WorldWideScience

Sample records for plasma electron source

  1. Pulsed Plasma Electron Sources

    Science.gov (United States)

    Krasik, Yakov

    2008-11-01

    Pulsed (˜10-7 s) electron beams with high current density (>10^2 A/cm^2) are generated in diodes with electric field of E > 10^6 V/cm. The source of electrons in these diodes is explosive emission plasma, which limits pulse duration; in the case E Hadas and Ya. E. Krasik, Europhysics Lett. 82, 55001 (2008).

  2. Plasma Cathode Electron Sources Physics, Technology, Applications

    CERN Document Server

    Oks, Efim

    2006-01-01

    This book fills the gap for a textbook describing this kind of electron beam source in a systematic and thorough manner: from physical processes of electron emission to examples of real plasma electron sources and their applications.

  3. Industrial application of electron sources with plasma emitters

    CERN Document Server

    Belyuk, S I; Rempe, N G

    2001-01-01

    Paper contains a description, operation, design and parameters of electron sources with plasma emitters. One presents examples of application of these sources as part of automated electron-beam welding lines. Paper describes application of such sources for electron-beam deposition of composite powders. Electron-beam deposition is used to rebuild worn out part and to increase strength of new parts of machines and tools. Paper presents some examples of rebuilding part and the advantages gained in this case

  4. Multifunctional bulk plasma source based on discharge with electron injection

    Energy Technology Data Exchange (ETDEWEB)

    Klimov, A. S.; Medovnik, A. V. [Tomsk State University of Control Systems and Radioelectronics, Tomsk 634050 (Russian Federation); Tyunkov, A. V. [Tomsk State University of Control Systems and Radioelectronics, Tomsk 634050 (Russian Federation); Institute of High Current Electronics, Tomsk 634055 (Russian Federation); Savkin, K. P.; Shandrikov, M. V.; Vizir, A. V. [Institute of High Current Electronics, Tomsk 634055 (Russian Federation)

    2013-01-15

    A bulk plasma source, based on a high-current dc glow discharge with electron injection, is described. Electron injection and some special design features of the plasma arc emitter provide a plasma source with very long periods between maintenance down-times and a long overall lifetime. The source uses a sectioned sputter-electrode array with six individual sputter targets, each of which can be independently biased. This discharge assembly configuration provides multifunctional operation, including plasma generation from different gases (argon, nitrogen, oxygen, acetylene) and deposition of composite metal nitride and oxide coatings.

  5. Potential applications of an electron cyclotron resonance multicusp plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.C.; Berry, L.A.; Gorbatkin, S.M.; Haselton, H.H.; Roberto, J.B.; Stirling, W.L. (Oak Ridge National Laboratory, Oak Ridge, TN (USA))

    1990-05-01

    An electron cyclotron resonance (ECR) multicusp plasmatron has been developed by feeding a multicusp bucket arc chamber with a compact ECR plasma source. This novel source produces large (about 25 cm diam), uniform (to within {plus minus}10%), dense ({gt}10{sup 11} cm{sup {minus}3}) plasmas of argon, helium, hydrogen, and oxygen. It has been operated to produce an oxygen plasma for etching 12.7 cm (5 in.) positive photoresist-coated silicon wafers with uniformity within {plus minus}8%. Results and potential applications of this new ECR plasma source for plasma processing of thin films are discussed.

  6. Multicomponent Consideration of Electron Fraction of ECR Source Plasma

    CERN Document Server

    Shirkov, G D

    1999-01-01

    The development of physical model and mathematical simulation methods of electron and ion accumulation and production in the ECR ion source is presented. New equations represent electrons in the ECR plasma as a multicomponent media. In the result any kind of experimental or analytical electron distribution function can be approximated with a series of Maxwellian distributions with different temperatures and partial weights. Main positive plasma potential is introduced into consideration in addition to the negative potential dip for highly charged ion confinement. This potential regulates the loss rate of primary cold electrons from the plasma volume and completes the total picture of ECR plasma behavior. The first test of new model and code with recent experimental data of RIKEN 18 GHz ECR source has shown some new opportunities for investigators to study the ECR ion sources.

  7. Oscillating plasma bubbles. III. Internal electron sources and sinks

    Energy Technology Data Exchange (ETDEWEB)

    Stenzel, R. L.; Urrutia, J. M. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)

    2012-08-15

    An internal electron source has been used to neutralize ions injected from an ambient plasma into a spherical grid. The resultant plasma is termed a plasma 'bubble.' When the electron supply from the filament is reduced, the sheath inside the bubble becomes unstable. The plasma potential of the bubble oscillates near but below the ion plasma frequency. Different modes of oscillations have been observed as well as a subharmonic and multiple harmonics. The frequency increases with ion density and decreases with electron density. The peak amplitude occurs for an optimum current and the instability is quenched at large electron densities. The frequency also increases if Langmuir probes inside the bubble draw electrons. Allowing electrons from the ambient plasma to enter, the bubble changes the frequency dependence on grid voltage. It is concluded that the net space charge density in the sheath determines the oscillation frequency. It is suggested that the sheath instability is caused by ion inertia in an oscillating sheath electric field which is created by ion bunching.

  8. Extraction of ions and electrons from audio frequency plasma source

    Directory of Open Access Journals (Sweden)

    N. A. Haleem

    2016-09-01

    Full Text Available Herein, the extraction of high ion / electron current from an audio frequency (AF nitrogen gas discharge (10 – 100 kHz is studied and investigated. This system is featured by its small size (L= 20 cm and inner diameter = 3.4 cm and its capacitive discharge electrodes inside the tube and its high discharge pressure ∼ 0.3 Torr, without the need of high vacuum system or magnetic fields. The extraction system of ion/electron current from the plasma is a very simple electrode that allows self-beam focusing by adjusting its position from the source exit. The working discharge conditions were applied at a frequency from 10 to 100 kHz, power from 50 – 500 W and the gap distance between the plasma meniscus surface and the extractor electrode extending from 3 to 13 mm. The extracted ion/ electron current is found mainly dependent on the discharge power, the extraction gap width and the frequency of the audio supply. SIMION 3D program version 7.0 package is used to generate a simulation of ion trajectories as a reference to compare and to optimize the experimental extraction beam from the present audio frequency plasma source using identical operational conditions. The focal point as well the beam diameter at the collector area is deduced. The simulations showed a respectable agreement with the experimental results all together provide the optimizing basis of the extraction electrode construction and its parameters for beam production.

  9. Shaping the electron beams with submicrosecond pulse duration in sources and electron accelerators with plasma emitters

    CERN Document Server

    Gushenets, V I

    2001-01-01

    One studies the techniques in use to shape submicrosecond electron beams and the physical processes associated with extraction of electrons from plasma in plasma emitters. Plasma emitter base sources and accelerators enable to generate pulse beams with currents varying from tens of amperes up to 10 sup 3 A, with current densities up to several amperes per a square centimeter, with pulse duration constituting hundreds of nanoseconds and with high frequencies of repetition

  10. Ribbon electron beam formation by a forevacuum plasma electron source

    Energy Technology Data Exchange (ETDEWEB)

    Klimov, A. S., E-mail: klimov@main.tusur.ru; Burdovitsin, V. A. [Tomsk State University of Control System and Radioelectronics (Russian Federation); Grishkov, A. A. [SB RAS, Institute of High Current Electronics (Russian Federation); Oks, E. M.; Zenin, A. A.; Yushkov, Yu. G. [Tomsk State University of Control System and Radioelectronics (Russian Federation)

    2016-01-15

    Results of the numerical analysis and experimental research on ribbon electron beam generation based on hollow cathode discharge at forevacuum gas pressure are presented. Geometry of the accelerating gap has modified. It lets us focus the ribbon electron beam and to transport it on a distance of several tens of centimeters in the absence of an axial magnetic field. The results of numerical simulations are confirmed by the experiment.

  11. Potential applications of an electron cyclotron resonance multicusp plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.C.; Berry, L.A.; Gorbatkin, S.M.; Haselton, H.H.; Roberto, J.B.; Schechter, D.E.; Stirling, W.L.

    1990-03-01

    An electric cyclotron resonance (ECR) multicusp plasmatron has been developed by feeding a multicusp bucket arc chamber with a compact ECR plasma source. This novel source produces large (about 25-cm- diam), uniform (to within {plus minus}10%), dense (>10{sup 11}--cm{sup {minus}3}) plasmas of argon, helium, hydrogen, and oxygen. It has been operated to produce an oxygen plasma for etching 12.7-cm (5-in.) positive photoresist-coated silicon wafers with uniformity within {plus minus}8%. Following a brief review of the large plasma source developed at Oak Ridge National Laboratory, the configuration and operation of the source are described and a discharge model is presented. Results from this new ECR plasma source and potential applications for plasma processing of thin films are discussed. 21 refs., 10 figs.

  12. Concept of a laser-plasma based electron source for sub-10 fs electron diffraction

    CERN Document Server

    Faure, J; Beaurepaire, B; Gallé, G; Vernier, A; Lifschitz, A

    2015-01-01

    We propose a new concept of an electron source for ultrafast electron diffraction with sub-10~fs temporal resolution. Electrons are generated in a laser-plasma accelerator, able to deliver femtosecond electron bunches at 5 MeV energy with kHz repetition rate. The possibility of producing this electron source is demonstrated using Particle-In-Cell simulations. We then use particle tracking simulations to show that this electron beam can be transported and manipulated in a realistic beamline, in order to reach parameters suitable for electron diffraction. The beamline consists of realistic static magnetic optics and introduces no temporal jitter. We demonstrate numerically that electron bunches with 5~fs duration and containing 1.5~fC per bunch can be produced, with a transverse coherence length exceeding 2~nm, as required for electron diffraction.

  13. Potential applications of a new microwave ECR (electron cyclotron resonance) multicusp plasma ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.C.

    1990-01-01

    A new microwave electron cyclotron resonance (ECR) multicusp plasma ion source using two ECR plasma production regions and multicusp plasma confinement has been developed at Oak Ridge National Laboratory. This source has been operated to produce uniform and dense plasmas over large areas of 300 to 400 cm{sup 2}. The plasma source has been operated with continuous argon gas feed and pulsed microwave power. The discharge initiation phenomena and plasma properties have been investigated and studied as functions of discharge parameters. Together with the discharge characteristics observed, a hypothetical discharge mechanism for this plasma source is reported and discussed. Potential applications, including plasma and ion-beam processing for manufacturing advanced microelectronics and for space electric propulsion, are discussed. 7 refs., 6 figs.

  14. Multicusp type Electron Cyclotron Resonance ion source for plasma processing

    Energy Technology Data Exchange (ETDEWEB)

    Amemiya, Hiroshi; Shigueoka, Yoshyuki (Institute of Physical and Chemical Research, Wako, Saitama (Japan)); Ishii, Shigeyuki

    1991-02-01

    A multi-cusp type ECR (electron cyclotron resonance) ion source is built with use of SmCo magnets and 2.45 GHz-TE{sub 11} circular mode microwave. The ion source is operated at pressures from 10{sup -4} to 10{sup -3} Torr with the input microwave power from 100 to 400 W. In hydrogen, the current density of H{sup +} is higher than those of H{sub 2}{sup +} and H{sub 3}{sup +}. The dependence of the fraction of each ion species on the power and pressure is measured and explained by rate equations. The source is operated also in other gases. Mass spectra in He, N{sub 2}, O{sub 2}, Ar and CH{sub 4} are shown together with the pressure and power dependences. Multicharged state of up to 3 has been obtained. (author).

  15. Inclined slot-excited annular electron cyclotron resonance plasma source for hyperthermal neutral beam generation.

    Science.gov (United States)

    You, H-J; Kim, D-W; Koo, M; Jang, S-O; Jung, Y-H; Hong, S-H; Lee, B-J

    2011-01-01

    An inclined slot-excited antenna (ISLAN) electron cyclotron resonance (ECR) plasma source is newly designed and constructed for higher flux hyperthermal neutral beam (HNB) generation. The developed ISLAN source is modified from vertical slot-excited antenna (VSLAN) source in two aspects: one is the use of inclined slots instead of vertical slots, and the other is a cusp magnetic field configuration rather than a toroidal configuration. Such modifications allow us to have more uniform arrangement of slots and magnets, then enabling plasma generation more uniform and thinner. Moreover, ECR plasma allows higher ionization rate, enabling plasma density higher even in submillitorr pressures, therefore decreasing the collision rate and∕or the reionization rate of the reflected atoms while passing through the plasma, and eventually getting higher flux of HNBs. In this paper, we report the design features and the plasma characteristics of the ISLAN source by doing plasma measurements and electromagnetic simulations. It was found that ISLAN source can be a high potential source for larger flux HNB generation; the source was found to give higher plasma densities and better uniformities than inductively coupled plasma source, particularly in low pressure ranges. Also, it is important that using ISLAN gives easier matching and better stability, i.e., ISLAN shows similar field patterns and good plasma symmetries irrespective of the variations of the mean diameter of the ring resonator and∕or the presence of a limiter or a reflector, and the operating pressures.

  16. Operation of a microwave plasma source for electron heating and antenna testing

    Science.gov (United States)

    Caughman, J. B. O.; Bigelow, T. S.; Diem, S. J.; Goulding, R. H.; Rasmussen, D. A.; Schaich, C. R.; White, T. L.

    2011-10-01

    One of the major challenges for magnetic fusion is the interaction of the plasma with materials. Linear plasma-material interaction test stands can benefit from additional electron heating of the high-density source plasma to increase the total plasma heat flux at the target to better simulate fusion reactor conditions (10-20 MW/m2). A microwave-based plasma experiment has begun at ORNL to study electron heating of over-dense plasmas and to provide a plasma environment for antenna testing. The plasma is generated by high-field launched whistler waves at 18 GHz to create a moderate-density plasma (ne ~1018/m3). Electron heating of the over-dense plasma is provided by either whistler waves or electron Bernstein waves at 6 GHz. In addition, a single strap mockup antenna, designed to operate at 40-50 MHz, is being constructed to study near-field plasma interactions. The antenna will be placed in the experiment's central vacuum chamber, which will act as an rf test facility. ORNL is managed by UT-Battelle, LLC, for the U.S. DOE under contract DE-AC-05-00OR22725.

  17. Injection of auxiliary electrons for increasing the plasma density in highly charged and high intensity ion sources

    Science.gov (United States)

    Odorici, F.; Malferrari, L.; Montanari, A.; Rizzoli, R.; Mascali, D.; Castro, G.; Celona, L.; Gammino, S.; Neri, L.

    2016-02-01

    Different electron guns based on cold- or hot-cathode technologies have been developed since 2009 at INFN for operating within ECR plasma chambers as sources of auxiliary electrons, with the aim of boosting the source performances by means of a higher plasma lifetime and density. Their application to microwave discharge ion sources, where plasma is not confined, has required an improvement of the gun design, in order to "screen" the cathode from the plasma particles. Experimental tests carried out on a plasma reactor show a boost of the plasma density, ranging from 10% to 90% when the electron guns are used, as explained by plasma diffusion models.

  18. Injection of auxiliary electrons for increasing the plasma density in highly charged and high intensity ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Odorici, F., E-mail: fabrizio.odorici@bo.infn.it; Malferrari, L.; Montanari, A. [INFN—Bologna, Viale B. Pichat, 6/2, 40127 Bologna (Italy); Rizzoli, R. [INFN—Bologna, Viale B. Pichat, 6/2, 40127 Bologna (Italy); CNR–Istituto per la Microelettronica ed i Microsistemi, Via Gobetti 101, 40129 Bologna (Italy); Mascali, D.; Castro, G.; Celona, L.; Gammino, S.; Neri, L. [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy)

    2016-02-15

    Different electron guns based on cold- or hot-cathode technologies have been developed since 2009 at INFN for operating within ECR plasma chambers as sources of auxiliary electrons, with the aim of boosting the source performances by means of a higher plasma lifetime and density. Their application to microwave discharge ion sources, where plasma is not confined, has required an improvement of the gun design, in order to “screen” the cathode from the plasma particles. Experimental tests carried out on a plasma reactor show a boost of the plasma density, ranging from 10% to 90% when the electron guns are used, as explained by plasma diffusion models.

  19. High electronegativity multi-dipolar electron cyclotron resonance plasma source for etching by negative ions

    DEFF Research Database (Denmark)

    Stamate, Eugen; Draghici, M.

    2012-01-01

    A large area plasma source based on 12 multi-dipolar ECR plasma cells arranged in a 3 x 4 matrix configuration was built and optimized for silicon etching by negative ions. The density ratio of negative ions to electrons has exceeded 300 in Ar/SF6 gas mixture when a magnetic filter was used...... to reduce the electron temperature to about 1.2 eV. Mass spectrometry and electrostatic probe were used for plasma diagnostics. The new source is free of density jumps and instabilities and shows a very good stability for plasma potential, and the dominant negative ion species is F-. The magnetic field...... in plasma volume is negligible and there is no contamination by filaments. The etching rate by negative ions measured in Ar/SF6/O-2 mixtures was almost similar with that by positive ions reaching 700 nm/min. (C) 2012 American Institute of Physics...

  20. Deposition of dielectric films on silicon using a fore-vacuum plasma electron source.

    Science.gov (United States)

    Zolotukhin, D B; Oks, E M; Tyunkov, A V; Yushkov, Yu G

    2016-06-01

    We describe an experiment on the use of a fore-vacuum-pressure, plasma-cathode, electron beam source with current up to 100 mA and beam energy up to 15 keV for deposition of Mg and Al oxide films on Si substrates in an oxygen atmosphere at a pressure of 10 Pa. The metals (Al and Mg) were evaporated and ionized using the electron beam with the formation of a gas-metal beam-plasma. The plasma was deposited on the surface of Si substrates. The elemental composition of the deposited films was analyzed.

  1. Deposition of dielectric films on silicon using a fore-vacuum plasma electron source

    Energy Technology Data Exchange (ETDEWEB)

    Zolotukhin, D. B.; Tyunkov, A. V.; Yushkov, Yu. G., E-mail: yuyushkov@gmail.com [Tomsk State University of Control Systems and Radioelectronics, 40 Lenin Ave., Tomsk 634050 (Russian Federation); Oks, E. M. [Tomsk State University of Control Systems and Radioelectronics, 40 Lenin Ave., Tomsk 634050 (Russian Federation); Institute of High Current Electronics SB RAS, 2/3, Akademichesky Ave., Tomsk 634055 (Russian Federation)

    2016-06-15

    We describe an experiment on the use of a fore-vacuum-pressure, plasma-cathode, electron beam source with current up to 100 mA and beam energy up to 15 keV for deposition of Mg and Al oxide films on Si substrates in an oxygen atmosphere at a pressure of 10 Pa. The metals (Al and Mg) were evaporated and ionized using the electron beam with the formation of a gas-metal beam-plasma. The plasma was deposited on the surface of Si substrates. The elemental composition of the deposited films was analyzed.

  2. Limitations of electron cyclotron resonance ion source performances set by kinetic plasma instabilities.

    Science.gov (United States)

    Tarvainen, O; Laulainen, J; Komppula, J; Kronholm, R; Kalvas, T; Koivisto, H; Izotov, I; Mansfeld, D; Skalyga, V

    2015-02-01

    Electron cyclotron resonance ion source (ECRIS) plasmas are prone to kinetic instabilities due to anisotropy of the electron energy distribution function stemming from the resonant nature of the electron heating process. Electron cyclotron plasma instabilities are related to non-linear interaction between plasma waves and energetic electrons resulting to strong microwave emission and a burst of energetic electrons escaping the plasma, and explain the periodic oscillations of the extracted beam currents observed in several laboratories. It is demonstrated with a minimum-B 14 GHz ECRIS operating on helium, oxygen, and argon plasmas that kinetic instabilities restrict the parameter space available for the optimization of high charge state ion currents. The most critical parameter in terms of plasma stability is the strength of the solenoid magnetic field. It is demonstrated that due to the instabilities the optimum Bmin-field in single frequency heating mode is often ≤0.8BECR, which is the value suggested by the semiempirical scaling laws guiding the design of modern ECRISs. It is argued that the effect can be attributed not only to the absolute magnitude of the magnetic field but also to the variation of the average magnetic field gradient on the resonance surface.

  3. Limitations of electron cyclotron resonance ion source performances set by kinetic plasma instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, O., E-mail: olli.tarvainen@jyu.fi; Laulainen, J.; Komppula, J.; Kronholm, R.; Kalvas, T.; Koivisto, H. [Department of Physics, University of Jyväskylä, 40500 Jyväskylä (Finland); Izotov, I.; Mansfeld, D. [Institute of Applied Physics, RAS, 46 Ul‘yanova St., 603950 Nizhny Novgorod (Russian Federation); Skalyga, V. [Institute of Applied Physics, RAS, 46 Ul‘yanova St., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina St., 603950 Nizhny Novgorod (Russian Federation)

    2015-02-15

    Electron cyclotron resonance ion source (ECRIS) plasmas are prone to kinetic instabilities due to anisotropy of the electron energy distribution function stemming from the resonant nature of the electron heating process. Electron cyclotron plasma instabilities are related to non-linear interaction between plasma waves and energetic electrons resulting to strong microwave emission and a burst of energetic electrons escaping the plasma, and explain the periodic oscillations of the extracted beam currents observed in several laboratories. It is demonstrated with a minimum-B 14 GHz ECRIS operating on helium, oxygen, and argon plasmas that kinetic instabilities restrict the parameter space available for the optimization of high charge state ion currents. The most critical parameter in terms of plasma stability is the strength of the solenoid magnetic field. It is demonstrated that due to the instabilities the optimum B{sub min}-field in single frequency heating mode is often ≤0.8B{sub ECR}, which is the value suggested by the semiempirical scaling laws guiding the design of modern ECRISs. It is argued that the effect can be attributed not only to the absolute magnitude of the magnetic field but also to the variation of the average magnetic field gradient on the resonance surface.

  4. Electron energy distributions and electron impact source functions in Ar/N{sub 2} inductively coupled plasmas using pulsed power

    Energy Technology Data Exchange (ETDEWEB)

    Logue, Michael D., E-mail: mdlogue@umich.edu; Kushner, Mark J., E-mail: mjkush@umich.edu [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109-2122 (United States)

    2015-01-28

    In plasma materials processing, such as plasma etching, control of the time-averaged electron energy distributions (EEDs) in the plasma allows for control of the time-averaged electron impact source functions of reactive species in the plasma and their fluxes to surfaces. One potential method for refining the control of EEDs is through the use of pulsed power. Inductively coupled plasmas (ICPs) are attractive for using pulsed power in this manner because the EEDs are dominantly controlled by the ICP power as opposed to the bias power applied to the substrate. In this paper, we discuss results from a computational investigation of EEDs and electron impact source functions in low pressure (5–50 mTorr) ICPs sustained in Ar/N{sub 2} for various duty cycles. We find there is an ability to control EEDs, and thus source functions, by pulsing the ICP power, with the greatest variability of the EEDs located within the skin depth of the electromagnetic field. The transit time of hot electrons produced in the skin depth at the onset of pulse power produces a delay in the response of the EEDs as a function of distance from the coils. The choice of ICP pressure has a large impact on the dynamics of the EEDs, whereas duty cycle has a small influence on time-averaged EEDs and source functions.

  5. Pulsed plasma electron sourcesa)

    Science.gov (United States)

    Krasik, Ya. E.; Yarmolich, D.; Gleizer, J. Z.; Vekselman, V.; Hadas, Y.; Gurovich, V. Tz.; Felsteiner, J.

    2009-05-01

    There is a continuous interest in research of electron sources which can be used for generation of uniform electron beams produced at E ≤105 V/cm and duration ≤10-5 s. In this review, several types of plasma electron sources will be considered, namely, passive (metal ceramic, velvet and carbon fiber with and without CsI coating, and multicapillary and multislot cathodes) and active (ferroelectric and hollow anodes) plasma sources. The operation of passive sources is governed by the formation of flashover plasma whose parameters depend on the amplitude and rise time of the accelerating electric field. In the case of ferroelectric and hollow-anode plasma sources the plasma parameters are controlled by the driving pulse and discharge current, respectively. Using different time- and space-resolved electrical, optical, spectroscopical, Thomson scattering and x-ray diagnostics, the parameters of the plasma and generated electron beam were characterized.

  6. Plasma breakdown diagnostics with the biased disc of electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, O; Ropponen, T; Toivanen, V; Arje, J; Koivisto, H [University of Jyvaeskylae, Department of Physics, Accelerator Laboratory, PO Box 35 (YFL), 40500 Jyvaeskylae (Finland)], E-mail: olli.tarvainen@jyu.fi

    2009-08-15

    The electron cyclotron resonance ion sources at the JYFL (University of Jyvaeskylae, Department of Physics) accelerator laboratory have been operated in pulsed mode to study the time-resolved current signal from the biased discs of the ion sources. The purpose of the experiments is to gain an understanding of the ion source parameters affecting the time required for the transition from neutral gas to plasma. It was observed that the plasma breakdown time depends strongly on the neutral gas density, gas species and density of seed electrons. In particular, it was observed that a low power microwave signal at secondary frequency makes the breakdown time virtually independent of the neutral gas density. The results can be utilized for operation of ECR ion sources in the so-called preglow mode. A simple qualitative model, which is in good agreement with the experiments, has been developed to interpret the results.

  7. Fullerene-rare gas mixed plasmas in an electron cyclotron resonance ion source

    CERN Document Server

    Asaji, T; Uchida, T; Minezaki, H; Ishihara, S; Racz, R; Muramatsu, M; Biri, S; Kitagawa, A; Kato, Y; Yoshida, Y

    2015-01-01

    A synthesis technology of endohedral fullerenes such as Fe@C60 has developed with an electron cyclotron resonance (ECR) ion source. The production of N@C60 was reported. However, the yield was quite low, since most fullerene molecules were broken in the ECR plasma. We have adopted gas-mixing techniques in order to cool the plasma and then reduce fullerene dissociation. Mass spectra of ion beams extracted from fullerene-He, Ar or Xe mixed plasmas were observed with a Faraday cup. From the results, the He gas mixing technique is effective against fullerene destruction.

  8. Laser-plasma electron accelerator for all-optical inverse Compton X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, K. [University of Tokyo, 2-22 Shirakata shirane, Tokai-mura, Naka-gun, Ibaraki 319-1188 (Japan)], E-mail: koyama@nuclear.jp; Yamazaki, A.; Maekawa, A.; Uesaka, M. [University of Tokyo, 2-22 Shirakata shirane, Tokai-mura, Naka-gun, Ibaraki 319-1188 (Japan); Hosokai, T. [Tokyo Institute of Technology, 4259 Nagatsuda-cho, Midori-ku, Yokohama 226-8503 (Japan); Miyashita, M. [Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); Masuda, S.; Miura, E. [AIST, Tsukuba-central-2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

    2009-09-01

    Inverse Compton scattering has been gaining attention as a process for the generation of X/{gamma}-ray, since it produces tunable X/{gamma}-ray pulses with a small cone angle of radiation. A table-top tunable Compton X/{gamma}-ray source would be realized by replacing a radio frequency (rf) linac with a laser wakefield accelerator (LWFA), which is one of the advanced accelerators. An empirical scaling law for the LWFA in the self-injection mode showed that the energy gain was inversely proportional to the plasma density. In order to effectively employ the LWFA as a Compton X/{gamma}-ray source, its stability must be improved. For this purpose, we are developing techniques for the injection of initial electrons by a localized wavebreaking at the density ramp of a plasma. The pointing stability and acceleration efficiency of the electron beam were significantly improved by applying an axial magnetic field to the plasma channel.

  9. On the role of secondary electrons in beam plasma generation inside a dielectric flask by fore-vacuum plasma-cathode electron source

    Science.gov (United States)

    Zolotukhin, D. B.; Burdovitsin, V. A.; Oks, E. M.

