Pub Date : 2004-09-27DOI: 10.1109/DEIV.2004.1418589
V. Choulkov
The existence of electron emission at fields some hundreds of times smaller than expected theoretically for an ideal metal surface one explains by emission increase due to local field enhancement at the sharp metallic point protruding from cathode surface. This paper offers a new mechanism explaining anomalous field emission by effect of natural rughness of crystal face of metal surface with atomic sizes (10-8-10-7 cm). It is shown that natural roughness with size about a few period of crystal lattice leads to production of emission sites where work function is significantly less thin work function at a perfectly smooth surface. The Richardson- Dashman thermo-field emission theory with Schottky correction is used for the calculations of current density at the sites. The electrical field change is evoked by natural roughness of crystal face is taken into account. An estimate of emission current in term of emission sites is performed. Then density of emission Sites on metal surface is computed by using the Statistical theory. Total emission current is determined as current averaged over emission sites distribution on metal surface. It is shown that the thermo-field electron emission from such sites play most important role in total emission at average electric field strength on surface 105-106V/cm.
{"title":"Effect of natural surface roughness on electron emission from metal in electric field","authors":"V. Choulkov","doi":"10.1109/DEIV.2004.1418589","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418589","url":null,"abstract":"The existence of electron emission at fields some hundreds of times smaller than expected theoretically for an ideal metal surface one explains by emission increase due to local field enhancement at the sharp metallic point protruding from cathode surface. This paper offers a new mechanism explaining anomalous field emission by effect of natural rughness of crystal face of metal surface with atomic sizes (10-8-10-7 cm). It is shown that natural roughness with size about a few period of crystal lattice leads to production of emission sites where work function is significantly less thin work function at a perfectly smooth surface. The Richardson- Dashman thermo-field emission theory with Schottky correction is used for the calculations of current density at the sites. The electrical field change is evoked by natural roughness of crystal face is taken into account. An estimate of emission current in term of emission sites is performed. Then density of emission Sites on metal surface is computed by using the Statistical theory. Total emission current is determined as current averaged over emission sites distribution on metal surface. It is shown that the thermo-field electron emission from such sites play most important role in total emission at average electric field strength on surface 105-106V/cm.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131494481","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418619
Y. Stishkov, A. Buyanov, I. Elagin, M. A. Pavleyno, A. A. Statuya
In thb paper, the new algorithm for the unipolar corona discharge computation by the finite-element package ANSYS Is proposed. A wire-plane electrode arrangement has been chosen, as an example. The invariability of the electric Intensity force lines In the case of corona discharge in comparison with the case without discharge Is a fundamental assumption of this algorithm. So the distribution of electric intensity in the case of the corona discharge E cor along a force line can be expressed by the formula E cor = S E el , where E el is an electric intensity in the case without discharge, S is a some scalar function of coordinates. The computational algorithm consists of several stages. At the first stage the electric field distribution without taking into account a volume charge was calculated. At the following stage force lines were constructed and distributions of a volume charge and an electric field at corona discharge was calculated along these lines. Further, the current density distribution was specified so that drop of potential along whole force line was equal to the applied voltage, and new calculation was made with the specified value of a current. As these tasks are non-standard for ANSYS package, special programs were developed for their calculation in this package. At last stage the accuracy of received solution was estimated. Estimation has shown the solution satisfies to the Initial equations of corona discharge with accuracy about 10-15 %. Then calculated density of electric forces was used for the electric wind task solution, therefore pressure and velocity distributions were received.
