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Plasma Science, IEEE Transactions on

Issue 4 • Date Aug. 2007

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Displaying Results 1 - 25 of 32
  • Table of contents

    Publication Year: 2007 , Page(s): C1 - 853
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  • IEEE Transactions on Plasma Science publication information

    Publication Year: 2007 , Page(s): C2
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  • Special Issue on Electrical Discharges in Vacuum

    Publication Year: 2007 , Page(s): 854 - 855
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  • Development of High-Voltage Vacuum Circuit Breakers in China

    Publication Year: 2007 , Page(s): 856 - 865
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1768 KB) |  | HTML iconHTML  

    This paper introduces research work on the development of high-voltage (HV) vacuum circuit breakers (VCBs) in China from its starting point in 1989 to 2006. In this period, a 126-kV two-breaks VCB prototype and a 126-kV single-break VCB prototype were developed. A latest 252-kV single-break interrupter prototype is introduced. Five HV VCBs technologies are discussed, which include HV vacuum insulation, high current interrupting technology with long contact gaps, increasing nominal current, operating mechanism characteristics, and contact bouncing damping. In vacuum insulation, adding a metal ring at the electrode back can decrease breakdown possibilities in the gap between the electrode back and the main shield. A surface melting layer of contact material could have an influence on voltage withstanding capability of a vacuum gap. For interrupting high current with long contact gaps, a strong axial magnetic field (AMF) is needed for better vacuum arc control. Therefore, a single coil AMF electrode is introduced. Heat radiators are effective to increase the nominal current of VCBs. Thermal analysis can help to give appropriate design parameters. There is an optimum opening characteristic that is helpful to improve the interrupting performance of VCBs. Permanent magnet operating mechanism and spring-type operating mechanism are suitable for HV VCBs. Contact bouncing in HV VCBs can be damped by installing contact spring and bellows on the stationary end of VCBs. View full abstract»

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  • Moving Arc Study and Plasma Diagnosis in Vacuum Interrupters With TMF Contacts

    Publication Year: 2007 , Page(s): 866 - 872
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (757 KB) |  | HTML iconHTML  

    Electrical and optical investigations are focused on a vacuum circuit breaker study. The short-circuit regime in the low-voltage network is exactly reproduced by a specific test circuit. The analysis of the phenomena during the high-current evolution and on the current-zero zone is made for the purpose of increasing the breaking capability of this kind of equipment. The displacement speed of the arc column on the surface of the contact pieces in the case of the transverse magnetic field solution is correlated with the spatial and temporal plasma diagnostic. For post-arc current being an important element defining the quality of the short-circuit interruption process, specific measurements are also performed. For better understanding of the high-current interruption in vacuum, the experimentally studied phenomena are mathematically modeled. View full abstract»

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  • Conditioning of Series Vacuum Interrupters (VIs) for Medium Voltage by Applying High-Frequency (HF) Current to Increase the Dielectric Strength of VIs

    Publication Year: 2007 , Page(s): 873 - 878
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (476 KB) |  | HTML iconHTML  

    According to well-known standards, e.g., IEC 62271-100, vacuum circuit breakers and particularly vacuum interrupters (VIs) have to fulfill miscellaneous forms of dielectric strength requirements depending on the rated voltage. Besides conventional conditioning methods, e.g., with alternating current, further techniques have to be investigated in the case of higher voltage levels. This paper describes the high-frequency (HF) current conditioning method with the objective to increase the dielectric strength of modern and very compact VIs for medium voltage applications. A test setup for conditioning of VIs in kilohertz range is presented. The conditioning current has peak values up to 10 kA, with durations of microseconds and voltages up to 135 kV (peak). The dielectric properties of the investigated VIs are described with emphasis on the obtainable lightning impulse withstand voltage level after one or more HF sequences. In addition, the surface microtopography and roughness of contact surfaces are analyzed by means of scanning electron and atomic force microscopy before and after applying HF conditioning. View full abstract»

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  • Withstand Voltage Characteristics of Two Series Vacuum Interrupters

    Publication Year: 2007 , Page(s): 879 - 884
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (486 KB) |  | HTML iconHTML  

