Pub Date : 1989-12-01DOI: 10.1109/PLASMA.1989.166277
S. Eways, R. Carrera, J. Dong, G. Hallock, E. Montalvo
The operation of the IGNITEX ignition tokamak from breakdown to shutdown is discussed. The pulse length of the discharge is extended by precooling the magnet structure to liquid nitrogen temperature between pulses. RF cavity resonance is used to break down the neutral gas and initiate the plasma discharge in a controllable and reproducible way. The structure of the vacuum toroidal cavity modes has been investigated analytically. A numerical study of the field mode structure and the mode evolution during the plasma buildup has been carried out. Plasma current, equilibrium, shaping, and control are provided by an internal inductor with five pairs of single-turn coils which are independently powered by homopolar generators. Plasma coupling is maximized by the proximity of the poloidal field system to the plasma column. The conducting massive structure surrounding the plasma should damp plasma displacements. The MHD plasma equilibrium throughout a typical IGNITEX discharge has been analyzed. The IGNITEX experiment will operate basically in the L-mode without limiter. However, separatrix configurations of equilibrium are easily obtained by minor changes in the pulse shape of the elongation coils.<>
{"title":"Operation of the IGNITEX tokamak","authors":"S. Eways, R. Carrera, J. Dong, G. Hallock, E. Montalvo","doi":"10.1109/PLASMA.1989.166277","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166277","url":null,"abstract":"The operation of the IGNITEX ignition tokamak from breakdown to shutdown is discussed. The pulse length of the discharge is extended by precooling the magnet structure to liquid nitrogen temperature between pulses. RF cavity resonance is used to break down the neutral gas and initiate the plasma discharge in a controllable and reproducible way. The structure of the vacuum toroidal cavity modes has been investigated analytically. A numerical study of the field mode structure and the mode evolution during the plasma buildup has been carried out. Plasma current, equilibrium, shaping, and control are provided by an internal inductor with five pairs of single-turn coils which are independently powered by homopolar generators. Plasma coupling is maximized by the proximity of the poloidal field system to the plasma column. The conducting massive structure surrounding the plasma should damp plasma displacements. The MHD plasma equilibrium throughout a typical IGNITEX discharge has been analyzed. The IGNITEX experiment will operate basically in the L-mode without limiter. However, separatrix configurations of equilibrium are easily obtained by minor changes in the pulse shape of the elongation coils.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129442840","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 : 1989-12-01DOI: 10.1109/PLASMA.1989.166142
H. Akiyama, N. Shimomura, K. Takasugi, T. Miyamoto, M. Sato, T. Tazima
Recent developments in pulsed power technology have increased interest in gas-puff Z-pinches as soft X-ray sources and for nuclear fusion. The pulse width of the pulsed power is extremely short, i.e. several tens of nanosecond, in comparison with the pulse width of the fast bank. Therefore, high current density is necessary to realize pinch phenomena within the pulse width. A self-crowbar switch that can be used to produce a slightly larger pulse has been proposed and tested. Experiments using the LIMAY-1 pulsed power generator are reported. The maximum stored energy, the output voltage, the pulse width, and the characteristic impedance are 13 kJ, 600 kV, 70 ns, and 3 Omega , respectively. The discharge starts at radial positions between 8 and 15 mm, after the Ar gas is injected. Then the pinch of the annular plasma occurs. The cathode and anode configurations have significant effects on the development of a homogeneous annular plasma. The discharges are grouped into four kinds of phenomena: vacuum discharges, Z-pinches without and with self-crowbar switches, and no Z-pinch with self-crowbar switches.<>
{"title":"Gas-puff Z-pinch on pulsed power generator with self-crowbar switch","authors":"H. Akiyama, N. Shimomura, K. Takasugi, T. Miyamoto, M. Sato, T. Tazima","doi":"10.1109/PLASMA.1989.166142","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166142","url":null,"abstract":"Recent developments in pulsed power technology have increased interest in gas-puff Z-pinches as soft X-ray sources and for nuclear fusion. The pulse width of the pulsed power is extremely short, i.e. several tens of nanosecond, in comparison with the pulse width of the fast bank. Therefore, high current density is necessary to realize pinch phenomena within the pulse width. A self-crowbar switch that can be used to produce a slightly larger pulse has been proposed and tested. Experiments using the LIMAY-1 pulsed power generator are reported. The maximum stored energy, the output voltage, the pulse width, and the characteristic impedance are 13 kJ, 600 kV, 70 ns, and 3 Omega , respectively. The discharge starts at radial positions between 8 and 15 mm, after the Ar gas is injected. Then the pinch of the annular plasma occurs. The cathode and anode configurations have significant effects on the development of a homogeneous annular plasma. The discharges are grouped into four kinds of phenomena: vacuum discharges, Z-pinches without and with self-crowbar switches, and no Z-pinch with self-crowbar switches.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"515 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132965746","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 : 1989-12-01DOI: 10.1109/PLASMA.1989.166275