本文提出了利用有限元软件ANSYS计算单极电晕放电的新算法。作为一个例子，我们选择了一种线-平面电极排列方式。电晕放电情况下与无放电情况下电强度线的不变性是该算法的一个基本假设。因此电晕放电情况下电强度沿力线的分布可以用公式E cor = S E el表示，其中E el是无放电情况下的电强度，S是坐标的标量函数。计算算法包括几个阶段。在第一阶段，计算了不考虑体积电荷的电场分布。在接下来的阶段，构造了力线，并沿这些线计算了电晕放电时体积电荷和电场的分布。进一步，指定电流密度分布，使整个力线上的电势降等于外加电压，并以指定的电流值重新计算。由于这些任务在ANSYS包中是非标准的，因此在ANSYS包中开发了专门的计算程序。最后对接收溶液的精度进行了估计。计算结果表明，该解满足电晕放电的初始方程，精度约为10- 15%。然后将计算得到的电力密度用于电风任务解，从而得到压力和速度分布。
{"title":"Methods of electric discharge modeling by ANSYS package","authors":"Y. Stishkov, A. Buyanov, I. Elagin, M. A. Pavleyno, A. A. Statuya","doi":"10.1109/DEIV.2004.1418619","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418619","url":null,"abstract":"In thb paper, the new algorithm for the unipolar corona discharge computation by the finite-element package ANSYS Is proposed. A wire-plane electrode arrangement has been chosen, as an example. The invariability of the electric Intensity force lines In the case of corona discharge in comparison with the case without discharge Is a fundamental assumption of this algorithm. So the distribution of electric intensity in the case of the corona discharge E cor along a force line can be expressed by the formula E cor = S E el , where E el is an electric intensity in the case without discharge, S is a some scalar function of coordinates. The computational algorithm consists of several stages. At the first stage the electric field distribution without taking into account a volume charge was calculated. At the following stage force lines were constructed and distributions of a volume charge and an electric field at corona discharge was calculated along these lines. Further, the current density distribution was specified so that drop of potential along whole force line was equal to the applied voltage, and new calculation was made with the specified value of a current. As these tasks are non-standard for ANSYS package, special programs were developed for their calculation in this package. At last stage the accuracy of received solution was estimated. Estimation has shown the solution satisfies to the Initial equations of corona discharge with accuracy about 10-15 %. Then calculated density of electric forces was used for the electric wind task solution, therefore pressure and velocity distributions were received.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132734677","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418604
Y. Inagawa, F. Miyazaki, K. Kato, M. Sakaki, H. Ichikawa, H. Okubol
Breakdown (BD) characteristics in vacuum are largely dependent on the electrode surface conditions, like the roughness etc. Therefore, in order to develop high voltage vacuum circuit breakers, the research how the electrode surface roughness affects the BD characteristics is important. This paper discussed the influence of the electrode surface roughness on ED conditioning process under non-uniform electric field in vacuum. Experimental results revealed that the difference of electrode surface roughness affected the BD region, the BD voltage, and the BD field strength, as well as the conditioning process.
{"title":"Effect of electrode surface roughness on breakdown conditioning process under non-uniform electric field in vacuum","authors":"Y. Inagawa, F. Miyazaki, K. Kato, M. Sakaki, H. Ichikawa, H. Okubol","doi":"10.1109/DEIV.2004.1418604","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418604","url":null,"abstract":"Breakdown (BD) characteristics in vacuum are largely dependent on the electrode surface conditions, like the roughness etc. Therefore, in order to develop high voltage vacuum circuit breakers, the research how the electrode surface roughness affects the BD characteristics is important. This paper discussed the influence of the electrode surface roughness on ED conditioning process under non-uniform electric field in vacuum. Experimental results revealed that the difference of electrode surface roughness affected the BD region, the BD voltage, and the BD field strength, as well as the conditioning process.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127900955","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418654
D. Gentsch, W. Shang
Vacuum interrupter especially with high short-circuit interruption ability are mostly equipped with contact systems based on two different principles. One of them is the widely used radial magnetic field contact (RMF), while the other is the axial magnetic field (AMF) contact system. By using a high speed CMOS digital video camera, different contact systems could be observed during arcing under short-circuit conditions. The investigation was concentrated on arc modes development with different contact systems and different arcing times, and focused on three contact systems such as one improved RMF and two different AMF systems. In case of the AMF systems both an unipolar and a quadrupolar contact system was considered.
{"title":"High-speed observations of arc modes on RMF- and AMF- contacts","authors":"D. Gentsch, W. Shang","doi":"10.1109/DEIV.2004.1418654","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418654","url":null,"abstract":"Vacuum interrupter especially with high short-circuit interruption ability are mostly equipped with contact systems based on two different principles. One of them is the widely used radial magnetic field contact (RMF), while the other is the axial magnetic field (AMF) contact system. By using a high speed CMOS digital video camera, different contact systems could be observed during arcing under short-circuit conditions. The investigation was concentrated on arc modes development with different contact systems and different arcing times, and focused on three contact systems such as one improved RMF and two different AMF systems. In case of the AMF systems both an unipolar and a quadrupolar contact system was considered.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117305218","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418598
S. Michizono, Y. Saito, Suharyanto, Y. Yamano, S. Kobayashi
Electrical breakdown is one of the most serious problems for developing compact and/or higher-voltage insulation in a vacuum. High secondary electron emission (SEE) yields result in the multipactor effect (electron multiplication on the dielectric surface). Multipactor induces not only discharging, but also excess surface heating, leading to localized surface melting. Thus, SEE at high temperature is important for understanding the actual breakdown process. The SEE yields of sapphire were measured at high temperature by a single-pulsed beam method with a scanning electron microscope (SEM) so as to avoid surface charging. In general, the effective SEE decreases by multipactor due to surface charging. Since the electrical conductivity becomes higher at a high temperature, effective SEE can be larger due to less surface charging. In order to estimate the surface charging, multi-pulse beams were injected to sapphire disks at room and high temperature.
