Pub Date : 2013-06-16DOI: 10.1109/PLASMA.2013.6633273
S. Cui, Xiyuan Li, Liwei Song
The electromagnetic rail-gun is a kind of high-energy device which uses a high-current electrical pulse to accelerate projectiles to hypersonic velocity, and the launch performance of the system is affected by the thermal characteristic during the launching process1. The electromagnetic rail-gun system is a multi-physics coupling field system2, so the different aspects and their interaction of the system should be considered when we analyze the performance of the barrel during the launching process. In this research, utilized finite element method to simulate the process that the armature squeezes the barrel, and the three-dimension finite element model of the barrel and the armature were established in the finite element analysis software ANSYS. The finite element models for eddy current heat, Joule heat and friction heat are established to simulate the transient thermal distribution, and the temperature distribution characteristic was analyzed. The magnetism-structure directly coupling analysis and the magnetism-thermal-structure analysis of the barrel were accomplished. Based on the analysis above, the stress and strain distribution, the magnetic field distribution and temperature distribution were obtained. Comparing the results of the two kinds of analyses above, how load distribution influences the displacement and the stress of the electromagnetic rail-gun, structure deformation influence the magnetic field and temperature field influence the structure were acquired. Finally, the research analysed the effect of the intensity and stiffness of the barrel under different current intensity, and the maximum current intensity that the rail can sustain with specified materials and structure was obtained, which has a reference value for further research.
{"title":"PPPS-2013: Multi-physics coupling field analysis of the electromagnetic rail-gun barrel","authors":"S. Cui, Xiyuan Li, Liwei Song","doi":"10.1109/PLASMA.2013.6633273","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6633273","url":null,"abstract":"The electromagnetic rail-gun is a kind of high-energy device which uses a high-current electrical pulse to accelerate projectiles to hypersonic velocity, and the launch performance of the system is affected by the thermal characteristic during the launching process1. The electromagnetic rail-gun system is a multi-physics coupling field system2, so the different aspects and their interaction of the system should be considered when we analyze the performance of the barrel during the launching process. In this research, utilized finite element method to simulate the process that the armature squeezes the barrel, and the three-dimension finite element model of the barrel and the armature were established in the finite element analysis software ANSYS. The finite element models for eddy current heat, Joule heat and friction heat are established to simulate the transient thermal distribution, and the temperature distribution characteristic was analyzed. The magnetism-structure directly coupling analysis and the magnetism-thermal-structure analysis of the barrel were accomplished. Based on the analysis above, the stress and strain distribution, the magnetic field distribution and temperature distribution were obtained. Comparing the results of the two kinds of analyses above, how load distribution influences the displacement and the stress of the electromagnetic rail-gun, structure deformation influence the magnetic field and temperature field influence the structure were acquired. Finally, the research analysed the effect of the intensity and stiffness of the barrel under different current intensity, and the maximum current intensity that the rail can sustain with specified materials and structure was obtained, which has a reference value for further research.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78469591","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 : 2013-06-16DOI: 10.1109/PLASMA.2013.6633403
Jana Kredl, Kai Ptach, J. Zhuang, J. Kolb
Non-thermal plasmas offer an effective method for sterilization. For medical applications, such as wound care or plaque removal, the plasma must be cold, i.e. at room temperature. Further it is necessary to conduct a treatment at atmospheric pressure in ambient air. One solution is offered by plasma jets that are generated from discharges operated with noble gases. Alternatively, a cold plasma jet can be generated directly from ambient air in a microhollow cathode discharge geometry. In this configuration a discharge is operated by a dc voltage on the order of 1-2 kV and currents of several milliamps. By flowing air through the discharge channel, a jet is expelled which reaches gas flow rates of about 8 slm room temperature within a few millimeters from the discharge. The efficacy of this setup was recently succesfully demonstrated against different bacteria and yeast1. The microorganisms were plated in 100-mm petri dishes and a 20 mm × 20 mm square was treated by moving the jet in a meander pattern across this area. C. kefyr was the most difficult to inactivate and required an exposure time of 215 s for a reduction of 4-log steps. Whereas for S. aureus a 5.5-log reduction was already achieved in 52 seconds and complete inactivation of 6-log steps in 111 s. Most interestingly it was found that S. aureus and C. kefyr were also affected far outside the immediate treatment area while the effect on other bacteria was limited only to the area directly exposed to the jet. We hypothesize that different interaction mechanisms are responsible for different inactivation rates and are in particular responsible for different inactivation patterns. The most dominant species that was found in the jet's effluent is nitric oxide (NO). Distributions of nitric oxides and different cell susceptibilities might therefore be responsible for the observed inactivation patterns. Accordingly, the topic of our study are nitric oxide concentrations depending on operating parameters, such as power dissipated in the plasma, and gas flow rates. In addition we consider the effect of humidity on the generation of radical species (and on the plasma chemistry in general) and with respect to the observed inactivation kinetics.
