Pub Date : 1989-05-22DOI: 10.1109/PLASMA.1989.166240
H. Rappaport, P. Latham, C. Striffler
Mode conversion theory has been applied to one-dimensional reflection in a time-varying inhomogeneous plasma, and numerical results have been obtained. Degenerate mode conversion, i.e. mode conversion between two eigenvectors of a plasma dispersion tensor with the same eigenvalues, can be analyzed using the same techniques as for nondegenerate mode conversion by adding several Maxwell two-fluid unknowns and equations into an initial description of the problem. This procedure has been applied to simple reflection in a slowly varying plasma with no magnetic field. Numerical methods permit evaluation of electric field in a time- and space-varying plasma without the use of mode-coupling theory. A finite-difference code was used to solve for field profiles in a one-dimensional gas cell with a slowly varying plasma density. Results have been obtained above and below the plasma critical density. They have been applied to microwave breakdown in the atmosphere.<>
{"title":"Simple reflection in an ionizing gas cloud","authors":"H. Rappaport, P. Latham, C. Striffler","doi":"10.1109/PLASMA.1989.166240","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166240","url":null,"abstract":"Mode conversion theory has been applied to one-dimensional reflection in a time-varying inhomogeneous plasma, and numerical results have been obtained. Degenerate mode conversion, i.e. mode conversion between two eigenvectors of a plasma dispersion tensor with the same eigenvalues, can be analyzed using the same techniques as for nondegenerate mode conversion by adding several Maxwell two-fluid unknowns and equations into an initial description of the problem. This procedure has been applied to simple reflection in a slowly varying plasma with no magnetic field. Numerical methods permit evaluation of electric field in a time- and space-varying plasma without the use of mode-coupling theory. A finite-difference code was used to solve for field profiles in a one-dimensional gas cell with a slowly varying plasma density. Results have been obtained above and below the plasma critical density. They have been applied to microwave breakdown in the atmosphere.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"144 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":"115373997","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.1989.166057
J. Borovsky
The temporal nature of the particle fluxes to conducting objects that are placed in low-density plasmas and then subjected to fast voltage pulses have been studied. Experimental measurements of the plasma return currents have been compared with theoretical predictions and with estimates of the currents obtained from particle-in-cell computer simulations. By means of the computer simulations, the temporal nature of the kinetic-energy distribution of plasma electrons and ions striking the rapidly biased objects has been examined. By means of computer simulations and laboratory experiments, the perturbations to the plasma by the rapidly charged objects have been studied. These perturbations include density cavity formation very near the objects, caused by particle absorption and particle acceleration, and cavitation away from the objects, driven by the oscillating two-stream instability.<>
{"title":"Laboratory experiments and computer simulations of the interaction of plasmas with rapidly charged objects","authors":"J. Borovsky","doi":"10.1109/PLASMA.1989.166057","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166057","url":null,"abstract":"The temporal nature of the particle fluxes to conducting objects that are placed in low-density plasmas and then subjected to fast voltage pulses have been studied. Experimental measurements of the plasma return currents have been compared with theoretical predictions and with estimates of the currents obtained from particle-in-cell computer simulations. By means of the computer simulations, the temporal nature of the kinetic-energy distribution of plasma electrons and ions striking the rapidly biased objects has been examined. By means of computer simulations and laboratory experiments, the perturbations to the plasma by the rapidly charged objects have been studied. These perturbations include density cavity formation very near the objects, caused by particle absorption and particle acceleration, and cavitation away from the objects, driven by the oscillating two-stream instability.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"11 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":"114171785","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.1989.166228
K. Mizuno, T. Oda, E. Hooper, K. Takiyama, K. Kawasaki, Y. Matsuda
