Electrothermal guns utilize an ablation stabilized pulsed capillary arc discharge to generate a high-pressure propellant gas. The plastic propellant, usually polyethylene, is ablated from the capillary walls by absorption of the radiative flux from the arc discharge. Similar capillary discharges have also been used to ignite conventional gun propellants in electrothermal-chemical (ETC) guns. During the rising part of the current pulse, there are rapid changes in the chamber pressure and temperature as shocks propagate from the capillary and then reflect from the base of the projectile and back into the capillary. This causes redistribution of the current density within the capillary altering the spatial ablation rates with time. MACH2 is a general purpose MHD code that has been used to simulate these complex electrical, hydrodynamic and radiation interactions for a 12 mm bore diameter electrothermal gun configuration tested at Institut St. Louis (ISL). The simulation domain includes the capillary discharge, and an expansion chamber extending to the projectile. The radiation was adjusted to match the measured pressure pulse and total ablated mass. Large radial and temporal variations in the velocity, temperature, density and radiation fields were observed in the simulations during the rising part of the current pulse. These results suggest that one-dimensional models may neglect some important physical processes.
{"title":"MACH2 simulations of an electrothermal gun","authors":"D. Keefer, R. Rhodes","doi":"10.1109/PPC.1999.823598","DOIUrl":"https://doi.org/10.1109/PPC.1999.823598","url":null,"abstract":"Electrothermal guns utilize an ablation stabilized pulsed capillary arc discharge to generate a high-pressure propellant gas. The plastic propellant, usually polyethylene, is ablated from the capillary walls by absorption of the radiative flux from the arc discharge. Similar capillary discharges have also been used to ignite conventional gun propellants in electrothermal-chemical (ETC) guns. During the rising part of the current pulse, there are rapid changes in the chamber pressure and temperature as shocks propagate from the capillary and then reflect from the base of the projectile and back into the capillary. This causes redistribution of the current density within the capillary altering the spatial ablation rates with time. MACH2 is a general purpose MHD code that has been used to simulate these complex electrical, hydrodynamic and radiation interactions for a 12 mm bore diameter electrothermal gun configuration tested at Institut St. Louis (ISL). The simulation domain includes the capillary discharge, and an expansion chamber extending to the projectile. The radiation was adjusted to match the measured pressure pulse and total ablated mass. Large radial and temporal variations in the velocity, temperature, density and radiation fields were observed in the simulations during the rising part of the current pulse. These results suggest that one-dimensional models may neglect some important physical processes.","PeriodicalId":11209,"journal":{"name":"Digest of Technical Papers. 12th IEEE International Pulsed Power Conference. (Cat. No.99CH36358)","volume":"18 1","pages":"658-661 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1999-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83520873","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}
Collective impact ionization has been used to explain lock-on in semi-insulating GaAs under high-voltage bias. The authors have used this theory to study some of the steady state properties of lock-on current filaments. In the steady state, the heat gained from the field is exactly compensated by the cooling due to phonon scattering. In the simplest approximation, the carrier distribution approaches a quasi-equilibrium Maxwell-Boltzmann distribution. In this report, the authors examine the validity of this approximation. They find that this approximation leads to a filament carrier density which is much lower than the high density needed to achieve a quasi-equilibrium distribution. Further work on this subject is in progress.