    2017-09-01

    The paper presents the results of experimental research and numerical simulation, demonstrating a considerable influence of secondary electrons on parameters of the beam-produced plasma generated at a pressure range of 1-13 Pa by injection of a continuous (with current of tens mA) electron beam into a dielectric (quartz) flask. An electron beam was formed by a fore-vacuum plasma-cathode electron source based on a hollow cathode discharge. The secondary electrons were emitted as a result of high-energy (3-8 keV) electron beam bombardment mainly a bottom end of the flask. These electrons provide an additional contribution to the ionization of the gas and also affect on the longitudinal distribution of the plasma density along the flask.

  10. Accessibility condition of wave propagation and multicharged ion production in electron cyclotron resonance ion source plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Yushi, E-mail: kato@eei.eng.osaka-u.ac.jp; Yano, Keisuke; Nishiokada, Takuya; Nagaya, Tomoki; Kimura, Daiju; Kumakura, Sho; Imai, Youta; Hagino, Shogo; Otsuka, Takuro; Sato, Fuminobu [Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan)

    2016-02-15

    A new tandem type source of electron cyclotron resonance (ECR) plasmas has been constructing for producing synthesized ion beams in Osaka University. Magnetic mirror field configuration with octupole magnets can be controlled to various shape of ECR zones, namely, in the 2nd stage plasma to be available by a pair mirror and a supplemental coil. Noteworthy correlations between these magnetic configurations and production of multicharged ions are investigated in detail, as well as their optimum conditions. We have been considering accessibility condition of electromagnetic and electrostatic waves propagating in ECR ion source plasma, and then investigated their correspondence relationships with production of multicharged ions. It has been clarified that there exits efficient configuration of ECR zones for producing multicharged ion beams experimentally, and then has been suggested from detail accessibility conditions on the ECR plasma that new resonance, i.e., upper hybrid resonance, must have occurred.

  11. Studies of plasma breakdown and electron heating on a 14 GHz ECR ion source through measurement of plasma bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Ropponen, T; Machicoane, G; Leitner, D [National Superconducting Cyclotron Laboratory, MSU, East Lansing, MI 48824 (United States); Tarvainen, O; Toivanen, V; Koivisto, H; Kalvas, T; Peura, P; Jones, P [University of Jyvaeskylae, Department of Physics, PO Box 35 (YFL), 40500 Jyvaeskylae (Finland); Izotov, I; Skalyga, V; Zorin, V [Institute of Applied Physics, RAS, 46 Ulyanov St., 603950 Nizhny Novgorod (Russian Federation); Noland, J, E-mail: tommi.ropponen@gmail.com, E-mail: olli.tarvainen@jyu.fi [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)

    2011-10-15

    Temporal evolution of plasma bremsstrahlung emitted by a 14 GHz electron cyclotron resonance ion source (ECRIS) operated in pulsed mode is presented in the energy range 1.5-400 keV with 100 {mu}s resolution. Such a high temporal resolution together with this energy range has never been measured before with an ECRIS. Data are presented as a function of microwave power, neutral gas pressure, magnetic field configuration and seed electron density. The saturation time of the bremsstrahlung count rate is almost independent of the photon energy up to 100 keV and exhibits similar characteristics with the neutral gas balance. The average photon energy during the plasma breakdown is significantly higher than that during the steady state and depends strongly on the density of seed electrons. The results are consistent with a theoretical model describing the evolution of the electron energy distribution function during the preglow transient.

  12. Laser-driven electron beamlines generated by coupling laser-plasma sources with conventional transport systems

    Energy Technology Data Exchange (ETDEWEB)

    Antici, P. [Istituto Nazionale di Fisica Nucleare (INFN), Laboratori Nazionali di Frascati, Via E. Fermi, 40, 00044 Frascati (Italy); SAPIENZA, University of Rome, Dip. SBAI, Via A. Scarpa 14, 00161 Rome (Italy); INFN - Sezione di Roma, c/o Dipartimento di Fisica - SAPIENZA, University of Rome, P.le Aldo Moro, 2 - 00185 Rome (Italy); Bacci, A.; Chiadroni, E.; Ferrario, M.; Rossi, A. R. [Istituto Nazionale di Fisica Nucleare (INFN), Laboratori Nazionali di Frascati, Via E. Fermi, 40, 00044 Frascati (Italy); Benedetti, C. [University of Bologna and INFN - Bologna (Italy); Lancia, L.; Migliorati, M.; Mostacci, A.; Palumbo, L. [SAPIENZA, University of Rome, Dip. SBAI, Via A. Scarpa 14, 00161 Rome (Italy); INFN - Sezione di Roma, c/o Dipartimento di Fisica - SAPIENZA, University of Rome, P.le Aldo Moro, 2 - 00185 Rome (Italy); Serafini, L. [INFN-Milan and Department of Physics, University of Milan, Via Celoria 16, 20133 Milan (Italy)

    2012-08-15

    Laser-driven electron beamlines are receiving increasing interest from the particle accelerator community. In particular, the high initial energy, low emittance, and high beam current of the plasma based electron source potentially allow generating much more compact and bright particle accelerators than what conventional accelerator technology can achieve. Using laser-generated particles as injectors for generating beamlines could significantly reduce the size and cost of accelerator facilities. Unfortunately, several features of laser-based particle beams need still to be improved before considering them for particle beamlines and thus enable the use of plasma-driven accelerators for the multiple applications of traditional accelerators. Besides working on the plasma source itself, a promising approach to shape the laser-generated beams is coupling them with conventional accelerator elements in order to benefit from both a versatile electron source and a controllable beam. In this paper, we perform start-to-end simulations to generate laser-driven beamlines using conventional accelerator codes and methodologies. Starting with laser-generated electrons that can be obtained with established multi-hundred TW laser systems, we compare different options to capture and transport the beams. This is performed with the aim of providing beamlines suitable for potential applications, such as free electron lasers. In our approach, we have analyzed which parameters are critical at the source and from there evaluated different ways to overcome these issues using conventional accelerator elements and methods. We show that electron driven beamlines are potentially feasible, but exploiting their full potential requires extensive improvement of the source parameters or innovative technological devices for their transport and capture.

  13. Laser-driven electron beamlines generated by coupling laser-plasma sources with conventional transport systems

    Science.gov (United States)

    Antici, P.; Bacci, A.; Benedetti, C.; Chiadroni, E.; Ferrario, M.; Rossi, A. R.; Lancia, L.; Migliorati, M.; Mostacci, A.; Palumbo, L.; Serafini, L.

    2012-08-01

    Laser-driven electron beamlines are receiving increasing interest from the particle accelerator community. In particular, the high initial energy, low emittance, and high beam current of the plasma based electron source potentially allow generating much more compact and bright particle accelerators than what conventional accelerator technology can achieve. Using laser-generated particles as injectors for generating beamlines could significantly reduce the size and cost of accelerator facilities. Unfortunately, several features of laser-based particle beams need still to be improved before considering them for particle beamlines and thus enable the use of plasma-driven accelerators for the multiple applications of traditional accelerators. Besides working on the plasma source itself, a promising approach to shape the laser-generated beams is coupling them with conventional accelerator elements in order to benefit from both a versatile electron source and a controllable beam. In this paper, we perform start-to-end simulations to generate laser-driven beamlines using conventional accelerator codes and methodologies. Starting with laser-generated electrons that can be obtained with established multi-hundred TW laser systems, we compare different options to capture and transport the beams. This is performed with the aim of providing beamlines suitable for potential applications, such as free electron lasers. In our approach, we have analyzed which parameters are critical at the source and from there evaluated different ways to overcome these issues using conventional accelerator elements and methods. We show that electron driven beamlines are potentially feasible, but exploiting their full potential requires extensive improvement of the source parameters or innovative technological devices for their transport and capture.

  14. Electron beam treatment of non-conducting materials by a fore-pump-pressure plasma-cathode electron beam source

    Energy Technology Data Exchange (ETDEWEB)

    Burdovitsin, V A; Klimov, A S; Medovnik, A V; Oks, E M, E-mail: burdov@fet.tusur.r [Tomsk State University of Control Systems and Radioelectronics, 634050, 40 Lenin Ave., Tomsk (Russian Federation)

    2010-10-15

    In the irradiation of an insulated target by an electron beam produced by a plasma-cathode electron beam source operating in the fore-vacuum pressure range (5-15 Pa), the target potential is much lower than the electron beam energy, offering the possibility of direct electron treatment of insulating materials. It is found that in the electron beam irradiation of a non-conducting target in a moderately high pressure range, the electron charge on the target surface is neutralized mainly by ions from a volume discharge established between the negatively charged target surface and the grounded walls of the vacuum chamber. This allows the possibility of direct electron beam treatment (heating, melting, welding) of ceramics and other non-conducting and semiconductor materials.

  15. Study of electron current extraction from a radio frequency plasma cathode designed as a neutralizer for ion source applications

    Energy Technology Data Exchange (ETDEWEB)

    Jahanbakhsh, Sina, E-mail: sinajahanbakhsh@gmail.com; Satir, Mert; Celik, Murat [Department of Mechanical Engineering, Bogazici University, Istanbul 34342 (Turkey)

    2016-02-15

    Plasma cathodes are insert free devices that are developed to be employed as electron sources in electric propulsion and ion source applications as practical alternatives to more commonly used hollow cathodes. Inductively coupled plasma cathodes, or Radio Frequency (RF) plasma cathodes, are introduced in recent years. Because of its compact geometry, and simple and efficient plasma generation, RF plasma source is considered to be suitable for plasma cathode applications. In this study, numerous RF plasma cathodes have been designed and manufactured. Experimental measurements have been conducted to study the effects of geometric and operational parameters. Experimental results of this study show that the plasma generation and electron extraction characteristics of the RF plasma cathode device strongly depend on the geometric parameters such as chamber diameter, chamber length, orifice diameter, orifice length, as well as the operational parameters such as RF power and gas mass flow rate.

  16. Generation of metal ions in the beam plasma produced by a forevacuum-pressure electron beam source

    Energy Technology Data Exchange (ETDEWEB)

    Tyunkov, A. V.; Yushkov, Yu. G., E-mail: YuYushkov@sibmail.com; Zolotukhin, D. B.; Klimov, A. S. [Tomsk State University of Control Systems and Radioelectronics, Tomsk 634050 (Russian Federation); Savkin, K. P. [High Current Electronics Institute, Russian Academy of Sciences, Tomsk 634055 (Russian Federation)

    2014-12-15

    We report on the production of metal ions of magnesium and zinc in the beam plasma formed by a forevacuum-pressure electron source. Magnesium and zinc vapor were generated by electron beam evaporation from a crucible and subsequently ionized by electron impact from the e-beam itself. Both gaseous and metallic plasmas were separately produced and characterized using a modified RGA-100 quadrupole mass-spectrometer. The fractional composition of metal isotopes in the plasma corresponds to their fractional natural abundance.

  17. Influence of gas pressure on electron beam emission current of pulsed cathodic-arc-based forevacuum plasma electron source

    Science.gov (United States)

    Burdovitsin, Victor A.; Kazakov, Andrey V.; Medovnik, Alexander V.; Oks, Efim M.

    2017-09-01

    We describe our experimental investigation of the effect of background gas pressure on the emission parameters of a pulsed cathodic-arc-based forevacuum-pressure plasma-cathode electron source. We find that increased gas pressure over the range 4-16 Pa significantly reduces the beam current rise-time and significantly increases the emission current amplitude. For example, at a discharge current of 20 A, increasing the working gas pressure from 4 Pa to 16 Pa increases the emission current from 8 A to 18 A and shortens the beam rise-time from 50 μs to 20 μs. This influence of gas pressure on the electron beam parameters can be explained by the effect of arc discharge current switching from the anode to emission. In our case, the current switching effect is caused by increased working gas pressure. In the forevacuum pressure range, the increase of the electron emission current with the growth of gas pressure is due to a rise in the emission plasma potential which is caused by ion back-streaming from the plasma formed in the electron beam transport region. A model describing the influence of gas pressure on the electron emission from the plasma is presented.

  18. The role of seed electrons on the plasma breakdown and preglow of electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, O.; Ropponen, T.; Toivanen, V.; Kalvas, T.; Koivisto, H. [Department of Physics, University of Jyvaskyla, Jyvaskyla 40500 (Finland); Thuillier, T. [LPSC, Universite Joseph Fourier Grenoble 1, CNRS/IN2P3, 38026 Grenoble, France and Institut National Polytechnique de Grenoble, 38026 Grenoble (France); Noland, J. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720 (United States)

    2010-02-15

    The 14 GHz Electron Cyclotron Resonance Ion Source at University of Jyvaeskylae, Department of Physics (JYFL) has been operated in pulsed mode in order to study the plasma breakdown and preglow effect. It was observed that the plasma breakdown time and preglow characteristics are affected by seed electrons provided by a continuous low power microwave signal at secondary frequency. Sustaining low density plasma during the off-period of high power microwave pulses at the primary frequency shifts the charge state distribution of the preglow transient toward higher charge states. This could be exploited for applications requiring fast and efficient ionization of radioactive elements as proposed for the Beta Beam project within the EURISOL design study, for example. In this article we present results measured with helium and neon.

  19. Low-Energy Plasma Focus Device as an Electron Beam Source

    Science.gov (United States)

    Seong Ling, Yap; Naresh Kumar, Nitturi; Lian Kuang, Lim; Chiow San, Wong

    2014-01-01

    A low-energy plasma focus device was used as an electron beam source. A technique was developed to simultaneously measure the electron beam intensity and energy. The system was operated in Argon filling at an optimum pressure of 1.7 mbar. A Faraday cup was used together with an array of filtered PIN diodes. The beam-target X-rays were registered through X-ray spectrometry. Copper and lead line radiations were registered upon usage as targets. The maximum electron beam charge and density were estimated to be 0.31 μC and 13.5 × 1016/m3, respectively. The average energy of the electron beam was 500 keV. The high flux of the electron beam can be potentially applicable in material sciences. PMID:25544952

  20. Low-Energy Plasma Focus Device as an Electron Beam Source

    Directory of Open Access Journals (Sweden)

    Muhammad Zubair Khan

    2014-01-01

    Full Text Available A low-energy plasma focus device was used as an electron beam source. A technique was developed to simultaneously measure the electron beam intensity and energy. The system was operated in Argon filling at an optimum pressure of 1.7 mbar. A Faraday cup was used together with an array of filtered PIN diodes. The beam-target X-rays were registered through X-ray spectrometry. Copper and lead line radiations were registered upon usage as targets. The maximum electron beam charge and density were estimated to be 0.31 μC and 13.5×1016/m3, respectively. The average energy of the electron beam was 500 keV. The high flux of the electron beam can be potentially applicable in material sciences.

  1. Diagnostics of plasma decay and afterglow transient of an electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, O; Ropponen, T; Toivanen, V; Kalvas, T; Arje, J; Koivisto, H, E-mail: olli.tarvainen@jyu.f [University of Jyvaeskylae, Department of Physics, Accelerator Laboratory PO Box 35 (YFL), 40500 Jyvaeskylae (Finland)

    2010-08-15

    The electron cyclotron resonance ion sources at the JYFL (University of Jyvaeskylae, Department of Physics) accelerator laboratory have been operated in pulsed mode to study the decay of bremsstrahlung emission and ion beam currents of different charge states. The purpose of the experiments is to gain understanding on the ion source parameters affecting the afterglow. It was observed that the bremsstrahlung emission characteristics during the afterglow and decay times of extracted ion beam currents are virtually independent of the ion source tuning parameters. The decay time of different charge states was found to be almost inversely proportional to the square of the ion charge. The result is in good agreement with a simple theoretical model based on diffusion of ions from the magnetic field of the ion source. It was observed that the plasma decay time is shorter in the case of the ion source with lower operation frequency and, thus, lower magnetic field strength. The scaling between the ion sources supports a model based on Bohm diffusion, arising from non-linear effects such as instabilities and fluctuating fields in turbulent plasma. The experiments provide information on the mechanisms causing instabilities during the plasma decay.

  2. A study on vacuum aspects of electron cyclotron resonance ion source plasma

    Science.gov (United States)

    Ghosh, S.; Taki, G. S.; Mallick, C.; Bhandari, R. K.

    2008-05-01

    The electron cyclotron resonance (ECR) ion source is special type hot plasma machine where the high temperature electrons co-exist with multiply charge state ions and neutrals. A few years ago 6.4 GHz. ECR ion source (VEC-ECR) was developed indigenously at VECC. This multiply charged ion source is being used continuously to inject heavy ion beams into the cyclotron. Vacuum plays the major role in ECR ion source. The water cooled plasma chamber is made from an oxygen free high conductivity copper billet to meet the suitable surface condition for vacuum purpose. The entire volume of the ion source is pumped by two 900 1/s special type oil diffusion pumps to achieve 5×10-8 Torr. Usually main plasma chamber is pumped by the plasma itself. Moreover a few 1/s additional pumping speed is provided through extraction hole and pumping slot on the extraction electrode. A study has been carried out to understand the role of vacuum on the multiply charged heavy ion production process. Considering the ion production and loss criteria, it is seen that for getting Ar18+ better vacuum is essential for lower frequency operation. So, an ECR ion source can give better charge state current output operating at higher frequency and stronger confining magnetic field under a specific vacuum condition. The low pressure condition is essential to minimize charge exchange loss due to recombination of multiply charged ions with the neutral atoms. A fixed ratio of neutral to electron density must be maintained for optimizing a particular charge state in the steady state condition. As the electron density is proportional to square of the injected microwave frequency (nevpropf2) a particular operating pressure is essential for a specific charge state. From the study, it has been obtained that the production of Ar18+ ions needs a pressure ~ 9.6×10-8 Torr for 6.4 GHz. ECR ion source. It is also obtained that an ECR ion source, works at a particular vacuum level, can give better charge state

  3. Unstable plasma characteristics in mirror field electron cyclotron resonance microwave ion source

    Indian Academy of Sciences (India)

    S K Angra; Parshant Kumar; R R Dongaonkar; R P Bajpai

    2000-05-01

    Electron cyclotron plasma reactor are prone to instabilities in specific input power [3–7] region (150–450 watts). In this region power absorption by gas molecules in the cavity is very poor and enhanced input power gets reflected substantially without increasing ion density. There are abrupt changes in plasma characteristics when input power was decreased from maximum to minimum, it was observed that reflected power changed from < 2% to ∼ 50%. Minimum two jumps in reflected power were noticed in this specific power region and these appear to be highly sensitive to three stub tuner position in the waveguide for this particular input power zone. Unstable plasma region of this source is found to be dependent upon the magnetic field strength. Some changes in reflected power are also noticed with pressure, flow and bias and they are random in nature.

  4. A Proposal for a Novel H- Ion Source Based on Electron Cyclotron Resonance Plasma Heating and Surface Ionization

    Science.gov (United States)

    Tarvainen, O.; Kurennoy, S.

    2009-03-01

    A design for a novel H- ion source based on electron cyclotron resonance plasma heating and surface ionization is presented. The plasma chamber of the source is an rf-cavity designed for TE111 eigenmode at 2.45 GHz. The desired mode is excited with a loop antenna. The ionization process takes place on a cesiated surface of a biased converter electrode. The H- ion beam is further "self-extracted" through the plasma region. The magnetic field of the source is optimized for plasma generation by electron cyclotron resonance heating, and beam extraction. The design features of the source are discussed in detail and the attainable H- ion current, beam emittance and duty factor of the novel source are estimated.

  5. Intense positron beam as a source for production of electron-positron plasma

    Science.gov (United States)

    Stoneking, M. R.; Horn-Stanja, J.; Stenson, E. V.; Pedersen, T. Sunn; Saitoh, H.; Hergenhahn, U.; Niemann, H.; Paschkowski, N.; Hugenschmidt, C.; Piochacz, C.

    2016-10-01

    We aim to produce magnetically confined, short Debye length electron-positron plasma and test predicted properties for such systems. A first challenge is obtaining large numbers of positrons; a table-top experiment (system size 5 cm) with a temperature less than 5 eV requires about 1010 positrons to have more than 10 Debye lengths in the system. The NEPOMUC facility at the FRM II research reactor in Germany is one of the world's most intense positron sources. We report on characterization (using a retarding field energy analyzer with magnetic field gradient) of the NEPOMUC beam as delivered to the open beam port at various beam energies and in both the re-moderated and primary beam configurations in order to design optimal trapping (and accumulation) schemes for production of electron-positron plasma. The intensity of the re-moderated (primary) beam is in the range 2 -3 x 107 /s (1 - 5 x 108 /s). The re-moderated beam is currently the most promising for direct injection and confinement experiments; it has a parallel energy spread of 15 - 35% and the transverse energy spread is 6 - 15% of the parallel energy. We report on the implications for injection and trapping in a dipole magnetic field as well as plans for beam development, in situ re-moderation, and accumulation. We also report results demonstrating a difference in phosphor luminescent response to low energy positrons versus electrons.

  6. Source formulation for electron-impact ionization for fluid plasma simulations

    DEFF Research Database (Denmark)

    Müller, S.H.; Holland, C.; Tynan, G.R.;

    2009-01-01

    The derivation of the correct functional form of source terms in plasma fluid theory is revisited. The relation between the fluid source terms and atomic physics differential cross sections is established for particle-impact ionization. It is shown that the interface between atomic and plasma...

  7. A two-stream plasma electron microwave source for high-power millimeter wave generation, phase 1

    Science.gov (United States)

    Guest, Gareth E.; Dandl, Raphael A.

    1989-03-01

    A novel high power millimeter/microwave source is proposed in which one or more pairs of interpenetrating streams of electrons, flowing through a background plasma in a static magnetic field are used to generate a hot-electron plasma that is confined in a mirror-like magnetic field. Energy stored in the anisotropic, hot-electron plasma is then used to amplify pulses of unstable plasma waves to large amplitude by selective deactivation of mechanisms that stabilize the hot-electron plasma during the energy accumulation phase when the density of hot electrons is rapidly increased through the beam-plasma interaction. The Phase 1 program has yielded a design for an experimental arrangement capable of verifying the key aspects of this novel source concept, as well as a theoretical framework for interpreting the empirical Phase 2 results produced by the experimental device and extrapolating those results to evaluate the suitability of the proposed source to meet the requirements of various high power microwave and millimeter wave defense and industrial applications. The experiments will be carried out in a timely and cost-effective way by employing the AMPHED (a CW magetic mirror) experimental facility at Applied Microwave Plasma Concepts (AMPC).

  8. Modification of anisotropic plasma diffusion via auxiliary electrons emitted by a carbon nanotubes-based electron gun in an electron cyclotron resonance ion source.

    Science.gov (United States)

    Malferrari, L; Odorici, F; Veronese, G P; Rizzoli, R; Mascali, D; Celona, L; Gammino, S; Castro, G; Miracoli, R; Serafino, T

    2012-02-01

    The diffusion mechanism in magnetized plasmas is a largely debated issue. A short circuit model was proposed by Simon, assuming fluxes of lost particles along the axial (electrons) and radial (ions) directions which can be compensated, to preserve the quasi-neutrality, by currents flowing throughout the conducting plasma chamber walls. We hereby propose a new method to modify Simon's currents via electrons injected by a carbon nanotubes-based electron gun. We found this improves the source performances, increasing the output current for several charge states. The method is especially sensitive to the pumping frequency. Output currents for given charge states, at different auxiliary electron currents, will be reported in the paper and the influence of the frequency tuning on the compensation mechanism will be discussed.

  9. Extraction of negative charges from an ion source: Transition from an electron repelling to an electron attracting plasma close to the extraction surface

    Science.gov (United States)

    Wimmer, Christian; Fantz, Ursel

    2016-08-01

    Large-scale sources for negative hydrogen ions, capable of delivering an extracted ion current of several ten amperes, are a key component of the neutral beam injection system of the upcoming ITER fusion device. Since the created heat load of the inevitably co-extracted electrons after magnetic separation from the extracted beam limits their tolerable amount, special care must be taken for the reduction of co-extracted electrons—in particular, in deuterium operation, where the larger amount of co-extracted electrons often limits the source performance. By biasing the plasma grid (PG, first grid of the extraction system) positively with respect to the source body, the plasma sheath in front of the PG can be changed from an electron repelling towards an electron attracting sheath. In this way, the flux of charged particles onto the PG can be varied, thus changing the bias current and inverse to it the amount of co-extracted electrons. The PG bias affects also the flux of surface-produced H - towards the plasma volume as well as the plasma symmetry in front of the plasma grid, strongly influenced by an E → × B → drift. The influence of varying PG sheath potential profile on the plasma drift, the negative hydrogen ion density, and the source performance at the prototype H - source is presented, comparing hydrogen and deuterium operation. The transition in the PG sheath profile takes place in both isotopes, with a minimum of co-extracted electrons formed in case of the electron attracting PG sheath. The co-extracted electron density in deuterium operation is higher than in hydrogen operation, which is accompanied by an increased plasma density in deuterium.

  10. Ion Behavior and Gas Mixing in electron cyclotron resonance plasmas as sources of highly charged ions (concept

    OpenAIRE

    Melin, G.; Drentje, A. G.; Girard, A; Hitz, D.

    1999-01-01

    Abstract: An ECR ion source is basically an ECR heated plasma confinement machine, with hot electrons and cold ions. The main parameters of the ion population have been analyzed, including temperature, losses, and confinement time. The "gas mixing" effect has been studied in this context. An expression is derived for determining the ion temperature from the values of all extracted ion currents. One aim is to study the ion temperature behavior in argon plasmas without and with mixing different...

  11. Electron cyclotron resonance ion source plasma chamber studies using a network analyzer as a loaded cavity probe

    Energy Technology Data Exchange (ETDEWEB)

    Toivanen, V.; Tarvainen, O.; Kauppinen, J.; Komppula, J.; Koivisto, H. [Department of Physics, University of Jyvaeskylae, Jyvaeskylae 40500 (Finland); Lyneis, C. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2012-02-15

    A method and first results utilizing a network analyzer as a loaded cavity probe to study the resonance properties of a plasma filled electron cyclotron resonance ion source (ECRIS) plasma chamber are presented. The loaded cavity measurements have been performed using a dual port technique, in which two separate waveguides were used simultaneously. One port was used to ignite and sustain the plasma with a microwave source operating around 11 GHz and the other was used to probe the cavity properties with the network analyzer using a frequency range around 14 GHz. The first results obtained with the JYFL 14 GHz ECRIS demonstrate that the presence of plasma has significant effects on the resonance properties of the cavity. With plasma the frequency dependent behavior is strongly damped and this trend strengthens with increasing microwave power.

  12. Ion Behavior and Gas Mixing in electron cyclotron resonance plasmas as sources of highly charged ions (concept

    NARCIS (Netherlands)

    Melin, G.; Drentje, A. G.; Girard, A.; Hitz, D.

    1999-01-01

    Abstract: An ECR ion source is basically an ECR heated plasma confinement machine, with hot electrons and cold ions. The main parameters of the ion population have been analyzed, including temperature, losses, and confinement time. The "gas mixing" effect has been studied in this context. An express

  13. Large area plasma source

    Science.gov (United States)

    Foster, John (Inventor); Patterson, Michael (Inventor)

    2008-01-01

    An all permanent magnet Electron Cyclotron Resonance, large diameter (e.g., 40 cm) plasma source suitable for ion/plasma processing or electric propulsion, is capable of producing uniform ion current densities at its exit plane at very low power (e.g., below 200 W), and is electrodeless to avoid sputtering or contamination issues. Microwave input power is efficiently coupled with an ionizing gas without using a dielectric microwave window and without developing a throat plasma by providing a ferromagnetic cylindrical chamber wall with a conical end narrowing to an axial entrance hole for microwaves supplied on-axis from an open-ended waveguide. Permanent magnet rings are attached inside the wall with alternating polarities against the wall. An entrance magnet ring surrounding the entrance hole has a ferromagnetic pole piece that extends into the chamber from the entrance hole to a continuing second face that extends radially across an inner pole of the entrance magnet ring.

  14. Development of a compact thermal lithium atom beam source for measurements of electron velocity distribution function anisotropy in electron cyclotron resonance plasmas.