    To realize the high-voltage vacuum circuit breaker, we investigated the voltage-distribution ratio after current interruption at the double-break vacuum circuit breaker. We used the spiral CuCr (20%) electrodes and the axial magnetic-field CuCr (50%) electrodes as the experimental electrodes. At the double-break vacuum circuit breaker, where two vacuum interruptions that had the same and different characteristics of the electrode structure and contact materials were connected in series, there was a bias in the voltage-distribution ratio of each vacuum interrupter after current interruption. This seems to be because there was difference in the postarc current that passed through each vacuum interrupter after current interruption. View full abstract»

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  • Charge and Velocity Distribution of Ions Emitted From Two Simultaneously Operating and Serially Connected Vacuum Arcs

    Publication Year: 2007 , Page(s): 885 - 890
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    Ion velocity distribution (IVD) and ion charge state distribution of silver ions in a plasma beam emitted by two compact, serially connected, and simultaneously operating vacuum arcs were measured using a dynamic time-of-flight diagnostics. The anode and cathode of each arc were made of two strips of silver layers pasted on an alumina wafer and separated by a narrow 100-mum gap. The two arcs were laterally separated by 0.015 m and located on the same horizontal plane, emitting two plasma plums, which merged into a single one and is few centimeters away from the arcs. Each arc was ignited by high- voltage breakdown on the alumina surface gap by 3-mus 100-A current. The IVD of the merged plasma beam was analyzed 0.7 m away from the arcs and compared with that of the ions emitted by a single arc. When only a single arc was active, the plasma beam consisted of more than 90% of Ag ions with an average velocity of langv1rang = (0.7-0.8) times 104 m/s and charge state z = 1. About 10% of the beam ion population consisted of oxygen and carbon. When the two arcs operated simultaneously, the form of the IVD was significantly different, containing a second peak with a velocity of langvpeakrang = (1.15-1.25) times 104 m/s, which is significantly higher than that observed with a single arc. However, the integrated ion charge in the merged beam was lower by 30% from the sum of the ion charge obtained from the plasma of each arc. It was found that the observed phenomena were correlated with a formation of conducting channel between the cathode of the first serially connected arc and the anode of the second arc, which is occurring when the plasma plums are expanding from the two arcs merged. When a physical barrier was inserted between the two arcs to prevent a contact between the two expanding plums, the observed plasma shunting did not occur, although the two beams merged in space beyond the barrier, as before. The effect on the IVD due to arc tra- nsfer from the first cathode to the second arc anode is currently being investigated. View full abstract»

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  • Delay Characteristics and Controller Design of a Triggered Vacuum Switch

    Publication Year: 2007 , Page(s): 891 - 896
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (442 KB) |  | HTML iconHTML  

    Two types of triggered vacuum switches (TVSs) named TVS-1 and TVS-2 with different configuration in trigger unit were described for investigating the delay characteristics. A design circuit for controlling the TVS is proposed herein. The trigger energy of the controller can be adjusted conveniently. By means of changing the trigger energy, the experimental data show that the delay and jitter times decrease with increasing trigger energy. The delay and jitter times decreases magnificently with the increasing voltage in the main gap. By increasing the main-gap voltage, the triggered probability increases. The TVS-2 has better performance in delay characteristics than TVS-1 because of the improvement in the trigger structure. With a trigger energy of 0.064 J, it is possible to fire both of the TVSs. For the TVS-2 case, the delay time decreases to 2.3 mus, and its jitter time decreases to 1.2 mus when the trigger energy is 1.6 J. View full abstract»

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  • Mathematical Model of the Vacuum Arc in an External Axial Magnetic Field

    Publication Year: 2007 , Page(s): 897 - 904
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB) |  | HTML iconHTML  

    A physical model of a vacuum arc is developed, which is used to construct a 1-D model and a 2-D two-fluid mathematical model. The 1-D model is based on the principle of compensation of radial magnetic forces. This model is used to derive analytical expressions for the critical values of current Icr and of the external magnetic field Bcr, which define the range of steady passage of current. The model describes both supersonic and subsonic modes of plasma flow. The possibilities of coexistence of these modes are discussed. The 2-D magnetohydrodynamic model is based on the method of trajectories, where a set of partial equations is reduced to a set of ordinary differential equations that are written for derivatives along the lines of the total current. The 2-D model is used to calculate supersonic flows of current for different geometries of the discharge gap and different magnitudes of the external magnetic field B0. Two-dimensional distributions of discharge parameters are obtained, including those of magnetic field components in view of the magnetic field of the Hall current. The distributions of current density are calculated, as well as the dependences Icr(B0) which tend to saturate in high values of B0. View full abstract»