{"title":"Steady state properties of lock-on current filaments in GaAs [pulsed power switches]","authors":"K. Kambour, S. Kang, C. Myles, H. Hjalmarson","doi":"10.1109/PPC.1999.823633","DOIUrl":"https://doi.org/10.1109/PPC.1999.823633","url":null,"abstract":"Collective impact ionization has been used to explain lock-on in semi-insulating GaAs under high-voltage bias. The authors have used this theory to study some of the steady state properties of lock-on current filaments. In the steady state, the heat gained from the field is exactly compensated by the cooling due to phonon scattering. In the simplest approximation, the carrier distribution approaches a quasi-equilibrium Maxwell-Boltzmann distribution. In this report, the authors examine the validity of this approximation. They find that this approximation leads to a filament carrier density which is much lower than the high density needed to achieve a quasi-equilibrium distribution. Further work on this subject is in progress.","PeriodicalId":11209,"journal":{"name":"Digest of Technical Papers. 12th IEEE International Pulsed Power Conference. (Cat. No.99CH36358)","volume":"21 1","pages":"791-794 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1999-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84163157","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}
Previously (1998), the authors reported on the operation and limitations of a six-point star gate design 125 mm thyristor pulsed power switch. An involute gate design has been developed that provides a significant increase in its ability to handle higher peak currents and di/dts. For this study, they selected a 2.5 kV symmetric version of the device. The test facility uses a 10 m/spl Omega/ PFN with a rectangular pulse width (FWHM) of 465 /spl mu/s. All tests were performed with an essentially shorted load in order to achieve 200 kA operation and to instantaneously apply a full voltage reversal in less than 3 /spl mu/S at the end of the current pulse. Reliable operation was demonstrated at 2.6 kV forward voltage with a reverse voltage of 2.3 kV. The peak current was 203 kA with a di/dt of 1.8 kA//spl mu/s. The charge was 82 C and the action was 13.8 MA/sup 2/s. The reverse charge was 0.19 C. The PFN was modified to reduce the impedance and simulate a sinusoidal pulse in excess of 1 kHz. Reliable operation was obtained at 221 kA with a di/dt at 2.0 kA//spl mu/s. The pulse width (FWHM) was 301 /spl mu/s. With a base width of 455 /spl mu/s. Forward voltage was 2.4 kV with a reverse voltage of 2.3 kV. The forward charge, reverse charge and action were 63 C, 0.51 C and 10.9 MA/sup 2/s respectively. Reliable repetitive operation was performed at 151 kA with a burst of 10 pulses and a 20 second interval between pulses. No temperature effects were observed.
{"title":"Single shot and burst repetitive operation of involute gate 125 mm symmetric thyristors up to 221 kA with a di/dt of 2.0 kA//spl mu/s","authors":"T. Podlesak, F. Simon, S. Schneider","doi":"10.1109/PPC.1999.825448","DOIUrl":"https://doi.org/10.1109/PPC.1999.825448","url":null,"abstract":"Previously (1998), the authors reported on the operation and limitations of a six-point star gate design 125 mm thyristor pulsed power switch. An involute gate design has been developed that provides a significant increase in its ability to handle higher peak currents and di/dts. For this study, they selected a 2.5 kV symmetric version of the device. The test facility uses a 10 m/spl Omega/ PFN with a rectangular pulse width (FWHM) of 465 /spl mu/s. All tests were performed with an essentially shorted load in order to achieve 200 kA operation and to instantaneously apply a full voltage reversal in less than 3 /spl mu/S at the end of the current pulse. Reliable operation was demonstrated at 2.6 kV forward voltage with a reverse voltage of 2.3 kV. The peak current was 203 kA with a di/dt of 1.8 kA//spl mu/s. The charge was 82 C and the action was 13.8 MA/sup 2/s. The reverse charge was 0.19 C. The PFN was modified to reduce the impedance and simulate a sinusoidal pulse in excess of 1 kHz. Reliable operation was obtained at 221 kA with a di/dt at 2.0 kA//spl mu/s. The pulse width (FWHM) was 301 /spl mu/s. With a base width of 455 /spl mu/s. Forward voltage was 2.4 kV with a reverse voltage of 2.3 kV. The forward charge, reverse charge and action were 63 C, 0.51 C and 10.9 MA/sup 2/s respectively. Reliable repetitive operation was performed at 151 kA with a burst of 10 pulses and a 20 second interval between pulses. No temperature effects were observed.","PeriodicalId":11209,"journal":{"name":"Digest of Technical Papers. 12th IEEE International Pulsed Power Conference. (Cat. No.99CH36358)","volume":"47 1","pages":"206-209 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1999-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84777858","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}
Prediction of the performance of intense electromagnetic transient, gaseous breakdown depends on various parameters used for the description of the gaseous media. Of these parameters, some describe the impact ionization cross section for stable atoms and molecules, and are specific for each species. These parameters are: the first ionization energy, E/sub i/, a scaling parameter which characterizes the collision cross section per electron volt of the species, and a parameter which represents the incident electron energy at which the peak impact ionization cross section occurs. This paper discusses the effect that these parameters have upon electrical breakdown performance in an intense electromagnetic transient environment.