{"title":"Operation of a cold DC operated air plasma jet for microbiol decontamination","authors":"Jana Kredl, Kai Ptach, J. Zhuang, J. Kolb","doi":"10.1109/PLASMA.2013.6633403","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6633403","url":null,"abstract":"Non-thermal plasmas offer an effective method for sterilization. For medical applications, such as wound care or plaque removal, the plasma must be cold, i.e. at room temperature. Further it is necessary to conduct a treatment at atmospheric pressure in ambient air. One solution is offered by plasma jets that are generated from discharges operated with noble gases. Alternatively, a cold plasma jet can be generated directly from ambient air in a microhollow cathode discharge geometry. In this configuration a discharge is operated by a dc voltage on the order of 1-2 kV and currents of several milliamps. By flowing air through the discharge channel, a jet is expelled which reaches gas flow rates of about 8 slm room temperature within a few millimeters from the discharge. The efficacy of this setup was recently succesfully demonstrated against different bacteria and yeast1. The microorganisms were plated in 100-mm petri dishes and a 20 mm × 20 mm square was treated by moving the jet in a meander pattern across this area. C. kefyr was the most difficult to inactivate and required an exposure time of 215 s for a reduction of 4-log steps. Whereas for S. aureus a 5.5-log reduction was already achieved in 52 seconds and complete inactivation of 6-log steps in 111 s. Most interestingly it was found that S. aureus and C. kefyr were also affected far outside the immediate treatment area while the effect on other bacteria was limited only to the area directly exposed to the jet. We hypothesize that different interaction mechanisms are responsible for different inactivation rates and are in particular responsible for different inactivation patterns. The most dominant species that was found in the jet's effluent is nitric oxide (NO). Distributions of nitric oxides and different cell susceptibilities might therefore be responsible for the observed inactivation patterns. Accordingly, the topic of our study are nitric oxide concentrations depending on operating parameters, such as power dissipated in the plasma, and gas flow rates. In addition we consider the effect of humidity on the generation of radical species (and on the plasma chemistry in general) and with respect to the observed inactivation kinetics.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80109606","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 : 2013-06-16DOI: 10.1109/PLASMA.2013.6634882
B. Appelbe, J. Chittenden
We present 3D MHD simulations of a 100kA deuterium filled dense plasma focus, carried out using the Gorgon MHD code. The simulations model the entire implosion from the run down phase to the pinch phase and accompanying neutron production.The electromagnetic fields that are generated in the plasma during the pinching phase are used in a hybrid (kinetic-fluid) code to model the non-thermal ion population produced by the plasma focus. Large electric fields accelerate ions to high (>100 key) energies. The hybrid code calculates fusion reactions between thermal and non-thermal ions and models the resulting neutron emission spectra. The shape of these neutron spectra are analyzed and related to the underlying plasma conditions. In particular, the degree of magnetization of the accelerated ions and the mean energy of accelerated ions can be determined from the neutron spectra. Comparisons are made with simulations of 13MA double shell deuterium gas puffs in which the neutron spectra produced by beam-target reactions are near-isotropic with broad FWHM due to the high level of magnetization of ion beams produced in the gas puff.