{"title":"Secondary electron emission and surface charging from alumina at high temperature","authors":"S. Michizono, Y. Saito, Suharyanto, Y. Yamano, S. Kobayashi","doi":"10.1109/DEIV.2004.1418598","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418598","url":null,"abstract":"Electrical breakdown is one of the most serious problems for developing compact and/or higher-voltage insulation in a vacuum. High secondary electron emission (SEE) yields result in the multipactor effect (electron multiplication on the dielectric surface). Multipactor induces not only discharging, but also excess surface heating, leading to localized surface melting. Thus, SEE at high temperature is important for understanding the actual breakdown process. The SEE yields of sapphire were measured at high temperature by a single-pulsed beam method with a scanning electron microscope (SEM) so as to avoid surface charging. In general, the effective SEE decreases by multipactor due to surface charging. Since the electrical conductivity becomes higher at a high temperature, effective SEE can be larger due to less surface charging. In order to estimate the surface charging, multi-pulse beams were injected to sapphire disks at room and high temperature.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127231001","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418593
N. V. Tatarinova, A. Baryshnikov
Studies of processes in pores of electrode surface were defined by two problems: 1) to suppress these processes in order to increase electrical strength of vacuum gap [1]; 2) to develop charged particle source with cold cathode based on these processes [2]. From the above references follows that at electrical field "strength values achieved in contemporary high voltage electron vacuum devices and electrophysical facilities prebreakdown currents, microdischarges and vacuum breakdown are defined by processes in micropores of electrodes (or the like defects). These processes are nothing but various stages of self-sustaining gas discharge development the final one being formation of cathode part over the surface of the pore. Voltage-current characteristics (VCCs) of prebreakdown currents attributed to processes in pores include linear and exponential parts. Line-to-exponent transition is defined, first of all, by vacuum, gap width and pore size, i.e., by degree of sagging of electrical field into the pore volume. More precisely, electrical field pattern depends on pore geometrical size relation, pore-depth-to-vacuum-gap-width ratio. To the greater extent this dependence is observed pore size being close to vacuum gap width. Pore configuration variation for the same pore size on electrode plane also defines voltage-current characteristics' exponential part appearance, i.e., vacuum gap breakdown. Creating special porous surface one can vary the electrical strength of vacuum insulation.
{"title":"Prebreakdown current dependency on size and configuration of electrode pores","authors":"N. V. Tatarinova, A. Baryshnikov","doi":"10.1109/DEIV.2004.1418593","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418593","url":null,"abstract":"Studies of processes in pores of electrode surface were defined by two problems: 1) to suppress these processes in order to increase electrical strength of vacuum gap [1]; 2) to develop charged particle source with cold cathode based on these processes [2]. From the above references follows that at electrical field \"strength values achieved in contemporary high voltage electron vacuum devices and electrophysical facilities prebreakdown currents, microdischarges and vacuum breakdown are defined by processes in micropores of electrodes (or the like defects). These processes are nothing but various stages of self-sustaining gas discharge development the final one being formation of cathode part over the surface of the pore. Voltage-current characteristics (VCCs) of prebreakdown currents attributed to processes in pores include linear and exponential parts. Line-to-exponent transition is defined, first of all, by vacuum, gap width and pore size, i.e., by degree of sagging of electrical field into the pore volume. More precisely, electrical field pattern depends on pore geometrical size relation, pore-depth-to-vacuum-gap-width ratio. To the greater extent this dependence is observed pore size being close to vacuum gap width. Pore configuration variation for the same pore size on electrode plane also defines voltage-current characteristics' exponential part appearance, i.e., vacuum gap breakdown. Creating special porous surface one can vary the electrical strength of vacuum insulation.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124890520","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418616
Gao Youhua, Wang Er-zhi, Liu Yanbin, Cao Yundong
In this paper, a new mathematical model combining electric field and current,field is introduced and finite element method is adopted to calkulate the transient electric field of the external insulation of the outdoor vacuum circuit breaker. Dielectric medium with permittivity E and conductivity y under lightning impulse is taken into account. The response caused by lightning impulse voltage i s expressed by Duhamel integration, which is regarded as the boundary excitation of solved region. Under lightning impulse voltage, the potential distributions of external insulation at representative time are shown. Electric intensity distribution curves on external insulation surface with respect to time are also calculated in this paper. The maximum of intensity on external insulation surface is also given, which are compared with the one in the static field. Some distinguishing features of the transient field arc also discussed. It is essential for vacuum circuit breaker insulation design.