    Science.gov (United States)

    Nishioka, T; Shikama, T; Nagamizo, S; Fujii, K; Zushi, H; Uchida, M; Iwamae, A; Tanaka, H; Maekawa, T; Hasuo, M

    2013-07-01

    The anisotropy of the electron velocity distribution function (EVDF) in plasmas can be deduced from the polarization of emissions induced by anisotropic electron-impact excitation. In this paper, we develop a compact thermal lithium atom beam source for spatially resolved measurements of the EVDF anisotropy in electron cyclotron resonance (ECR) plasmas. The beam system is designed such that the ejected beam has a slab shape, and the beam direction is variable. The divergence and flux of the beam are evaluated by experiments and calculations. The developed beam system is installed in an ECR plasma device with a cusp magnetic field, and the LiI 2s-2p emission (670.8 nm) is observed in low-pressure helium plasma. The two-dimensional distributions of the degree and direction of the polarization in the LiI emission are measured by a polarization imaging system. The evaluated polarization distribution suggests the spatial variation of the EVDF anisotropy.

  15. Production of electron cyclotron resonance plasma by using multifrequencies microwaves and active beam profile control on a large bore electron cyclotron resonance ion source with permanent magnets.

    Science.gov (United States)

    Kato, Yushi; Watanabe, Takeyoshi; Matsui, Yuuki; Hirai, Yoshiaki; Kutsumi, Osamu; Sakamoto, Naoki; Sato, Fuminobu; Iida, Toshiyuki

    2010-02-01

    A new concept on magnetic field with all magnets on plasma production and confinement has been proposed to enhance efficiency of an electron cyclotron resonance (ECR) plasma for broad and dense ion beam source under the low pressure. The magnetic field configuration is constructed by a pair of magnets assembly, i.e., comb-shaped magnet which cylindrically surrounds the plasma chamber. The resonance zones corresponding to the fundamental ECR for 2.45 GHz and 11-13 GHz frequencies are constructed at different positions. The profiles of the plasma parameters in the ECR ion source are different from each frequency of microwave. Large bore extractor is set at the opposite side against the microwave feeds. It is found that differences of their profiles also appear at those of ion beam profiles. We conducted to launch simultaneously multiplex frequencies microwaves controlled individually, and tried to control the profiles of the plasma parameters and then those of extracted ion beam.

  16. Electron cyclotron resonance ion source plasma characterization by X-ray spectroscopy and X-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Mascali, David, E-mail: davidmascali@lns.infn.it; Castro, Giuseppe; Celona, Luigi; Neri, Lorenzo; Gammino, Santo [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Biri, Sándor; Rácz, Richárd; Pálinkás, József [Institute for Nuclear Research (Atomki), Hungarian Academy of Sciences, Bem tér 18/c, H-4026 Debrecen (Hungary); Caliri, Claudia [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Università degli Studi di Catania, Dip.to di Fisica e Astronomia, via Santa Sofia 64, 95123 Catania (Italy); Romano, Francesco Paolo [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); CNR, Istituto per i Beni Archeologici e Monumentali, Via Biblioteca 4, 95124 Catania (Italy); Torrisi, Giuseppe [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Università Mediterranea di Reggio Calabria, DIIES, Via Graziella, I-89100 Reggio Calabria (Italy)

    2016-02-15

    An experimental campaign aiming to investigate electron cyclotron resonance (ECR) plasma X-ray emission has been recently carried out at the ECRISs—Electron Cyclotron Resonance Ion Sources laboratory of Atomki based on a collaboration between the Debrecen and Catania ECR teams. In a first series, the X-ray spectroscopy was performed through silicon drift detectors and high purity germanium detectors, characterizing the volumetric plasma emission. The on-purpose developed collimation system was suitable for direct plasma density evaluation, performed “on-line” during beam extraction and charge state distribution characterization. A campaign for correlating the plasma density and temperature with the output charge states and the beam intensity for different pumping wave frequencies, different magnetic field profiles, and single-gas/gas-mixing configurations was carried out. The results reveal a surprisingly very good agreement between warm-electron density fluctuations, output beam currents, and the calculated electromagnetic modal density of the plasma chamber. A charge-coupled device camera coupled to a small pin-hole allowing X-ray imaging was installed and numerous X-ray photos were taken in order to study the peculiarities of the ECRIS plasma structure.

  17. X-ray spectroscopy of warm and hot electron components in the CAPRICE source plasma at EIS testbench at GSI

    Energy Technology Data Exchange (ETDEWEB)

    Mascali, D., E-mail: davidmascali@lns.infn.it; Celona, L.; Castro, G.; Torrisi, G.; Neri, L.; Gammino, S.; Ciavola, G. [Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud, – Via S. Sofia 62, 95123 Catania (Italy); Maimone, F.; Maeder, J.; Tinschert, K.; Spaedtke, K. P.; Rossbach, J.; Lang, R. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt (Germany); Romano, F. P. [Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud, – Via S. Sofia 62, 95123 Catania (Italy); IBAM, CNR, Via Biblioteca 4, 95124 Catania (Italy); Musumarra, A.; Altana, C.; Caliri, C. [Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud, – Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Università degli Studi di Catania, via S. Sofia 64, 95123 Catania (Italy)

    2014-02-15

    An experimental campaign aiming to detect X radiation emitted by the plasma of the CAPRICE source – operating at GSI, Darmstadt – has been carried out. Two different detectors (a SDD – Silicon Drift Detector and a HpGe – hyper-pure Germanium detector) have been used to characterize the warm (2–30 keV) and hot (30–500 keV) electrons in the plasma, collecting the emission intensity and the energy spectra for different pumping wave frequencies and then correlating them with the CSD of the extracted beam measured by means of a bending magnet. A plasma emissivity model has been used to extract the plasma density along the cone of sight of the SDD and HpGe detectors, which have been placed beyond specific collimators developed on purpose. Results show that the tuning of the pumping frequency considerably modifies the plasma density especially in the warm electron population domain, which is the component responsible for ionization processes: a strong variation of the plasma density near axis region has been detected. Potential correlations with the charge state distribution in the plasma are explored.

  18. Plasma electron source for the generation of wide-aperture pulsed beam at forevacuum pressures

    Energy Technology Data Exchange (ETDEWEB)

    Oks, E.; Burdovitsin, V.; Medovnik, A.; Yushkov, Yu. [Tomsk State University of Control Systems and Radioelectronics, Tomsk 634050 (Russian Federation)

    2013-02-15

    This article reports on design and application of wide-aperture pulsed beam source, based on hollow cathode discharge. The source is intended for electron beam generation in pressure range 2-15 Pa. Multi-aperture extraction system, used in a source, provided beam cross-section uniformity of 10% on diameter 40 mm. The limiting values of the current density, pulse duration, and accelerating voltage are 350 mA/cm{sup 2}, 250 {mu}s, and 10 kV, respectively. These parameters are sufficient for surface modification of various materials, including non-conducting matters.

  19. Controlled generation of comb-like electron beams in plasma channels for polychromatic inverse Thomson γ-ray sources

    Science.gov (United States)

    Kalmykov, S. Y.; Davoine, X.; Ghebregziabher, I.; Lehe, R.; Lifschitz, A. F.; Shadwick, B. A.

    2016-03-01

    Propagating a relativistically intense, negatively chirped laser pulse (the bandwidth  >150 nm) in a plasma channel makes it possible to generate background-free, comb-like electron beams—sequences of synchronized bunches with a low phase-space volume and controlled energy spacing. The tail of the pulse, confined in the accelerator cavity (an electron density ‘bubble’), experiences periodic focusing, while the head, which is the most intense portion of the pulse, steadily self-guides. Oscillations of the cavity size cause periodic injection of electrons from the ambient plasma, creating an electron energy comb with the number of components, their mean energy, and energy spacing dependent on the channel radius and pulse length. These customizable electron beams enable the design of a tunable, all-optical source of pulsed, polychromatic γ-rays using the mechanism of inverse Thomson scattering, with up to  ˜10-5 conversion efficiency from the drive pulse in the electron accelerator to the γ-ray beam. Such a source may radiate  ˜107 quasi-monochromatic photons per shot into a microsteradian-scale cone. The photon energy is distributed among several distinct bands, each having sub-30% energy spread, with a highest energy of 12.5 MeV.

  20. Influence of microwave driver coupling design on plasma density at Testbench for Ion sources Plasma Studies, a 2.45 GHz Electron Cyclotron Resonance Plasma Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Megía-Macías, A.; Vizcaíno-de-Julián, A. [E.S.S. Bilbao, Edificio Cosimet, Landabarri 2, 48940-Leioa, Vizcaya (Spain); Cortázar, O. D., E-mail: dcortazar@essbilbao.org [E.S.S. Bilbao, Edificio Cosimet, Landabarri 2, 48940-Leioa, Vizcaya (Spain); Universidad de Castilla-La Mancha, ETSII, C.J. Cela s/n, 13170 Ciudad Real (Spain)

    2014-03-15

    A comparative study of two microwave driver systems (preliminary and optimized) for a 2.45 GHz hydrogen Electron Cyclotron Resonance plasma generator has been conducted. The influence on plasma behavior and parameters of stationary electric field distribution in vacuum, i.e., just before breakdown, along all the microwave excitation system is analyzed. 3D simulations of resonant stationary electric field distributions, 2D simulations of external magnetic field mapping, experimental measurements of incoming and reflected power, and electron temperature and density along the plasma chamber axis have been carried out. By using these tools, an optimized set of plasma chamber and microwave coupler has been designed paying special attention to the optimization of stationary electric field value in the center of the plasma chamber. This system shows a strong stability on plasma behavior allowing a wider range of operational parameters and even sustaining low density plasma formation without external magnetic field. In addition, the optimized system shows the capability to produce values of plasma density four times higher than the preliminary as a consequence of a deeper penetration of the magnetic resonance surface in relative high electric field zone by keeping plasma stability. The increment of the amount of resonance surface embedded in the plasma under high electric field is suggested as a key factor.

  1. Analysis of H atoms in a negative ion source plasma with the non-equilibrium electron energy distribution function.

    Science.gov (United States)

    Koga, S; Shibata, T; Terasaki, R; Kameyama, N; Hatayama, A; Bacal, M; Tsumori, K

    2012-02-01

    In negative ion sources for the neutral beam injection, it is important to calculate H atom flux onto the plasma grid (PG) surface for the evaluation of H(-) production on the PG surface. We have developed a neutral (H(2) molecules and H atoms) transport code. In the present study, the neutral transport code is applied to the analysis of the H(2) and H transport in a NIFS-R&D ion source in order to calculate the flux onto the PG surface. Taking into account non-equilibrium feature of the electron energy distribution function (EEDF), i.e., the fast electron component, we have done the neutral transport simulation. The results suggest that the precise evaluation of the EEDF, especially in the energy range 15 eV < E < 30 eV is important for the dissociation rate of H(2) molecules by the electron impact collision and the resultant H atom flux on the PG.

  2. Simulations on the influence of the spatial distribution of source electrons on the plasma in a cusped-field thruster

    Science.gov (United States)

    Brandt, Tim; Trottenberg, Thomas; Groll, Rodion; Jansen, Frank; Hey, Franz Georg; Johann, Ulrich; Kersten, Holger; Braxmaier, Claus

    2015-06-01

    We present results from simulations on the influence of source electrons on the plasma properties in a magnetic cusps environment. Our simulations are based on the VSim/Vorpal particle-in-cell plasma simulation package. Magnetic cusps are a typical feature of High Efficiency Multistage Plasma Thrusters (HEMPTs). This research is part of an effort to downscale a HEMPT to thrust levels in the μN and sub- μN regime. The aim is to fulfill the requirements of upcoming formation flight satellites and probes. Those missions demand very precise attitude control. In order to get the necessary insight, the plasma of a section of the HEMPT discharge chamber is simulated with idealized boundary conditions. The results for such a section at two different distributions of source electrons are shown. A significant increase of the overall ion number is recognized for one of the distributions. Comparisons with published similar simulations are made. Factors that should be important for improvements of this thruster type are highlighted.

  3. Plasma diagnosis as a tool for the determination of the parameters of electron beam evaporation and sources of ionization

    Science.gov (United States)

    Mukherjee, Jaya; Dileep Kumar, V.; Yadav, S. P.; Barnwal, Tripti A.; Dikshit, Biswaranjan

    2016-07-01

    The atomic vapor generated by electron beam heating is partially ionized due to atom-atom collisions (Saha ionization) and electron impact ionization, which depend upon the source temperature and area of evaporation as compared to the area of electron beam bombardment on the target. When electron beam evaporation is carried out by inserting the target inside an insulating liner to reduce conductive heat loss, it is expected that the area of evaporation becomes significantly more than the area of electron beam bombardment on the target, resulting in reduced electron impact ionization. To assess this effect and to quantify the parameters of evaporation, such as temperature and area of evaporation, we have carried out experiments using zirconium, tin and aluminum as a target. By measuring the ion content using a Langmuir probe, in addition to measuring the atomic vapor flux at a specific height, and by combining the experimental data with theoretical expressions, we have established a method for simultaneously inferring the source temperature, evaporation area and ion fraction. This assumes significance because the temperature cannot be reliably measured by an optical pyrometer due to the wavelength dependent source emissivity and reflectivity of thin film mirrors. In addition, it also cannot be inferred from only the atomic flux data at a certain height as the area of evaporation is unknown (it can be much more than the area of electron bombardment, especially when the target is placed in a liner). Finally, the reason for the lower observed electron temperatures of the plasma for all the three cases is found to be the energy loss due to electron impact excitation of the atomic vapor during its expansion from the source.

  4. The electron-cyclotron maser instability as a source of plasma radiation. [Solar radio bursts

    Science.gov (United States)

    Winglee, R. M.; Dulk, G. A.

    1986-01-01

    The generation of continuum bursts from the sun at dm and m wavelengths (in particular, type IV bursts) via the electron-cyclotron-maser instability is examined. The maser instability can be driven by an electron distribution with either a loss-cone anisotropy or a peak at large pitch angles. For omega(p)/Omega(e) much greater than 1, the maser emission is produced by electrons interacting through a harmonic (cyclotron) resonance and is electrostatic, being in the upper hybrid mode at frequencies approximately equal to omega(p). Coalescence processes are required to convert the electrostatic waves into transverse radiation which can escape from the source region. Whether the resultant spectrum is nearly a smooth continuum or has a zebra-stripe pattern (both of which occur in type IV bursts) depends on the form of the electron distribution, inhomogeneities in the density and magnetic field, and whether the maser reaches saturation. For at least the case of some type IV dm bursts with fine structure, comparison with observations seems to indicate that the electrons producing the emission are more likely to have a loss-cone distribution, and that the maser instability is not at saturation.

  5. Customizable electron beams from optically controlled laser plasma acceleration for γ-ray sources based on inverse Thomson scattering

    Science.gov (United States)

    Kalmykov, S. Y.; Davoine, X.; Ghebregziabher, I.; Shadwick, B. A.

    2016-09-01

    Laser wakefield acceleration of electrons in the blowout regime can be controlled by tailoring the laser pulse phase and the plasma target. The 100 nm-scale bandwidth and negative frequency chirp of the optical driver compensate for the nonlinear frequency red-shift imparted by wakefield excitation. This mitigates pulse self-steepening and suppresses continuous injection. The plasma channel suppresses diffraction of the pulse leading edge, further reducing self-steepening, making injection even quieter. Besides, the channel destabilizes the pulse tail confined within the accelerator cavity (the electron density "bubble"), causing oscillations in the bubble size. The resulting periodic injection generates background-free comb-like beams - sequences of synchronized, low phase-space volume bunches. Controlling the number of bunches, their energy, and energy spacing by varying the channel radius and the pulse length (as permitted by the large bandwidth) enables the design of a tunable, all-optical source of polychromatic, pulsed γ-rays using the mechanism of inverse Thomson scattering. Such source may radiate ~107 quasi-monochromatic 10 MeV-scale photons per shot into a microsteradian-scale observation angle. The photon energy is distributed among several distinct bands, each having sub-25% energy spread dictated by the mrad-scale divergence of electron beam.

  6. Microwave emission related to cyclotron instabilities in a minimum-B electron cyclotron resonance ion source plasma

    Science.gov (United States)

    Izotov, I.; Tarvainen, O.; Mansfeld, D.; Skalyga, V.; Koivisto, H.; Kalvas, T.; Komppula, J.; Kronholm, R.; Laulainen, J.

    2015-08-01

    Electron cyclotron resonance ion sources (ECRIS) have been essential in the research and applications of nuclear physics over the past 40 years. They are extensively used in a wide range of large-scale accelerator facilities for the production of highly charged heavy ion beams of stable and radioactive elements. ECRISs are susceptible to kinetic instabilities due to resonance heating mechanism leading to anisotropic electron velocity distribution function. Instabilities of cyclotron type are a proven cause of frequently observed periodic bursts of ‘hot’ electrons and bremsstrahlung, accompanied with emission of microwave radiation and followed by considerable drop of multiply charged ions current. Detailed studies of the microwave radiation associated with the instabilities have been performed with a minimum-B 14 GHz ECRIS operating on helium, oxygen and argon plasmas. It is demonstrated that during the development of cyclotron instability ‘hot’ electrons emit microwaves in sub-microsecond scale bursts at temporally descending frequencies in the 8-15 GHz range with two dominant frequencies of 11.09 and 12.59 GHz regardless of ECRIS settings i.e. magnetic field strength, neutral gas pressure or species and microwave power. The experimental data suggest that the most probable excited plasma wave is a slow extraordinary Z-mode propagating quasi-longitudinally with respect to the external magnetic field.

  7. Diagnostics of a charge breeder electron cyclotron resonance ion source helium plasma with the injection of ^{23}Na^{1+} ions

    Directory of Open Access Journals (Sweden)

    O. Tarvainen

    2016-05-01

    Full Text Available This work describes the utilization of an injected ^{23}Na^{1+} ion beam as a diagnostics of the helium plasma of a charge breeder electron cyclotron resonance ion source. The obtained data allows estimating the upper limit for the ion-ion collision mean-free path of the incident sodium ions, the lower limit of ion-ion collision frequencies for all charge states of the sodium ions and the lower limit of the helium plasma density. The ion-ion collision frequencies of high charge state ions are shown to be at least on the order of 1–10 MHz and the plasma density is estimated to be on the order of 10^{11}  cm^{-3} or higher. The experimental results are compared to simulations of the ^{23}Na^{1+} capture into the helium plasma. The results indicate that the lower breeding efficiency of light ions in comparison to heavier elements is probably due to different capture efficiencies in which the in-flight ionization of the incident 1+ ions plays a vital role.

  8. Photo-transmutation of long-lived radionuclide 135Cs by laser-plasma driven electron source

    Science.gov (United States)

    Wang, X.-L.; Tan, Z.-Y.; Luo, W.; Zhu, Z.-C.; Wang, X.-D.; Song, Y.-M.

    2016-09-01

    Relativistic electrons, accelerated by the laser ponderomotive force, can be focused onto a high-Z convertor to generate high-brightness beams of gamma-rays, which in turn can be used to induce photonuclear reactions. In this work, the possibility of photo-transmutation of long-lived radionuclide Cs-135 by laser-plasma driven electron source has been demonstrated through Geant4 simulations. High energy electron generation, bremsstrahlung and photonuclear reaction have been observed at four different laser intensities of 10^{20} W/cm^2, 5 times 10^{20} W/cm^2, 10^{21} W/cm^2 and 5 times 10^{21} W/cm^2, respectively. It was shown that the laser intensity and the target geometry have strong effect on the transmutation reaction yield. At different laser intensities the recommended target sizes were found to obtain the maximum reaction yield. The remarkable feature of this work is to evaluate the optimal laser intensity to produce maximum reaction yield of 10^8 per Joule in laser pulse energy, which is 10^{21} W/cm^2. Our study suggests photo-transmutation driven by laser-based electron source as a promising approach for experimental research into transmutation reactions, with potential applications to nuclear waste management.

  9. The effect of plasma electrode collar structure on the performance of the JYFL 14 GHz electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Toivanen, V., E-mail: ville.toivanen@jyu.fi; Tarvainen, O.; Komppula, J.; Koivisto, H.

    2013-10-21

    The influence of a so-called collar structure on the performance of the JYFL 14 GHz electron cyclotron resonance ion source (ECRIS) has been studied experimentally at the Department of Physics, University of Jyväskylä (JYFL). The collar is a cylindrical structure extruding inwards from the plasma electrode. The collar length was varied between 5 and 60 mm. For some ion species a moderate performance improvement was achieved in terms of extracted beam current and transverse emittance up to 30 mm collar length. Longer collars resulted in a substantial performance decrease. Different collar materials, i.e. nonmagnetic stainless steel, aluminum and Al{sub 2}O{sub 3}, and a wide range of ion species for elements ranging from {sup 14}N to {sup 82}Kr were studied. No clear material or ion species dependent behavior was observed. The experiments suggest that the extracted ions originate from a plasma volume which is at a considerable axial distance from the extraction aperture. Furthermore it is concluded that a substantial space exists surrounding the collar that could be utilized for applying novel techniques to boost the performance of ECR ion sources. -- Highlights: • Effects of a so-called collar structure studied with AECR-U type ion source. • Moderate improvement to source performance when collar is not too long. • No clear collar material or ion species dependent behavior is observed. • Results suggest that the extracted ions originate from plasma volume far from extraction. • Results suggest that the space around extraction aperture could be utilized productively.

  10. Some plasma aspects and plasma diagnostics of ion sources.

    Science.gov (United States)

    Wiesemann, Klaus

    2008-02-01

    We consider plasma properties in the most advanced type of plasma ion sources, electron cyclotron resonance ion sources for highly charged ions. Depending on the operation conditions the plasma in these sources may be highly ionized, which completely changes its transport properties. The most striking difference to weakly ionized plasma is that diffusion will become intrinsically ambipolar. We further discuss means of plasma diagnostics. As noninvasive diagnostic methods we will discuss analysis of the ion beam, optical spectroscopy, and measurement of the x-ray bremsstrahlung continuum. From beam analysis and optical spectroscopy one may deduce ion densities, and electron densities and distribution functions as a mean over the line of sight along the axis (optical spectroscopy) or at the plasma edge (ion beam). From x-ray spectra one obtains information about the population of highly energetic electrons and the energy transfer from the driving electromagnetic waves to the plasma -- basic data for plasma modeling.

  11. V.U.V. plasma spectroscopy diagnostic of electron cyclotron resonance multicharged ion sources; Diagnostic de plasmas crees dans des sources d'ions multicharges a resonance cyclotronique electronique par spectroscopie V.U.V

    Energy Technology Data Exchange (ETDEWEB)

    Berreby, R

    1997-12-15

    To characterize the multicharged ions within the plasma of an E.C.R. ion source, the V.U.V. spectroscopy is used as a non invasive diagnostic of excited matter. In E.C.R.I. S. (electron cyclotron resonance ion source) electrons are heated and magnetically confined within the mirror machine to overcome the successive ionization potentials of the desired elements. As the electrons bounce inside the magnetic configuration in their gyration movement, they interact with the microwaves injected into the source at the resonance frequency. To enhance the performances in high charge states and extracted currents delivered by E.C.R.I.S., the fundamental parameters of the plasma created in these machines must be known. The goal of spectroscopic diagnostics in the V.U.V. range installed on the sources is to determine electron density and temperature on one hand, and the ionic densities and confinement time on the other hand. We used microchannel plates as detector on a 3 meter grazing incidence spectrometer equipped with a 600 lines/mm holographic grating. The calibration of the whole grating with detector was performed by two different methods. These are the branching ratio and charge exchange methods. Identification of lines emitted by a plasma, which gather the whole charge states of ions is necessary to make an exhaustive study of the plasma state. And finally, the determination of plasma parameters like electron density and temperature and ion densities and confinement times that uses theoretical models were the aim of this work. (author)

  12. Analysis of H atoms in a negative ion source plasma with the non-equilibrium electron energy distribution function

    Energy Technology Data Exchange (ETDEWEB)

    Koga, S.; Shibata, T.; Terasaki, R.; Kameyama, N.; Hatayama, A. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Bacal, M. [LPP, Ecole Polytechnique, Palaiseau, UPMC, Universite PARIS-SUD 11, UMR CNRS 7648 (France); Tsumori, K. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)

    2012-02-15

    In negative ion sources for the neutral beam injection, it is important to calculate H atom flux onto the plasma grid (PG) surface for the evaluation of H{sup -} production on the PG surface. We have developed a neutral (H{sub 2} molecules and H atoms) transport code. In the present study, the neutral transport code is applied to the analysis of the H{sub 2} and H transport in a NIFS-R and D ion source in order to calculate the flux onto the PG surface. Taking into account non-equilibrium feature of the electron energy distribution function (EEDF), i.e., the fast electron component, we have done the neutral transport simulation. The results suggest that the precise evaluation of the EEDF, especially in the energy range 15 eV < E < 30 eV is important for the dissociation rate of H{sub 2} molecules by the electron impact collision and the resultant H atom flux on the PG.

  13. Non-ambipolar Electron Source Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A device to produce electron beams from magnetized plasma created with rf fields combined with electron extraction by electron sheaths is proposed. The source can...

  14. Photo-transmutation of long-lived radionuclide Cs-135 by laser-plasma driven electron source

    CERN Document Server

    Wang, X L; Zhu, Z C; Wang, X D; Song, Y M

    2016-01-01

    Relativistic electrons, accelerated by the laser ponderomotive force, can be focused onto a high-Z convertor to generate high-brightness beams of gamma-rays, which in turn can be used to induce photonuclear reactions. In this work, the possibility of photo-transmutation of long-lived radionuclide Cs-135 by laser-plasma driven electron source has been demonstrated through Geant4 simulations. High energy electron generation, bremsstrahlung and photonuclear reaction have been observed at four different laser intensities of 10^{20} W/cm^2, 5 times 10^{20} W/cm^2, 10^{21} W/cm^2 and 5 times 10^{21} W/cm^2, respectively. It was shown that the laser intensity and the target geometry have strong effect on the transmutation reaction yield. At different laser intensities the recommended target sizes were found to obtain the maximum reaction yield. The remarkable feature of this work is to evaluate the optimal laser intensity to produce maximum reaction yield of 10^8 per Joule in laser pulse energy, which is 10^{21} W/c...

  15. Waveguide slot-excited long racetrack electron cyclotron resonance plasma source for roll-to-roll (scanning) processing.

    Science.gov (United States)

    You, H-J

    2013-07-01

    We present a SLot-excited ANtenna (SLAN) long racetrack ECR plasma source that is utilized for roll-to-roll plasma processing such as thin film encapsulation of large-area OLED (organic light emitting diode) panel or modification of fabric surfaces. This source is designed to be long, and to operate under high density uniform plasma with sub-milli-torr pressures. The above features are accomplished by a slot-excited long racetrack resonator with a toroidal geometry of magnetic field ECR configuration, and reinforced microwave electric distributions along the central region of plasma chamber. Also, a new feature has been added to the source. This is to employ a tail plunger, which allows the microwave electric field and the uniformity of the plasma profile to be easily adjustable. We have successfully generated Ar plasmas operating with the microwave power of 0.5-3 kW in the pressure range of 0.2-10 mTorr. The plasma is uniform (racetrack-SLAN source.

  16. Electron Beam Ion Sources

    OpenAIRE

    Zschornacka, G.; Schmidt, M.; Thorn, A.

    2014-01-01

    Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviole...

  17. Ion sources with arc-discharge plasma box driven by directly heated LaB(6) electron emitter or cold cathode.

    Science.gov (United States)

    Ivanov, Alexander A; Davydenko, Vladimir I; Deichuli, Petr P; Shulzhenko, Grigori I; Stupishin, Nikolay V

    2008-02-01

    In the Budker Institute, Novosibirsk, an ion source with arc-discharge plasma box has been developed in the recent years for application in thermonuclear devices for plasma diagnostics. Several modifications of the ion source were provided with extracted current ranging from 1 to 7 A and pulse duration of up to 4 s. Initially, the arc-discharge plasma box with cold cathode was used, with which pulse duration is limited to 2 s by the cathode overheating and sputtering in local arc spots. Recently, a directly heated LaB(6) electron emitter was employed instead, which has extended lifetime compared to the cold cathode. In the paper, characteristics of the beam produced with both arrangements of the plasma box are presented.