J. Ling, M. Barrington, R. Carrera, D. Tesar
An in-vessel remote maintenance system (IVRMS) for the IGNITEX ignition tokamak first-wall system is discussed. The design emphasizes simplicity, reliability, and low cost. Diagnostic hardware, power supplies, and fueling and vacuum systems will be located after the primary shielding so that they will be accessible for maintenance and adjustment between pulses. The essential tasks to be performed by the IVRMS are inspection of first wall and diagnostic penetrations for damage and vacuum leaks and repair of damaged areas by welding and beryllium-spray-coating techniques. Its main element is an articulated boom with nine degrees of freedom, used to position the end effectors to the desired location. Positioning of the end effectors with poloidal precision is obtained by using a guiding jig which will be deployed and attached to the first wall. The control module will be teleoperated with tach-learn capability. A self-transporting storage chamber with internal decontamination capability is envisioned. The feasibility of using frameless, lightweight, self-contained actuator modules with molded, carbon-fiber links is being studied. This design can result in a stiff articulated boom with a compact cross-sectional area suitable for use in the IGNITEX device.<>
{"title":"In-vessel maintenance on the IGNITEX experiment","authors":"J. Ling, M. Barrington, R. Carrera, D. Tesar","doi":"10.1109/PLASMA.1989.166275","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166275","url":null,"abstract":"An in-vessel remote maintenance system (IVRMS) for the IGNITEX ignition tokamak first-wall system is discussed. The design emphasizes simplicity, reliability, and low cost. Diagnostic hardware, power supplies, and fueling and vacuum systems will be located after the primary shielding so that they will be accessible for maintenance and adjustment between pulses. The essential tasks to be performed by the IVRMS are inspection of first wall and diagnostic penetrations for damage and vacuum leaks and repair of damaged areas by welding and beryllium-spray-coating techniques. Its main element is an articulated boom with nine degrees of freedom, used to position the end effectors to the desired location. Positioning of the end effectors with poloidal precision is obtained by using a guiding jig which will be deployed and attached to the first wall. The control module will be teleoperated with tach-learn capability. A self-transporting storage chamber with internal decontamination capability is envisioned. The feasibility of using frameless, lightweight, self-contained actuator modules with molded, carbon-fiber links is being studied. This design can result in a stiff articulated boom with a compact cross-sectional area suitable for use in the IGNITEX device.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123708516","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 : 1989-12-01DOI: 10.1109/PLASMA.1989.166017
M. Werst, M. Driga, K. Hsieh, W. Weldon
The design and analysis of a scaled-down prototype (0.06 scale in linear dimensions) of the toroidal field (TF) magnet of the Texas fusion ignition experiment (IGNITEX) is discussed. The primary goal of the IGNITEX Technology Demonstrator (ITD) is to prove the operation of a low-cost, single-turn, 20-T toroidal coil powdered by the Balcones homopolar generator (HPG) power supply. The selection of the prototype TF coil scale of 0.06 is based on the linear relationship between the current that can be delivered with the Balcones HPG and the need to achieve a 20-T field in IGNITEX. The design philosophy of the magnet has been to use materials with the highest strength and electrical conductivity available and preload it as much as possible. The single-turn coil eliminates the need for turn-to-turn insulation and therefore better utilizes the available inner leg area for stress and thermal management. The objectives of the ITD program are outlined.<>