As part of the Microwave Tokamak Experiment (MTX), a method has been developed to measure the spatially resolved microwave electric field in plasmas. It combines laser-induced-fluorescence spectroscopy with a neutral particle beam (laser-aided particle probe spectroscopy). The RF electric field has been previously measured in small laboratory experiments. The MTX plasma, however, has a much higher density and temperature. One of the most difficult problems is to provide a sufficient density of the radiating atoms in the center of the (burned out) plasma. The authors propose that a sufficient density can be obtained with a small helium neutral-beam probe. A dye laser will be used to pump the helium atoms from the metastable level. The metastable helium atoms will be excited when they traverse a tiny metal-vapor chamber, or they will be produced by the collisional excitation in MTX plasma. The microwave electric field in the MTX plasma is expected to be several hundred kilovolts per centimeter. Therefore, the forbidden line will be strongly excited by the Stark effect. The intensity of the forbidden line emission will be measured to estimate the microwave electric field.<>
{"title":"Experimental design of spectroscopic measurements of microwave electric field in MTX tokamak plasma","authors":"K. Mizuno, T. Oda, E. Hooper, K. Takiyama, K. Kawasaki, Y. Matsuda","doi":"10.1109/PLASMA.1989.166228","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166228","url":null,"abstract":"As part of the Microwave Tokamak Experiment (MTX), a method has been developed to measure the spatially resolved microwave electric field in plasmas. It combines laser-induced-fluorescence spectroscopy with a neutral particle beam (laser-aided particle probe spectroscopy). The RF electric field has been previously measured in small laboratory experiments. The MTX plasma, however, has a much higher density and temperature. One of the most difficult problems is to provide a sufficient density of the radiating atoms in the center of the (burned out) plasma. The authors propose that a sufficient density can be obtained with a small helium neutral-beam probe. A dye laser will be used to pump the helium atoms from the metastable level. The metastable helium atoms will be excited when they traverse a tiny metal-vapor chamber, or they will be produced by the collisional excitation in MTX plasma. The microwave electric field in the MTX plasma is expected to be several hundred kilovolts per centimeter. Therefore, the forbidden line will be strongly excited by the Stark effect. The intensity of the forbidden line emission will be measured to estimate the microwave electric field.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"32 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":"114367848","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.1989.166199
K. Kim, W. Choe
A laser-produced plasma in the underdense region (n>
低密度区域(n>)激光产生的等离子体
{"title":"A self-similar modeling and transport analysis of laser-produced coronas","authors":"K. Kim, W. Choe","doi":"10.1109/PLASMA.1989.166199","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166199","url":null,"abstract":"A laser-produced plasma in the underdense region (n<n/sub c/) is known to be well described by the isothermal expansion model. However, most previous work did not include the effects of the self-generated magnetic field (approximately a few megagauss), which is supposed to affect the physical behavior of laser-produced plasmas profoundly. The previous isothermal expansion model has been extended by the authors to include the effects of the self-generated magnetic field. Location of the critical density surface is assumed to be determined exclusively by adiabatic expansion of the overdose region, but the overdense and underdense solutions are matched across the critical density surface. The model has been used to study hot electron transport in the presence of the self-generated magnetic field.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"24 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":"122542901","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.1989.166122
A. Pregenzer, J. Woodworth, T. Lockner, S. Rosenthal, K. Bieg, M. Desjarlais, R. Coats
Summary form only. In order to propagate a lithium ion beam to the axis at PBFA II (Particle Beam Fusion Accelerator II), a specific magnetic field geometry is required. If the ions lose no energy in the gas cell, and if lithium ions originate at the anode in the singly charged state and are stripped to the triply charged state in the gas cell membrane, conservation of canonical angular momentum requires that Psi /sub a/=-2 Psi /sub g/, where Psi is the magnetic field stream function and the subscripts a and g refer to its values at the anode and the gas cell, respectively. When Psi not=0, it has proved difficult experimentally to operate the diode efficiently and reliably. It has been hypothesized that the difficulty is associated with the dynamics of virtual cathode formation. Experiments have been carried out, along with analytical and simulation studies, to elucidate this problem. Factors that appear to be important are the anode surface area, the magnitude and uniformity of the magnetic insulation between the cathode tip and the active anode surface, the amount of radial magnetic flux in the diode feeds, and the magnetic field topology in the diode region. These factors may alter the dynamics of charge accumulation in the diode and thereby affect the timing of ion current.<>