  18. Field emission electron source

    Science.gov (United States)

    Zettl, Alexander Karlwalter; Cohen, Marvin Lou

    2000-01-01

    A novel field emitter material, field emission electron source, and commercially feasible fabrication method is described. The inventive field emission electron source produces reliable electron currents of up to 400 mA/cm.sup.2 at 200 volts. The emitter is robust and the current it produces is not sensitive to variability of vacuum or the distance between the emitter tip and the cathode. The novel emitter has a sharp turn-on near 100 volts.

  19. Polarized Electron Source Developments

    Energy Technology Data Exchange (ETDEWEB)

    Charles K. Sinclair

    1990-02-23

    Presently, only two methods of producing beams of polarized electrons for injection into linear accelerators are in use. Each of these methods uses optical pumping by circularly polarized light to produce electron polarization. In one case, electron polarization is established in metastable helium atoms, while in the other case, the polarized electrons are produced in the conduction band of appropriate semiconductors. The polarized electrons are liberated from the helium metastable by chemi-ionization, and from the semiconductors by lowering the work function at the surface of the material. Developments with each of these sources since the 1988 Spin Physics Conference are reviewed, and the prospects for further improvements discussed.

  20. An ultracold low emittance electron source

    CERN Document Server

    Xia, G; Murray, A J; Bellan, L; Bertsche, W; Appleby, R B; Mete, O; Chattopadhyay, S

    2014-01-01

    Ultracold atom-based electron sources have recently been proposed as an alternative to the conventional photo-injectors or thermionic electron guns widely used in modern particle accelerators. The advantages of ultracold atom-based electron sources lie in the fact that the electrons extracted from the plasma (created from near threshold photo-ionization of ultracold atoms) have a very low temperature, i.e. down to tens of Kelvin. Extraction of these electrons has the potential for producing very low emittance electron bunches. These features are crucial for the next generation of particle accelerators, including free electron lasers, plasma-based accelerators and future linear colliders. The source also has many potential direct applications, including ultrafast electron diffraction (UED) and electron microscopy, due to its intrinsically high coherence. In this paper, the basic mechanism of ultracold electron beam production is discussed and our new research facility for an ultracold, low emittance electron s...

  1. Electron Beam Ion Sources

    CERN Document Server

    Zschornacka, G.; Thorn, A.

    2013-12-16

    Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviolet, visible light) from highly charged ions. This chapter gives an overview of EBIS physics, the principle of operation, and the known technical solutions. Using examples, the performance of EBISs as well as their applications in various fields of basic research, technology and medicine are discussed.

  2. Plasma parameters controlled by remote electron shower in a double plasma device

    Science.gov (United States)

    Mishra, M. K.; Phukan, A.

    2012-07-01

    The principal feature of this experiment is the electron showers consisting of three tungsten wires embedded by the plasma, which are heated up consequently emitting electrons inside the diffused plasma to control the plasma parameters in the discharge section of a double plasma device. These cold electrons emitted by the heated filament are free from maintenance of discharge which is sustained in the source section. The target plasma, where electrons are injected is produced as a result of diffusion from the source section. It is found that, plasma density and plasma potential can be effectively controlled in this way.

  3. Meter scale plasma source for plasma wakefield experiments

    Science.gov (United States)

    Vafaei-Najafabadi, N.; Shaw, J. L.; Marsh, K. A.; Joshi, C.; Hogan, M. J.

    2012-12-01

    High accelerating gradients generated by a high density electron beam moving through plasma has been used to double the energy of the SLAC electron beam [1]. During that experiment, the electron current density was high enough to generate its own plasma without significant head erosion. In the newly commissioned FACET facility at SLAC, the peak current will be lower and without pre-ionization, head erosion will be a significant challenge for the planned experiments. In this work we report on our design of a meter scale plasma source for these experiments to effectively avoid the problem of head erosion. The plasma source is based on a homogeneous metal vapor gas column that is generated in a heat pipe oven [2]. A lithium oven over 30 cm long at densities over 1017 cm-3 has been constructed and tested at UCLA. The plasma is then generated by coupling a 10 TW short pulse Ti:Sapphire laser into the gas column using an axicon lens setup. The Bessel profile of the axicon setup creates a region of high intensity that can stretch over the full length of the gas column with approximately constant diameter. In this region of high intensity, the alkali metal vapor is ionized through multi-photon ionization process. In this manner, a fully ionized meter scale plasma of uniform density can be formed. Methods for controlling the plasma diameter and length will also be discussed.

  4. Meter scale plasma source for plasma wakefield experiments

    Energy Technology Data Exchange (ETDEWEB)

    Vafaei-Najafabadi, N.; Shaw, J. L.; Marsh, K. A.; Joshi, C.; Hogan, M. J. [Department of Electrical Engineering, University of California Los Angeles, Los Angeles, CA 90095 (United States); SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States)

    2012-12-21

    High accelerating gradients generated by a high density electron beam moving through plasma has been used to double the energy of the SLAC electron beam [1]. During that experiment, the electron current density was high enough to generate its own plasma without significant head erosion. In the newly commissioned FACET facility at SLAC, the peak current will be lower and without pre-ionization, head erosion will be a significant challenge for the planned experiments. In this work we report on our design of a meter scale plasma source for these experiments to effectively avoid the problem of head erosion. The plasma source is based on a homogeneous metal vapor gas column that is generated in a heat pipe oven [2]. A lithium oven over 30 cm long at densities over 10{sup 17} cm{sup -3} has been constructed and tested at UCLA. The plasma is then generated by coupling a 10 TW short pulse Ti:Sapphire laser into the gas column using an axicon lens setup. The Bessel profile of the axicon setup creates a region of high intensity that can stretch over the full length of the gas column with approximately constant diameter. In this region of high intensity, the alkali metal vapor is ionized through multi-photon ionization process. In this manner, a fully ionized meter scale plasma of uniform density can be formed. Methods for controlling the plasma diameter and length will also be discussed.

  5. Plasma wake field XUV radiation source

    Energy Technology Data Exchange (ETDEWEB)

    Prono, Daniel S. (Los Alamos, NM); Jones, Michael E. (Los Alamos, NM)

    1997-01-01

    A XUV radiation source uses an interaction of electron beam pulses with a gas to create a plasma radiator. A flowing gas system (10) defines a circulation loop (12) with a device (14), such as a high pressure pump or the like, for circulating the gas. A nozzle or jet (16) produces a sonic atmospheric pressure flow and increases the density of the gas for interacting with an electron beam. An electron beam is formed by a conventional radio frequency (rf) accelerator (26) and electron pulses are conventionally formed by a beam buncher (28). The rf energy is thus converted to electron beam energy, the beam energy is used to create and then thermalize an atmospheric density flowing gas to a fully ionized plasma by interaction of beam pulses with the plasma wake field, and the energetic plasma then loses energy by line radiation at XUV wavelengths Collection and focusing optics (18) are used to collect XUV radiation emitted as line radiation when the high energy density plasma loses energy that was transferred from the electron beam pulses to the plasma.

  6. RF Electron Gun with Driven Plasma Cathode

    CERN Document Server

    Khodak, Igor

    2005-01-01

    It's known that RF guns with plasma cathodes based on solid-state dielectrics are able to generate an intense electron beam. In this paper we describe results of experimental investigation of the single cavity S-band RF gun with driven plasma cathode. The experimental sample of the cathode based on ferroelectric ceramics has been designed. Special design of the cathode permits to separate spatially processes of plasma development and electron acceleration. It has been obtained at RF gun output electron beam with particle energy ~500 keV, pulse current of 4 A and pulse duration of 80 ns. Results of experimental study of beam parameters are referred in. The gun is purposed to be applied as the intense electron beam source for electron linacs.

  7. 21 CFR 640.60 - Source Plasma.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Source Plasma. 640.60 Section 640.60 Food and... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.60 Source Plasma. The proper name of the product shall be Source Plasma. The product is defined as the fluid portion of human blood...

  8. Miniaturized cathodic arc plasma source

    Science.gov (United States)

    Anders, Andre; MacGill, Robert A.

    2003-04-15

    A cathodic arc plasma source has an anode formed of a plurality of spaced baffles which extend beyond the active cathode surface of the cathode. With the open baffle structure of the anode, most macroparticles pass through the gaps between the baffles and reflect off the baffles out of the plasma stream that enters a filter. Thus the anode not only has an electrical function but serves as a prefilter. The cathode has a small diameter, e.g. a rod of about 1/4 inch (6.25 mm) diameter. Thus the plasma source output is well localized, even with cathode spot movement which is limited in area, so that it effectively couples into a miniaturized filter. With a small area cathode, the material eroded from the cathode needs to be replaced to maintain plasma production. Therefore, the source includes a cathode advancement or feed mechanism coupled to cathode rod. The cathode also requires a cooling mechanism. The movable cathode rod is housed in a cooled metal shield or tube which serves as both a current conductor, thus reducing ohmic heat produced in the cathode, and as the heat sink for heat generated at or near the cathode. Cooling of the cathode housing tube is done by contact with coolant at a place remote from the active cathode surface. The source is operated in pulsed mode at relatively high currents, about 1 kA. The high arc current can also be used to operate the magnetic filter. A cathodic arc plasma deposition system using this source can be used for the deposition of ultrathin amorphous hard carbon (a-C) films for the magnetic storage industry.

  9. Spectroscopic characterization of atmospheric pressure um-jet plasma source

    CERN Document Server

    Bibinov, Nikita; Bahre, Hendrik; Awakowicz, Peter; der Gathen, Volker Schulz-von

    2011-01-01

    A radio frequency um-jet plasma source is studied using He/O2 mixture. This um-jet can be used for different applications as a source of chemical active species e.g. oxygen atoms, molecular metastables and ozone. Using absolutely-calibrated optical emission spectroscopy and numerical simulation, the gas temperature in active plasma region and plasma parameters (electron density and electron distribution function) are determined. Concentrations of oxygen atoms and ozone in the plasma channel and in the effluent of the plasma source are measured using emission and absorption spectroscopy. To interpret the measured spatial distributions, the steady-state species' concentrations are calculated using determined plasma parameters and gas temperature. At that the influence of the surface processes and gas flow regime on the loss of the active species in the plasma source are discussed. The measured spatial distributions of oxygen atom and ozone densities are compared with the simulated ones.

  10. Spatial control of processing plasmas in a multicusp plasma source equipped with a movable magnetic filter

    Energy Technology Data Exchange (ETDEWEB)

    Fukumasa, O.; Naitou, H.; Sakiyama, S. (Yamaguchi Univ., Yamaguchi (Japan))

    1991-12-20

    The plasma chemical vapor deposition (p-CVD) method has been used in the preparation of various sorts of thin films such as hydrogenated amorphous silicon films and hydrogenated amorphous carbon films, etc. and the application feasibility of a magnetically filtered multicusp plasma source has been studied. In this paper, it is confirmed that plasma parameters (H {sub 2} - ch {sub 4} or Ar-CH {sub 4} plasmas) are spatially well controlled by using both a movable magnetic filter and a plasma grid. Plasma parameters change sharply across the magnetic filter at any filter position and the whole plasma is divided clearly into the region of source plasma with high-energy electrons and the region of diffused plasma without high-energy electrons. Concerning the role of the magnetic filter which reflects preferentially high-energy electrons, a study is made through computer simulation. 7 refs., 9 figs.

  11. A simple electron plasma wave

    Science.gov (United States)

    Brodin, G.; Stenflo, L.

    2017-03-01

    Considering a class of solutions where the density perturbations are functions of time, but not of space, we derive a new exact large amplitude wave solution for a cold uniform electron plasma. This result illustrates that most simple analytical solutions can appear even if the density perturbations are large.

  12. Profiles of ion beams and plasma parameters on a multi-frequencies microwaves large bore electron cyclotron resonance ion source with permanent magnets.

    Science.gov (United States)

    Kato, Yushi; Sakamoto, Naoki; Kiriyama, Ryutaro; Takenaka, Tomoya; Kurisu, Yosuke; Nozaki, Dai; Sato, Fuminobu; Iida, Toshiyuki

    2012-02-01

    In order to contribute to various applications of plasma and beams based on an electron cyclotron resonance, a new concept on magnetic field with all magnets on plasma production and confinement has been proposed with enhanced efficiency for broad and dense ion beam. The magnetic field configuration consists of a pair of comb-shaped magnet surrounding plasma chamber cylindrically. Resonance zones corresponding for 2.45 GHz and 11-13 GHz frequencies are positioned at spatially different positions. We launch simultaneously multiplex frequencies microwaves operated individually, try to control profiles of the plasma parameters and the extracted ion beams, and to measure them in detail.

  13. Multicapillary cathode controlled by a ferroelectric plasma source

    Science.gov (United States)

    Gleizer, J. Z.; Hadas, Y.; Krasik, Ya. E.

    2008-06-01

    We present results of high-current microsecond and sub-microsecond duration electron beam generation in a ~200 kV diode with a multicapillary dielectric cathode (MCDC) assisted by a ferroelectric plasma source (FPS). Electron beam current densities are achieved up to 40 A/cm2. It was shown that the operation of the MCDC is determined by the parameters of the plasma flow generated by the FPS. Also, it was found that the high resistivity of the plasma produced inside the capillaries allows effective de-coupling of individual capillary plasma discharges which results in uniform electron beam generation.

  14. A simple electron plasma wave

    Energy Technology Data Exchange (ETDEWEB)

    Brodin, G., E-mail: gert.brodin@physics.umu.se [Department of Physics, Umeå University, SE-901 87 Umeå (Sweden); Stenflo, L. [Department of Physics, Linköping University, SE-581 83 Linköping (Sweden)

    2017-03-18

    Considering a class of solutions where the density perturbations are functions of time, but not of space, we derive a new exact large amplitude wave solution for a cold uniform electron plasma. This result illustrates that most simple analytical solutions can appear even if the density perturbations are large. - Highlights: • The influence of large amplitude electromagnetic waves on electrostatic oscillations is found. • A generalized Mathieu equation is derived. • Anharmonic wave profiles are computed numerically.

  15. The physics of Electron Beam Ion Sources

    Energy Technology Data Exchange (ETDEWEB)

    Stockli, M.P.; Cocke, C.L.

    1990-01-01

    There are 13 Electron Beam Ion Sources in operation which produce highly charged ions, up to Th[sup 80+] and Xe[sup 53+]. Most of the sources are used to study these ions under electron impact or when recombining with gaseous or solid targets. That provides an insight into the atomic physics of these highly charged ions and into the physics of the plasma in which such ions can be found. This paper reviews the present knowledge of atomic processes, important in the production of such ions with an EBIS.

  16. The physics of Electron Beam Ion Sources

    Energy Technology Data Exchange (ETDEWEB)

    Stockli, M.P.; Cocke, C.L.

    1990-12-31

    There are 13 Electron Beam Ion Sources in operation which produce highly charged ions, up to Th{sup 80+} and Xe{sup 53+}. Most of the sources are used to study these ions under electron impact or when recombining with gaseous or solid targets. That provides an insight into the atomic physics of these highly charged ions and into the physics of the plasma in which such ions can be found. This paper reviews the present knowledge of atomic processes, important in the production of such ions with an EBIS.

  17. Identifying the source of super-high energetic electrons in the presence of pre-plasma in laser-matter interaction at relativistic intensities

    CERN Document Server

    Wu, D; Luan, S X; Yu, W

    2015-01-01

    The generation of super-high energetic electrons influenced by pre-plasma in relativistic intensity laser matter interaction is studied in a one-dimensional slab approximation with particle-in-cell simulations. Different pre-plasma scale-lengths of $1\\ \\mu\\text{m}$, $5\\ \\mu\\text{m}$, $10\\ \\mu\\text{m}$ and $15\\ \\mu\\text{m}$ are considered, showing an increase in both particle number and cut-off kinetic energy of energetic electrons with the increase of pre-plasma scale-length, and the obtained cut-off electron energies greatly exceeding the ponderomotive energies. A two-stage electron acceleration model is proposed to explain the underlying physics. The first stage is attributed to the synergetic acceleration by longitudinal electric field and laser pulse, with the efficiency depending on the pre-plasma scale-length. The fast electrons pre-accelerated in the first stage could build up an intense electrostatic potential with the potential energy several times as large of the initial electron kinetic energy. Par...

  18. Identifying the source of super-high energetic electrons in the presence of pre-plasma in laser-matter interaction at relativistic intensities

    Science.gov (United States)

    Wu, D.; Krasheninnikov, S. I.; Luan, S. X.; Yu, W.

    2017-01-01

    The generation of super-high energetic electrons influenced by pre-plasma in relativistic intensity laser-matter interaction is studied in a one-dimensional slab approximation with particle-in-cell simulations. Different pre-plasma scale lengths and laser intensities are considered, showing an increase in both particle number and cut-off kinetic energy of electrons with the increase of pre-plasma scale length and laser intensity, the cut-off kinetic energy greatly exceeding the corresponding laser ponderomotive energy. A two-stage electron acceleration model is proposed to explain the underlying physics. The first stage is attributed to the synergetic acceleration by longitudinal electric field and counter-propagating laser pulses, and a scaling law is obtained with efficiency depending on the pre-plasma scale length and laser intensity. These electrons pre-accelerated in the first stage could build up an intense electrostatic potential barrier with maximal value several times as large as the initial electron kinetic energy. Some of the energetic electrons could be further accelerated by reflection off the electrostatic potential barrier, with their finial kinetic energies significantly higher than the values pre-accelerated in the first stage.

  19. Optical plasma torch electron bunch generation in plasma wakefield accelerators

    Directory of Open Access Journals (Sweden)

    G. Wittig

    2015-08-01

    Full Text Available A novel, flexible method of witness electron bunch generation in plasma wakefield accelerators is described. A quasistationary plasma region is ignited by a focused laser pulse prior to the arrival of the plasma wave. This localized, shapeable optical plasma torch causes a strong distortion of the plasma blowout during passage of the electron driver bunch, leading to collective alteration of plasma electron trajectories and to controlled injection. This optically steered injection is more flexible and faster when compared to hydrodynamically controlled gas density transition injection methods.

  20. Plasma-Based Ion Beam Sources

    Energy Technology Data Exchange (ETDEWEB)

    Loeb, H. W.

    2005-07-01

    Ion beam sources cover a broad spectrum of scientific and technical applications delivering ion currents between less than 1 mA and about 100 A at acceleration voltages between 100 V and 100 kV. The ions are mostly generated by electron collisions in a gas discharge and then extracted from the discharge plasma, focused and post-accelerated by single- or multi-aperture electrode systems. Some important applications require the neutralization of the exhausted beam either by charge exchange or by admixture of electrons. In the first part of the paper, the theory of ionization by electron impact, the energy and carrier balances in the plasma, and the extraction and focusing mechanisms will be outlined. The principles of the preferred gas discharges and of the ion beam sources based on them are discussed; i.e. of the Penning, bombardment, arc, duoplasmatron, radio frequency, and microwave types. In the second part of the paper, the special requirements of the different applications are described together with the related source hardware. One distinguishes: 1. Single-aperture ion sources producing protons, heavy ions, isotope ions, etc. for particle accelerators, ion microprobes, mass spectrometers, isotope separators, etc.; quality determinative quantities are brightness, emittance, energy width, etc. 2. Broad-beam multi-aperture injector sources for fusion machines with positive or negative deuterium ions; very high beam densities, small portions of molecular ions, flat beam profiles with small divergence angles, etc. are required. 3. Broad-beam multi-aperture ion thrusters for space propulsion operated with singly charged xenon ions; high efficiencies, reliable operation, and long lifetimes are most important. Spin-offs are applied in industry for material processing. Referring to these applications, the following sources will be described in some detail: 1. Cold cathode and filament driven sources, capillary arc and plasmatron types, microwave and ECR-sources. 2

  1. Electron thermal transport in tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Konings, J.A.

    1994-11-30

    The process of fusion of small nuclei thereby releasing energy, as it occurs continuously in the sun, is essential for the existence of mankind. The same process applied in a controlled way on earth would provide a clean and an abundant energy source, and be the long term solution of the energy problem. Nuclear fusion requires an extremely hot (10{sup 8} K) ionized gas, a plasma, that can only be maintained if it is kept insulated from any material wall. In the so called `tokamak` this is achieved by using magnetic fields. The termal insulation, which is essential if one wants to keep the plasma at the high `fusion` temperature, can be predicted using basic plasma therory. A comparison with experiments in tokamaks, however, showed that the electron enery losses are ten to hundred times larger than this theory predicts. This `anomalous transport` of thermal energy implies that, to reach the condition for nuclear fusion, a fusion reactor must have very large dimensions. This may put the economic feasibility of fusion power in jeopardy. Therefore, in a worldwide collaboration, physicists study tokamak plasmas in an attempt to understand and control the energy losses. From a scientific point of view, the mechanisms driving anomalous transport are one of the challenges in fudamental plasma physics. In Nieuwegein, a tokamak experiment (the Rijnhuizen Tokamak Project, RTP) is dedicated to the study of anomalous transport, in an international collaboration with other laboratories. (orig./WL).

  2. Dense Plasma Focus - From Alternative Fusion Source to Versatile High Energy Density Plasma Source for Plasma Nanotechnology

    Science.gov (United States)

    Rawat, R. S.

    2015-03-01

    The dense plasma focus (DPF), a coaxial plasma gun, utilizes pulsed high current electrical discharge to heat and compress the plasma to very high density and temperature with energy densities in the range of 1-10 × 1010 J/m3. The DPF device has always been in the company of several alternative magnetic fusion devices as it produces intense fusion neutrons. Several experiments conducted on many different DPF devices ranging over several order of storage energy have demonstrated that at higher storage energy the neutron production does not follow I4 scaling laws and deteriorate significantly raising concern about the device's capability and relevance for fusion energy. On the other hand, the high energy density pinch plasma in DPF device makes it a multiple radiation source of ions, electron, soft and hard x-rays, and neutrons, making it useful for several applications in many different fields such as lithography, radiography, imaging, activation analysis, radioisotopes production etc. Being a source of hot dense plasma, strong shockwave, intense energetic beams and radiation, etc, the DPF device, additionally, shows tremendous potential for applications in plasma nanoscience and plasma nanotechnology. In the present paper, the key features of plasma focus device are critically discussed to understand the novelties and opportunities that this device offers in processing and synthesis of nanophase materials using, both, the top-down and bottom-up approach. The results of recent key experimental investigations performed on (i) the processing and modification of bulk target substrates for phase change, surface reconstruction and nanostructurization, (ii) the nanostructurization of PLD grown magnetic thin films, and (iii) direct synthesis of nanostructured (nanowire, nanosheets and nanoflowers) materials using anode target material ablation, ablated plasma and background reactive gas based synthesis and purely gas phase synthesis of various different types of

  3. Impedance Source Power Electronic Converters

    DEFF Research Database (Denmark)

    Liu, Yushan; Abu-Rub, Haitham; Ge, Baoming

    Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable...... and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key...... control methods. Presents the latest power conversion solutions that aim to advance the role of power electronics into industries and sustainable energy conversion systems. Compares impedance source converter/inverter applications in renewable energy power generation and electric vehicles as well...

  4. Effect of Substrate Potential on Plasma Parameters of Magnetic Multicusp Plasma Source

    Science.gov (United States)

    Ueda, Yoshio; Goto, Masahiro

    1998-06-01

    The effect of substrate potential on plasmas produced in a magnetic multicusp plasma source has been studied experimentally. Plasma parameters such as electron temperature and plasma potential are estimated from electron energy distribution function numerically calculated from probe current-voltage characteristics. For a substrate potential of -150 V with respect to the source chamber, which is much lower than substrate floating potentials, the plasma parameters are not affected by the application of the potential. However, for the case where the substrate is shorted with the source chamber, the high energy component of electrons significantly decreases in comparison with the floating case leading to the reduction of electron temperature. In this case, plasma potential is positive with respect to the substrate to suppress electron loss but its absolute value is only of the order of electron temperature in eV, which is much lower than the potential between the plasma and the substrate in the floating case. This discharge mode could be advantageous in significantly reducing the ion impact energy to the substrate plate.

  5. MAGNETIC FIELD GRADIENT EFFECTS ON ION FLUX BEHAVIORS IN ECR PLASMA SOURCES

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The available electron cyclotron resonance plasma source has been simulated in two-dimensional configuration space (z, r) and three-dimensional velocity space (Vz, Vr Vθ). The simulation is focused on the magnetic field gradient effects on ion flux behaviors in electron cyclotron resonance plasma sources. The simulation results show that, when the magnetic field gradients increase, electron temperature, plasma density, ionization rate, and ion flux in Zdirection would decrease, while ion energy and plasma potential would increase.

  6. The study of helicon plasma source.

    Science.gov (United States)

    Miao, Ting-Ting; Zhao, Hong-Wei; Liu, Zhan-Wen; Shang, Yong; Sun, Liang-Ting; Zhang, Xue-Zhen; Zhao, Huan-Yu

    2010-02-01

    Helicon plasma source is known as efficient generator of uniform and high density plasma. A helicon plasma source was developed for investigation of plasma neutralization and plasma lens in the Institute of Modern Physics in China. In this paper, the characteristics of helicon plasma have been studied by using Langmuir four-probe and a high argon plasma density up to 3.9x10(13) cm(-3) have been achieved with the Nagoya type III antenna at the conditions of the magnetic intensity of 200 G, working gas pressure of 2.8x10(-3) Pa, and rf power of 1200 W with a frequency of 27.12 MHz. In the experiment, the important phenomena have been found: for a given magnetic induction intensity, the plasma density became greater with the increase in rf power and tended to saturation, and the helicon mode appeared at the rf power between 200 and 400 W.

  7. Impedance source power electronic converters

    CERN Document Server

    Liu, Yushan; Ge, Baoming; Blaabjerg, Frede; Ellabban, Omar; Loh, Poh Chiang

    2016-01-01

    Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key features: Comprehensive analysis of the impedance source converter/inverter topologies, including typical topologies and derived topologies. Fully explains the design and control techniques of impedance source converters/inverters, including hardware design and control parameter design for corresponding control methods. Presents the latest power conversion solutions that aim to advance the role of pow...

  8. Electron Kinetics in Hypersonic Plasmas Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this SBIR project is to advance the state-of-the-art in computations of hypersonic plasmas by adding high-fidelity kinetic models for electrons. Electron...

  9. Physical investigation of a quad confinement plasma source

    Science.gov (United States)

    Knoll, Aaron; Lucca Fabris, Andrea; Young, Christopher; Cappelli, Mark

    2016-10-01

    Quad magnetic confinement plasma sources are novel magnetized DC discharges suitable for applications in a broad range of fields, particularly space propulsion, plasma etching and deposition. These sources contain a square discharge channel with magnetic cusps at the four lateral walls, enhancing plasma confinement and electron residence time inside the device. The magnetic field topology is manipulated using four independent electromagnets on each edge of the channel, tuning the properties of the generated plasma. We characterize the plasma ejected from the quad confinement sources using a combination of traditional electrostatic probes and non-intrusive laser-based diagnostics. Measurements show a strong ion acceleration layer located 8 cm downstream of the exit plane, beyond the extent of the magnetic field. The ion velocity field is investigated with different magnetic configurations, demonstrating how ion trajectories may be manipulated. C.Y. acknowledges support from the DOE NSSA Stewardship Science Graduate Fellowship under contract DE-FC52-08NA28752.

  10. Collapse of nonlinear electron plasma waves in a plasma layer

    Science.gov (United States)

    Grimalsky, V.; Koshevaya, S.; Rapoport, Yu; Kotsarenko, A.

    2016-10-01

    The excitation of nonlinear electron plasma waves in the plasma layer is investigated theoretically. This excitation is realized by means of initial oscillatory perturbations of the volume electron concentration or by initial oscillatory distributions of the longitudinal electron velocity. The amplitudes of the initial perturbations are small and the manifestation of the volume nonlinearity is absent. When the amplitudes of the initial perturbations exceed some thresholds, the values of the electron concentration near the plasma boundary increase catastrophically. The maxima of the electron concentration reach extremely high magnitudes, and sharp peaks in the electron concentration occur, which are localized both in the longitudinal and transverse directions. This effect is interpreted as wave collapse near the plasma boundary.