{"title":"The effect of variation of collisional gas parameters on theoretical electromagnetic transient breakdowns","authors":"D. Scholfield, J. Gahl, J. L. Borovina","doi":"10.1109/PPC.1999.823789","DOIUrl":"https://doi.org/10.1109/PPC.1999.823789","url":null,"abstract":"Prediction of the performance of intense electromagnetic transient, gaseous breakdown depends on various parameters used for the description of the gaseous media. Of these parameters, some describe the impact ionization cross section for stable atoms and molecules, and are specific for each species. These parameters are: the first ionization energy, E/sub i/, a scaling parameter which characterizes the collision cross section per electron volt of the species, and a parameter which represents the incident electron energy at which the peak impact ionization cross section occurs. This paper discusses the effect that these parameters have upon electrical breakdown performance in an intense electromagnetic transient environment.","PeriodicalId":11209,"journal":{"name":"Digest of Technical Papers. 12th IEEE International Pulsed Power Conference. (Cat. No.99CH36358)","volume":"12 1","pages":"1396-1399 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1999-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90442452","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}
Albeit far from maturity, inductive storage is a promising technology for electromagnetic launchers. A system comprising a railgun coupled to an inductive storage power supply is analyzed again in this paper. An analytical nondimensional treatment of the lossless case is given, readily allowing the assessment of the performance limits of such a system. A lossy system has been analyzed numerically. A conclusion is drawn that, at the discharge process, the coil losses are of minor importance compared to the rail losses.
{"title":"To the theory of parallel railgun driven by an inductive storage power supply","authors":"A. Pokryvailo","doi":"10.1109/PPC.1999.823776","DOIUrl":"https://doi.org/10.1109/PPC.1999.823776","url":null,"abstract":"Albeit far from maturity, inductive storage is a promising technology for electromagnetic launchers. A system comprising a railgun coupled to an inductive storage power supply is analyzed again in this paper. An analytical nondimensional treatment of the lossless case is given, readily allowing the assessment of the performance limits of such a system. A lossy system has been analyzed numerically. A conclusion is drawn that, at the discharge process, the coil losses are of minor importance compared to the rail losses.","PeriodicalId":11209,"journal":{"name":"Digest of Technical Papers. 12th IEEE International Pulsed Power Conference. (Cat. No.99CH36358)","volume":"10 17 1","pages":"1345-1348 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1999-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80645187","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}
S. Lam, J. Banister, B. Christensen, R. Schneider, B. Whitton, S. Wong, L. Pressley, S. Seiler
Double-EAGLE has been serving as a reliable user radiation facility for the past 15 years. It is primarily a 2-MV, 4-MA, 85-ns pulse generator driving PRS or diode loads. It can be operated in short- and long-pulse modes for both positive and negative polarities to meet the requirements of the radiation front-end load. In the negative, short pulse mode, the generator delivers more than 4 MA current to the PRS load with a pulsewidth of about 85 ns, and in the long pulse mode, the generator delivers the same amount of current with a pulsewidth of 180 ns. In the positive short pulse mode, Double-EAGLE delivers multi-MA currents and 2 MV voltage into reflex diodes for user radiation. We have made substantial improvements in the reliability of Double-EAGLE by improving the operation of the water switches and the triggered gas switches. The machine can now operate consistently with better than 10 ns synchronization between the two EAGLE modules. We present the Double-EAGLE facility operation data and capability.
{"title":"Improvement on Double-EAGLE machine synchronization in both negative and positive modes of operation","authors":"S. Lam, J. Banister, B. Christensen, R. Schneider, B. Whitton, S. Wong, L. Pressley, S. Seiler","doi":"10.1109/PPC.1999.823804","DOIUrl":"https://doi.org/10.1109/PPC.1999.823804","url":null,"abstract":"Double-EAGLE has been serving as a reliable user radiation facility for the past 15 years. It is primarily a 2-MV, 4-MA, 85-ns pulse generator driving PRS or diode loads. It can be operated in short- and long-pulse modes for both positive and negative polarities to meet the requirements of the radiation front-end load. In the negative, short pulse mode, the generator delivers more than 4 MA current to the PRS load with a pulsewidth of about 85 ns, and in the long pulse mode, the generator delivers the same amount of current with a pulsewidth of 180 ns. In the positive short pulse mode, Double-EAGLE delivers multi-MA currents and 2 MV voltage into reflex diodes for user radiation. We have made substantial improvements in the reliability of Double-EAGLE by improving the operation of the water switches and the triggered gas switches. The machine can now operate consistently with better than 10 ns synchronization between the two EAGLE modules. We present the Double-EAGLE facility operation data and capability.","PeriodicalId":11209,"journal":{"name":"Digest of Technical Papers. 12th IEEE International Pulsed Power Conference. (Cat. No.99CH36358)","volume":"55 1","pages":"1453-1455 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1999-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79848080","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}
Magneto-cumulative generators are high-power sources of magnetic energy pulses. Duration and shape of the pulses, created by these generators lies in a rather narrow range, which is determined by detonation velocity of the most powerful high explosive substances, used in these generators. Different schemes and device for generator parameters agreement with load parameters are used for formation of current pulses of different shape and duration on a wide load values range. These schemes and devices include inductive coupling of generator contour with load contour, accumulation of magnetic energy, created by MCG and its commutation to the load using breaking units, which use phase transition metal-insulator at conductor temperature increase, current open switches and different types of plasma-erosion open switches. The main purpose of these schemes and devices is to create current pulse of required shape with comparable or higher power value, than developed by MCG, on the load. We describe the source of high-power energy pulses, based on MCG. Transformer energy bending from MCG, breaking units, made of electrically exploding wires, and noncontrollable sharpening discharger are used in this source.
