859.2019.9009612","url":null,"abstract":"The utilization of external field windings in electromagnetic launchers provides an additional electromagnetic field between the rails of an electromagnetic launcher which increases the Lorentz force acting on the armature in the acceleration direction. However, additional magnetic field created by the conventional copper windings are very limited due to their low maximum current carrying capability. Therefore, using high temperature superconductors (HTS) with a current carrying capability up to 100 A/mm2 for the external coils can be used to increase the magnetic field density between rails. This paper presents an optimization study for the design of two external coils with rectangular tape YBCO superconducting wire. The HTS coils are proposed to increase the efficiency of a 3 meter long launcher with 25 mm x 20 mm rectangular bore caliber. The optimization parameters are selected as the magnitude of the DC coil current, the coil position, the number of turns of the coil, and the number of coil layers. Also, the objective function of the optimization is the electromagnetic force acting on the armature, which is dependent of the rail current and B field on the armature. During the operation of the launcher and the external coils, it is critical to prevent quenching of the HTS coils due to the perpendicular and tangential magnetic field on the coils, temperature and current density of the coils. In order to estimate the quench and calculate the objective function, finite element analysis (FEA) is used in 2D. Real coded genetic algorithm (RCGA) is also used as optimization method. The results of the optimization study shows that HTS coil augmentation is feasible for small caliber railguns. The HTS coil position is limited by cryogenic chamber and rail containment dimensions. The maximum coil current is determined by the self field due to cancellation B field generated by the rails and the coils. For 500 kA rail current the force acting on the armature increases from 55 kN to 70 kN with and increase rate of 26%, a muzzle velocity increase from 1650 m/s to 1900 m/s with an increase rate of 12% and a muzzle energy increase from 160 kJ to 210 kJ with and increase rate of 25% when external HTS coil augmentation is used.","PeriodicalId":103240,"journal":{"name":"2019 IEEE Pulsed Power & Plasma Science (PPPS)","volume":"102 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131847909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/PPPS34859.2019.9009861
S. Kusano, K. Takahashi, T. Sasaki, T. Kikuchi
We have measured the thermal and electrical conductivities of fusion material in warm dense matter (WDM) region. The method is an isochoric heating using pulsed-power discharge with a ruby capillary. The electrical conductivity is estimated from the shape of WDM and the measured voltage-current waveform. The thermal conductivity is estimated by the thermal conduction measured from the WDM temperature to the ruby capillary temperature using laser-induced fluorescence. The electrical conductivity of gold at the density of 0.01ps were 4×104 to 9×104S/m with the temperature ranging from 1.5×104 to 8×104 K. The thermal conductivity of tungsten at the density of 0.0 1ps was 30 to 40 W/m·K with the temperature ranging from 8.0×103 to 1.2×104 K.
{"title":"Experimental measurement of thermal and electrical conductivities in warm dense state generated by pulsed-power discharge for efficient energy conversion of fast ignition","authors":"S. Kusano, K. Takahashi, T. Sasaki, T. Kikuchi","doi":"10.1109/PPPS34859.2019.9009861","DOIUrl":"https://doi.org/10.1109/PPPS34859.2019.9009861","url":null,"abstract":"We have measured the thermal and electrical conductivities of fusion material in warm dense matter (WDM) region. The method is an isochoric heating using pulsed-power discharge with a ruby capillary. The electrical conductivity is estimated from the shape of WDM and the measured voltage-current waveform. The thermal conductivity is estimated by the thermal conduction measured from the WDM temperature to the ruby capillary temperature using laser-induced fluorescence. The electrical conductivity of gold at the density of 0.01ps were 4×104 to 9×104S/m with the temperature ranging from 1.5×104 to 8×104 K. The thermal conductivity of tungsten at the density of 0.0 1ps was 30 to 40 W/m·K with the temperature ranging from 8.0×103 to 1.2×104 K.","PeriodicalId":103240,"journal":{"name":"2019 IEEE Pulsed Power & Plasma Science (PPPS)","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121249974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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