  11. Surface-wave plasma source with magnetic multicusp fields; Multicusp jiba tojikome hyomenha plasma gen

    Energy Technology Data Exchange (ETDEWEB)

    Tsuda, M.; Ono, K.; Tsuchihashi, M.; Hanazaki, M.; Komemura, T. [Mitsubishi Electric Corp., Tokyo (Japan)

    1998-11-01

    A new-type microwave plasma source has been developed for materials processing. The plasma reactor employed a launcher of azimuthally symmetric surface waves at a frequency of 2.45 GHz and also magnetic multicusp fields around the reactor chamber walls. This configuration yielded high-density (Ne {>=} 10{sup 11}cm{sup -3}) plasmas sustained by surface waves even at low gas pressures below 10 m Torr, following easy plasma ignition by electron cyclotron resonance (ECR) discharges. Electrical and optical diagnostics were made to obtain the plasma properties in Ar. It was shown that a transition from ECR excited to surface-wave excited plasmas occurs under conditions where the plasma electron density exceeds a critical value of Ne-1 times 10{sup 11}cm{sup -3}. 21 refs., 14 figs.

  12. High intensity polarized electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, C.K.

    1980-10-01

    The status of the polarized electron source development program at SLAC will be reviewed. Emission currents of 60 A, corresponding to a space charge limited current density of 180 A/cm/sup 2/, have been obtained from GaAs photocathodes. Electron beam polarization 20% greater than that obtainable from GaAs cathodes has been observed from multilayer GaAs-GaAlAs structures. Work in progress to produce high beam polarization from II-IV-V/sub 2/ chalcopyrite photocathodes will also be described.

  13. Characteristics of Cylindrical Microwave Plasma Source at Low Pressure

    Science.gov (United States)

    Park, Seungil; Youn, S.; Kim, S. B.; Yoo, S. J.

    2016-10-01

    A microwave plasma source with a cylindrical resonance cavity has been proposed to generate the plasma at low pressure. This plasma source consists of magnetron, waveguide, antenna, and cavity. The microwave generating device is a commercial magnetron with 1 kW output power at the frequency of 2.45 GHz. The microwave is transmitted through the rectangular waveguide with the whistle shape, and coupled to the cavity by the slot antenna. The resonant mode of the cylindrical cavity is the TE111 mode. The operating pressure is between 0.1 Torr and 0.3 Torr with the Argon and nitrogen gas. The electron temperature and electron number density of argon plasma were measured with the optical emission spectroscopy measurement. And Ar1s5 metastable density was measured using tunable diode laser absorption spectroscopy (TDLAS). The plasma diagnostic results of a cylindrical microwave plasma source would be described in this study. This work was supported by R&D Program of ``Plasma Advanced Technology for Agriculture and Food (Plasma Farming)'' through the National Fusion Research Institute of Korea (NFRI) funded by the Government funds.

  14. Plasma chemistry in electron-beam sustained discharges

    Science.gov (United States)

    Turner, Miles

    2016-09-01

    There are many emerging applications that exploit the exotic chemical characteristics of plasmas. Some of these applications, if deployed on an industrial scale, involve processing much larger volumes of gas than seems reasonable using any atmospheric pressure plasma source in wide use today. We note that an electron-beam sustained discharge permits the creation of a atmospheric pressure plasma with reasonable uniformity, large volme, and widely controllable electron temperature. Robust and durable electron beam sources now exist that would facilitate such applications. In this paper we discuss the general advantages of this approach, and we present a modelling study concerned with the production of NO in mixtures of N2 and O2, looking towards plasma aided manufacturing of fertilizers.

  15. Surface plasma source with saddle antenna radio frequency plasma generator.

    Science.gov (United States)

    Dudnikov, V; Johnson, R P; Murray, S; Pennisi, T; Piller, C; Santana, M; Stockli, M; Welton, R

    2012-02-01

    A prototype RF H(-) surface plasma source (SPS) with saddle (SA) RF antenna is developed which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability. Several versions of new plasma generators with small AlN discharge chambers and different antennas and magnetic field configurations were tested in the plasma source test stand. A prototype SA SPS was installed in the Spallation Neutron Source (SNS) ion source test stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency up to 1.6 mA∕kW. Control experiments with H(-) beam produced by SNS SPS with internal and external antennas were conducted. A new version of the RF triggering plasma gun has been designed. A saddle antenna SPS with water cooling is fabricated for high duty factor testing.

  16. Electron density and plasma dynamics of a colliding plasma experiment

    Energy Technology Data Exchange (ETDEWEB)

    Wiechula, J., E-mail: wiechula@physik.uni-frankfurt.de; Schönlein, A.; Iberler, M.; Hock, C.; Manegold, T.; Bohlender, B.; Jacoby, J. [Plasma Physics Group, Institute of Applied Physics, Goethe University, 60438 Frankfurt am Main (Germany)

    2016-07-15

    We present experimental results of two head-on colliding plasma sheaths accelerated by pulsed-power-driven coaxial plasma accelerators. The measurements have been performed in a small vacuum chamber with a neutral-gas prefill of ArH{sub 2} at gas pressures between 17 Pa and 400 Pa and load voltages between 4 kV and 9 kV. As the plasma sheaths collide, the electron density is significantly increased. The electron density reaches maximum values of ≈8 ⋅ 10{sup 15} cm{sup −3} for a single accelerated plasma and a maximum value of ≈2.6 ⋅ 10{sup 16} cm{sup −3} for the plasma collision. Overall a raise of the plasma density by a factor of 1.3 to 3.8 has been achieved. A scaling behavior has been derived from the values of the electron density which shows a disproportionately high increase of the electron density of the collisional case for higher applied voltages in comparison to a single accelerated plasma. Sequences of the plasma collision have been taken, using a fast framing camera to study the plasma dynamics. These sequences indicate a maximum collision velocity of 34 km/s.

  17. Studies on plasma production in a large volume system using multiple compact ECR plasma sources

    Science.gov (United States)

    Tarey, R. D.; Ganguli, A.; Sahu, D.; Narayanan, R.; Arora, N.

    2017-01-01

    This paper presents a scheme for large volume plasma production using multiple highly portable compact ECR plasma sources (CEPS) (Ganguli et al 2016 Plasma Source Sci. Technol. 25 025026). The large volume plasma system (LVPS) described in the paper is a scalable, cylindrical vessel of diameter  ≈1 m, consisting of source and spacer sections with multiple CEPS mounted symmetrically on the periphery of the source sections. Scaling is achieved by altering the number of source sections/the number of sources in a source section or changing the number of spacer sections for adjusting the spacing between the source sections. A series of plasma characterization experiments using argon gas were conducted on the LVPS under different configurations of CEPS, source and spacer sections, for an operating pressure in the range 0.5-20 mTorr, and a microwave power level in the range 400-500 W per source. Using Langmuir probes (LP), it was possible to show that the plasma density (~1  -  2  ×  1011 cm-3) remains fairly uniform inside the system and decreases marginally close to the chamber wall, and this uniformity increases with an increase in the number of sources. It was seen that a warm electron population (60-80 eV) is always present and is about 0.1% of the bulk plasma density. The mechanism of plasma production is discussed in light of the results obtained for a single CEPS (Ganguli et al 2016 Plasma Source Sci. Technol. 25 025026).

  18. Saturn Plasma Sources and Associated Transport Processes

    Science.gov (United States)

    Blanc, M.; Andrews, D. J.; Coates, A. J.; Hamilton, D. C.; Jackman, C. M.; Jia, X.; Kotova, A.; Morooka, M.; Smith, H. T.; Westlake, J. H.

    2015-10-01

    This article reviews the different sources of plasma for Saturn's magnetosphere, as they are known essentially from the scientific results of the Cassini-Huygens mission to Saturn and Titan. At low and medium energies, the main plasma source is the H2O cloud produced by the "geyser" activity of the small satellite Enceladus. Impact ionization of this cloud occurs to produce on the order of 100 kg/s of fresh plasma, a source which dominates all the other ones: Titan (which produces much less plasma than anticipated before the Cassini mission), the rings, the solar wind (a poorly known source due to the lack of quantitative knowledge of the degree of coupling between the solar wind and Saturn's magnetosphere), and the ionosphere. At higher energies, energetic particles are produced by energy diffusion and acceleration of lower energy plasma produced by the interchange instabilities induced by the rapid rotation of Saturn, and possibly, for the highest energy range, by contributions from the CRAND process acting inside Saturn's magnetosphere. Discussion of the transport and acceleration processes acting on these plasma sources shows the importance of rotation-induced radial transport and energization of the plasma, and also shows how much the unexpected planetary modulation of essentially all plasma parameters of Saturn's magnetosphere remains an unexplained mystery.

  19. Alternative modeling methods for plasma-based Rf ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Veitzer, Seth A., E-mail: veitzer@txcorp.com; Kundrapu, Madhusudhan, E-mail: madhusnk@txcorp.com; Stoltz, Peter H., E-mail: phstoltz@txcorp.com; Beckwith, Kristian R. C., E-mail: beckwith@txcorp.com [Tech-X Corporation, Boulder, Colorado 80303 (United States)

    2016-02-15

    Rf-driven ion sources for accelerators and many industrial applications benefit from detailed numerical modeling and simulation of plasma characteristics. For instance, modeling of the Spallation Neutron Source (SNS) internal antenna H{sup −} source has indicated that a large plasma velocity is induced near bends in the antenna where structural failures are often observed. This could lead to improved designs and ion source performance based on simulation and modeling. However, there are significant separations of time and spatial scales inherent to Rf-driven plasma ion sources, which makes it difficult to model ion sources with explicit, kinetic Particle-In-Cell (PIC) simulation codes. In particular, if both electron and ion motions are to be explicitly modeled, then the simulation time step must be very small, and total simulation times must be large enough to capture the evolution of the plasma ions, as well as extending over many Rf periods. Additional physics processes such as plasma chemistry and surface effects such as secondary electron emission increase the computational requirements in such a way that even fully parallel explicit PIC models cannot be used. One alternative method is to develop fluid-based codes coupled with electromagnetics in order to model ion sources. Time-domain fluid models can simulate plasma evolution, plasma chemistry, and surface physics models with reasonable computational resources by not explicitly resolving electron motions, which thereby leads to an increase in the time step. This is achieved by solving fluid motions coupled with electromagnetics using reduced-physics models, such as single-temperature magnetohydrodynamics (MHD), extended, gas dynamic, and Hall MHD, and two-fluid MHD models. We show recent results on modeling the internal antenna H{sup −} ion source for the SNS at Oak Ridge National Laboratory using the fluid plasma modeling code USim. We compare demonstrate plasma temperature equilibration in two

  20. Alternative modeling methods for plasma-based Rf ion sources

    Science.gov (United States)

    Veitzer, Seth A.; Kundrapu, Madhusudhan; Stoltz, Peter H.; Beckwith, Kristian R. C.

    2016-02-01

    Rf-driven ion sources for accelerators and many industrial applications benefit from detailed numerical modeling and simulation of plasma characteristics. For instance, modeling of the Spallation Neutron Source (SNS) internal antenna H- source has indicated that a large plasma velocity is induced near bends in the antenna where structural failures are often observed. This could lead to improved designs and ion source performance based on simulation and modeling. However, there are significant separations of time and spatial scales inherent to Rf-driven plasma ion sources, which makes it difficult to model ion sources with explicit, kinetic Particle-In-Cell (PIC) simulation codes. In particular, if both electron and ion motions are to be explicitly modeled, then the simulation time step must be very small, and total simulation times must be large enough to capture the evolution of the plasma ions, as well as extending over many Rf periods. Additional physics processes such as plasma chemistry and surface effects such as secondary electron emission increase the computational requirements in such a way that even fully parallel explicit PIC models cannot be used. One alternative method is to develop fluid-based codes coupled with electromagnetics in order to model ion sources. Time-domain fluid models can simulate plasma evolution, plasma chemistry, and surface physics models with reasonable computational resources by not explicitly resolving electron motions, which thereby leads to an increase in the time step. This is achieved by solving fluid motions coupled with electromagnetics using reduced-physics models, such as single-temperature magnetohydrodynamics (MHD), extended, gas dynamic, and Hall MHD, and two-fluid MHD models. We show recent results on modeling the internal antenna H- ion source for the SNS at Oak Ridge National Laboratory using the fluid plasma modeling code USim. We compare demonstrate plasma temperature equilibration in two-temperature MHD models

  1. Effective attraction between oscillating electrons in plasma

    CERN Document Server

    Dvornikov, Maxim

    2011-01-01

    We consider the effective interaction between electrons due to the exchange of virtual acoustic waves in low temperature plasma. Electrons are supposed to participate in rapid oscillations and form a spherically symmetric soliton like structure. We show that under certain conditions this effective interaction can result in the attraction between oscillating electrons and can be important for the dynamics of a plasmoid. Some possible applications of the obtained results to the theory of natural long lived plasma structures are also discussed.

  2. Etching with atomic precision by using low electron temperature plasma

    Science.gov (United States)

    Dorf, L.; Wang, J.-C.; Rauf, S.; Monroy, G. A.; Zhang, Y.; Agarwal, A.; Kenney, J.; Ramaswamy, K.; Collins, K.

    2017-07-01

    There has been a steady increase in sub-nm precision requirement for many critical plasma etching processes in the semiconductor industry. In addition to high selectivity and low controllable etch rate, an important requirement of atomic precision etch processes is no (or minimal) damage to the remaining material surface. It has traditionally not been possible to avoid damage in conventional radio-frequency (RF) plasma processing systems, even during layer-by-layer or ‘atomic layer’ etch. To meet these increasingly stringent requirements, it is necessary to have an accurate control over ion energy and ion/radical composition during plasma processing. In this work, a new plasma etch system designed to facilitate atomic precision plasma processing is presented. An electron sheet beam parallel to the substrate surface is used to produce a plasma in this system. This plasma has a significantly lower electron temperature T e ~ 0.3 eV and ion energy E i  plasmas. Electron beam plasmas also have a higher ion-to-radical ratio compared to RF plasmas, so this plasma etch system employs an independent radical source for accurate control over relative ion and radical concentrations. A low frequency RF bias capability that allows control of ion energy in the 2-50 eV range is another important component of this plasma etch system. The results of etching of a variety of materials and structures in this low-electron temperature plasma system are presented in this study: (1) layer-by-layer etching of p-Si at E i ~ 25-50 eV using electrical and gas cycling is demonstrated; (2) continuous etching of epi-grown µ-Si in Cl2-based plasmas is performed, showing that surface damage can be minimized by keeping E i  etching at low E i.

  3. RF Plasma modeling of the Linac4 H− ion source

    CERN Document Server

    Mattei, S; Hatayama, A; Lettry, J; Kawamura, Y; Yasumoto, M; Schmitzer, C

    2013-01-01

    This study focuses on the modelling of the ICP RF-plasma in the Linac4 H− ion source currently being constructed at CERN. A self-consistent model of the plasma dynamics with the RF electromagnetic field has been developed by a PIC-MCC method. In this paper, the model is applied to the analysis of a low density plasma discharge initiation, with particular interest on the effect of the external magnetic field on the plasma properties, such as wall loss, electron density and electron energy. The use of a multi-cusp magnetic field effectively limits the wall losses, particularly in the radial direction. Preliminary results however indicate that a reduced heating efficiency results in such a configuration. The effect is possibly due to trapping of electrons in the multi-cusp magnetic field, preventing their continuous acceleration in the azimuthal direction.

  4. Inertial Electrostatic Confinement (IEC) Fusion using Helicon Injected Plasma Source

    Science.gov (United States)

    Miley, George; Ahern, Drew; Bowman, Jaerd

    2016-10-01

    The use of an external plasma source with the IEC has the advantage that the background pressure in the IEC chamber can be low. This then enables a deep potential well formation for ion confinement. Also unit efficiency is increase due to minimization of ion losses through charge exchange. This technique is under study experimentally for use in a plasma jet propulsion unit and as an IEC type neutron source. Current work has studied the effect of locating the IEC grids off-center in the vacuum chamber, near the plasma entrance from the Helicon. With double grids, the relative potentials employed are also key factors in device performance. Electron emitters are added for space charge neutralization in the case of plasma jet propulsion. Plasma simulations are used to supplement the experiments. Specifically, the electric field and the magnetic field effects on energetic ion trajectories are examined for varying configurations. Funding by NASA, Air Force Research Lab and NPL Associates.

  5. Modeling of low pressure plasma sources for microelectronics fabrication

    Science.gov (United States)

    Agarwal, Ankur; Bera, Kallol; Kenney, Jason; Likhanskii, Alexandre; Rauf, Shahid

    2017-10-01

    Chemically reactive plasmas operating in the 1 mTorr–10 Torr pressure range are widely used for thin film processing in the semiconductor industry. Plasma modeling has come to play an important role in the design of these plasma processing systems. A number of 3-dimensional (3D) fluid and hybrid plasma modeling examples are used to illustrate the role of computational investigations in design of plasma processing hardware for applications such as ion implantation, deposition, and etching. A model for a rectangular inductively coupled plasma (ICP) source is described, which is employed as an ion source for ion implantation. It is shown that gas pressure strongly influences ion flux uniformity, which is determined by the balance between the location of plasma production and diffusion. The effect of chamber dimensions on plasma uniformity in a rectangular capacitively coupled plasma (CCP) is examined using an electromagnetic plasma model. Due to high pressure and small gap in this system, plasma uniformity is found to be primarily determined by the electric field profile in the sheath/pre-sheath region. A 3D model is utilized to investigate the confinement properties of a mesh in a cylindrical CCP. Results highlight the role of hole topology and size on the formation of localized hot-spots. A 3D electromagnetic plasma model for a cylindrical ICP is used to study inductive versus capacitive power coupling and how placement of ground return wires influences it. Finally, a 3D hybrid plasma model for an electron beam generated magnetized plasma is used to understand the role of reactor geometry on plasma uniformity in the presence of E  ×  B drift.

  6. High Current, High Density Arc Plasma as a New Source for WiPAL

    Science.gov (United States)

    Waleffe, Roger; Endrizzi, Doug; Myers, Rachel; Wallace, John; Clark, Mike; Forest, Cary; WiPAL Team

    2016-10-01

    The Wisconsin Plasma Astrophysics Lab (WiPAL) has installed a new array of nineteen plasma sources (plasma guns) on its 3 m diameter, spherical vacuum vessel. Each gun is a cylindrical, molybdenum, washer-stabilized, arc plasma source. During discharge, the guns are maintained at 1.2 kA across 100 V for 10 ms by the gun power supply establishing a high density plasma. Each plasma source is fired independently allowing for adjustable plasma parameters, with densities varying between 1018 -1019 m-3 and electron temperatures of 5-15 eV. Measurements were characterized using a 16 tip Langmuir probe. The plasma source will be used as a background plasma for the magnetized coaxial plasma gun (MCPG), the Terrestrial Reconnection Experiment (TREX), and as the plasma source for a magnetic mirror experiment. Temperature, density, and confinement results will be presented. This work is supported by the DoE and the NSF.

  7. Development of a long-slot microwave plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Kuwata, Y., E-mail: euo1304@mail4.doshisha.ac.jp; Kasuya, T.; Miyamoto, N.; Wada, M. [Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

    2016-02-15

    A 20 cm long 10 cm wide microwave plasma source was realized by inserting two 20 cm long 1.5 mm diameter rod antennas into the plasma. Plasma luminous distributions around the antennas were changed by magnetic field arrangement created by permanent magnets attached to the source. The distributions appeared homogeneous in one direction along the antenna when the spacing between the antenna and the source wall was 7.5 mm for the input microwave frequency of 2.45 GHz. Plasma density and temperature at a plane 20 cm downstream from the microwave shield were measured by a Langmuir probe array at 150 W microwave power input. The measured electron density and temperature varied over space from 3.0 × 10{sup 9} cm{sup −3} to 5.8 × 10{sup 9} cm{sup −3}, and from 1.1 eV to 2.1 eV, respectively.

  8. Hollow-Cathode Source Generates Plasma

    Science.gov (United States)

    Deininger, W. D.; Aston, G.; Pless, L. C.

    1989-01-01

    Device generates argon, krypton, or xenon plasma via thermionic emission and electrical discharge within hollow cathode and ejects plasma into surrounding vacuum. Goes from cold start up to full operation in less than 5 s after initial application of power. Exposed to moist air between operations without significant degradation of starting and running characteristics. Plasma generated by electrical discharge in cathode barrel sustained and aided by thermionic emission from emitter tube. Emitter tube does not depend on rare-earth oxides, making it vulnerable to contamination by exposure to atmosphere. Device modified for use as source of plasma in laboratory experiments or industrial processes.

  9. Properties of Trapped Electron Bunches in a Plasma Wakefield Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Kirby, Neil; /SLAC

    2009-10-30

    Plasma-based accelerators use the propagation of a drive bunch through plasma to create large electric fields. Recent plasma wakefield accelerator (PWFA) experiments, carried out at the Stanford Linear Accelerator Center (SLAC), successfully doubled the energy for some of the 42 GeV drive bunch electrons in less than a meter; this feat would have required 3 km in the SLAC linac. This dissertation covers one phenomenon associated with the PWFA, electron trapping. Recently it was shown that PWFAs, operated in the nonlinear bubble regime, can trap electrons that are released by ionization inside the plasma wake and accelerate them to high energies. These trapped electrons occupy and can degrade the accelerating portion of the plasma wake, so it is important to understand their origins and how to remove them. Here, the onset of electron trapping is connected to the drive bunch properties. Additionally, the trapped electron bunches are observed with normalized transverse emittance divided by peak current, {epsilon}{sub N,x}/I{sub t}, below the level of 0.2 {micro}m/kA. A theoretical model of the trapped electron emittance, developed here, indicates that the emittance scales inversely with the square root of the plasma density in the non-linear 'bubble' regime of the PWFA. This model and simulations indicate that the observed values of {epsilon}{sub N,x}/I{sub t} result from multi-GeV trapped electron bunches with emittances of a few {micro}m and multi-kA peak currents. These properties make the trapped electrons a possible particle source for next generation light sources. This dissertation is organized as follows. The first chapter is an overview of the PWFA, which includes a review of the accelerating and focusing fields and a survey of the remaining issues for a plasma-based particle collider. Then, the second chapter examines the physics of electron trapping in the PWFA. The third chapter uses theory and simulations to analyze the properties of the trapped

  10. Sources of Pressure in Titan's Plasma Environment

    CERN Document Server

    Achilleos, N; Bertucci, C; Guio, P; Romanelli, N; Sergis, N

    2013-01-01

    In order to analyze varying plasma conditions upstream of Titan, we have combined a physical model of Saturn's plasmadisk with a geometrical model of the oscillating current sheet. During modeled oscillation phases where Titan is furthest from the current sheet, the main sources of plasma pressure in the near-Titan space are the magnetic pressure and, for disturbed conditions, the hot plasma pressure. When Titan is at the center of the sheet, the main source is the dynamic pressure associated with Saturn's cold, subcorotating plasma. Total pressure at Titan (dynamic plus thermal plus magnetic) typically increases by a factor of five as the current sheet center is approached. The predicted incident plasma flow direction deviates from the orbital plane of Titan by < 10 deg. These results suggest a correlation between the location of magnetic pressure maxima and the oscillation phase of the plasmasheet.

  11. The ILC polarized electron source

    CERN Document Server

    Brachmann, Axel; Garwin, Edward; Kirby, Robert; Luh Dah An; Maruyama, Takashi; Prepost, Richard; Schultz, David; Sheppard, John

    2005-01-01

    The SLC polarized electron source (PES) can meet the expected requirements of the International Linear Collider (ILC) for polarization, charge and lifetime. However, experience with newer and successful PES designs at JLAB, Mainz and elsewhere can be incorporated into a first-generation ILC source that will emphasize reliability and stability without compromising the photocathode performance. The long pulse train for the ILC may introduce new challenges for the PES, and in addition more reliable and stable operation of the PES may be achievable if appropriate R&D is carried out for higher voltage operation and for a simpler load-lock system. The outline of the R&D program currently taking shape at SLAC and elsewhere is discussed. The principal components of the proposed ILC PES, including the laser system necessary for operational tests, are described.

  12. Negative plasma potential relative to electron-emitting surfaces.

    Science.gov (United States)

    Campanell, M D

    2013-09-01

    Most works on plasma-wall interaction predict that with strong electron emission, a nonmonotonic "space-charge-limited" (SCL) sheath forms where the plasma potential is positive relative to the wall. We show that a fundamentally different sheath structure is possible where the potential monotonically increases toward a positively charged wall that is shielded by a single layer of negative charge. No ion-accelerating presheath exists in the plasma and the ion wall flux is zero. An analytical solution of the "inverse sheath" regime is demonstrated for a general plasma-wall system where the plasma electrons and emitted electrons are Maxwellian with different temperatures. Implications of the inverse sheath effect are that (a) the plasma potential is negative, (b) ion sputtering vanishes, (c) no charge is lost at the wall, and (d) the electron energy flux is thermal. To test empirically what type of sheath structure forms under strong emission, a full plasma bounded by strongly emitting walls is simulated. It is found that inverse sheaths form at the walls and ions are confined in the plasma. This result differs from past particle-in-cell simulation studies of emission which contain an artificial "source sheath" that accelerates ions to the wall, leading to a SCL sheath at high emission intensity.

  13. Ions beams and ferroelectric plasma sources

    Science.gov (United States)

    Stepanov, Anton

    Near-perfect space-charge neutralization is required for the transverse compression of high perveance ion beams for ion-beam-driven warm dense matter experiments, such as the Neutralized Drift Compression eXperiment (NDCX). Neutralization can be accomplished by introducing a plasma in the beam path, which provides free electrons that compensate the positive space charge of the ion beam. In this thesis, charge neutralization of a 40 keV, perveance-dominated Ar+ beam by a Ferroelectric Plasma Source (FEPS) is investigated. First, the parameters of the ion beam, such as divergence due to the extraction optics, charge neutralization fraction, and emittance were measured. The ion beam was propagated through the FEPS plasma, and the effects of charge neutralization were inferred from time-resolved measurements of the transverse beam profile. In addition, the dependence of FEPS plasma parameters on the configuration of the driving pulser circuit was studied to optimize pulser design. An ion accelerator was constructed that produced a 30-50 keV Ar + beam with pulse duration angle divergence of 0.87°. The measurements show that near-perfect charge neutralization with FEPS can be attained. No loss of ion beam current was detected, indicating the absence of a neutral cloud in the region of beam propagation, which would cause beam loss to charge exchange collisions. This provides evidence in favor of using FEPS in a future Heavy Ion Fusion accelerator. The FEPS discharge was investigated based on current-voltage measurements in the pulser circuit. Different values of series resistance and storage capacitance in the pulser circuit were used. The charged particle current emitted by the FEPS into vacuum was measured from the difference in forward and return currents in the driving circuit. It was found that FEPS is an emitter of negative charge, and that electron current emission begins approximately 0.5 mus after the fast-rising high voltage pulse is applied and lasts for tens

  14. Plasma production for electron acceleration by resonant plasma wave

    Science.gov (United States)

    Anania, M. P.; Biagioni, A.; Chiadroni, E.; Cianchi, A.; Croia, M.; Curcio, A.; Di Giovenale, D.; Di Pirro, G. P.; Filippi, F.; Ghigo, A.; Lollo, V.; Pella, S.; Pompili, R.; Romeo, S.; Ferrario, M.

    2016-09-01

    Plasma wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10-100 GV/m), enabling acceleration of electrons to GeV energy in few centimeter. However, the quality of the electron bunches accelerated with this technique is still not comparable with that of conventional accelerators (large energy spread, low repetition rate, and large emittance); radiofrequency-based accelerators, in fact, are limited in accelerating field (10-100 MV/m) requiring therefore hundred of meters of distances to reach the GeV energies, but can provide very bright electron bunches. To combine high brightness electron bunches from conventional accelerators and high accelerating fields reachable with plasmas could be a good compromise allowing to further accelerate high brightness electron bunches coming from LINAC while preserving electron beam quality. Following the idea of plasma wave resonant excitation driven by a train of short bunches, we have started to study the requirements in terms of plasma for SPARC_LAB (Ferrario et al., 2013 [1]). In particular here we focus on hydrogen plasma discharge, and in particular on the theoretical and numerical estimates of the ionization process which are very useful to design the discharge circuit and to evaluate the current needed to be supplied to the gas in order to have full ionization. Eventually, the current supplied to the gas simulated will be compared to that measured experimentally.