{"title":"Magnetocumulative source of high-power pulses with double inductive energy storage","authors":"Yu. V. Vilkov, A. Kravchenko, V. Selemir","doi":"10.1109/PPC.1999.823617","DOIUrl":"https://doi.org/10.1109/PPC.1999.823617","url":null,"abstract":"Magneto-cumulative generators are high-power sources of magnetic energy pulses. Duration and shape of the pulses, created by these generators lies in a rather narrow range, which is determined by detonation velocity of the most powerful high explosive substances, used in these generators. Different schemes and device for generator parameters agreement with load parameters are used for formation of current pulses of different shape and duration on a wide load values range. These schemes and devices include inductive coupling of generator contour with load contour, accumulation of magnetic energy, created by MCG and its commutation to the load using breaking units, which use phase transition metal-insulator at conductor temperature increase, current open switches and different types of plasma-erosion open switches. The main purpose of these schemes and devices is to create current pulse of required shape with comparable or higher power value, than developed by MCG, on the load. We describe the source of high-power energy pulses, based on MCG. Transformer energy bending from MCG, breaking units, made of electrically exploding wires, and noncontrollable sharpening discharger are used in this source.","PeriodicalId":11209,"journal":{"name":"Digest of Technical Papers. 12th IEEE International Pulsed Power Conference. (Cat. No.99CH36358)","volume":"8 1","pages":"732-734 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1999-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78246909","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}
R. Baksht, B. Kovalchuk, V. Kokshenev, N. Kurmaev, A. Labetsky, V. Oreshkin, A. Russkikh, A. Fedunin, A. Shishlov
Long time implosion experiments with argon double gas puffs have been conducted on the GIT-12 pulsed current generator at the current level of 2.2-2.4 MA. The double gas puff was used as one of the alternative ways to provide a stable implosion at long implosion time. In the experiments the implosion time was in the range from 230 to 340 ns. The results of the experiments were compared to the results of the 2D snow plow simulations. The experiments and the simulations show that the final pinch is sufficiently stable, when the inner-to-outer shell mass ratio is greater than 0.7. The maximum argon K-shell yield obtained in the experiments is equal to 740 J/cm with the radiation power of 220 GW/cm. At the long implosion times, the K-shell yield obtained in the double gas puff implosion is twice as much as the K-shell yield of 4 cm radius single gas puff with the radiation power increased more than an order of magnitude.
{"title":"Study of the mass ratio effect on double gas puff implosion dynamics","authors":"R. Baksht, B. Kovalchuk, V. Kokshenev, N. Kurmaev, A. Labetsky, V. Oreshkin, A. Russkikh, A. Fedunin, A. Shishlov","doi":"10.1109/PPC.1999.823697","DOIUrl":"https://doi.org/10.1109/PPC.1999.823697","url":null,"abstract":"Long time implosion experiments with argon double gas puffs have been conducted on the GIT-12 pulsed current generator at the current level of 2.2-2.4 MA. The double gas puff was used as one of the alternative ways to provide a stable implosion at long implosion time. In the experiments the implosion time was in the range from 230 to 340 ns. The results of the experiments were compared to the results of the 2D snow plow simulations. The experiments and the simulations show that the final pinch is sufficiently stable, when the inner-to-outer shell mass ratio is greater than 0.7. The maximum argon K-shell yield obtained in the experiments is equal to 740 J/cm with the radiation power of 220 GW/cm. At the long implosion times, the K-shell yield obtained in the double gas puff implosion is twice as much as the K-shell yield of 4 cm radius single gas puff with the radiation power increased more than an order of magnitude.","PeriodicalId":11209,"journal":{"name":"Digest of Technical Papers. 12th IEEE International Pulsed Power Conference. (Cat. No.99CH36358)","volume":"57 1","pages":"1041-1044 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1999-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77960949","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}
The terawatt iodine laser system ASTERIX IV, which has been recently transferred from Germany to the Czech Republic, is presently being commissioned in a new user facility called PALS (Prague Asterix Laser System). The PALS facility is scheduled to provide its beam time to the international user community from early 2000. In this paper, the state-of-the-art of the PALS project is described and the major upgrades PALS will offer to its users are briefly discussed.