{"title":"Simulations of a dense plasma focus with characterization of the neutron emission","authors":"B. Appelbe, J. Chittenden","doi":"10.1109/PLASMA.2013.6634882","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6634882","url":null,"abstract":"We present 3D MHD simulations of a 100kA deuterium filled dense plasma focus, carried out using the Gorgon MHD code. The simulations model the entire implosion from the run down phase to the pinch phase and accompanying neutron production.The electromagnetic fields that are generated in the plasma during the pinching phase are used in a hybrid (kinetic-fluid) code to model the non-thermal ion population produced by the plasma focus. Large electric fields accelerate ions to high (>100 key) energies. The hybrid code calculates fusion reactions between thermal and non-thermal ions and models the resulting neutron emission spectra. The shape of these neutron spectra are analyzed and related to the underlying plasma conditions. In particular, the degree of magnetization of the accelerated ions and the mean energy of accelerated ions can be determined from the neutron spectra. Comparisons are made with simulations of 13MA double shell deuterium gas puffs in which the neutron spectra produced by beam-target reactions are near-isotropic with broad FWHM due to the high level of magnetization of ion beams produced in the gas puff.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76407373","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 : 2013-06-16DOI: 10.1109/PLASMA.2013.6633276
S. Rice, J. Verboncoeur
Summary form only given. Multipactor is a resonant phenomenon in which an electromagnetic field causes a free electron to impact a surface, resulting in the surface emitting one or more secondary electrons. If the surface geometry and electromagnetic fields are appropriately arranged, the secondary electrons can then be accelerated and again impact a surface in the bounding geometry. If the net number of secondary electrons participating in multipactor is non-decreasing, then the process can repeat indefinitely. This phenomenon is of considerable practical interest in the design and operation of high power resonant structures. When the secondary electron yield (SEY) of a material measured as a function of the incident electron kinetic energy, the curve follows a similar shape for many materials: At low incident kinetic energies, the SEY is low; at intermediate kinetic energies, the SEY is maximized at a material-dependent energy; at high kinetic energies, the SEY tapers down to zero with increasing energy. In order multipactor to be self-sustaining, the average SEY over multipactor path must be at least unity. This means that multipactor can only be sustained within a certain material-dependent range of incident electron kinetic energies. This research investigates the feasibility of suppressing multipactor through the use of higher-order cavity modes which will modify the incident kinetic energy of impacting electrons. Since the SEY is dependent upon kinetic energy of the incident electron, our goal is modify impacting electron velocities to reduce the average SEY less than unity such that multipactor is not sustainable. Preliminary computer simulations are presented which demonstrate this concept in reducing or eliminating multipactor in a 2-dimensional coaxial cavity geometry.
{"title":"Multipactor suppression via higher-order modes","authors":"S. Rice, J. Verboncoeur","doi":"10.1109/PLASMA.2013.6633276","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6633276","url":null,"abstract":"Summary form only given. Multipactor is a resonant phenomenon in which an electromagnetic field causes a free electron to impact a surface, resulting in the surface emitting one or more secondary electrons. If the surface geometry and electromagnetic fields are appropriately arranged, the secondary electrons can then be accelerated and again impact a surface in the bounding geometry. If the net number of secondary electrons participating in multipactor is non-decreasing, then the process can repeat indefinitely. This phenomenon is of considerable practical interest in the design and operation of high power resonant structures. When the secondary electron yield (SEY) of a material measured as a function of the incident electron kinetic energy, the curve follows a similar shape for many materials: At low incident kinetic energies, the SEY is low; at intermediate kinetic energies, the SEY is maximized at a material-dependent energy; at high kinetic energies, the SEY tapers down to zero with increasing energy. In order multipactor to be self-sustaining, the average SEY over multipactor path must be at least unity. This means that multipactor can only be sustained within a certain material-dependent range of incident electron kinetic energies. This research investigates the feasibility of suppressing multipactor through the use of higher-order cavity modes which will modify the incident kinetic energy of impacting electrons. Since the SEY is dependent upon kinetic energy of the incident electron, our goal is modify impacting electron velocities to reduce the average SEY less than unity such that multipactor is not sustainable. Preliminary computer simulations are presented which demonstrate this concept in reducing or eliminating multipactor in a 2-dimensional coaxial cavity geometry.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76209177","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 : 2013-06-16DOI: 10.1109/PLASMA.2013.6633295
H. Rahman, M. Binderbauer, N. Rostoker, F. Wessel
Summary form only given. In the standard MHD formulation the effects of finite gyroradius and gyroperiod are usually absent. To include these effects we have modified MACH2, a 2D MHD code, and then simulated recent experiments performed at Tri Alpha Energy, Inc.1 and the University of CA, Irvine.2 In the experiments an azimuthal-electric field is produced by a flux coil that is co-axially located with the plasma.3 In the presence of a pre-formed, magnetized plasma the Eθ field induces a diamagnetic-plasma current that reverses the applied-magnetic field, forming a FRC. The simulations suggest that the azimuthal current is due initially to ion flow, until the FRC is formed, when the electrons are free to accelerate in the field-free region, near the magnetic-null. For the same set of initial parameters there is good agreement between the simulations and the experiments.