{"title":"Changes in diode operating characteristics as a function of applied magnetic field geometry","authors":"A. Pregenzer, J. Woodworth, T. Lockner, S. Rosenthal, K. Bieg, M. Desjarlais, R. Coats","doi":"10.1109/PLASMA.1989.166122","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166122","url":null,"abstract":"Summary form only. In order to propagate a lithium ion beam to the axis at PBFA II (Particle Beam Fusion Accelerator II), a specific magnetic field geometry is required. If the ions lose no energy in the gas cell, and if lithium ions originate at the anode in the singly charged state and are stripped to the triply charged state in the gas cell membrane, conservation of canonical angular momentum requires that Psi /sub a/=-2 Psi /sub g/, where Psi is the magnetic field stream function and the subscripts a and g refer to its values at the anode and the gas cell, respectively. When Psi not=0, it has proved difficult experimentally to operate the diode efficiently and reliably. It has been hypothesized that the difficulty is associated with the dynamics of virtual cathode formation. Experiments have been carried out, along with analytical and simulation studies, to elucidate this problem. Factors that appear to be important are the anode surface area, the magnitude and uniformity of the magnetic insulation between the cathode tip and the active anode surface, the amount of radial magnetic flux in the diode feeds, and the magnetic field topology in the diode region. These factors may alter the dynamics of charge accumulation in the diode and thereby affect the timing of ion current.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"25 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":"122586014","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.1989.165969
O. Hankins, M. Bourham, O. Auciello, J. Stock, J. Gilligan, B. Wehring
Summary form only. The plasma device called SIRENS was designed and constructed to study the phenomena occurring during the interaction of a high-heat flux with a material surface. The device works on the same principle as an electrothermal mass accelerator. A plasma is produced by the ablation of an insulating cylindrical sleeve of Lexan between two tungsten alloy electrodes. The plasma is joule-heated by currents of up to 100 kA and pressure-driven through a stainless steel barrel. A cylindrical material sample (aluminum or Lexan) is placed inside the barrel. A series of experiments were performed to study the erosion/ablation process of the Lexan insulator sleeve and the barrel samples (aluminum and Lexan) for different discharge energies. Erosion measurements were made by individually weighing the sample sections. Selected sections were analyzed using SEM and EDXA, and optical emission spectroscopy of visible light was performed. Other diagnostics used included Rogowski coils, B-dot probes, high-voltage probes, and pressure transducers. The ablation of the Lexan insulator sleeve compared well with predicted results for 10% transmission of heat flux to the surface.<>
{"title":"Parametric studies of high-heat-flux-induced erosion of surfaces in an electrothermal accelerator","authors":"O. Hankins, M. Bourham, O. Auciello, J. Stock, J. Gilligan, B. Wehring","doi":"10.1109/PLASMA.1989.165969","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.165969","url":null,"abstract":"Summary form only. The plasma device called SIRENS was designed and constructed to study the phenomena occurring during the interaction of a high-heat flux with a material surface. The device works on the same principle as an electrothermal mass accelerator. A plasma is produced by the ablation of an insulating cylindrical sleeve of Lexan between two tungsten alloy electrodes. The plasma is joule-heated by currents of up to 100 kA and pressure-driven through a stainless steel barrel. A cylindrical material sample (aluminum or Lexan) is placed inside the barrel. A series of experiments were performed to study the erosion/ablation process of the Lexan insulator sleeve and the barrel samples (aluminum and Lexan) for different discharge energies. Erosion measurements were made by individually weighing the sample sections. Selected sections were analyzed using SEM and EDXA, and optical emission spectroscopy of visible light was performed. Other diagnostics used included Rogowski coils, B-dot probes, high-voltage probes, and pressure transducers. The ablation of the Lexan insulator sleeve compared well with predicted results for 10% transmission of heat flux to the surface.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"36 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":"125408462","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.1989.166222