{"title":"Prague Asterix Laser System-a new high power facility","authors":"K. Jungwirth, J. Ullschmied, K. Rohlena, B. Rus","doi":"10.1109/PPC.1999.823689","DOIUrl":"https://doi.org/10.1109/PPC.1999.823689","url":null,"abstract":"The terawatt iodine laser system ASTERIX IV, which has been recently transferred from Germany to the Czech Republic, is presently being commissioned in a new user facility called PALS (Prague Asterix Laser System). The PALS facility is scheduled to provide its beam time to the international user community from early 2000. In this paper, the state-of-the-art of the PALS project is described and the major upgrades PALS will offer to its users are briefly discussed.","PeriodicalId":11209,"journal":{"name":"Digest of Technical Papers. 12th IEEE International Pulsed Power Conference. (Cat. No.99CH36358)","volume":"50 1","pages":"1010-1013 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1999-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85699088","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}
Y. Saveliev, W. Sibbett, S. Spark, B. Kerr, M. I. Harbour, S. C. Douglas
Cathode plasma expansion into a vacuum gap is one of the major physical mechanisms affecting the relativistic magnetron (RM) performance and causing a so-called pulse shortening. Therefore, development of new cathode technologies may lead to a significant enhancement of the microwave pulse length, efficiency and power of RMs. The authors are currently conducting a series of experiments with various cathodes with an aim towards improving the RM characteristics. The first results of this research were reported at the BEAMS'98 Conference (Haifa, Israel). In this paper, a more detailed analysis of the experimental data is presented. A primary objective in this research was to determine how the cathode geometry and type of the emission surface would influence major RM characteristics such as microwave pulse duration, output power and magnetron efficiency. The authors found that the cathode geometry influences strongly the RM operation but that the type of emission surface has much less significance. The cathode end caps, which have been mostly abandoned after transition from classical to relativistic magnetrons, were shown to be able to increase the microwave power and RM efficiency without facilitating the pulse shortening effect.
{"title":"Comparative study of a relativistic magnetron performance with various cathodes","authors":"Y. Saveliev, W. Sibbett, S. Spark, B. Kerr, M. I. Harbour, S. C. Douglas","doi":"10.1109/PPC.1999.825446","DOIUrl":"https://doi.org/10.1109/PPC.1999.825446","url":null,"abstract":"Cathode plasma expansion into a vacuum gap is one of the major physical mechanisms affecting the relativistic magnetron (RM) performance and causing a so-called pulse shortening. Therefore, development of new cathode technologies may lead to a significant enhancement of the microwave pulse length, efficiency and power of RMs. The authors are currently conducting a series of experiments with various cathodes with an aim towards improving the RM characteristics. The first results of this research were reported at the BEAMS'98 Conference (Haifa, Israel). In this paper, a more detailed analysis of the experimental data is presented. A primary objective in this research was to determine how the cathode geometry and type of the emission surface would influence major RM characteristics such as microwave pulse duration, output power and magnetron efficiency. The authors found that the cathode geometry influences strongly the RM operation but that the type of emission surface has much less significance. The cathode end caps, which have been mostly abandoned after transition from classical to relativistic magnetrons, were shown to be able to increase the microwave power and RM efficiency without facilitating the pulse shortening effect.","PeriodicalId":11209,"journal":{"name":"Digest of Technical Papers. 12th IEEE International Pulsed Power Conference. (Cat. No.99CH36358)","volume":"41 1","pages":"198-201 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1999-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85720447","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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