{"title":"Numerical analysis of the external insulation of outdoor vacuum circuit breaker under lightning impulse voltage","authors":"Gao Youhua, Wang Er-zhi, Liu Yanbin, Cao Yundong","doi":"10.1109/DEIV.2004.1418616","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418616","url":null,"abstract":"In this paper, a new mathematical model combining electric field and current,field is introduced and finite element method is adopted to calkulate the transient electric field of the external insulation of the outdoor vacuum circuit breaker. Dielectric medium with permittivity E and conductivity y under lightning impulse is taken into account. The response caused by lightning impulse voltage i s expressed by Duhamel integration, which is regarded as the boundary excitation of solved region. Under lightning impulse voltage, the potential distributions of external insulation at representative time are shown. Electric intensity distribution curves on external insulation surface with respect to time are also calculated in this paper. The maximum of intensity on external insulation surface is also given, which are compared with the one in the static field. Some distinguishing features of the transient field arc also discussed. It is essential for vacuum circuit breaker insulation design.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133373254","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418664
Y. Korolev, O. B. Frants, V. G. Geyman, R. V. Ivashov, N. Landl, I. A. Shemyakin, R. Bischoff, K. Frank, I. Petzenhauser
The quenching of a high pulsed current in the pseudospark discharge is accompanied by an inductive voltage kick at the gap and by formation of an electron beam at the discharge axis. The paper deals with the investigation of this phenomenon. The main idea of the proposed physical mechanism is that the electrons are accelerated in a double electric layer, The main electrode gap of the pseudospark discharge forms by which forms during the quenching process between the hollow cathode plasma and the near-anode plasma. Interpretation of the experimental data on this basis is presented.
{"title":"Current quenching in the pseudospark discharge and generation of a fast electron beam","authors":"Y. Korolev, O. B. Frants, V. G. Geyman, R. V. Ivashov, N. Landl, I. A. Shemyakin, R. Bischoff, K. Frank, I. Petzenhauser","doi":"10.1109/DEIV.2004.1418664","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418664","url":null,"abstract":"The quenching of a high pulsed current in the pseudospark discharge is accompanied by an inductive voltage kick at the gap and by formation of an electron beam at the discharge axis. The paper deals with the investigation of this phenomenon. The main idea of the proposed physical mechanism is that the electrons are accelerated in a double electric layer, The main electrode gap of the pseudospark discharge forms by which forms during the quenching process between the hollow cathode plasma and the near-anode plasma. Interpretation of the experimental data on this basis is presented.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121863617","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418656
D. Shmelev
The 2D magnetohydrodynamic model of the low current vacuum arc under action of strong axial magnetic field (AMF) is presented. It is supposed that modelled low current arc (LCA) is the part of high current vacuum arc, witch operate in multicathode spot mode and can be treated as the array of independently burning LCA.
{"title":"Low current vacuum arc in strong axial magnetic field","authors":"D. Shmelev","doi":"10.1109/DEIV.2004.1418656","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418656","url":null,"abstract":"The 2D magnetohydrodynamic model of the low current vacuum arc under action of strong axial magnetic field (AMF) is presented. It is supposed that modelled low current arc (LCA) is the part of high current vacuum arc, witch operate in multicathode spot mode and can be treated as the array of independently burning LCA.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128797965","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 : 2004-09-27DOI: 10.1109/DEIV.2004.1418627
B. Juettner
High speed pictures of arc spots on copper cathodes in vacuum have been taken with high time and space resolution (10 ns and 3 μm, respeetively). They reveal that the spots are located at the rim of large craters, sometimes turning around the crater center with velocities in excess of 1000 d s . On a time scale of milliseconds the spots frequently come hack to their previous locations (memory effect). Supplementary experiments with aolyhdenum and tungsten cathodes show that the appearance of the spots can he controlled by small amounts of oxides and carbides, whereas high temperatures strongly reduce the probability the spot ignition. From these observations it is concluded that cold field electron emission is the base for the spot displacement even if the field appears to he relatively low.
{"title":"The influence of the surface structure on the behavior of arc cathode spots in vacuum","authors":"B. Juettner","doi":"10.1109/DEIV.2004.1418627","DOIUrl":"https://doi.org/10.1109/DEIV.2004.1418627","url":null,"abstract":"High speed pictures of arc spots on copper cathodes in vacuum have been taken with high time and space resolution (10 ns and 3 μm, respeetively). They reveal that the spots are located at the rim of large craters, sometimes turning around the crater center with velocities in excess of 1000 d s . On a time scale of milliseconds the spots frequently come hack to their previous locations (memory effect). Supplementary experiments with aolyhdenum and tungsten cathodes show that the appearance of the spots can he controlled by small amounts of oxides and carbides, whereas high temperatures strongly reduce the probability the spot ignition. From these observations it is concluded that cold field electron emission is the base for the spot displacement even if the field appears to he relatively low.","PeriodicalId":137370,"journal":{"name":"XXIst International Symposium on Discharges and Electrical Insulation in Vacuum, 2004. Proceedings. ISDEIV.","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115639107","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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