A. Zigler
An ambient plasma with a low temperature (<10 eV) and high density (>10/sup 19/ cm/sup -3/) is formed from a rectangular slot in a capillary discharge. This plasma, moving at approximately 2*10/sup 6/ cm/s, exits out of a 1-cm-long, 200- mu m-wide slit. A high-energy Q-switched laser in a cylindrical focusing geometry irradiates the ambient plasma, creating a rectangular parallelepiped of laser-heated plasma. The geometry, initial conditions, and versatility of this source are suited to the generation of amplified soft X-ray lasing along the 1-cm length. The capillary-discharge-produced ambient plasma lasts on the order of 8 mu s, during which an ambient plasma is being produced and will replace the heated plasma approximately every 10 ns. Thus, one can create in a single event, i.e. capillary discharge and laser-pulse chain, numerous heated plasma pulses. In the current work, a mode-locked laser was used to produce a train of many pulses at the oscillator. Instead of switching out a single pulse, three pulses were switched out from the laser oscillator and delivered to a chain of amplifiers. This chain of laser pulses, spaced at intervals >10 ns, is focused onto the ambient plasma. This method can be used to construct an X-ray laser cavity.<>
{"title":"X-ray laser cavity based on multiple pulse laser excitation of capillary discharge","authors":"A. Zigler","doi":"10.1109/PLASMA.1989.166222","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166222","url":null,"abstract":"An ambient plasma with a low temperature (<10 eV) and high density (>10/sup 19/ cm/sup -3/) is formed from a rectangular slot in a capillary discharge. This plasma, moving at approximately 2*10/sup 6/ cm/s, exits out of a 1-cm-long, 200- mu m-wide slit. A high-energy Q-switched laser in a cylindrical focusing geometry irradiates the ambient plasma, creating a rectangular parallelepiped of laser-heated plasma. The geometry, initial conditions, and versatility of this source are suited to the generation of amplified soft X-ray lasing along the 1-cm length. The capillary-discharge-produced ambient plasma lasts on the order of 8 mu s, during which an ambient plasma is being produced and will replace the heated plasma approximately every 10 ns. Thus, one can create in a single event, i.e. capillary discharge and laser-pulse chain, numerous heated plasma pulses. In the current work, a mode-locked laser was used to produce a train of many pulses at the oscillator. Instead of switching out a single pulse, three pulses were switched out from the laser oscillator and delivered to a chain of amplifiers. This chain of laser pulses, spaced at intervals >10 ns, is focused onto the ambient plasma. This method can be used to construct an X-ray laser cavity.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"15 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":"125430313","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.1989.166000
J. Booske, D. Radack, T. Antonsen, S. Bidwell, W. Destler, V. Granatstein, P. Latham, B. Levush, I. Mayergoyz, A. Serbeto, Z. X. Zhang, H. Freund
The authors have reported on the status of their program to develop a high-average-power (0.1-1.0 MW), millimeter-wave (0.5 mm>
作者报告了他们开发高平均功率(0.1-1.0 MW)，毫米波(0.5 mm>
{"title":"Progress in high-power millimeter-wave FELs with short period wigglers and sheet electron beams","authors":"J. Booske, D. Radack, T. Antonsen, S. Bidwell, W. Destler, V. Granatstein, P. Latham, B. Levush, I. Mayergoyz, A. Serbeto, Z. X. Zhang, H. Freund","doi":"10.1109/PLASMA.1989.166000","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166000","url":null,"abstract":"The authors have reported on the status of their program to develop a high-average-power (0.1-1.0 MW), millimeter-wave (0.5 mm<or= lambda <or=2.0 mm) FEL using a short-period wiggler (0.5 cm <or=l/sub w/<or=1.5 cm) and a sheet electron beam (V/sub b/<or=1 MV). Results on the transmission of wiggler-focused sheet beams through narrow waveguide gaps have been obtained, and detailed theoretical simulations and experimental measurements have been carried out. The authors have also described recent achievements in wiggler magnet development and two proof-of-principle FEL experiments.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"62 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":"126273835","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.1989.166101
W. Byszewski