{"title":"PPPS-2013: Ion-current FRC using a modified MHD model","authors":"H. Rahman, M. Binderbauer, N. Rostoker, F. Wessel","doi":"10.1109/PLASMA.2013.6633295","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6633295","url":null,"abstract":"Summary form only given. In the standard MHD formulation the effects of finite gyroradius and gyroperiod are usually absent. To include these effects we have modified MACH2, a 2D MHD code, and then simulated recent experiments performed at Tri Alpha Energy, Inc.1 and the University of CA, Irvine.2 In the experiments an azimuthal-electric field is produced by a flux coil that is co-axially located with the plasma.3 In the presence of a pre-formed, magnetized plasma the Eθ field induces a diamagnetic-plasma current that reverses the applied-magnetic field, forming a FRC. The simulations suggest that the azimuthal current is due initially to ion flow, until the FRC is formed, when the electrons are free to accelerate in the field-free region, near the magnetic-null. For the same set of initial parameters there is good agreement between the simulations and the experiments.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86887405","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 : 2013-06-16DOI: 10.1109/PLASMA.2013.6633440
Qingguo Yang, Shao-tong Zhou, Guanhua Chen, Xianbin Huang, H. Cai, Zeren Li
Summary form only given. A device that integrates a Johann-type spectrometer with the x-ray PIN diodes, positioned accurately on the rowland circle of the cylindrical bent crystal with different Bragg angles to aim at different spectral lines, has been developed for measuring th e time-resolved K-shell line emissions of the imploding Al wire array. Four typical channels respectively keyed to the Al ion hydrogen-like (Hα, 0.7171 nm and Hβ, 0.6052 nm) and helium-like (Heα, 0.7757 nm and Hβ, 0.6634 nm) resonance lines are designed and the signal ratios of the Hα line to the Heα line has been used to retrieve the time-dependent electron temperature. The designing principle of the spectrometer is described and the preliminary experimental results on the YANG and PTS accelerator are presented and analyzed.
{"title":"PPPS-2013: Optical and x-ray diagnostics time-resolved K-shell line spectra measu rement of the imploding al wire array","authors":"Qingguo Yang, Shao-tong Zhou, Guanhua Chen, Xianbin Huang, H. Cai, Zeren Li","doi":"10.1109/PLASMA.2013.6633440","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6633440","url":null,"abstract":"Summary form only given. A device that integrates a Johann-type spectrometer with the x-ray PIN diodes, positioned accurately on the rowland circle of the cylindrical bent crystal with different Bragg angles to aim at different spectral lines, has been developed for measuring th e time-resolved K-shell line emissions of the imploding Al wire array. Four typical channels respectively keyed to the Al ion hydrogen-like (H<sub>α</sub>, 0.7171 nm and H<sub>β</sub>, 0.6052 nm) and helium-like (He<sub>α</sub>, 0.7757 nm and H<sub>β</sub>, 0.6634 nm) resonance lines are designed and the signal ratios of the H<sub>α</sub> line to the He<sub>α</sub> line has been used to retrieve the time-dependent electron temperature. The designing principle of the spectrometer is described and the preliminary experimental results on the YANG and PTS accelerator are presented and analyzed.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87162621","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 : 2013-06-16DOI: 10.1109/PLASMA.2013.6634879
Long H. B. Nguyen, T. Antonsen, G. Nusinovich
Summary form only given. Recent demands on power and frequency lead to consideration of sheet electron beams with large aspect ratios1. New SWSs need to be developed to interact with these sheet electron beams2,3. In this paper, we consider a planar sheath-like structure with metal conductors on the surface of two surrounding dielectric layers. The structure can be easily microfabricated with current technology, resulting in excellent reliability and repeatability3. The motivation for the sheath nature of the structure is to allow the period of the structure to be shortened without changing the pitch of the conductors. The shortened period raises the frequency of backward wave modes thus suppressing them. The multiple conductors in the sheath open the possibility of transverse modes which can interact with the beam. These, however, will have transverse components in their group velocity and will propagate out of the structure. We assume the sheath approximation and fields having propagation constant kz and ky in the longitudinal and transverse direction respectively. Matching analytically the fields at the conducting sheaths boundaries, we obtain a transcendental dispersion relation. Three solutions propagate to zero frequency, one having even parity in axial electric field and the other two having odd parity. The even parity solution interacts strongly with the electron beam, hence is the operating mode. The transverse propagation modes have neither even nor odd parity, and some of them intersect what would be the beam line. However, their group velocities are essentially parallel to the conductors on either the upper or lower sheaths at those intersecting points. Thus they will be heavily damped in a structure with finite lateral extent. The Pierce parameter is analyzed and calculated for a beam with voltage at 19.5kV, current at 3.5A, wave frequency at 35GHz, and tunnel width equal to 0.6452cm while tunnel height is 0.07cm. This gives an expected gain rate of 11.8dB/cm.
