12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103)最新文献_第9页

Tools for MHD simulation of hot dense plasma 热致密等离子体MHD模拟工具

12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103) Pub Date : 1998-06-07 DOI: 10.1109/BEAMS.1998.822412

S. Semushin, B. Etlicher

{"title":"Tools for MHD simulation of hot dense plasma","authors":"S. Semushin, B. Etlicher","doi":"10.1109/BEAMS.1998.822412","DOIUrl":"https://doi.org/10.1109/BEAMS.1998.822412","url":null,"abstract":"The complexity of physical problems in plasma demands special tools for its analysis. The primary source of data is, of coarse, the physical experiment. But, sufficiently complete comprehension of physical phenomenon is actually impossible without the numerical simulation, which is more and more often named as computational experiment. Moreover, computational experiment usually provides more complete set of data, which becomes credible only after verification by experiment. The processes under consideration (such as different Z-pinches, plasma opening switches-POS, plasma focus and others) have some common features. Fist of all, they are non-stationary and subjected to divers instabilities. Another common feature is a big difference in time and spatial scales, and small local details are very often significant for global process development. This means, that some kind of adaptation is inevitable for numerical simulations. Traditional lagrangian approach can be also considered as adaptation, based on the mass, but it is not applicable to the problems with high level of convection or mixing. Two numerical methods for MHD plasma simulation and corresponding codes are presented here. The first code ASTRE uses original adaptive mesh refinement algorithm, the other one, Z+ is based on classical arbitrary lagrangian-eulerian algorithm. These two approaches are complimentary. Each of them has its own advantages and specific application domains, but each of them covers the majority of the problems under consideration.","PeriodicalId":410823,"journal":{"name":"12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128253533","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}

引用次数: 1

Studying the electron beam characteristics of magnetron injection guns with a metal secondary emission cathode 研究了金属二次发射阴极磁控管注射枪的电子束特性

12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103) Pub Date : 1998-06-07 DOI: 10.1109/BEAMS.1998.822464

M. Ayzatsky, A.N. Dovnya, P. Gladkikh, V. V. Zakutin, V. Kushnir, V. Mitrochenko, N.G. Reshetn'yak, V. P. Romas’ko, V. Pokas, Y. Tur

{"title":"Studying the electron beam characteristics of magnetron injection guns with a metal secondary emission cathode","authors":"M. Ayzatsky, A.N. Dovnya, P. Gladkikh, V. V. Zakutin, V. Kushnir, V. Mitrochenko, N.G. Reshetn'yak, V. P. Romas’ko, V. Pokas, Y. Tur","doi":"10.1109/BEAMS.1998.822464","DOIUrl":"https://doi.org/10.1109/BEAMS.1998.822464","url":null,"abstract":"The problem of extending the life-time, of increasing the pulse and average power of many RF-sources is closely related to the design of their electron guns. As it is known, the magnetron injecting guns with secondary emission metallic cathodes (SEMI) are specified by the high current emission density and long life-time. The main goal of these investigations is to determine the advantages and limitations of using SEMIGs as the electron source in high-power RF devices and accelerator injector systems. At this stage we have studied some questions concerning the operational beam stability, voltage and current increasing. The experiments have been performed by using the experimental setup to investigate SEMIG linear electron beam parameters from single and multiple beams gun assemblies with the anode voltage up to 100 kV, pulse duration up to 10 /spl mu/s, repetition rate 50 Hz and 0.1-0.2 T magnetic field strength. Pulse-to-pulse long-term stability of the annular electron beams (internal diameter nearly equal to the cathode diameter, wide of ring 1-2 mm (wavelength of cyclotron oscillations)) with beam density up to 70 A/cm/sup 2/ (10/sup 10/-10/sup 11/ e/sup -//cm/sup 3/) have been achieved. It is shown, that the cathode diameter extension provides a proportionate increasing of the beam current, and in the case of multiple beam gun assemblies we have separate identical electron beams with the similar parameters of single-beam gun.","PeriodicalId":410823,"journal":{"name":"12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115092281","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}

引用次数: 0

Influence of electrons reflected from target on operation of diode and triode electron sources 目标反射电子对二极管和三极管电子源工作的影响

12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103) Pub Date : 1998-06-07 DOI: 10.1109/BEAMS.1998.822465

V. Engelko, V. Kuznetsov, G. Mueller, G. Viazmenova

{"title":"Influence of electrons reflected from target on operation of diode and triode electron sources","authors":"V. Engelko, V. Kuznetsov, G. Mueller, G. Viazmenova","doi":"10.1109/BEAMS.1998.822465","DOIUrl":"https://doi.org/10.1109/BEAMS.1998.822465","url":null,"abstract":"When an electron source and a target are immersed in an external magnetic field electrons reflected from a target do not disappear but move along magnetic force lines to the source region where they are rereflected back to the target by the source electric field. Penetration of reflected electrons into the source can lead to distortion of the source electric field and through this to change of the limiting current density emitted by a cathode. Results of calculations of the limiting current density in the diode and triode schemes of an electron source in the presence of reflected electrons are presented. Density of the space charge of reflected electrons was calculated taking into account their real energy distribution obtained by means of Monte Carlo simulation. It was found that penetration of reflected electrons in the diode can decrease essentially the limiting current density. When electrons are reflected with the same energy the maximum lowering of the current density is as much as 3 for reflection coefficient k=1 and 2 for k=0.5. Real lowering of the current density for tungsten target is 1.5. Results of calculations are in a good agreement with experimental data. The analysis performed shows that consideration of reflected electrons is necessary for correct calculation of the beam power density at the target and the distribution of the energy density deposited into the target.","PeriodicalId":410823,"journal":{"name":"12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114961711","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}