{"title":"High field, single turn toroidal magnetic technology demonstration for IGNITEX","authors":"M. Werst, M. Driga, K. Hsieh, W. Weldon","doi":"10.1109/PLASMA.1989.166017","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166017","url":null,"abstract":"The design and analysis of a scaled-down prototype (0.06 scale in linear dimensions) of the toroidal field (TF) magnet of the Texas fusion ignition experiment (IGNITEX) is discussed. The primary goal of the IGNITEX Technology Demonstrator (ITD) is to prove the operation of a low-cost, single-turn, 20-T toroidal coil powdered by the Balcones homopolar generator (HPG) power supply. The selection of the prototype TF coil scale of 0.06 is based on the linear relationship between the current that can be delivered with the Balcones HPG and the need to achieve a 20-T field in IGNITEX. The design philosophy of the magnet has been to use materials with the highest strength and electrical conductivity available and preload it as much as possible. The single-turn coil eliminates the need for turn-to-turn insulation and therefore better utilizes the available inner leg area for stress and thermal management. The objectives of the ITD program are outlined.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126245286","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 : 1989-12-01DOI: 10.1109/PLASMA.1989.166067
Y. Nagayama, A. Ejiri, A. Fujisawa, T. Fujita, J. Matsui, K. Miyamoto, K. Saito, Y. Shimazu, K. Shimoji, K. Yamagishi
The impurity ion, proton, and electron temperatures on a reversed field pinch (RFP) and an ultra-low-q (ULQ) plasma in the REPUTE-1 torus device have been measured. Typical examples of ion and the electron temperatures in the RFP plasma are shown. The experimental results are the following: (1) The electron temperature is lower than the proton temperature. (2) The impurity ion temperature is higher than the proton temperature in the low-density RFP plasma. (3) During the q-value transition phase in the ULQ, the impurity temperature becomes quite high, but the proton temperature is unchanged. The results are not expected from the classical Ohmic heating theory. Relaxation and MHD instability are candidates to explain the results.<>
{"title":"Temperature measurements on RFP and ULQ experiments in REPUTE-1","authors":"Y. Nagayama, A. Ejiri, A. Fujisawa, T. Fujita, J. Matsui, K. Miyamoto, K. Saito, Y. Shimazu, K. Shimoji, K. Yamagishi","doi":"10.1109/PLASMA.1989.166067","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166067","url":null,"abstract":"The impurity ion, proton, and electron temperatures on a reversed field pinch (RFP) and an ultra-low-q (ULQ) plasma in the REPUTE-1 torus device have been measured. Typical examples of ion and the electron temperatures in the RFP plasma are shown. The experimental results are the following: (1) The electron temperature is lower than the proton temperature. (2) The impurity ion temperature is higher than the proton temperature in the low-density RFP plasma. (3) During the q-value transition phase in the ULQ, the impurity temperature becomes quite high, but the proton temperature is unchanged. The results are not expected from the classical Ohmic heating theory. Relaxation and MHD instability are candidates to explain the results.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130672899","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 : 1989-12-01DOI: 10.1109/PLASMA.1989.166280
R. Bickerton, W. Booth, R. Carrera, G. Fu, G. Hallock, E. Montalvo, M. Rosenbluth, J. Van Dam
Computer simulations, which provide part of the scientific basis for the design of IGNITEX, show that a volume-averaged temperature of 4 keV can be reached by pure ohmic heating while remaining in stable operating regimes. These predictions are consistent with experimental results of present high-field tokamaks. The experimental program is divided into three phases covering a three year operating period. The first year, after full commissioning of the magnet, vacuum, and data systems, will be used to study plasma shape, position, and profile control and to find optimum operating regimes for the experiment using hydrogen fuel. During this phase, final calibration and refinement of the diagnostics systems will take place. During the second year deuterium fuel will be used in the experiment. Studies of isotope-ratio control will be carried out. Additionally, during these phases, scaling laws for high-density, high-temperature, ohmically heated plasmas will be studied. The first D-T experiments will be performed during the last part of the second year of operation. These will provide limited neutron and alpha production and allow final refinement of neutron and alpha diagnostics. The ignited phase of the experiment will continue throughout the third year. During this time, alpha physics experiments will be conducted.<>
{"title":"Experimental program for the fusion ignition experiment IGNITEX","authors":"R. Bickerton, W. Booth, R. Carrera, G. Fu, G. Hallock, E. Montalvo, M. Rosenbluth, J. Van Dam","doi":"10.1109/PLASMA.1989.166280","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166280","url":null,"abstract":"Computer simulations, which provide part of the scientific basis for the design of IGNITEX, show that a volume-averaged temperature of 4 keV can be reached by pure ohmic heating while remaining in stable operating regimes. These predictions are consistent with experimental results of present high-field tokamaks. The experimental program is divided into three phases covering a three year operating period. The first year, after full commissioning of the magnet, vacuum, and data systems, will be used to study plasma shape, position, and profile control and to find optimum operating regimes for the experiment using hydrogen fuel. During this phase, final calibration and refinement of the diagnostics systems will take place. During the second year deuterium fuel will be used in the experiment. Studies of isotope-ratio control will be carried out. Additionally, during these phases, scaling laws for high-density, high-temperature, ohmically heated plasmas will be studied. The first D-T experiments will be performed during the last part of the second year of operation. These will provide limited neutron and alpha production and allow final refinement of neutron and alpha diagnostics. The ignited phase of the experiment will continue throughout the third year. During this time, alpha physics experiments will be conducted.