{"title":"Open planar sheath slow-wave structure","authors":"Long H. B. Nguyen, T. Antonsen, G. Nusinovich","doi":"10.1109/PLASMA.2013.6634879","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6634879","url":null,"abstract":"Summary form only given. Recent demands on power and frequency lead to consideration of sheet electron beams with large aspect ratios1. New SWSs need to be developed to interact with these sheet electron beams2,3. In this paper, we consider a planar sheath-like structure with metal conductors on the surface of two surrounding dielectric layers. The structure can be easily microfabricated with current technology, resulting in excellent reliability and repeatability3. The motivation for the sheath nature of the structure is to allow the period of the structure to be shortened without changing the pitch of the conductors. The shortened period raises the frequency of backward wave modes thus suppressing them. The multiple conductors in the sheath open the possibility of transverse modes which can interact with the beam. These, however, will have transverse components in their group velocity and will propagate out of the structure. We assume the sheath approximation and fields having propagation constant kz and ky in the longitudinal and transverse direction respectively. Matching analytically the fields at the conducting sheaths boundaries, we obtain a transcendental dispersion relation. Three solutions propagate to zero frequency, one having even parity in axial electric field and the other two having odd parity. The even parity solution interacts strongly with the electron beam, hence is the operating mode. The transverse propagation modes have neither even nor odd parity, and some of them intersect what would be the beam line. However, their group velocities are essentially parallel to the conductors on either the upper or lower sheaths at those intersecting points. Thus they will be heavily damped in a structure with finite lateral extent. The Pierce parameter is analyzed and calculated for a beam with voltage at 19.5kV, current at 3.5A, wave frequency at 35GHz, and tunnel width equal to 0.6452cm while tunnel height is 0.07cm. This gives an expected gain rate of 11.8dB/cm.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86311736","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 : 2013-06-16DOI: 10.1109/PLASMA.2013.6634859
C. Huang, C. Burkhart, B. Morris, B. Lam, M. Nguyen, M. Kemp, F. Rafael, H. Sanders, C. Dunham
Summary form only given. There are 243 line type modulators in Linac gallery to power klystrons at SLAC two-mile accelerator. High power thyratron is used as PFN switch in each modulator to produce pulses for Klystron operation through a step-up pulse transformer. About 83 modulators are used for LCLS operating at repetition rate of 120Hz. The thyratron average life time is about 16k hours, much shorter than state of the art solid state switches. Solid state switch will improve overall modulator performance by increasing switch life time and reliability, and decreasing maintenance intervention. In the paper, development of a solid state thyratron replacement switch for LCLS modulator will be presented, including switch specifications, electrical performance, timing jitter, pulse amplitude stability, thermal performance, and up to date long term reliability, etc.