High-current-density diffuse discharges in high-pressure, electronegative gas mixtures have been studied in an impedance-matched (50 Omega ) transmission line system. A traveling voltage waveform with an amplitude up to 40 kV, a risetime of 2 ns, and a total pulse width of 100 ns was used. Gas mixtures of C/sub 3/F/sub 8/ and He in the pressure range between 100 and 600 torr were investigated in a uniform field formed by plane parallel electrodes. The low-current-density diffuse discharge operates at a constant voltage. At a current density of about 100 A/cm/sub 2/ and higher additional ionization processes related to power loading cause the operating voltage to drop. A further increase in current density would, however, enhance the recombination rate, causing the operating voltage to rise. The objective of this work was to identify the minimum operating voltage and corresponding current density. A decrease in the operating (E/N)s of a diffuse discharge in a 50:50 mixture of C/sub 3/F/sub 8/:He is shown as a function of reduced current density. Additional decreases of (E/N)/sub s/ observed during the discharge are indicated. Both results are a consequence of power loading.<>
{"title":"Voltage-current characteristics of a high current diffuse discharge","authors":"W. Byszewski","doi":"10.1109/PLASMA.1989.166101","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166101","url":null,"abstract":"High-current-density diffuse discharges in high-pressure, electronegative gas mixtures have been studied in an impedance-matched (50 Omega ) transmission line system. A traveling voltage waveform with an amplitude up to 40 kV, a risetime of 2 ns, and a total pulse width of 100 ns was used. Gas mixtures of C/sub 3/F/sub 8/ and He in the pressure range between 100 and 600 torr were investigated in a uniform field formed by plane parallel electrodes. The low-current-density diffuse discharge operates at a constant voltage. At a current density of about 100 A/cm/sub 2/ and higher additional ionization processes related to power loading cause the operating voltage to drop. A further increase in current density would, however, enhance the recombination rate, causing the operating voltage to rise. The objective of this work was to identify the minimum operating voltage and corresponding current density. A decrease in the operating (E/N)s of a diffuse discharge in a 50:50 mixture of C/sub 3/F/sub 8/:He is shown as a function of reduced current density. Additional decreases of (E/N)/sub s/ observed during the discharge are indicated. Both results are a consequence of power loading.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"1 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":"129570657","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.1989.166063
M. Cho, N. Hershkowitz, T. Intrator
The plasma potential is typically assumed to float above an anode potential by an amount that is a few times the electron temperature (T/sub e//e). The difference between the plasma potential and the anode potential can be estimated by considering the particle production and loss. However, it has been reported experimentally that the plasma potential of a steady-state plasma can be more negative than the anode potential with a potential dip ( approximately T/sub e//e) in front of the anode. Particle and power balances have been carried out to estimate the bulk plasma potential of a hot-filament discharge plasma produced in a multidipole plasma device. The bulk plasma potential dependence on the positive DC bias applied to the anode is analyzed, and the predicted characteristics of the plasma potential dependence are compared to the experimental results. A steady-state potential dip in front of the anode has been experimentally observed using emissive probes with the zero emission inflection point method, and the conditions for the potential dip formation have been derived.<>
{"title":"Particle and power balances of hot-filament discharge plasmas in a multi-dipole device in the presence of a positively biased electrode","authors":"M. Cho, N. Hershkowitz, T. Intrator","doi":"10.1109/PLASMA.1989.166063","DOIUrl":"https://doi.org/10.1109/PLASMA.1989.166063","url":null,"abstract":"The plasma potential is typically assumed to float above an anode potential by an amount that is a few times the electron temperature (T/sub e//e). The difference between the plasma potential and the anode potential can be estimated by considering the particle production and loss. However, it has been reported experimentally that the plasma potential of a steady-state plasma can be more negative than the anode potential with a potential dip ( approximately T/sub e//e) in front of the anode. Particle and power balances have been carried out to estimate the bulk plasma potential of a hot-filament discharge plasma produced in a multidipole plasma device. The bulk plasma potential dependence on the positive DC bias applied to the anode is analyzed, and the predicted characteristics of the plasma potential dependence are compared to the experimental results. A steady-state potential dip in front of the anode has been experimentally observed using emissive probes with the zero emission inflection point method, and the conditions for the potential dip formation have been derived.<<ETX>>","PeriodicalId":165717,"journal":{"name":"IEEE 1989 International Conference on Plasma Science","volume":"1 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":"130546312","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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