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  • Numerical Simulation of a Moving High-Current Vacuum Arc Driven by a Transverse Magnetic Field (TMF)

    Publication Year: 2007 , Page(s): 905 - 911
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (717 KB) |  | HTML iconHTML  

    This paper deals with the numerical simulation of the constricted high-current vacuum arc (>15 kA), driven by a transverse magnetic field (TMF), as found in vacuum circuit breakers applying the TMF arc control. The magnetohydrodynamic approach, together with the detailed heat transfer and evaporation equations for the electrodes, is used to describe the arc behavior self-consistently, restricted to 2-D. A newly developed model describes the cathode attachment of the constricted arc, as a large laterally extended foot points, instead of regular cathode spots. The arc maintains itself when the electrode temperatures are higher than 3400 K on the cathode and 2900 K on the anode. This model leads to the characterization of the physical quantities of the arc plasma and describes the arc motion. A stepwise movement of the arc results due to different instantaneous velocities of the current attachment areas at the cathode and anode. View full abstract»

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  • A PIC-MCC Simulation of the High-Voltage Interruption Ability of a Vacuum Interrupter

    Publication Year: 2007 , Page(s): 912 - 919
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (403 KB) |  | HTML iconHTML  

    In order to examine the ultimate high-voltage interruption ability of a vacuum interrupter, a particle in cell-Monte Carlo collision computer simulation was conducted under the following conditions. Residual charged and neutral particles at current zero were arranged between the electrodes. The particle conditions were obtained from an extrapolated value of experimental data. Secondary electron emission and self-sputtering effects due to ion bombardment were also considered for the simulation. The simulation voltage, which also represents the recovery voltage, was applied between the electrodes. From the results of a simulation on a 168-kV/25-kA 40-mm-diameter one-break interrupter, it was found that the breaking ability is most influenced by the initial neutral particle density. The charged particle density and the secondary electron emission coefficient were found to have a lesser effect on the breaking capability. Consequently, it is estimated that the self-sputtering coefficient from ion bombardment is one of the most important parameters for metal vapor supply after current zero. View full abstract»

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  • Simulation of the Thermal Process of Anode in Drawn Vacuum Arc

    Publication Year: 2007 , Page(s): 920 - 924
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (221 KB) |  | HTML iconHTML  

    In this paper, a transient 2-D finite-element model was developed to simulate the anode activities of drawn vacuum arc. Some important thermal processes of anode, e.g., the temperature distribution, melt, and evaporation, have been investigated for copper vacuum arc of 27.5 kA (rms) with different separation current. The dimension of eroded region on anode due to melt and evaporation was simulated and compared with other experiments. View full abstract»

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  • Vacuum Circuit Breaker Postarc Current Modelling Based on the Theory of Langmuir Probes

    Publication Year: 2007 , Page(s): 925 - 932
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (300 KB) |  | HTML iconHTML  

    High-resolution measurements on the postarc current in vacuum circuit breakers (VCBs) reveal a period, immediately following current-zero, in which the voltage remains practically zero. The most widely used model for simulating the interaction between the postarc current with the electrical circuit lacks a proper explanation for this event, and hence, it needs to be complemented. We demonstrate that the breaker's electrical behavior during this zero-voltage period can be explained by using the theory of a Langmuir probe. Such probes are used to investigate plasma properties such as the ion density and the electron temperature, and we extrapolate its theory to the VCB. After the voltage-zero period, when the transient recovery voltage starts to rise, the breaker's electrical behavior is mainly determined by the expansion of an ionic space-charge sheath in front of the cathode. In addition to the current from the Langmuir probe model, the time change of the electric field inside the sheath gives a displacement current. Instead of solving the complicated plasma equations to find the displacement current, we use an approximation by simulating it with the aid of a voltage-dependent sheath capacitance. We programmed the model as a function block in Matlab's SimPowerSystems to facilitate its application in different electrical circuits. View full abstract»

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  • Interaction of a Vacuum Arc With an SF6 Arc in a Hybrid Circuit Breaker During High-Current Interruption

    Publication Year: 2007 , Page(s): 933 - 938
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (682 KB) |  | HTML iconHTML  