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"66 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132331252","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 : 1989-12-01DOI: 10.1109/PLASMA.1989.166227
J. Zieliński, G. Hallock
Several recent experiments have heavy-ion-beam-probe diagnostics with analyzers that are located in regions outside of the vacuum system where the magnetic field strength is several hundred gauss or higher. The combination of high secondary particle velocity and high magnetic field inside the analyzer produces magnetic forces that are not negligible when compared to the electric force on these particles. Large errors in the measured plasma potential can result if the magnetic field is not properly taken into account. If the magnetic field is homogeneous, a completely analytic treatment of the analyzer is possible. The analyzer gain and the location and shape of the secondary beam image on the detector plates can be determined without having to calculate the entire trajectory through the analyzer. If the field is not homogeneous, a numerical calculation of the trajectory is necessary.<>
{"title":"Magnetic field effects in electrostatic analyzers used for heavy ion beam probe measurements","authors":"J. Zieliński, G. Hallock","doi":"10.1109/PLASMA.1989.166227","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166227","url":null,"abstract":"Several recent experiments have heavy-ion-beam-probe diagnostics with analyzers that are located in regions outside of the vacuum system where the magnetic field strength is several hundred gauss or higher. The combination of high secondary particle velocity and high magnetic field inside the analyzer produces magnetic forces that are not negligible when compared to the electric force on these particles. Large errors in the measured plasma potential can result if the magnetic field is not properly taken into account. If the magnetic field is homogeneous, a completely analytic treatment of the analyzer is possible. The analyzer gain and the location and shape of the secondary beam image on the detector plates can be determined without having to calculate the entire trajectory through the analyzer. If the field is not homogeneous, a numerical calculation of the trajectory is necessary.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114472100","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 : 1989-05-22DOI: 10.1109/PLASMA.1989.166070
P. Green, S. Robertson
A seven-channel, f14 polychrometer with UV quartz optics has been constructed for ion temperature measurements on the Reversatron II RFP (R/a=50 cm/8 cm). The spectrometer has a focal length of 1.1 m and utilizes an 1800-line/mm grating. The spectrum is spread over a linear array of photomultiplier tubes by a 2-mm-diameter quartz cylinder lens. Resolution is below 0.1 AA, and channel separation is 0.4 AA. Initial measurements have been made in 25-kA helium discharges with no conducting shell surrounding the resistive vacuum chamber. The He I line at 3888 AA, which is predominantly from the plasma edge, indicates T/sub i/ approximately=8 eV. The He II line at 4685 AA, which is less weighted by the edge, indicates T/sub i/ approximately=17 eV. A search is being made for impurity lines that are indicative of the central region of the discharge. Similar measurements will be made with other boundary conditions.<>
在reveratron II RFP (R/ A =50 cm/8 cm)上构建了一个7通道，f14紫外石英光学多色计，用于离子温度测量。光谱仪的焦距为1.1米，采用1800线/毫米光栅。光谱通过直径2毫米的石英柱面透镜分布在光电倍增管的线性阵列上。分辨率低于0.1 AA，通道间隔为0.4 AA。最初的测量是在25ka氦气放电中进行的，在电阻真空室周围没有导电壳。3888aa处的He I线主要来自等离子体边缘，表明T/sub I /约= 8ev。4685 AA处的He II线被边缘加权较小，表示T/sub i/约=17 eV。正在寻找指示放电中心区域的杂质线。类似的测量将在其他边界条件下进行。
{"title":"Ion temperature in the Reversatron II RFP","authors":"P. Green, S. Robertson","doi":"10.1109/PLASMA.1989.166070","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166070","url":null,"abstract":"A seven-channel, f14 polychrometer with UV quartz optics has been constructed for ion temperature measurements on the Reversatron II RFP (R/a=50 cm/8 cm). The spectrometer has a focal length of 1.1 m and utilizes an 1800-line/mm grating. The spectrum is spread over a linear array of photomultiplier tubes by a 2-mm-diameter quartz cylinder lens. Resolution is below 0.1 AA, and channel separation is 0.4 AA. Initial measurements have been made in 25-kA helium discharges with no conducting shell surrounding the resistive vacuum chamber. The He I line at 3888 AA, which is predominantly from the plasma edge, indicates T/sub i/ approximately=8 eV. The He II line at 4685 AA, which is less weighted by the edge, indicates T/sub i/ approximately=17 eV. A search is being made for impurity lines that are indicative of the central region of the discharge. Similar measurements will be made with other boundary conditions.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121809652","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 : 1989-05-22DOI: 10.1109/PLASMA.1989.166258