  15. Plasma production for electron acceleration by resonant plasma wave

    Energy Technology Data Exchange (ETDEWEB)

    Anania, M.P., E-mail: maria.pia.anania@lnf.infn.it [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); Biagioni, A.; Chiadroni, E. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); Cianchi, A. [University of Rome Tor Vergata - INFN, via della Ricerca Scientifica, 1, 00133 Roma (Italy); INFN, Via della Ricerca Scientifica, 1, 00133 Roma (Italy); Croia, M.; Curcio, A. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); University of Rome La Sapienza, Piazzale Aldo Moro, 2, 00185 Roma (Italy); Di Giovenale, D.; Di Pirro, G.P. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); Filippi, F. [University of Rome La Sapienza, Piazzale Aldo Moro, 2, 00185 Roma (Italy); Ghigo, A.; Lollo, V.; Pella, S.; Pompili, R. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); Romeo, S. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy); University of Rome La Sapienza, Piazzale Aldo Moro, 2, 00185 Roma (Italy); Ferrario, M. [INFN - LNF, via Enrico Fermi, 40, 00044 Frascati (Italy)

    2016-09-01

    Plasma wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10–100 GV/m), enabling acceleration of electrons to GeV energy in few centimeter. However, the quality of the electron bunches accelerated with this technique is still not comparable with that of conventional accelerators (large energy spread, low repetition rate, and large emittance); radiofrequency-based accelerators, in fact, are limited in accelerating field (10–100 MV/m) requiring therefore hundred of meters of distances to reach the GeV energies, but can provide very bright electron bunches. To combine high brightness electron bunches from conventional accelerators and high accelerating fields reachable with plasmas could be a good compromise allowing to further accelerate high brightness electron bunches coming from LINAC while preserving electron beam quality. Following the idea of plasma wave resonant excitation driven by a train of short bunches, we have started to study the requirements in terms of plasma for SPARC-LAB (Ferrario et al., 2013 [1]). In particular here we focus on hydrogen plasma discharge, and in particular on the theoretical and numerical estimates of the ionization process which are very useful to design the discharge circuit and to evaluate the current needed to be supplied to the gas in order to have full ionization. Eventually, the current supplied to the gas simulated will be compared to that measured experimentally.

  16. Intense ion beam generation, plasma radiation source and plasma opening switch research

    Science.gov (United States)

    Hammer, D. A.; Coleman, M. D.; Qi, N.; Similon, P. L.; Sudan, R. N.

    1989-04-01

    This report describes research on intense ion beam diodes, plasma opening switches and dense z-pinch plasma radiators. Laser induced fluorescence spectroscopy has been used to map the electrostatic potential profile in a plasma-prefilled magnetically insulated ion diode. In a simple planar diode, the measured profile is inconsistent with the electrons being confined in a sheath near the cathode by the magnetic field. Rather, the profile implies the presence of electrons throughout the accelerating gap. A theoretical model of the penetration of current and magnetic field into a plasma, and of the current-driven effective collision frequency has been developed. The snowplow action of the rising magnetic field causes a steep rise in the plasma density at the leading edge. The subsequent multistreaming of the ions caused by ion reflection at the current layer could lead to ion heating through collective effects. The two-dimensional electron flow in the plasma cathode vacuum gap is also treated. Dense z-pinch plasma radiation source experiments have been initiated on the LION accelerator using gas puff and fine wire loads. The x-pinch was found to be a more effective way to generate soft x-rays than a single wire pinch or a gas puff implosion. Plasma opening switch experiments being initiated, and plasma anode ion diode development work being terminated are also briefly described.

  17. Study of Coupling between a Plasma Source and Plasma Fluctuations

    Science.gov (United States)

    Berumen, Jorge; Chu, Feng; Hood, Ryan; Mattingly, Sean; Rogers, Anthony; Skiff, Fred

    2014-10-01

    An experimental study on the coupling between a plasma source and plasma fluctuations in a cylindrical, magnetized, singly-ionized Argon inductively-coupled gas discharge plasma that is weakly collisional is presented. Typical plasma conditions are n ~1010 cm-3 Te ~ 3 eV and B ~ 1 kG. Amplitude Modulation (AM) of the inductively-coupled RF plasma source is produced near the fundamental-mode ion-acoustic wave frequency (~1 kHz) to study the effects of the source-wave interaction and plasma production. Density fluctuation measurements are implemented using Laser-Induced Fluorescence techniques and Langmuir probes. We apply coherent detection with respect to the wave frequency to obtain the perturbed ion distribution function associated with the waves. Measurements of fluctuating I-V traces from a Langmuir probe array and antenna current load are also used to show the effects of the interaction. We would like to acknowledge DOE DE-FG02-99ER54543 for their financial support throughout this research.

  18. Development of plasma cathode electron guns

    Science.gov (United States)

    Oks, Efim M.; Schanin, Peter M.

    1999-05-01

    The status of experimental research and ongoing development of plasma cathode electron guns in recent years is reviewed, including some novel upgrades and applications to various technological fields. The attractiveness of this kind of e-gun is due to its capability of creating high current, broad or focused beams, both in pulsed and steady-state modes of operation. An important characteristic of the plasma cathode electron gun is the absence of a thermionic cathode, a feature which leads to long lifetime and reliable operation even in the presence of aggressive background gas media and at fore-vacuum gas pressure ranges such as achieved by mechanical pumps. Depending on the required beam parameters, different kinds of plasma discharge systems can be used in plasma cathode electron guns, such as vacuum arcs, constricted gaseous arcs, hollow cathode glows, and two kinds of discharges in crossed E×B fields: Penning and magnetron. At the present time, plasma cathode electron guns provide beams with transverse dimension from fractional millimeter up to about one meter, beam current from microamperes to kiloamperes, beam current density up to about 100 A/cm2, pulse duration from nanoseconds to dc, and electron energy from several keV to hundreds of keV. Applications include electron beam melting and welding, surface treatment, plasma chemistry, radiation technologies, laser pumping, microwave generation, and more.

  19. Plasma-based EUV light source

    Science.gov (United States)

    Shumlak, Uri; Golingo, Raymond; Nelson, Brian A.

    2010-11-02

    Various mechanisms are provided relating to plasma-based light source that may be used for lithography as well as other applications. For example, a device is disclosed for producing extreme ultraviolet (EUV) light based on a sheared plasma flow. The device can produce a plasma pinch that can last several orders of magnitude longer than what is typically sustained in a Z-pinch, thus enabling the device to provide more power output than what has been hitherto predicted in theory or attained in practice. Such power output may be used in a lithography system for manufacturing integrated circuits, enabling the use of EUV wavelengths on the order of about 13.5 nm. Lastly, the process of manufacturing such a plasma pinch is discussed, where the process includes providing a sheared flow of plasma in order to stabilize it for long periods of time.

  20. Characteristics and potential applications of an ORNL microwave ECR multicusp plasma ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.C.

    1990-01-01

    A new microwave electron cyclotron resonance (ECR) multicusp plasma ion source that has two ECR plasma production regions and uses multicusp plasma confinement has been developed at Oak Ridge National Laboratory. This source has been operated to produce uniform and dense plasma over large areas of 300 to 400 cm{sup 2} and could be scaled up to produce uniform plasma over 700 cm{sup 2} or larger. The plasma source has been operated with continuous argon gas feed and pulsed microwave power. The working gases used were argon, helium, hydrogen, and oxygen. The discharge initiation phenomena and plasma properties have been investigated and studied as functions of the discharge parameters. The discharge characteristics and a hypothetical discharge mechanism for this plasma source are described and discussed. Potential applications, including plasma and ion-beam sources for manufacturing advanced microelectronics, for space electric propulsion, and for fusion research, are discussed. 10 refs., 10 figs.

  1. Overdense plasma generation in a compact ion source

    Science.gov (United States)

    Castro, G.; Mascali, D.; Gammino, S.; Torrisi, G.; Romano, F. P.; Celona, L.; Altana, C.; Caliri, C.; Gambino, N.; Lanaia, D.; Miracoli, R.; Neri, L.; Sorbello, G.

    2017-05-01

    Electron cyclotron resonance ion sources (ECRIS) are widely used plasma based machines for the production of intense ion beams in science and industry. The performance of modern devices is limited by the presence of the density cut-off, above which electromagnetic (EM) waves sustaining the plasma are reflected. We hereby discuss the systematic data analysis of electrostatic wave generation in an ECR prototype operating at 3.75 GHz-0.1 THz. In particular, electron Bernstein waves (EBW) have been excited. EBW have already been generated in large-scale plasma devices for thermonuclear fusion purposes. In ion sources where L c ˜ λ RF (L c being the plasma chamber size and λ RF the pumping wave wavelength) the EM field assumes a modal behaviour; thus both plasma and EM field self-organize so that no optical-like wave launching is possible (i.e. the cavity effect dominates on the optical path). The collected data, however, supported by 3D full-wave simulations, actually demonstrate that a Budden-type X-B conversion scenario can be established above some critical RF power thresholds, operating in an off-ECR regime. The generation and absorption of the EBW has been demonstrated by the presence of three peculiar signatures: along with the establishment of an overdense plasma, generation of supra-thermal electrons and modification (non-linear broadening) of the EM spectrum measured within the plasma have been observed. At the threshold establishing such a heating regime, the collected data provide evidence for a fast rotation of the electron fluid.

  2. Observation of Hot Electrons in Surface-Wave Plasmas Excited by Surface Plasmon Polaritons

    Institute of Scientific and Technical Information of China (English)

    HU Ye-Lin; CHEN Zhao-Quan; LIU Ming-Hai; HONG Ling-Li; LI Ping; ZHENG Xiao-Liang; XIA Guang-Qing; HU Xi-Wei

    2011-01-01

    The electron energy distribution functions (EEDFs) are studied in the planar-type surface-wave plasma (SWP)caused by resonant excitation of surface plasmon polaritons (SPPs) using a single cylindrical probe.Sustained plasma characteristics can be considered as a bi-Maxwellian EEDF,which correspond to a superposition of the bulk low-temperature electron and the high-energy electron beam-like part.The beam component energy is pronounced at about 10eV but the bulk part is lower than 3.5eV.The hot electrons included in the proposed plasmas play a significant role in plasma heating and further affect the discharge chemistry.During the past several years,in the fabrication ofamorphous or crystalline silicon films,diamond film synthesis and carbon nanotube growth,the large-area overdense plasma source has been useful.In electronic device fabrication techniques such as etching,ashing or plasma chemical vapor deposition,overdense electrons and radicals are required,especially hot electrons.Among the various plasma devices,the planar-type surface-wave plasma (SWP) source is an advanced plasma source,which is a type of promising plasma source satisfying the above rigorous requirements for large-area plasma processing.%The electron energy distribution functions (EEDFs) are studied in the planar-type surface-wave plasma (SWP) caused by resonant excitation of surface plasmon polaritons (SPPs) using a single cylindrical probe. Sustained plasma characteristics can be considered as a bi-Maxwellian EEDF, which correspond to a superposition of the bulk low-temperature electron and the high-energy electron beam-like part. The beam component energy is pronounced at about 10 eV but the bulk part is lower than 3.5 eV. The hot electrons included in the proposed plasmas play a significant role in plasma heating and further affect the discharge chemistry.

  3. Electron acceleration in a post-flare decimetric continuum source

    CERN Document Server

    Subramanian, P; Karlick'y, M; Sych, R; Sawant, H S; Ananthakrishnan, S; Subramanian, Prasad

    2007-01-01

    Aims: To calculate the power budget for electron acceleration and the efficiency of the plasma emission mechanism in a post-flare decimetric continuum source. Methods: We have imaged a high brightness temperature ($\\sim 10^{9}$K) post-flare source at 1060 MHz with the Giant Metrewave Radio Telescope (GMRT). We use information from these images and the dynamic spectrum from the Hiraiso spectrograph together with the theoretical method described in Subramanian & Becker (2006) to calculate the power input to the electron acceleration process. The method assumes that the electrons are accelerated via a second-order Fermi acceleration mechanism. Results: We find that the power input to the nonthermal electrons is in the range $3\\times 10^{25}$--$10^{26}$ erg/s. The efficiency of the overall plasma emission process starting from electron acceleration and culminating in the observed emission could range from $2.87\\times 10^{-9}$ to $2.38 \\times 10^{-8}$.

  4. Electron kinetics in capacitively coupled plasmas modulated by electron injection

    Science.gov (United States)

    Zhang, Ya; Peng, Yanli; Innocenti, Maria Elena; Jiang, Wei; Wang, Hong-yu; Lapenta, Giovanni

    2017-09-01

    The controlling effect of an electron injection on the electron energy distribution function (EEDF) and on the energetic electron flux, in a capacitive radio-frequency argon plasma, is studied using a one-dimensional particle-in-cell/Monte Carlo collisions model. The input power of the electron beam is as small as several tens of Watts with laboratory achievable emission currents and energies. With the electron injection, the electron temperature decreases but with a significant high energy tail. The electron density, electron temperature in the sheath, and electron heating rate increase with the increasing emission energy. This is attributed to the extra heating of the energetic electrons in the EEDF tail. The non-equilibrium EEDF is obtained for strong non-local distributions of the electric field, electron heating rate, excitation, and ionization rate, indicating the discharge has transited from a volume heating (α-mode dominated) into a sheath heating (γ-mode dominated) type. In addition, the electron injection not only modifies the self-bias voltage, but also enhances the electron flux that can reach the electrodes. Moreover, the relative population of energetic electrons significantly increases with the electron injection compared to that without the electron injection, relevant for modifying the gas and surface chemistry reactions.

  5. Electron Bernstein Wave Emission from RFP Plasmas

    Science.gov (United States)

    Nornberg, M. D.; Thomas, M.; Anderson, J.; Forest, C. B.

    1998-11-01

    Electron cyclotron emission (ECE) has proven to be a powerfull diagnostic tool in tokamak plasmas for determining the time evolution of the electron temperature profile. The standard technique of observing O-mode or X-mode electromagnetic waves normal to the magnetic field is not applicable to reversed field pinch (RFP) plasmas since the plasma frequency is much larger than the electron cyclotron frequency. We are investigating the use of electron Bernstein waves (presumed to be in thermal equilibrium with the electrons) through the aip.org/journal_cgi/ getpdf?KEY=PRLTAO&cvips=PRLTAO000078000018003467000001>O-X-B mode conversion process. At oblique incidence, the evanescent layer separating the plamsa cutoff from the cyclotron cutoff vanishes, allowing conversion of the Bernstein mode waves to the extraordinary mode and finally to the ordinary mode. The O-mode radiation is received by a phased array antenna consisting of two waveguides on the edge of the plasma, and the spectrum of emitted radiation is measured using a radiometer spanning 4-8 GHz. In addition to providing information about the electron temperature profile, the spectrum can provide a novel method of measuring the central magnetic field strength for current profile reconstructions.

  6. Correlations in a partially degenerate electron plasma

    Energy Technology Data Exchange (ETDEWEB)

    Chihara, Junzo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    The density-functional theory proves that an ion-electron mixture can be treated as a one-component liquid interacting only via a pairwise interaction in the evaluation of the ion-ion radial distribution function (RDF), and provides a set of integral equations: one is an integral equation for the ion-ion RDF and another for an effective ion-ion interaction, which depends on the ion-ion RDF. This formulation gives a set of integral equation to calculate plasma structures with combined use of the electron-electron correlations in a partially degenerate electron plasma. Therefore, it is important for this purpose to determine the electron-electron correlations at a arbitrary temperature. Here, they are calculated by the quantal version of the hypernetted chain (HNC) equation. On the basis of the jellium-vacancy model, the ionic and electronic structures of rubidium are calculated for the range from liquid metal to plasma states by increasing the temperature at the fixed density using the electron-correlation results. (author)

  7. Plasma sources of solar system magnetospheres

    CERN Document Server

    Blanc, Michel; Chappell, Charles; Krupp, Norbert

    2016-01-01

    This volume reviews what we know of the corresponding plasma source for each intrinsically magnetized planet. Plasma sources fall essentially in three categories: the solar wind, the ionosphere (both prevalent on Earth), and the satellite-related sources. Throughout the text, the case of each planet is described, including the characteristics, chemical composition and intensity of each source. The authors also describe how the plasma generated at the source regions is transported to populate the magnetosphere, and how it is later lost. To summarize, the dominant sources are found to be the solar wind and sputtered surface ions at Mercury, the solar wind and ionosphere at Earth (the relative importance of the two being discussed in a specific introductory chapter), Io at Jupiter and – a big surprise of the Cassini findings – Enceladus at Saturn. The situation for Uranus and Neptune, which were investigated by only one fly-by each, is still open and requires further studies and exploration. In the final cha...

  8. Cross-field transport of electrons at the magnetic throat in an annular plasma reactor

    Science.gov (United States)

    Zhang, Yunchao; Charles, Christine; Boswell, Rod

    2017-01-01

    Cross-field transport of electrons has been studied at the magnetic throat of the annular Chi-Kung reactor. This annular configuration allows the creation of a low pressure argon plasma with two distinct electron heating locations by independently operating a radio-frequency antenna surrounding the outer source tube, or an antenna housed inside the inner source tube. The two antenna cases show opposite variation trends in radial profiles of electron energy probability function, electron density, plasma potential and electron temperature. The momentum and energy transport coefficients are obtained from the electron energy probability functions, and the related electron fluxes follow the path of electron cooling across the magnetic throat.

  9. Electronic transport in partially ionized water plasmas

    Science.gov (United States)

    French, Martin; Redmer, Ronald

    2017-09-01

    We use ab initio simulations based on density functional theory to calculate the electrical and thermal conductivities of electrons in partially ionized water plasmas at densities above 0.1 g/cm3. The resulting conductivity data are then fitted to analytic expressions for convenient application. For low densities, we develop a simple and fully analytic model for electronic transport in low-density plasmas in the chemical picture using the relaxation-time approximation. In doing so, we derive a useful analytic expression for electronic transport cross sections with neutral particles, based on a model potential. In the regime of thermal ionization, electrical conductivities from the analytic model agree with the ab initio data within a factor of 2. Larger deviations are observed for the thermal conductivity, and their origin is discussed. Our results are relevant for modeling the interior and evolution of water-rich planets as well as for technical plasma applications.

  10. Dependence of the source performance on plasma parameters at the BATMAN test facility

    Energy Technology Data Exchange (ETDEWEB)

    Wimmer, C.; Fantz, U. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany)

    2015-04-08

    The investigation of the dependence of the source performance (high j{sub H{sup −}}, low j{sub e}) for optimum Cs conditions on the plasma parameters at the BATMAN (Bavarian Test MAchine for Negative hydrogen ions) test facility is desirable in order to find key parameters for the operation of the source as well as to deepen the physical understanding. The most relevant source physics takes place in the extended boundary layer, which is the plasma layer with a thickness of several cm in front of the plasma grid: the production of H{sup −}, its transport through the plasma and its extraction, inevitably accompanied by the co-extraction of electrons. Hence, a link of the source performance with the plasma parameters in the extended boundary layer is expected. In order to characterize electron and negative hydrogen ion fluxes in the extended boundary layer, Cavity Ring-Down Spectroscopy and Langmuir probes have been applied for the measurement of the H{sup −} density and the determination of the plasma density, the plasma potential and the electron temperature, respectively. The plasma potential is of particular importance as it determines the sheath potential profile at the plasma grid: depending on the plasma grid bias relative to the plasma potential, a transition in the plasma sheath from an electron repelling to an electron attracting sheath takes place, influencing strongly the electron fraction of the bias current and thus the amount of co-extracted electrons. Dependencies of the source performance on the determined plasma parameters are presented for the comparison of two source pressures (0.6 Pa, 0.45 Pa) in hydrogen operation. The higher source pressure of 0.6 Pa is a standard point of operation at BATMAN with external magnets, whereas the lower pressure of 0.45 Pa is closer to the ITER requirements (p ≤ 0.3 Pa)

  11. Dependence of the source performance on plasma parameters at the BATMAN test facility

    Science.gov (United States)

    Wimmer, C.; Fantz, U.

    2015-04-01

    The investigation of the dependence of the source performance (high jH-, low je) for optimum Cs conditions on the plasma parameters at the BATMAN (Bavarian Test MAchine for Negative hydrogen ions) test facility is desirable in order to find key parameters for the operation of the source as well as to deepen the physical understanding. The most relevant source physics takes place in the extended boundary layer, which is the plasma layer with a thickness of several cm in front of the plasma grid: the production of H-, its transport through the plasma and its extraction, inevitably accompanied by the co-extraction of electrons. Hence, a link of the source performance with the plasma parameters in the extended boundary layer is expected. In order to characterize electron and negative hydrogen ion fluxes in the extended boundary layer, Cavity Ring-Down Spectroscopy and Langmuir probes have been applied for the measurement of the H- density and the determination of the plasma density, the plasma potential and the electron temperature, respectively. The plasma potential is of particular importance as it determines the sheath potential profile at the plasma grid: depending on the plasma grid bias relative to the plasma potential, a transition in the plasma sheath from an electron repelling to an electron attracting sheath takes place, influencing strongly the electron fraction of the bias current and thus the amount of co-extracted electrons. Dependencies of the source performance on the determined plasma parameters are presented for the comparison of two source pressures (0.6 Pa, 0.45 Pa) in hydrogen operation. The higher source pressure of 0.6 Pa is a standard point of operation at BATMAN with external magnets, whereas the lower pressure of 0.45 Pa is closer to the ITER requirements (p ≤ 0.3 Pa).

  12. Mirror-field confined compact plasma source using permanent magnet for plasma processings

    Science.gov (United States)

    Goto, Tetsuya; Sato, Kei-ichiro; Yabuta, Yuki; Sugawa, Shigetoshi

    2016-12-01

    A mirror-field confined compact electron cyclotron resonance (ECR) plasma source using permanent magnets was developed, aiming for the realization of high-quality plasma processings where high-density reactive species are supplied to a substrate with minimizing the ion bombardment damages. The ECR position was located between a microwave transmissive window and a quartz limiter, and plasmas were transported from the ECR position to a midplane of the magnetic mirror field through the quartz limiter. Thus, a radius of core plasma could be determined by the limiter, which was 15 mm in this study. Plasma parameters were investigated by the Langmuir probe measurement. High-density plasma larger than 1011 cm-3 could be produced by applying 5.85-GHz microwave power of 10 W or more. For the outside region of the core plasma where a wafer for plasma processings will be set at, the ion current density was decreased dramatically with distance from the core plasma and became smaller by approximately two orders of magnitude that in the core plasma region for the radial position of 40 mm, suggesting the realization of reduction in ion bombardment damages.

  13. Mirror-field confined compact plasma source using permanent magnet for plasma processings.

    Science.gov (United States)

    Goto, Tetsuya; Sato, Kei-Ichiro; Yabuta, Yuki; Sugawa, Shigetoshi

    2016-12-01

    A mirror-field confined compact electron cyclotron resonance (ECR) plasma source using permanent magnets was developed, aiming for the realization of high-quality plasma processings where high-density reactive species are supplied to a substrate with minimizing the ion bombardment damages. The ECR position was located between a microwave transmissive window and a quartz limiter, and plasmas were transported from the ECR position to a midplane of the magnetic mirror field through the quartz limiter. Thus, a radius of core plasma could be determined by the limiter, which was 15 mm in this study. Plasma parameters were investigated by the Langmuir probe measurement. High-density plasma larger than 10(11) cm(-3) could be produced by applying 5.85-GHz microwave power of 10 W or more. For the outside region of the core plasma where a wafer for plasma processings will be set at, the ion current density was decreased dramatically with distance from the core plasma and became smaller by approximately two orders of magnitude that in the core plasma region for the radial position of 40 mm, suggesting the realization of reduction in ion bombardment damages.

  14. Microwave Absorption in Electron Cyclotron Resonance Plasma

    Institute of Scientific and Technical Information of China (English)

    LIU Ming-Hai; HU Xi-Wei; WU Qin-Chong; YU Guo-Yang

    2000-01-01

    The microwave power absorption in electron cyclotron resonance plasma reactor was investigated with a twodimensional hybrid-code. Simulation results indicated that there are two typical power deposition profiles over the entire parameter region: (1) microwave power deposition peaks on the axis and decreases in radial direction,(2) microwave power deposition has its maximum at some radial position, i.e., a hollow distribution. The spatial distribution of electron temperature resembles always to the microwave power absorption profile. The dependence of plasma parameter on the gas pressure is discussed also.

  15. High dielectric constant ceramics for ion-electron sources

    CERN Document Server

    Boscolo, I

    2002-01-01

    Ferroelectric disks, coated with proper electrodes, can easily produce a dense plasma cloud when excited with a high-voltage pulse. This plasma can be a source of either electrons or ions depending on the sign of the extracting field set in front of the disk. We present the behavior of the disks operating at high frequency as emitters of both electrons and ions in two experimental configurations: (a) without and (b) with two screening grids. These two screening grids are inserted when the plasma must be confined within the cathode region. The system is capable of providing ion pulses of a few hundred milliamperes, whose length can range from a hundred nanoseconds to dozen microseconds. The electron pulses of energetic electrons have typically an amplitude higher than a couple of amperes. Tests at MHz repetition rate were positive as for stable operation.

  16. 微推力ECR离子推力器等离子体源电子获能计算分析%Calculation Analysis on Electron Heating within Plasma Source Used by Micro ECR Ion Thruster

    Institute of Scientific and Technical Information of China (English)

    汤明杰; 杨涓; 冯冰冰; 金逸舟; 罗立涛

    2015-01-01

    为满足小型航天器的微推进需求,开展了微推力电子回旋共振(ECR)离子推力器的计算研究。实现该推力器的关键是ECR等离子体源合理的磁场和电场分布数值计算,从而使电子在穿过ECR谐振区时能够获得最大能量。为此以双环形永磁材料结构作为磁路,分别以直线形、环形和盘形微波耦合天线产生微波电磁场,同时改变等离子体源特征长度,利用有限元软件计算并分析ECR等离子体源内磁场和微波电场的分布规律以及电子在ECR区的获能规律。结果以微波输入功率5W、频率4.2GHz为例,发现环形耦合天线与较短等离子体源特征长度的结构组合可使电子在ECR区的获能指标达到最大且分布最佳。%To satisfy the propulsion need of small spacecrafts,it is essential to calculate characteristics of mi⁃cro electron cyclotron resonance(ECR)ion thruster. To get the maximum energy absorbed by electrons when passing through ECR layer,calculation of reasonable magnetic and electric field distribution in the plasma source is a key problem. In this article,the conformation of magnetic circuit was formed by two annular permanent mag⁃nets,microwave electromagnetic fields were generated separately by the linear,ring and dish-shaped antennas, and characteristic lengths of plasma source were altered several times. Through the calculation by applying finite element method,the important distribution of magnetic and microwave electric fields,and energy to heat electron were obtained. It is found that with 5W power and 4.2GHz frequency of input microwave,the structural combina⁃tion of ring coupling antenna and shorter characteristic length of plasma source allows electron heating index to get the maximum value and the optimal distribution in ECR layer.

  17. Launched electrons in plasma opening switches

    Science.gov (United States)

    Mendel, C. W., Jr.; Rochau, G. E.; Sweeney, M. A.; McDaniel, D. H.; Quintenz, J. P.; Savage, M. E.; Lindman, E. L.; Kindel, J. M.