    A hybrid circuit breaker consists of a series-connected vacuum- and SF6 interrupter. The vacuum interrupter has the function to withstand very steep-rising transient recovery voltages, whereas the SF6 interrupter is stressed with the peak of it. Full scale tests are described of a 145-kV prototype, which is subjected to short-line faults based on 63 kA. During these tests, current through the breaker and voltages across both interrupters were monitored with a high-resolution measurement system. It is shown that the principal idea works correctly. From measured results, it is demonstrated that the interaction between the two arcs of completely different physical nature has a positive effect on the interruption: Immediately before current zero, the SF6 arc assists the vacuum arc to interrupt, whereas after current zero, the vacuum arc assists the SF6 arc in the recovery against the recovery voltage. From the analysis of the measurements, it becomes clear that high values of post arc current (up to 30 A) have (at least initially) a positive effect on the breaker performance. Detailed modeling of the interaction of arc-arc and arc-circuit is described, showing a good agreement with the measured results. The model is used to predict the voltage distribution across both interrupters when other (capacitive) voltage grading is applied in the design than present during the tests. View full abstract»

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  • High-Current Vacuum Arc in a Strong Axial Magnetic Field

    Publication Year: 2007 , Page(s): 939 - 945
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (366 KB) |  | HTML iconHTML  

    The high-current vacuum arcs (HCVA) with high average current densities (J0 les 3 kA/cm2) in strong axial magnetic fields (AMFs) Bn les 1.2 T were studied. The typical V-shape of Volt-Tesla characteristic (VTC) has been shown to retain in strong AMF and at raising the current density, the quantitative parameters change, though. The nature and causes of the changes are discussed. The main factors to define VTC in strong AMF have been shown to be the electrode material and the arc length. It has been confirmed the conclusion of our previous work that, in strong AMF, the cathode attachment size for an arc in a quasi-stationary state is defined by AMF induction and arc length. The quantitative comparison of VTC and voltage of a low-current arc under the action of magnetic field, inclined to the arc axis, encounters difficulties arising in describing of HCVA as an aggregate of independent cathode jets at moderate values of the AMF induction. View full abstract»

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  • Effect of Amplitude and Inclination of Magnetic Field on Low-Current Vacuum Arc

    Publication Year: 2007 , Page(s): 946 - 952
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (287 KB) |  | HTML iconHTML  

    This paper dealt with the investigation of a vacuum arc of the length 0 les h les 10 mm with the current 30 les I les 300 A, which burned at electrodes of HCOF Cu and CuCr30 composition. The dependence of such characteristics as mean current passed by a cathode spot Is and average arc-burning voltage U on the amplitude of the induction vector of external uniform magnetic field Boarr = Boarrn + Boarrt and its inclination angle alpha to the axis perpendicular to the electrode surfaces was investigated. At alphararrpi/2, Is has been found to be strongly dependent on the amplitude of vector B, but at moderate values of alpha, the dependence of Is on B practically vanishes. The arc voltage was noisy. The low-frequency (104-105 Hz) variation of the arc voltage at fixed I and B was found to correlate with the structure of the cathode attachment - the number of separately existing spots. Depending on arc current I and on alpha, variation of the number of spots may bring about both growth and drop of the low-frequency voltage by as much as ~volt. The dependence of average arc voltage U on Bn at fixed current J was studied at different values of Bt. The curves have been shown to distinctly split into three portions: a rapid drop (portion 1), a constancy (portion 2), and a slow (square-rootlike) growth (portion 3) of the voltage. Transition from portions 1 to 2 takes place at certain values of magnetic-field inclination angle alpha1 and transition from portions 2 to 3 at alpha2. It has been shown that alpha2 is strongly dependent on the electrode material, whereas alpha1 is practically independent of it. The characteristic values of alpha have been found to be (weakly) dependent on the arc length. The obtained results are of interest not only for better understanding of the processes in low-current arcs but also for the explanation of r- egularities that define the behavior of high-current vacuum arcs stabilized by axial magnetic fields. View full abstract»

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  • Studies of the Stable Stage of the Electric Arc Burning at the Contact Separation in a Vacuum Gap With a Transverse Magnetic Field

    Publication Year: 2007 , Page(s): 953 - 958
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (318 KB) |  | HTML iconHTML  