{"title":"Linac modulator solid state switch development for thyratron replacement at SLAC","authors":"C. Huang, C. Burkhart, B. Morris, B. Lam, M. Nguyen, M. Kemp, F. Rafael, H. Sanders, C. Dunham","doi":"10.1109/PLASMA.2013.6634859","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6634859","url":null,"abstract":"Summary form only given. There are 243 line type modulators in Linac gallery to power klystrons at SLAC two-mile accelerator. High power thyratron is used as PFN switch in each modulator to produce pulses for Klystron operation through a step-up pulse transformer. About 83 modulators are used for LCLS operating at repetition rate of 120Hz. The thyratron average life time is about 16k hours, much shorter than state of the art solid state switches. Solid state switch will improve overall modulator performance by increasing switch life time and reliability, and decreasing maintenance intervention. In the paper, development of a solid state thyratron replacement switch for LCLS modulator will be presented, including switch specifications, electrical performance, timing jitter, pulse amplitude stability, thermal performance, and up to date long term reliability, etc.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82677660","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}
Breast cancer is one of the most threatening malignant tumors among women, the incidence of which is rising year by year. Despite of early screening and improvement in breast cancer management that have increased the 5-year survive rate, the requirement for novel and more efficient therapy for breast cancer is still quite urgent. In the recent decades, nanosecond pulsed electric fields, known as NsPEFs, have been proved to be able to induce cell apoptosis and tumor inhibition in various cancers. In this study, we established breast cancer animal model with MCF-7 cell line on Balb/c nude mice. An electric field over 30kV/cm was generated between to the two pads of the clamp, where the tumor was placed. Tumors were treated with nsPEFs on three consecutive days, and day 0 was set as the day when nsPEFs treatment was finished. Within 2 weeks after treatment, it was observed that tumor growth was significantly inhibited. The average volume and weight of pulsed tumors was almost 1/9 of that of unpulsed tumors. Morphological changes were observed in a 3.0T clinical magnetic resonance imaging (MRI) system with an own-made surface coil on day0, day7 and day14, which showed the shrinkage of the tumors. Apoptosis and hemorrhagic necrosis in tumor cells were inspected after nsPEFs treatement by H&E staining. Immuno-histological tests indicated VEGF expression in tumor cells was strongly suppressed. Tumor blood vessel density was calculated and found decreased after nsPEFs treatment. The results suggest nsPEFs can inhibit breast cancer development and suppress tumor blood vessel growth, which may serve as a novel therapy for breast cancer in the future.
{"title":"Nanosecond pulsed electric fields inhibit breast cancer development and suppress tumor blood vessel growth","authors":"Shan Wu, Yu Wang, Jinsong Guo, Qunzhi Chen, Jue Zhang, Jing Fang","doi":"10.1109/PPC.2013.6627554","DOIUrl":"https://doi.org/10.1109/PPC.2013.6627554","url":null,"abstract":"Breast cancer is one of the most threatening malignant tumors among women, the incidence of which is rising year by year. Despite of early screening and improvement in breast cancer management that have increased the 5-year survive rate, the requirement for novel and more efficient therapy for breast cancer is still quite urgent. In the recent decades, nanosecond pulsed electric fields, known as NsPEFs, have been proved to be able to induce cell apoptosis and tumor inhibition in various cancers. In this study, we established breast cancer animal model with MCF-7 cell line on Balb/c nude mice. An electric field over 30kV/cm was generated between to the two pads of the clamp, where the tumor was placed. Tumors were treated with nsPEFs on three consecutive days, and day 0 was set as the day when nsPEFs treatment was finished. Within 2 weeks after treatment, it was observed that tumor growth was significantly inhibited. The average volume and weight of pulsed tumors was almost 1/9 of that of unpulsed tumors. Morphological changes were observed in a 3.0T clinical magnetic resonance imaging (MRI) system with an own-made surface coil on day0, day7 and day14, which showed the shrinkage of the tumors. Apoptosis and hemorrhagic necrosis in tumor cells were inspected after nsPEFs treatement by H&E staining. Immuno-histological tests indicated VEGF expression in tumor cells was strongly suppressed. Tumor blood vessel density was calculated and found decreased after nsPEFs treatment. The results suggest nsPEFs can inhibit breast cancer development and suppress tumor blood vessel growth, which may serve as a novel therapy for breast cancer in the future.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82903536","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 : 2013-06-16DOI: 10.1109/PLASMA.2013.6635140
A. Talebitaher, S. Kalaiselvi, P. Lee, S. V. Springham, T. L. Tan, R. Rawat
Summary form only given. The optical investigation of the plasma dynamics in breakdown, axial and radial phases of fast miniature plasma focus (FMPF-3) device under repetitive opeartion is being performed by means of laser shadowgraphy. Uniform parallel light beams are provided by using a monochrome (532 nm) Nd:YAG short pulsed laser (120 ps). A Phantom V211 high speed camera with a maximum resolution of 1280 × 800 pixels and minimum exposure time of 2 μs is used to capture the images. All sequential signals with adjustable timing are provided by a programmable STM32f4 microcontroller board which allows the user to preset all required timing for each of the individual devices. A series of shots are performed, at different repetition rates, with automatic time increasing with reference to a selected reference time instant on discharge current. After each set of experiments, the sequence of the images from the laser shadowgraphy is correlated with the current derivative signal. The results show the different shape, size and density of the plasma sheath and final pinch column for pure hydrogen/deuterium and admixture gas operation. They also illustrate the MHD instability formation in different gas pressure and admixture ratios.
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