引用次数: 0

Ion emission from plasma in the presence of charge transfer 电荷转移时等离子体的离子发射

12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103) Pub Date : 1998-06-07 DOI: 10.1109/BEAMS.1998.817007

S.P. Nikulin

{"title":"Ion emission from plasma in the presence of charge transfer","authors":"S.P. Nikulin","doi":"10.1109/BEAMS.1998.817007","DOIUrl":"https://doi.org/10.1109/BEAMS.1998.817007","url":null,"abstract":"Usually particles do not collide in the accelerating gap of ion sources, because the gas pressure in the gap should be low to provide a high electric strength. However, the gas discharge systems of the sources may allow for such gas conditions that the ion free path becomes comparable with dimensions of the systems. This is due to the pressure differential between the accelerating and gas-discharge systems of the sources and also to the fact that dimensions of the gas-discharge chambers may by far exceed the length of the accelerating gaps. Given these conditions, the relationships derived for the collisionless regime cannot be used to evaluate the ion current flowing from the discharge system to the accelerating gap. These relationships need be refined allowing for charge transfer. The goal of this study was to ascertain how collisions affect the value of the ion emission current over the pressure interval where the collisionless mode of the ion motion (the ion velocity is determined by the potential difference passed) is replaced by motion in a strong electric field (the ion velocity is proportional to the square root of the electric field intensity).","PeriodicalId":410823,"journal":{"name":"12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131205358","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}

引用次数: 0

Numerical study of foilless diode 无箔二极管的数值研究

12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103) Pub Date : 1998-06-07 DOI: 10.1109/BEAMS.1998.816973

Zhimin Sung, Guozhi Liu, Yajun Fan, H. Shao

引用次数: 2

Optical guiding and stability of intense short laser pulses in plasma channels 强短激光脉冲在等离子体通道中的光导与稳定性

12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103) Pub Date : 1998-06-07 DOI: 10.1109/BEAMS.1998.822401

P. Sprangle, B. Hafizi

引用次数: 0

MWCG with biperiodic output section 具有双周期输出部分的MWCG

12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103) Pub Date : 1998-06-07 DOI: 10.1109/BEAMS.1998.816966

M. Deichuly, V. Koshelev

引用次数: 0

Nanometer-sized YSZ powders production by means of target evaporation using high-efficient pulsed-repetitive CO/sub 2/-laser 利用高效脉冲重复CO/sub - 2激光靶蒸发法制备纳米YSZ粉末

12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103) Pub Date : 1998-06-07 DOI: 10.1109/BEAMS.1998.817028

V. Osipov, Y. Kotov, M. Ivanov, O. Samatov, S. Sokovnin, P. B. Smirnov

引用次数: 0

General scaling of pulse shortening in explosive-emission-driven microwave sources 爆炸发射驱动微波源脉冲缩短的一般标度

12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103) Pub Date : 1998-06-07 DOI: 10.1109/BEAMS.1998.816947

J. Benford, D. Price

{"title":"General scaling of pulse shortening in explosive-emission-driven microwave sources","authors":"J. Benford, D. Price","doi":"10.1109/BEAMS.1998.816947","DOIUrl":"https://doi.org/10.1109/BEAMS.1998.816947","url":null,"abstract":"Microwave generation in devices that depend on synchronization between an electron beam and a resonant cavity or slow wave structure can be disrupted by changes in either. Explosive-emission-driven microwave sources use plasma as the electron source in the diode. This plasma is conductive enough to act as the boundary for both the applied diode voltage and the microwave electric field. The motion of this plasma can effectively change the dimensions of either the electron beam diode or the cavity and will thereby cause resonance destruction. This shortens the microwave pulse length /spl tau//sub /spl mu//. Using simple models of cathode plasma motion and plasma speed dependence on diode current, we derive a scaling relation between microwave power and microwave pulse length. This general model of the process predicts that, for a Child-Langmuir diode, microwave power falls as P/spl prop//spl tau//sub /spl mu///sup -5/3/ and that pulse energy falls as E/spl prop//spl tau//sub /spl mu///sup -2/3/. Therefore, energy efficiency declines as the pulse length is extended. We compare with data from magnetrons, MILOs and BWOs, with good agreement. Explosive-emission-driven microwave sources are fundamentally limited by the speed of the diode plasma and can be improved by finding cathode materials that generate slower plasmas.","PeriodicalId":410823,"journal":{"name":"12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133457294","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}

引用次数: 0

Investigation of plasma-beam amplifiers with reference to use in communication systems 等离子束放大器的研究及其在通信系统中的应用

12th International Conference on High-Power Particle Beams. BEAMS'98. Proceedings (Cat. No.98EX103) Pub Date : 1998-06-07 DOI: 10.1109/BEAMS.1998.816980

V. Perevodchikov, Y. Kuznetzov, L. Mitin, A. Shapiro, M. Zavjalov

引用次数: 0