    Experimental studies have been carried out on characteristics of the direct current vacuum arc during contact separation in axially symmetrical magnetic field that has predominantly a radial component. The study results on the dynamics of the plasma flow and voltage at the vacuum arc are presented for the stable stage of the arc at currents in the range of 50-300 A. Experimental relationships between the stable stage duration and the values of the current and the induction of the magnetic field are obtained. The performed studies enabled to determine and interpret typical peculiarities of the development of the stable stage of vacuum arc during the contact separation. It is shown that during the contact separation the voltage of the arc increases slowly from 15 to 25-30 V up to the transition into unstable stage of the arc. In this period, one discharge channel burns in the intercontact gap. The duration of the stable stage has a statistical character and its average value increases with current and decreases with the radial component of magnetic field induction. The observed phenomena are explained in terms of a 1-D stationary model of plasma flow in the transverse magnetic field. The instability is caused by a crisis in the plasma flow resulting from the decrease of velocity of fast cathode ions to the ion-sound velocity. The calculations of the stable stage duration of arc burning made within this model are in fair agreement with the obtained experimental results. View full abstract»

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  • Effect of Axially Symmetric Magnetic Fields for Dynamics of Low-Current DC Vacuum Arc Plasma

    Publication Year: 2007 , Page(s): 959 - 965
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (756 KB) |  | HTML iconHTML  

    In this paper, effects of four types of axially symmetric magnetic fields on the dynamics of low-current dc vacuum arc plasma, which is less than 30 A, were examined. Arcs were ignited by the opening of the butt contacts made of zinc. In the axial magnetic field, the arc plasma was restricted within a column, and the arc voltage rose with increasing gap length. When a magnet was arranged behind the cathode, the cathode spot rotated in the opposite direction to the Lorentz force (-J times B) on the edge of the circular-rod cathode. On the other hand, when a magnet was arranged behind the anode, the arc plasma was constricted on the anode side, and the lifetimes of the arcs became longer, although the arc voltage rose with increasing gap length. The compression effect of the axial component of the magnetic field was analyzed by introducing a simple magnetic piston model, and the experimental diameters of the arc column showed a good agreement with the model. View full abstract»

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  • Transient Cathode Spot Operation at a Microprotrusion in a Vacuum Arc

    Publication Year: 2007 , Page(s): 966 - 972
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB) |  | HTML iconHTML  

    A physical model and system of equations was formulated to describe transient cathode spot evolution at a single protrusion. The model considered the self-consistent processes including protrusion heating, kinetics of cathode vaporization, plasma generation, and current continuity. The time dependencies of spot current, current density, and protrusion size were calculated, taking into account the heat flux from the plasma (surface heat source) and Joule energy (volume source). The plasma density, temperature, degree of vapor ionization, electron current fraction, and cathode erosion rate were calculated as functions of the protrusion size, which reduced in time during the spot operation. It was shown that the spot operation on the protrusion was limited by the disappearance of the protrusion due to cathode erosion. The protrusion disappearance time determined the duration of the transient arc spot at a single protrusion. It was calculated that 1-5 mum protrusions reduce their size significantly due to evaporation in 0.5-10 mus, respectively. The smaller time of protrusion destruction occurs due to it relatively high heating, which was mostly by the heat flux from the surrounding plasma. View full abstract»

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  • Measurement of Ion Flux as a Function of Background Gas Pressure in a Hot Refractory Anode Vacuum Arc

    Publication Year: 2007 , Page(s): 973 - 979
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (318 KB) |  | HTML iconHTML  

    The hot refractory anode vacuum arc (HRAVA) is a metallic plasma source in which plasma expands radially from the interelectrode gap and may deposit substrates circumferentially disposed around the electrode axis. The dependence of copper ion flux expanding from the HRAVA interelectrode gap was determined as a function of background gas pressure. The fraction of the ion flux in the radially expanding plasma flux was obtained by measuring the ion current and the film thickness. Experiments were conducted with arc currents of 145-250 A, a molybdenum anode, and an electrode separation of about 10 mm. The saturation ion current was measured with a circular flat probe with 10-mm diameter biased at -30 V with respect to the anode. It was found that the collected ion current in vacuum was almost constant during the first 30 s of the arc - ~2.5 mA/cm2 at a distance of 110 mm from the arc axis, with an arc current of 200 A, and increased to a steady-state value in the developed HRAVA (t > 40 s) of ~5.5 mA/cm2. The measured ion current in argon, nitrogen, and helium environments and the deposition rate in nitrogen remained approximately constant with background gas pressure up to some critical pressure and, then, decreased with pressure eventually reaching zero. The critical pressures were 2, 4, and 10 Pa for argon, nitrogen, and helium, respectively. The critical nitrogen pressure for the deposition rate was 2 Pa in contrast with 4 Pa for the ion current. The ion fraction in total deposition flux was 0.6 in vacuum and decreased with nitrogen pressure, except that a local maximum of ~0.8 was observed at ~13 Pa. View full abstract»