S. Kuo, Y. S. Zhang
The dynamic behavior of the propagation of high-power microwave pulses depends on the intensity, frequency, and width of the pulse and the physical processes occurring during the interaction of the pulse with the air. An attempt has been made experimentally to single out these processes. The experiment was conducted in a large Plexiglass chamber filled with dry air at various pressures. A microwave pulse was fed into the cube by an S-band microwave horn placed at one side of the chamber. A second S-band horn placed at the opposite side of the chamber was used to receive the transmitted pulse. The microwave power was generated by a magnetron tube driven by a soft tube modulator. The magnetron produces a 1-MW peak output power at 3.2 GHz. The Paschen breakdown condition was determined. Two mechanisms responsible for two different degrees of tail erosion were identified. A self-consistent theoretical model is being developed to describe the experimental results.<>
{"title":"Propagation of high power microwave pulses in the air","authors":"S. Kuo, Y. S. Zhang","doi":"10.1109/PLASMA.1989.166258","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166258","url":null,"abstract":"The dynamic behavior of the propagation of high-power microwave pulses depends on the intensity, frequency, and width of the pulse and the physical processes occurring during the interaction of the pulse with the air. An attempt has been made experimentally to single out these processes. The experiment was conducted in a large Plexiglass chamber filled with dry air at various pressures. A microwave pulse was fed into the cube by an S-band microwave horn placed at one side of the chamber. A second S-band horn placed at the opposite side of the chamber was used to receive the transmitted pulse. The microwave power was generated by a magnetron tube driven by a soft tube modulator. The magnetron produces a 1-MW peak output power at 3.2 GHz. The Paschen breakdown condition was determined. Two mechanisms responsible for two different degrees of tail erosion were identified. A self-consistent theoretical model is being developed to describe the experimental results.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121815209","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 : 1989-05-22DOI: 10.1109/PLASMA.1989.166239
J. Santoru, R. Schumacher
Electron-beam-excited, counterpropagating electron plasma wave (EPWs) interact nonlinearly through the plasma three-wave mixing process to generate electromagnetic radiation at twice the plasma frequency. Radiation saturation is not observed up to beam current densities of 2 A/cm/sup 2/, where the peak power is 8 kW. To investigate the saturation mechanism and maximize the radiation generation efficiency, plasma-cathode electron beams, which can provide up to 20 A/cm/sup 2/ at 30 kV, have been installed. The counterpropagating EPW topology required for three-wave mixing was created using a single high-current-density electron beam by means of a backscattering process. When the background plasma was generated by electron-beam-gas impact ionization, the current density threshold for single-beam radiation emission was about 12 A/cm/sup 2/. Scaling experiments have explored the two-beam and single-beam radiation generation processes.<>
{"title":"Millimeter-wave radiation generated via plasma three-wave mixing using high-current density counter-streaming electron beams","authors":"J. Santoru, R. Schumacher","doi":"10.1109/PLASMA.1989.166239","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166239","url":null,"abstract":"Electron-beam-excited, counterpropagating electron plasma wave (EPWs) interact nonlinearly through the plasma three-wave mixing process to generate electromagnetic radiation at twice the plasma frequency. Radiation saturation is not observed up to beam current densities of 2 A/cm/sup 2/, where the peak power is 8 kW. To investigate the saturation mechanism and maximize the radiation generation efficiency, plasma-cathode electron beams, which can provide up to 20 A/cm/sup 2/ at 30 kV, have been installed. The counterpropagating EPW topology required for three-wave mixing was created using a single high-current-density electron beam by means of a backscattering process. When the background plasma was generated by electron-beam-gas impact ionization, the current density threshold for single-beam radiation emission was about 12 A/cm/sup 2/. Scaling experiments have explored the two-beam and single-beam radiation generation processes.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117140526","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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