    Plasma opening switches have provided a means to improve the characteristics of super-power pulse generators. Recent advances involving plasma control with fast and slow magnetic fields have made these switches more versatile, allowing for improved switch uniformity, triggering, and opening current levels that are set by the level of auxiliary fields. Such switches necessarily involve breaks in the translational symmetry of the transmission line geometry and therefore affect the electron flow characteristics of the line. These symmetry breaks are the result of high electric field regions caused by plasma conductors remaining in the transmission line, ion beams crossing the line, or auxilliary magnetic field regions. Symmetry breaks cause the canonical momentum of the electrons to change, thereby moving them away from the cathode. Additional electrons are pulled from the cathode into the magnetically insulated flow, resulting in an excess of electron flow over that expected for the voltage and line current downstream of the switch. These electrons are called launched electrons. Unless they are recaptured at the cathode or else are fed into the load and used beneficially, they cause a large power loss downstream. Examples are shown of SuperMite and PBFA II data showing these losses, the tools used to study them are explained, and the mechanisms employed to mitigate the problem are discussed. The losses will be reduced primarily by reducing the amount of launched electron flow.

  18. A Microfabricated Inductively Coupled Plasma Excitation Source

    Institute of Scientific and Technical Information of China (English)

    WANG Yong-Qing; PU Yong-Ni; SUN Rong-Xia; TANG Yu-Jun; CHEN Wen-Jun; LOU Jian-Zhong; MA Wen

    2008-01-01

    A novel miniaturization of inductively coupled plasma(ICP)source based on printed circuit produced using micro-fabrication techniques is presented.The basic parameters of the novel ICP,including its radio frequency,power loss,size,and argon consumption are less than 1% of that for the case of atmospheric pressure ICP source.For example,at 100 Pa of argon gas pressure,the present ICP source can be ignited by using the rf power less than 3.5 W.Potential applications of the ICP is discussed.

  19. Large-Area Permanent-Magnet ECR Plasma Source

    Science.gov (United States)

    Foster, John E.

    2007-01-01

    A 40-cm-diameter plasma device has been developed as a source of ions for material-processing and ion-thruster applications. Like the device described in the immediately preceding article, this device utilizes electron cyclotron resonance (ECR) excited by microwave power in a magnetic field to generate a plasma in an electrodeless (noncontact) manner and without need for an electrically insulating, microwave-transmissive window at the source. Hence, this device offers the same advantages of electrodeless, windowless design - low contamination and long operational life. The device generates a uniform, high-density plasma capable of sustaining uniform ion-current densities at its exit plane while operating at low pressure [magnetic field in this device is generated by a permanent-magnet circuit that is optimized to generate resonance surfaces. The microwave power is injected on the centerline of the device. The resulting discharge plasma jumps into a "high mode" when the input power rises above 150 W. This mode is associated with elevated plasma density and high uniformity. The large area and uniformity of the plasma and the low operating pressure are well suited for such material-processing applications as etching and deposition on large silicon wafers. The high exit-plane ion-current density makes it possible to attain a high rate of etching or deposition. The plasma potential is <3 V low enough that there is little likelihood of sputtering, which, in plasma processing, is undesired because it is associated with erosion and contamination. The electron temperature is low and does not vary appreciably with power.

  20. Weakly nonlinear electron plasma waves in collisional plasmas

    DEFF Research Database (Denmark)

    Pecseli, H. L.; Rasmussen, J. Juul; Tagare, S. G.

    1986-01-01

    The nonlinear evolution of a high frequency plasma wave in a weakly magnetized, collisional plasma is considered. In addition to the ponderomotive-force-nonlinearity the nonlinearity due to the heating of the electrons is taken into account. A set of nonlinear equations including the effect...... of a constantly maintained pump wave is derived and a general dispersion relation describing the modulation of the high frequency wave due to different low frequency responses is obtained. Particular attention is devoted to a purely growing modulation. The relative importance of the ponderomotive force...

  1. Plasma Sources for Medical Applications - A Comparison of Spot Like Plasmas and Large Area Plasmas

    Science.gov (United States)

    Weltmann, Klaus-Dieter

    2015-09-01

    Plasma applications in life science are currently emerging worldwide. Whereas today's commercially available plasma surgical technologies such as argon plasma coagulation (APC) or ablation are mainly based on lethal plasma effects on living systems, the newly emerging therapeutic applications will be based on selective, at least partially non-lethal, possibly stimulating plasma effects on living cells and tissue. Promising results could be obtained by different research groups worldwide revealing a huge potential for the application of low temperature atmospheric pressure plasma in fields such as tissue engineering, healing of chronic wounds, treatment of skin diseases, tumor treatment based on specific induction of apoptotic processes, inhibition of biofilm formation and direct action on biofilms or treatment of dental diseases. The development of suitable and reliable plasma sources for the different therapies requires an in-depth knowledge of their physics, chemistry and parameters. Therefore much basic research still needs to be conducted to minimize risk and to provide a scientific fundament for new plasma-based medical therapies. It is essential to perform a comprehensive assessment of physical and biological experiments to clarify minimum standards for plasma sources for applications in life science and for comparison of different sources. One result is the DIN-SPEC 91315, which is now open for further improvements. This contribution intends to give an overview on the status of commercial cold plasma sources as well as cold plasma sources still under development for medical use. It will discuss needs, prospects and approaches for the characterization of plasmas from different points of view. Regarding the manageability in everyday medical life, atmospheric pressure plasma jets (APPJ) and dielectric barrier discharges (DBD) are of special interest. A comprehensive risk-benefit assessment including the state of the art of commercial sources for medical use

  2. Tunable Electron Multibunch Production in Plasma Wakefield Accelerators

    CERN Document Server

    Hidding, B; Wittig, G; Aniculaesei, C; Jaroszynski, D; McNeil, B W J; Campbell, L T; Islam, M R; Ersfeld, B; Sheng, Z -M; Xi, Y; Deng, A; Rosenzweig, J B; Andonian, G; Murokh, A; Hogan, M J; Bruhwiler, D L; Cormier, E

    2014-01-01

    Synchronized, independently tunable and focused $\\mu$J-class laser pulses are used to release multiple electron populations via photo-ionization inside an electron-beam driven plasma wave. By varying the laser foci in the laboratory frame and the position of the underdense photocathodes in the co-moving frame, the delays between the produced bunches and their energies are adjusted. The resulting multibunches have ultra-high quality and brightness, allowing for hitherto impossible bunch configurations such as spatially overlapping bunch populations with strictly separated energies, which opens up a new regime for light sources such as free-electron-lasers.

  3. Plasmas in compact traps: From ion sources to multidisciplinary research

    Science.gov (United States)

    Mascali, D.; Musumarra, A.; Leone, F.; Galatà, A.; Romano, F. P.; Gammino, S.

    2017-09-01

    In linear (minimum-B) magneto-static traps dense and hot plasmas are heated by electromagnetic radiation in the GHz domain via the Electron Cyclotron Resonance (ECR). The values of plasma density, temperature and confinement times ( n_eτ_i>10^{13} cm ^{-3} s; T_e>10 keV) are similar to the ones of thermonuclear plasmas. The research in this field -devoted to heating and confinement optimization- has been supported by numerical modeling and advanced diagnostics, for probing the plasma especially in a non-invasive way. ECR-based systems are nowadays able to produce extremely intense (tens or hundreds of mA) beams of light ions (p, d, He), and relevant currents of heavier elements (C, O, N) up to heavy ions like Xe, Pb, U. Such beams can be extracted from the trap by a proper electrostatic system. The above-mentioned properties make these plasmas very attractive for interdisciplinary researches also, such as i) nuclear decays rates measurements in stellar-like conditions, ii) energy conversion studies, being exceptional sources of short-wavelength electromagnetic radiation (EUV, X-rays, hard X-rays and gammas, useful in material science and archaeometry), iii) environments allowing precise spectroscopical measurements as benchmarks for magnetized astrophysical plasmas. The talk will give an overview about the state-of-the-art in the field of intense ion sources, and some new perspectives for interdisciplinary research, with a special attention to the developments based at INFN-LNS.

  4. Nonquasineutral electron vortices in nonuniform plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Angus, J. R.; Richardson, A. S.; Swanekamp, S. B.; Schumer, J. W. [Plasma Physics Division, Naval Research Laboratory, Washington, District of Columbia 20375 (United States); Ottinger, P. F. [Engility Corporation, Chantilly, Virginia 20151 (United States)

    2014-11-15

    Electron vortices are observed in the numerical simulation of current carrying plasmas on fast time scales where the ion motion can be ignored. In plasmas with nonuniform density n, vortices drift in the B × ∇n direction with a speed that is on the order of the Hall speed. This provides a mechanism for magnetic field penetration into a plasma. Here, we consider strong vortices with rotation speeds V{sub ϕ} close to the speed of light c where the vortex size δ is on the order of the magnetic Debye length λ{sub B}=|B|/4πen and the vortex is thus nonquasineutral. Drifting vortices are typically studied using the electron magnetohydrodynamic model (EMHD), which ignores the displacement current and assumes quasineutrality. However, these assumptions are not strictly valid for drifting vortices when δ ≈ λ{sub B}. In this paper, 2D electron vortices in nonuniform plasmas are studied for the first time using a fully electromagnetic, collisionless fluid code. Relatively large amplitude oscillations with periods that correspond to high frequency extraordinary modes are observed in the average drift speed. The drift speed W is calculated by averaging the electron velocity field over the vorticity. Interestingly, the time-averaged W from these simulations matches very well with W from the much simpler EMHD simulations even for strong vortices with order unity charge density separation.

  5. Twisted electron-acoustic waves in plasmas

    Science.gov (United States)

    Aman-ur-Rehman, Ali, S.; Khan, S. A.; Shahzad, K.

    2016-08-01

    In the paraxial limit, a twisted electron-acoustic (EA) wave is studied in a collisionless unmagnetized plasma, whose constituents are the dynamical cold electrons and Boltzmannian hot electrons in the background of static positive ions. The analytical and numerical solutions of the plasma kinetic equation suggest that EA waves with finite amount of orbital angular momentum exhibit a twist in its behavior. The twisted wave particle resonance is also taken into consideration that has been appeared through the effective wave number qeff accounting for Laguerre-Gaussian mode profiles attributed to helical phase structures. Consequently, the dispersion relation and the damping rate of the EA waves are significantly modified with the twisted parameter η, and for η → ∞, the results coincide with the straight propagating plane EA waves. Numerically, new features of twisted EA waves are identified by considering various regimes of wavelength and the results might be useful for transport and trapping of plasma particles in a two-electron component plasma.

  6. Burning plasmas in ITER for energy source

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Nobuyuki [Atomic Energy Commission, Tokyo (Japan)

    2002-10-01

    Fusion research and development has two aspects. One is an academic research on science and technology, i.e., discovery and understanding of unexpected phenomena and, development of innovative technology, respectively. The other is energy source development to realize fusion as a viable energy future. Fusion research has been made remarkable progress in the past several decades, and ITER will soon realize burning plasma that is essential for both academic research and energy development. With ITER, scientific research on unknown phenomena such as self-organization of the plasma in burning state will become possible and it contributes to create a variety of academic outcome. Fusion researchers will have a responsibility to generate actual energy, and electricity generation immediately after the success of burning plasma control experiment in ITER is the next important step that has to be discussed seriously. (author)

  7. Application of Nonlocal Electron Kinetics to Plasma Technologies

    Science.gov (United States)

    Kaganovich, Igor D.

    2011-10-01

    Partially ionized plasmas are typically in a highly non-equilibrium thermodynamic state: the electrons are not in equilibrium with the neutral particle species or the ions, and the electrons are also not in equilibrium within their own ensemble, which results in a significant departure of the electron velocity distribution function (EVDF) from a Maxwellian. These non-equilibrium conditions provide considerable freedom to choose optimal plasma parameters for applications, which make gas-discharge plasmas remarkable tools for a variety of plasma applications, including plasma processing, discharge lighting, plasma propulsion, particle beam sources, and nanotechnology. Significant progress in understanding the formation of non-Maxwellian EVDF in the self-consistent electric fields has been one of the major achievements in the low-temperature plasmas during the last decade. This progress was made possible by a synergy between full-scale particle-in-cell simulations, analytical models, and experiments. Specific examples include rf discharges, dc discharges with auxiliary electrodes, Hall thruster discharges. In each example, nonlocal kinetic effects are identified as the main mechanisms responsible for the surprising degree of discharge self-organization. These phenomena include: explosive generation of cold electrons with rf power increase in low-pressure rf discharges; abrupt changes in discharge structure with increased bias voltage on a third electrode in a dc discharge with hot cathode; absence of a steady-state regime in Hall thruster discharges with intense secondary electron emission due to coupling of the sheath properties and the EVDF. In collaboration with Y. Raitses, A.V. Khrabrov, M. Campanell, V. I. Demidov, D. Sydorenko, I. Schweigert, and A. S. Mustafaev. Research supported by the U.S. Department of Energy.

  8. Laser ion source with solenoid for Brookhaven National Laboratory-electron beam ion source.

    Science.gov (United States)

    Kondo, K; Yamamoto, T; Sekine, M; Okamura, M

    2012-02-01

    The electron beam ion source (EBIS) preinjector at Brookhaven National Laboratory (BNL) is a new heavy ion-preinjector for relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Laser ion source (LIS) is a primary ion source provider for the BNL-EBIS. LIS with solenoid at the plasma drift section can realize the low peak current (∼100 μA) with high charge (∼10 nC) which is the BNL-EBIS requirement. The gap between two solenoids does not cause serious plasma current decay, which helps us to make up the BNL-EBIS beamline.

  9. Potential applications of a new microwave ECR multicusp plasma ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.C. (Fusion Energy Div., Oak Ridge National Lab., TN (USA))

    1991-05-01

    A new microwave electron cyclotron resonance (ECR) multicusp plasma ion source using two ECR plasma production regions and multicusp plasma confinement has been developed at Oak Ridge National Laboratory. This source has been operated to produce uniform and dense plasmas over large areas of 300-400 cm{sup 2}. The plasma source has been operated with continuous argon gas feed and pulsed microwave power. The discharge initiation phenomena and plasma properties have been investigated and studied as functions of discharge parameters. Together with the discharge characteristics observed, a hypothetical discharge mechanism for this plasma source is reported and discussed. Potential applications, including plasma and ion-beam processing for manufacturing advanced microelectronics and for space electric propulsion, are discussed. (orig.).

  10. Energetic electron spectra in Saturn's plasma sheet

    Science.gov (United States)

    Carbary, J. F.; Paranicas, C.; Mitchell, D. G.; Krimigis, S. M.; Krupp, N.

    2011-07-01

    The differential spectra of energetic electrons (27-400 keV) in Saturn's plasma sheet can be characterized by power law or kappa distributions. Using all available fluxes from 2005 to 2010, fits to these distributions reveal a striking and consistent pattern of radial dependence in Saturn's plasma sheet (∣z∣ constant throughout the Cassini mission. Inward of about 10 RS, the presence of the electron radiation belts and losses of lower-energy electrons to the gas and grain environment give rise to the very hard spectra in the inner magnetosphere, while the hard spectra in the outer magnetosphere may derive from auroral acceleration at high latitudes. The gradual softening of the spectra from 20 to 10 RS is explained by inward radial diffusion.

  11. Plasma electron-hole kinematics: momentum conservation

    CERN Document Server

    Hutchinson, I H

    2016-01-01

    We analyse the kinematic properties of a plasma electron hole: a non-linear self-sustained localized positive electric potential perturbation, trapping electrons, that behaves as a coherent entity. When a hole accelerates or grows in depth, ion and electron plasma momentum is changed both within the hole and outside it, by an energization process we call jetting. We present a comprehensive analytic calculation of the momentum changes of an isolated general one-dimensional hole. The conservation of the total momentum gives the hole's kinematics, determining its velocity evolution. Our results explain many features of the behavior of hole speed observed in numerical simulations, including self-acceleration at formation, and hole pushing and trapping by ion streams.

  12. Temporal evolution of electron beam generated Argon plasma in pasotron device

    Science.gov (United States)

    Khandelwal, Neha; Pal, U. N.; Prakash, Ram; Choyal, Y.

    2016-10-01

    The plasma- assisted slow wave oscillator (PASOTRON) is a high power microwave source in which the electron beam in the interaction region is confined by the background plasma. The plasma is generated by impact ionization of background gas with the electron beam. A model has been developed for temporal evolution of Argon plasma in pasotron device. In this model, we consider electron beam of energy E interacting with Argon gas. The resulting ionization creates quasi neutral argon plasma composed of argon Ar atoms, singly ionized ions Ar+1and electrons having energy from 0 to E. Electron impact excitation, ionization, radiative decay, radiative recombination and three body recombination processes are considered in this model. Population of ground and excited states of argon atom, ground state of argon ion as well as the population of electron energy groups is calculated by solving time dependent rate equations. Temporal evolution of electron beam generated plasma is given.

  13. Relativistic runaway electrons in tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Jaspers, R.E.

    1995-02-03

    Runaway electrons are inherently present in a tokamak, in which an electric field is applied to drive a toroidal current. The experimental work is performed in the tokamak TEXTOR. Here runaway electrons can acquire energies of up to 30 MeV. The runaway electrons are studied by measuring their synchrotron radiation, which is emitted in the infrared wavelength range. The studies presented are unique in the sense that they are the first ones in tokamak research to employ this radiation. Hitherto, studies of runaway electrons revealed information about their loss in the edge of the discharge. The behaviour of confined runaways was still a terra incognita. The measurement of the synchrotron radiation allows a direct observation of the behaviour of runaway electrons in the hot core of the plasma. Information on the energy, the number and the momentum distribution of the runaway electrons is obtained. The production rate of the runaway electrons, their transport and the runaway interaction with plasma waves are studied. (orig./HP).

  14. The ITER full size plasma source device design

    Energy Technology Data Exchange (ETDEWEB)

    Sonato, P. [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti 4, I-35127 Padova (Italy)], E-mail: piergiorgio.sonato@igi.cnr.it; Agostinetti, P.; Anaclerio, G.; Antoni, V.; Barana, O.; Bigi, M.; Boldrin, M. [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti 4, I-35127 Padova (Italy); Cavenago, M. [INFN, Legnaro, Padova (Italy); Dal Bello, S.; Palma, M. Dalla [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti 4, I-35127 Padova (Italy); Daniele, A. [ENEA, Frascati, Roma (Italy); D' Arienzo, M.; De Lorenzi, A.; Ferro, A.; Fiorentin, A.; Gaio, E.; Gazza, E.; Grando, L.; Fantini, F.; Fellin, F. [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti 4, I-35127 Padova (Italy)] (and others)

    2009-06-15

    In the framework of the strategy for the development and the procurement of the NB systems for ITER, it has been decided to build in Padova a test facility, including two experimental devices: a full size plasma source with low voltage extraction and a full size NB injector at full beam power (1 MV). These two different devices will separately address the main scientific and technological issues of the 17 MW NB injector for ITER. In particular the full size plasma source of negative ions will address the ITER performance requirements in terms of current density and uniformity, limitation of the electron/ion ratio and stationary operation at full current with high reliability and constant performances for the whole operating time up to 1 h. The required negative ion current density to be extracted from the plasma source ranges from 290 A/m{sup 2} in D{sub 2} (D{sup -}) and 350 A/m{sup 2} in H{sub 2} (H{sup -}) and these values should be obtained at the lowest admissible neutral pressure in the plasma source volume, nominally at 0.3 Pa. The electron to ion ratio should be limited to less than 1 and the admissible ion inhomogeneity extracted from the grids should be better than 10% on the whole plasma cross-section having a surface exposed to the extraction grid of the order of 1 m{sup 2}. The main design choices will be presented in the paper as well as an overview of the design of the main components and systems.

  15. Power Sources for Ultra Low Power Electronics

    Science.gov (United States)

    2000-06-12

    DARPA asked JASON to examine the issue of power sources for low power electronics with a specific emphasis on the properties of nuclear batteries and...integrated power sources combining power and electronics. During the 1998 Summer Study a workshop was held to provide background for the study, with

  16. LPI: electron source for LIL

    CERN Document Server

    Photographic Service

    1991-01-01

    This is where the beam for LEP began. The round metal box at the far right contains the electron-emitting cathode. After extraction, the low-energy electrons are focused with solenoids (blue) and formed into bunches. The "buncher", partly buried in the first solenoid, is fed by the descending brown transmission line. From there on, it was a long way through LIL-V, LIL-W, EPA, PS, SPS, and finally LEP.

  17. Temperature peaking at beginning of breakdown in 2.45 GHz pulsed off-resonance electron cyclotron resonance ion source hydrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Cortazar, O. D. [Universidad de Castilla-La Mancha. E.T.S.I.I., Camilo J. Cela s/n, 13071-C. Real (Spain); Megia-Macias, A.; Vizcaino-de-Julian, A. [E.S.S. Bilbao, Edificio Cosimet, Landabarri 2, 48940-Leioa, Vizcaya (Spain)

    2012-10-15

    An experimental study of temperature and density evolution during breakdown in off-resonance ECR hydrogen plasma is presented. Under square 2.45 GHz microwave excitation pulses with a frequency of 50 Hz and relative high microwave power, unexpected transient temperature peaks that reach 18 eV during 20 {mu}s are reported at very beginning of plasma breakdown. Decays of such peaks reach final stable temperatures of 5 eV at flat top microwave excitation pulse. Evidence of interplay between incoming power and duty cycle giving different kind of plasma parameters evolutions engaged to microwave coupling times is observed. Under relative high power conditions where short microwave coupling times are recorded, high temperature peaks are measured. However, for lower incoming powers and longer coupling times, temperature evolves gradually to a higher final temperature without peaking. On the other hand, the early instant where temperature peaks are observed also suggest a possible connection with preglow processes during breakdown in ECRIS plasmas.

  18. Nonlinear Electron Waves in Strongly Magnetized Plasmas

    DEFF Research Database (Denmark)

    Pécseli, Hans; Juul Rasmussen, Jens

    1980-01-01

    dynamics in the analysis is also demonstrated. As a particular case the authors investigate nonlinear waves in a strongly magnetized plasma filled wave-guide, where the effects of finite geometry are important. The relevance of this problem to laboratory experiments is discussed.......Weakly nonlinear dispersive electron waves in strongly magnetized plasma are considered. A modified nonlinear Schrodinger equation is derived taking into account the effect of particles resonating with the group velocity of the waves (nonlinear Landau damping). The possibility of including the ion...

  19. Characterization of electron temperature by simulating a multicusp ion source

    Science.gov (United States)

    Yeon, Yeong Heum; Ghergherehchi, Mitra; Kim, Sang Bum; Jun, Woo Jung; Lee, Jong Chul; Mohamed Gad, Khaled Mohamed; Namgoong, Ho; Chai, Jong Seo

    2016-12-01

    Multicusp ion sources are used in cyclotrons and linear accelerators to produce high beam currents. The structure of a multicusp ion source consists of permanent magnets, filaments, and an anode body. The configuration of the array of permanent magnets, discharge voltage of the plasma, extraction bias voltage, and structure of the multicusp ion source body decide the quality of the beam. The electrons are emitted from the filament by thermionic emission. The emission current can be calculated from thermal information pertaining to the filament, and from the applied voltage and current. The electron trajectories were calculated using CST Particle Studio to optimize the plasma. The array configuration of the permanent magnets decides the magnetic field inside the ion source. The extraction bias voltage and the structure of the multicusp ion source body decide the electric field. Optimization of the electromagnetic field was performed with these factors. CST Particle Studio was used to calculate the electron temperature with a varying permanent magnet array. Four types of permanent magnet array were simulated to optimize the electron temperature. It was found that a 2-layer full line cusp field (with inverse field) produced the best electron temperature control behavior.

  20. Speciation analysis by gas chromatography with plasma source spectrometric detection

    Science.gov (United States)

    Łobiński, Ryszard; Adams, Freddy C.

    State-of-the-art species-selective analysis by gas chromatography (GC) with plasma source spectrometric detection is discussed for organometal and organometalloid compounds. Various plasmas, inductively coupled plasma, microwave induced plasma, capacitatively coupled plasma, direct current plasma and alternating current plasma, are characterized and critically compared as sources of radiation for atomic emission spectrometry and sources of ions for mass spectrometry. Interfaces between gas chromatography (packed, wide-bore, capillary and multicapillary) and plasma source spectrometry are characterized. Particular emphasis is given to applications of GC with plasma source detection to real-world analytical problems, which are comprehensively reviewed. The use of plasmas for the acquisition of auxiliary molecular information such as empirical formulae and structural information is discussed. Recent developments relating to sample preparation and presentation to the hyphenated system are addressed. The most significant trends in speciation analysis are highlighted.

  1. Plasma ignition and steady state simulations of the Linac4 H$^{-}$ ion source

    CERN Document Server

    Mattei, S; Yasumoto, M; Hatayama, A; Lettry, J; Grudiev, A

    2014-01-01

    The RF heating of the plasma in the Linac4 H- ion source has been simulated using an Particle-in-Cell Monte Carlo Collision method (PIC-MCC). This model is applied to investigate the plasma formation starting from an initial low electron density of 1012 m-3 and its stabilization at 1018 m-3. The plasma discharge at low electron density is driven by the capacitive coupling with the electric field generated by the antenna, and as the electron density increases the capacitive electric field is shielded by the plasma and induction drives the plasma heating process. Plasma properties such as e-/ion densities and energies, sheath formation and shielding effect are presented and provide insight to the plasma properties of the hydrogen plasma.

  2. Electron Heating in a Relativistic, Weibel-Unstable Plasma

    CERN Document Server

    Kumar, Rahul; Gedalin, Michael

    2015-01-01

    The dynamics of two initially unmagnetized relativistic counter-streaming homogeneous ion-electron plasma beams are simulated in two dimensions using the particle-in-cell (PIC) method. It is shown that current filaments, which form due to the Weibel instability, develop a large scale longitudinal electric field in the direction opposite to the current carried by the filaments as predicted by theory. Fast moving ions in the current filaments decelerate due to this longitudinal electric field. The same longitudinal electric field, which is partially inductive and partially electrostatic, is identified as the main source of acceleration of electrons in the current filaments. The transverse electric field, though larger than the longitudinal one, is shown to play a smaller role in heating electrons, contrary to previous claims. It is found that, in 1D, the electrons become strongly magnetized and are \\textit{not} accelerated beyond their initial kinetic energy. Rather, the heating of the electrons is enhanced by ...

  3. 21 CFR 640.74 - Modification of Source Plasma.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Modification of Source Plasma. 640.74 Section 640...) BIOLOGICS ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.74 Modification of Source Plasma. (a) Upon approval by the Director, Center for Biologics Evaluation and Research, Food and...

  4. Plasma source mass spectrometry in experimental nutrition.

    Science.gov (United States)

    Barnes, R M

    1998-01-01

    The development and commercial availability of plasma ion source, specifically inductively coupled plasma, mass spectrometers (ICP-MS) have significantly extended the potential application of stable isotopes for nutritional modeling. The status of research and commercial ICP-MS instruments, and their applications and limitations for stable isotopic studies are reviewed. The consequences of mass spectroscopic resolution and measurement sensitivity obtainable with quadrupole, sector, time-of-flight, and trap instruments on stable isotope analysis are examined. Requirements for reliable isotope measurements with practical biological samples including tissues and fluids are considered. The possibility for stable isotope analysis in chemically separated compounds (speciation) also is explored. On-line compound separations by chromatography or electrophoresis, for example, have been combined instrumentally with ICP-MS. Som possibilities and requirements are described for stable isotope speciation analysis.

  5. Magnetic plasma confinement for laser ion source.

    Science.gov (United States)

    Okamura, M; Adeyemi, A; Kanesue, T; Tamura, J; Kondo, K; Dabrowski, R

    2010-02-01

    A laser ion source (LIS) can easily provide a high current beam. However, it has been difficult to obtain a longer beam pulse while keeping a high current. On occasion, longer beam pulses are required by certain applications. For example, more than 10 micros of beam pulse is required for injecting highly charged beams to a large sized synchrotron. To extend beam pulse width, a solenoid field was applied at the drift space of the LIS at Brookhaven National Laboratory. The solenoid field suppressed the diverging angle of the expanding plasma and the beam pulse was widened. Also, it was observed that the plasma state was conserved after passing through a few hundred gauss of the 480 mm length solenoid field.