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  • Droplets Evaporation in Vacuum Arc Plasma

    Publication Year: 2007 , Page(s): 980 - 985
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (394 KB) |  | HTML iconHTML  

    A method of cleaning vacuum arc plasma from the droplet fraction of cathode erosion by creating conditions favorable for ignition and further operation of "droplet spots" in plasma is proposed. Such conditions are realized in the reflective arc discharge. Plasma of this discharge has substantially higher temperature and density in comparison with plasma of usual vacuum arc at the same current. The experiments performed have shown that, in contrast with the usual vacuum arc, arc at the reflective discharge mode results in several times decrease in the number of droplets residuary after passage through plasma. The experimental results are being discussed in the term of heat exchange between droplets and surrounding plasma. The method proposed opens up new possibilities of cleaning vacuum arc plasma from droplets. View full abstract»

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  • Plasma Devices Based on the Plasma Lens—A Review of Results and Applications

    Publication Year: 2007 , Page(s): 986 - 991
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (638 KB) |  | HTML iconHTML  

    We review some novel developments of the electrostatic plasma lens and some new plasma devices based on the plasma-optical idea of magnetic insulation of electrons and equipotentialization along magnetic field lines. The plasma lens configuration of crossed electric and magnetic fields provides an attractive and simple method in establishing a stable plasma discharge at low pressure and has been used to develop some cost-effective low-maintenance plasma devices for ion cleaning, surface activation, and polishing of substrates prior to film deposition. Recent embodiments of these devices use permanent magnets and possess considerable flexibility with respect to spatial configuration. View full abstract»

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  • Review of Cathodic Arc Deposition for Preparing Droplet-Free Thin Films

    Publication Year: 2007 , Page(s): 992 - 999
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1054 KB) |  | HTML iconHTML  

    Cathodic arc plasma is one of the potential ion plating physical vapor deposition methods to prepare protective coatings on cutting tools, metal mold, etc. In particular, TiN, CrN, and TiAlN films are coated on industrial cutting tools using cathodic arc plasma. However, the cathode spot of the vacuum arc generates macrodroplets as coproducts of cathodic arc plasma containing high-energy ions. These macrodroplets may pose problems with smooth-surface films that are used for advanced high-precision applications. This paper reviews cathode phenomena particularly for a graphite cathode, the techniques for reduction of macrodroplet generation, and the techniques for macrodroplet removal from the processing plasma. The reduction technique includes steered arc, pulsed arcs, etc. The removal technique includes shielded arcs and filtered arcs. Recent filtered arc deposition systems are referred. View full abstract»

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  • Purity of Nb and Pb Films Deposited by an Ultrahigh Vacuum Cathodic Arc

    Publication Year: 2007 , Page(s): 1000 - 1003
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (344 KB) |  | HTML iconHTML  

    This paper reports on recent progress in the application of ultrahigh vacuum arc technology, which was proposed as an alternative solution for the deposition of thin superconducting films of pure niobium upon the inner surfaces of RF cavities designed for particle accelerators. New experiments were conducted to deposit superconducting films of pure niobium and lead needed for the modern accelerator technology. Presented scanning electron microscopy, scattered ion mass spectroscopy technique, and glow discharge-optical emission spectroscopy studies of such produced Nb and Pb films showed that the concentration level of impurities is lower than 0.2% and 1%, respectively. Achieved cleanliness goes together with outstanding superconducting properties. The main experimental results and characteristics of arc-deposited thin superconducting films are discussed, and the progress achieved recently in the formation of such films is presented. View full abstract»

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IEEE Transactions on Plasma Sciences focuses on plasma science and engineering, including: magnetofluid dynamics and thermionics; plasma dynamics; gaseous electronics and arc technology.

 

 

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