  6. An ultracompact X-ray source based on a laser-plasma undulator.

    Science.gov (United States)

    Andriyash, I A; Lehe, R; Lifschitz, A; Thaury, C; Rax, J-M; Krushelnick, K; Malka, V

    2014-08-22

    The capability of plasmas to sustain ultrahigh electric fields has attracted considerable interest over the last decades and has given rise to laser-plasma engineering. Today, plasmas are commonly used for accelerating and collimating relativistic electrons, or to manipulate intense laser pulses. Here we propose an ultracompact plasma undulator that combines plasma technology and nanoengineering. When coupled with a laser-plasma accelerator, this undulator constitutes a millimetre-sized synchrotron radiation source of X-rays. The undulator consists of an array of nanowires, which are ionized by the laser pulse exiting from the accelerator. The strong charge-separation field, arising around the wires, efficiently wiggles the laser-accelerated electrons. We demonstrate that this system can produce bright, collimated and tunable beams of photons with 10-100 keV energies. This concept opens a path towards a new generation of compact synchrotron sources based on nanostructured plasmas.

  7. Laser-produced plasma source system development

    Science.gov (United States)

    Fomenkov, Igor V.; Brandt, David C.; Bykanov, Alexander N.; Ershov, Alexander I.; Partlo, William N.; Myers, David W.; Böwering, Norbert R.; Vaschenko, Georgiy O.; Khodykin, Oleh V.; Hoffman, Jerzy R.; Vargas L., Ernesto; Simmons, Rodney D.; Chavez, Juan A.; Chrobak, Christopher P.

    2007-03-01

    This paper describes the development of laser produced plasma (LPP) technology as an EUV source for advanced scanner lithography applications in high volume manufacturing. EUV lithography is expected to succeed 193 nm immersion technology for critical layer patterning below 32 nm beginning with beta generation scanners in 2009. This paper describes the development status of subsystems most critical to the performance to meet joint scanner manufacturer requirements and semiconductor industry standards for reliability and economic targets for cost of ownership. The intensity and power of the drive laser are critical parameters in the development of extreme ultraviolet LPP lithography sources. The conversion efficiency (CE) of laser light into EUV light is strongly dependent on the intensity of the laser energy on the target material at the point of interaction. The total EUV light generated then scales directly with the total incident laser power. The progress on the development of a short pulse, high power CO2 laser for EUV applications is reported. The lifetime of the collector mirror is a critical parameter in the development of extreme ultra-violet LPP lithography sources. The deposition of target materials and contaminants, as well as sputtering of the collector multilayer coating and implantation of incident particles can reduce the reflectivity of the mirror substantially over the exposure time even though debris mitigation schemes are being employed. The results of measurements of high energy ions generated by a short-pulse CO2 laser on a laser-produced plasma EUV light source with Sn target are presented. Droplet generation is a key element of the LPP source being developed at Cymer for EUV lithography applications. The main purpose of this device is to deliver small quantities of liquid target material as droplets to the laser focus. The EUV light in such configuration is obtained as a result of creating a highly ionized plasma from the material of the

  8. Probing Runaway Electrons with Nanoparticle Plasma Jet

    Science.gov (United States)

    Bogatu, I. N.; Thompson, J. R.; Galkin, S. A.; Kim, J. S.

    2014-10-01

    The injection of C60/C nanoparticle plasma jet (NPPJ) into tokamak plasma during a major disruption has the potential to probe the runaway electrons (REs) during different phases of their dynamics and diagnose them through spectroscopy of C ions visible/UV lines. A C60/C NPPJ of ~75 mg, high-density (>1023 m-3), hyper-velocity (>4 km/s), and uniquely fast response-to-delivery time (~1 ms) has been demonstrated on a test bed. It can rapidly and deeply deliver enough mass to increase electron density to ~2.4 × 1021 m-3, ~60 times larger than typical DIII-D pre-disruption value. We will present the results of our investigations on: 1) C60 fragmentation and gradual release of C atoms along C60 NPPJ penetration path through the RE carrying residual cold plasma, 2) estimation of photon emissivity coefficient for the lines of the C ions, and 3) simulation of C60/C PJ penetration to the RE beam location in equivalent conditions to the characteristic ~1 T B-field of DIII-D. The capabilities of this injection technique provide a unique possibility in understanding and controlling the RE beam, which is a critical problem for ITER. Work supported by US DOE DE-SC0011864 Grant.

  9. Vacuum laser acceleration of relativistic electrons using plasma mirror injectors

    CERN Document Server

    Thévenet, M; Kahaly, S; Vincenti, H; Vernier, A; Quéré, F; Faure, J

    2015-01-01

    Accelerating particles to relativistic energies over very short distances using lasers has been a long standing goal in physics. Among the various schemes proposed for electrons, vacuum laser acceleration has attracted considerable interest and has been extensively studied theoretically because of its appealing simplicity: electrons interact with an intense laser field in vacuum and can be continuously accelerated, provided they remain at a given phase of the field until they escape the laser beam. But demonstrating this effect experimentally has proved extremely challenging, as it imposes stringent requirements on the conditions of injection of electrons in the laser field. Here, we solve this long-standing experimental problem for the first time by using a plasma mirror to inject electrons in an ultraintense laser field, and obtain clear evidence of vacuum laser acceleration. With the advent of PetaWatt class lasers, this scheme could provide a competitive source of very high charge (nC) and ultrashort rela...

  10. High Power Light Gas Helicon Plasma Source For VASMIR

    Science.gov (United States)

    Squire, J. P.; Chang-Diaz, F. R.; Glover, T. W.; Jacobson, V. T.; McCaskill, G. E.; Winter, D. S.; Baity, F. W.; Carter, M. D.; Goulding, R. H.

    2004-01-01

    The VASIMR space propulsion development effort relies on a high power (greater than 10kW) helicon source to produce a dense flowing plasma (H, D and He) target for ion cyclotron resonance (ICR) acceleration of the ions. Subsequent expansion in an expanding magnetic field (magnetic nozzle) converts ion lunetic energy to directed momentum. This plasma source must have critical features to enable an effective propulsion device. First, it must ionize most of the input neutral flux of gas, thus producing a plasma stream with a high degree of ionization for application of ICR power. This avoids propellant waste and potential power losses due to charge exchange. Next, the plasma stream must flow into a region of high magnetic field (approximately 0.5 T) for efficient ICR acceleration. Third, the ratio of input power to plasma flux must be low, providing an energy per ion-electron pair approaching 100 eV. Lastly, the source must be robust and capable of very long life-times (years). In our helicon experiment (VX-10) we have measured a ratio of input gas to plasma flux near 100%. The plasma flows from the helicon region (B approximately 0.1 T) into a region with a peak magnetic field of 0.8 T. The energy input per ion-electron pair has been measured at 300 plus or minus 100 eV. Recent results at Oak Ridge National Laboratory (ORNL) show an enhanced efficiency mode of operation with a high power density, over 5 kW in a 5 cm diameter tube. Our helicon is presently 9 cm in diameter and operates up to 3.5 kW of input power. An upgrade to a power level of 10 kW is underway. Much of our recent work has been with a Boswell double-saddle antenna design. We are also converting the antenna design to a helical type. With these modifications, we anticipate an improvement in the ionization efficiency. This paper presents the results from scaling the helicon in the VX-10 device from 3.5 to 10 kW. We also compare the operation with a double-saddle to a helical antenna design. Finally, we

  11. High Power Light Gas Helicon Plasma Source For VASMIR

    Science.gov (United States)

    Squire, J. P.; Chang-Diaz, F. R.; Glover, T. W.; Jacobson, V. T.; McCaskill, G. E.; Winter, D. S.; Baity, F. W.; Carter, M. D.; Goulding, R. H.

    2004-01-01

    The VASIMR space propulsion development effort relies on a high power (greater than 10kW) helicon source to produce a dense flowing plasma (H, D and He) target for ion cyclotron resonance (ICR) acceleration of the ions. Subsequent expansion in an expanding magnetic field (magnetic nozzle) converts ion lunetic energy to directed momentum. This plasma source must have critical features to enable an effective propulsion device. First, it must ionize most of the input neutral flux of gas, thus producing a plasma stream with a high degree of ionization for application of ICR power. This avoids propellant waste and potential power losses due to charge exchange. Next, the plasma stream must flow into a region of high magnetic field (approximately 0.5 T) for efficient ICR acceleration. Third, the ratio of input power to plasma flux must be low, providing an energy per ion-electron pair approaching 100 eV. Lastly, the source must be robust and capable of very long life-times (years). In our helicon experiment (VX-10) we have measured a ratio of input gas to plasma flux near 100%. The plasma flows from the helicon region (B approximately 0.1 T) into a region with a peak magnetic field of 0.8 T. The energy input per ion-electron pair has been measured at 300 plus or minus 100 eV. Recent results at Oak Ridge National Laboratory (ORNL) show an enhanced efficiency mode of operation with a high power density, over 5 kW in a 5 cm diameter tube. Our helicon is presently 9 cm in diameter and operates up to 3.5 kW of input power. An upgrade to a power level of 10 kW is underway. Much of our recent work has been with a Boswell double-saddle antenna design. We are also converting the antenna design to a helical type. With these modifications, we anticipate an improvement in the ionization efficiency. This paper presents the results from scaling the helicon in the VX-10 device from 3.5 to 10 kW. We also compare the operation with a double-saddle to a helical antenna design. Finally, we

  12. Electromagnetic radiation and nonlinear energy flow in an electron beam-plasma system

    Science.gov (United States)

    Whelan, D. A.; Stenzel, R. L.

    1985-01-01

    It is shown that the unstable electron-plasma waves of a beam-plasma system can generate electromagnetic radiation in a uniform plasma. The generation mechanism is a scattering of the unstable electron plasma waves off ion-acoustic waves, producing electromagnetic waves whose frequency is near the local plasma frequency. The wave vector and frequency matching conditions of the three-wave mode coupling are experimentally verified. The electromagnetic radiation is observed to be polarized with the electric field parallel to the beam direction, and its source region is shown to be localized to the unstable plasma wave region. The frequency spectrum shows negligible intensity near the second harmonic of the plasma frequency. These results suggest that the observed electromagnetic radiation of type III solar bursts may be generated near the local plasma frequency and observed downstream where the wave frequency is near the harmonic of the plasma frequency.

  13. Comet plasma densities deduced from refraction of occulted radio sources

    Energy Technology Data Exchange (ETDEWEB)

    Wright, C.S. (Commonwealth Department of Science, Ionospheric Prediction Service, Narrabri, New South Wales, Australia); Nelson, G.J. (Commonwealth Scientific and Industrial Research Organization, Div. of Radiophysics, Narrabri, New South Wales, Australia)

    1979-04-01

    Observations of the occultation of radio sources by comet plasma tails are used to derive the electron density and density gradients in the tails. Occultations of source Culgoora-1 0300+16 by Comet Kohoutek and of Culgoora-1 2313-14 by Comet West were measured by radioheliograph at 80 MHz. After corrections for ionospheric refraction, a 2 arcmin anomaly was observed in the declination of 0300+16, attributed to refraction by the tail of Comet Kohoutek, while none was observed for Comet West. The maximum electron density in the tail of Comet Kohoutek is calculated to be 2 x 10 to the 4th/cu cm, while that of Comet West is 5 x 10 to the 4th/cu cm, with density gradients of about 0.05 per cu cm per km. The direction of refraction observed suggests that the tail of Kohoutek is either highly asymmetric about its axis or has the form of a hollow, cylindrical plasma sheath. The high electron densities observed in Kohoutek may indicate the presence of undetected ion species or a low ionization loss rate.

  14. Electron Capture in a Fully Ionized Plasma

    CERN Document Server

    Widom, A; Srivastava, Y N

    2014-01-01

    Properties of fully ionized water plasmas are discussed including plasma charge density oscillations and the screening of the Coulomb law especially in the dilute classical Debye regime. A kinetic model with two charged particle scattering events determines the transition rate per unit time for electron capture by a nucleus with the resulting nuclear transmutations. Two corrections to the recent Maiani et al. calculations are made: (i) The Debye screening length is only employed within its proper domain of validity. (ii) The WKB approximation employed by Maiani in the long De Broglie wave length limit is evidently invalid. We replace this incorrect approximation with mathematically rigorous Calogero inequalities in order to discuss the scattering wave functions. Having made these corrections, we find a verification for our previous results based on condensed matter electro-weak quantum field theory for nuclear transmutations in chemical batteries.

  15. Compact tunable Compton x-ray source from laser-plasma accelerator and plasma mirror

    CERN Document Server

    Tsai, Hai-En; Shaw, Joseph; Li, Zhengyan; Arefiev, Alexey V; Zhang, Xi; Zgadzaj, Rafal; Henderson, Watson; Khudik, V; Shvets, G; Downer, M C

    2014-01-01

    We present results of the first tunable Compton backscattering (CBS) x-ray source that is based on the easily aligned combination of a laser-plasma accelerator (LPA) and a plasma mirror (PM). The LPA is driven in the blowout regime by 30 TW, 30 fs laser pulses, and produces high-quality, tunable, quasi-monoenergetic electron beams. A thin plastic film near the gas jet exit efficiently retro-reflects the LPA driving pulse with relativistic intensity into oncoming electrons to produce $2\\times10^{7}$ CBS x-ray photons per shot with 10-20 mrad angular divergence and 50 % (FWHM) energy spread without detectable bremsstrahlung background. The x-ray central energy is tuned from 75 KeV to 200 KeV by tuning the LPA e-beam central energy. Particle-in-cell simulations of the LPA, the drive pulse/PM interaction and CBS agree well with measurements.

  16. Ferroelectric plasma sources for NDCX-II and heavy ion drivers

    Energy Technology Data Exchange (ETDEWEB)

    Gilson, E.P., E-mail: egilson@pppl.gov [Princeton Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey, 08543 (United States); Davidson, R.C.; Efthimion, P.C.; Kaganovich, I.D. [Princeton Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey, 08543 (United States); Kwan, J.W.; Lidia, S.M.; Ni, P.A.; Roy, P.K.; Seidl, P.A.; Waldron, W.L. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California, 94720 (United States); Barnard, J.J.; Friedman, A. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California, 94550 (United States)

    2014-01-01

    A barium titanate ferroelectric cylindrical plasma source has been developed, tested and delivered for the Neutralized Drift Compression Experiment NDCX-II at Lawrence Berkeley National Laboratory (LBNL). The plasma source design is based on the successful design of the NDCX-I plasma source. A 7 kV pulse applied across the 3.8 mm-thick ceramic cylinder wall produces a large polarization surface charge density that leads to breakdown and plasma formation. The plasma that fills the NDCX-II drift section upstream of the final-focusing solenoid has a plasma number density exceeding 10{sup 10} cm{sup −3} and an electron temperature of several eV. The operating principle of the ferroelectric plasma source are reviewed and a detailed description of the installation plans is presented. The criteria for plasma sources with larger number density will be given, and concepts will be presented for plasma sources for driver applications. Plasma sources for drivers will need to be highly reliable, and operate at several Hz for millions of shots.

  17. Ferroelectric plasma sources for NDCX-II and heavy ion drivers

    Science.gov (United States)

    Gilson, E. P.; Davidson, R. C.; Efthimion, P. C.; Kaganovich, I. D.; Kwan, J. W.; Lidia, S. M.; Ni, P. A.; Roy, P. K.; Seidl, P. A.; Waldron, W. L.; Barnard, J. J.; Friedman, A.

    2014-01-01

    A barium titanate ferroelectric cylindrical plasma source has been developed, tested and delivered for the Neutralized Drift Compression Experiment NDCX-II at Lawrence Berkeley National Laboratory (LBNL). The plasma source design is based on the successful design of the NDCX-I plasma source. A 7 kV pulse applied across the 3.8 mm-thick ceramic cylinder wall produces a large polarization surface charge density that leads to breakdown and plasma formation. The plasma that fills the NDCX-II drift section upstream of the final-focusing solenoid has a plasma number density exceeding 1010 cm-3 and an electron temperature of several eV. The operating principle of the ferroelectric plasma source are reviewed and a detailed description of the installation plans is presented. The criteria for plasma sources with larger number density will be given, and concepts will be presented for plasma sources for driver applications. Plasma sources for drivers will need to be highly reliable, and operate at several Hz for millions of shots.

  18. Electron beam ion source and electron beam ion trap (invited).

    Science.gov (United States)

    Becker, Reinard; Kester, Oliver

    2010-02-01

    The electron beam ion source (EBIS) and its trap variant [electron beam ion trap (EBIT)] celebrated their 40th and 20th anniversary, respectively, at the EBIS/T Symposium 2007 in Heidelberg. These technologically challenging sources of highly charged ions have seen a broad development in many countries over the last decades. In contrast to most other ion sources the recipe of improvement was not "sorcery" but a clear understanding of the physical laws and obeying the technological constraints. This review will report important achievements of the past as well as promising developments in the future.

  19. Electron beam ion source and electron beam ion trap (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Reinard [Scientific Software Service, Kapellenweg 2a, D-63571 Gelnhausen (Germany); Kester, Oliver [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States)

    2010-02-15

    The electron beam ion source (EBIS) and its trap variant [electron beam ion trap (EBIT)] celebrated their 40th and 20th anniversary, respectively, at the EBIS/T Symposium 2007 in Heidelberg. These technologically challenging sources of highly charged ions have seen a broad development in many countries over the last decades. In contrast to most other ion sources the recipe of improvement was not ''sorcery'' but a clear understanding of the physical laws and obeying the technological constraints. This review will report important achievements of the past as well as promising developments in the future.

  20. Plasma ignition schemes for the SNS radio-frequency driven H- source

    Energy Technology Data Exchange (ETDEWEB)

    Schenkel, T.; Staples, J.W.; Thomae, W.; Reijonen, J.; Gough, R.A.; Leung, K.N.; Keller, R.

    2001-09-06

    The H{sup -} ion source for the Spallation Neutron Source (SNS) is a cesiated, radio-frequency driven (2 MHz) multicusp volume source which operates at a duty cycle of 6% (1 ms pulses and 60 Hz). In pulsed RF driven plasma sources, ignition of the plasma affects the stability of source operation and the antenna lifetime. We are reporting on investigations of different ignition schemes, based on secondary electron generation in the plasma chamber by UV light, a hot filament, a low power RF plasma (cw, 13.56 MHz), as well as source operation solely with the high power (40 kW) 2 MHz RF. We find that the dual frequency, single antenna scheme is most attractive for the operating conditions of the SNS H{sup -} source.

  1. PIC/MCC simulation for magnetized capacitively coupled plasmas driven by combined dc/rf sources

    Science.gov (United States)

    Yang, Shali; Zhang, Ya; Jiang, Wei; Wang, Hongyu; Wang, Shuai

    2016-09-01

    Hybrid dc/rf capacitively coupled plasma (CCP) sources have been popular in substrate etching due to their simplicity in the device structure and better plasma property. In this work, the characteristics of magnetized capacitively coupled plasmas driven by combined dc/rf sources are described by a one-dimensional Particle-in-cell/Monte Carlo collision (PIC/MCC) model. The simulation is using a rf source of 13.56MHz in argon and at a low pressure of 50mTorr. The effects of dc voltage and magnetic field on the plasmas are examined for 200-400V and 0-200Gs. It is found that, to some extent, dc voltage will increase the plasma density, but plasma density drops with increasing dc voltage. The magnetic field will enhance the plasma density significantly, due to the magnetic field will increase the electron life time and decrease the loss to the electrodes. In the bulk plasma, electron temperature is increased with the magnetic field but decreased with the dc voltage. The electron temperature in sheath is higher than in bulk plasma, due to stochastic heating in sheath is greater than Ohmic heating in bulk plasma under low gas pressure. National Natural Science Foundation of China (11405067, 11105057, 11305032, 11275039).

  2. High-density operation of the Proto-MPEX High Intensity Plasma Source

    Science.gov (United States)

    Caughman, J. B. O.; Goulding, R. H.; Biewer, T. M.; Bigelow, T. S.; Campbell, I. H.; Caneses, J.; Diem, S. J.; Martin, E. H.; Parish, C. M.; Rapp, J.; Ray, H. B.; Shaw, G. C.; Showers, M. A.; Donovan, D.; Piotrowicz, P. A.; Martin, D. C.

    2016-10-01

    The Prototype Materials Plasma Experiment (Proto-MPEX) is a linear high-intensity RF plasma source that combines a high-density helicon plasma generator with ion and electron heating sections. It is being used to study the physics of heating over-dense plasmas in a linear configuration with the goal of delivering a plasma heat flux of 10 MW/m2 at a target. The helicon plasma is produced by coupling 13.56 MHz RF power at levels of >100 kW. A 30 kW ion cyclotron antenna has recently been installed, and microwaves at 28 GHz ( 150 kW) are coupled to the electrons in the over-dense helicon plasma via Electron Bernstein Waves (EBW). High plasma densities near the target have been produced in D ( 5 x1019/m3) , and electron temperatures range from 3 to >10 eV, depending on the source parameters. IR camera images of the target plate indicate plasma heat depositions >10 MW/m2 for some operating conditions. Details of the experimental results of the operational domain with respect to Te and ne as well as results from initial plasma material interaction tests will be presented. ORNL is managed by UT-Battelle, LLC, for the U.S. DOE under contract DE-AC-05-00OR22725.

  3. Multibeam Electron Source using MEMS Electron Optical Components

    Energy Technology Data Exchange (ETDEWEB)

    Someren, B van; Bruggen, M J van; Zhang, Y; Hagen, C W; Kruit, P [Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands)

    2006-04-01

    Recent developments in electron beam equipment have given rise to ever more complex electron optical (EO) designs. Until now these designs were realized using standard workshop techniques like drilling, turning etc. With the need for even more complex designs to advance electron optics, we use the possibilities of manufacturing EO components with MEMS fabrication techniques. This leads to different design rules in the EO design. One can use one of the strong points of MEMS fabrication, mass manufacturing of identical and reliable components within tight specifications. One of our designs that demonstrates this is presented in this paper, the multi-beam electron source. We are developing an electron source for use in a standard scanning electron microscope that produces 100 beams instead of one. The design is made so that the performance in terms of spot size and current per beam is equal to the performance of the beam from a single beam source, around 1 nm and 25 pA. Furthermore, since we modify the SEM for nanolithography purposes, it is necessary to switch each of the individual beams on and off. For that purpose we integrate an array of blanker electrodes in the source unit.

  4. Plasma electrons as tracers of distant magnetotail structure: ISEE-3

    Energy Technology Data Exchange (ETDEWEB)

    Baker, D.N.; Bame, S.J.; Gosling, J.T.; Gussenhoven, M.S.

    1988-01-01

    Electrons in the 50-500 eV energy range commonly exhibit strong, field-aligned bidirectional anisotropies in the distant (r > 100 Rg) geomagnetic tail lobes and are found to occur predominantly in the lobe directly connected to the sun along the interplanetary magnetic field in the open magnetosphere model (north lobe for away interplanetary sectors and south lobe for toward sectors). Data show the transition from unidirectional (sheath) electron populations to bidirectional (lobe) populations at the distant magnetopause. This demonstrates the open nature of the distant magnetotail and shows that the source of the higher-energy, bidirectional lobe electrons is the tailward-directed electron heat flux population in the magnetosheath. The field-aligned lobe electron phase space densities above 200 eV at ISEE-3 agree well with DMSP-measured polar rain phase space densities near the polar cap and the spectral slopes above 200 eV also are similar. Below 100-200 eV there is a thermal electron population in the distant tail, arising from local entry of plasma through the distant magnetopause, which is not present at DMSP altitudes. These data show that the suprathermal tail lobe electrons are essentially a test particle population which can move freely along field lines to form polar rain; in contrast, the thermal electrons are bound to the tailward-flowing lobe ion population far down the tail and thus cannot reach the polar cap regions.

  5. Electron waves and resonances in bounded plasmas

    CERN Document Server

    Vandenplas, Paul E

    1968-01-01

    General theoretical methods and experimental techniques ; the uniform plasma slab-condenser system ; the hollow cylindrical plasma ; scattering of a plane electromagnetic wave by a plasma column in steady magnetic fields (cold plasma approximation) ; hot non-uniform plasma column ; metallic and dielectric resonance probes, plasma-dielectric coated antenna, general considerations.

  6. Electron Storage Ring Development for ICS Sources

    Energy Technology Data Exchange (ETDEWEB)

    Loewen, Roderick [Lyncean Technologies, Inc., Palo Alto, CA (United States)

    2015-09-30

    There is an increasing world-wide interest in compact light sources based on Inverse Compton Scattering. Development of these types of light sources includes leveraging the investment in accelerator technology first developed at DOE National Laboratories. Although these types of light sources cannot replace the larger user-supported synchrotron facilities, they offer attractive alternatives for many x-ray science applications. Fundamental research at the SLAC National Laboratory in the 1990’s led to the idea of using laser-electron storage rings as a mechanism to generate x-rays with many properties of the larger synchrotron light facilities. This research led to a commercial spin-off of this technology. The SBIR project goal is to understand and improve the performance of the electron storage ring system of the commercially available Compact Light Source. The knowledge gained from studying a low-energy electron storage ring may also benefit other Inverse Compton Scattering (ICS) source development. Better electron storage ring performance is one of the key technologies necessary to extend the utility and breadth of applications of the CLS or related ICS sources. This grant includes a subcontract with SLAC for technical personnel and resources for modeling, feedback development, and related accelerator physics studies.

  7. A New Atmospheric Pressure Microwave Plasma Source (APMPS)

    Institute of Scientific and Technical Information of China (English)

    LIU Liang; ZHANG Guixin; LI Yinan; ZHU Zhijie; WANG Xinxin; LUO Chengmu

    2008-01-01

    An atmospheric pressure microwave plasma source (APMPS) that can generate a large volume of plasma at an atmospheric pressure has been developed at Tsinghua University. This paper presents the design of this APMPS, the theoretical consideration of microwave plasma ignition and the simulation results, including the distributions of the electric field and power density inside the cavity as well as the accuracy of the simulation results. In addition, a method of producing an atmospheric pressure microwave plasma and some relevant observations of the plasma are also provided. It. is expected that this research would be useful for further developing atmospheric pressure microwave plasma sources and expanding the scope of their applications.

  8. Characterization of an atmospheric pressure air plasma source for polymer surface modification

    Science.gov (United States)

    Yang, Shujun; Tang, Jiansheng

    2013-10-01

    An atmospheric pressure air plasma source was generated through dielectric barrier discharge (DBD). It was used to modify polyethyleneterephthalate (PET) surfaces with very high throughput. An equivalent circuit model was used to calculate the peak average electron density. The emission spectrum from the plasma was taken and the main peaks in the spectrum were identified. The ozone density in the down plasma region was estimated by Absorption Spectroscopy. NSF and ARC-ODU

  9. Dynamics of Ion Beam Charge Neutralization by Ferroelectric Plasma Sources

    Science.gov (United States)

    Stepanov, Anton D.; Gilson, Erik P.; Grisham, Larry R.; Kaganovich, Igor D.; Davidson, Ronald C.; Ji, Qing; Persaud, Arun; Seidl, Peter A.; Schenkel, Thomas

    2016-10-01

    Ferroelectric Plasma Sources (FEPSs) can generate plasma that provides effective space-charge neutralization of intense high-perveance ion beams. Here we present experimental results on charge neutralization of a high-perveance 38 keV Ar+ beam by a FEPS plasma. By comparing the measured beam radius with the envelope model for space-charge expansion, it is shown that a charge neutralization fraction of 98% is attainable. The transverse electrostatic potential of the ion beam is reduced from 15 V before neutralization to 0.3 V, implying that the energy of the neutralizing electrons is below 0.3 eV. Near-complete charge neutralization is established 5 μs after the driving pulse is applied to the FEPS, and can last for 35 μs. It is argued that the duration of neutralization is much longer than a reasonable lifetime of the plasma produced in the sub- μs surface discharge. Measurements of current flow in the driving circuit of the FEPS suggest that plasma can be generated for tens of μs after the high voltage pulse is applied. This is confirmed by fast photography of the plasma in the 1-meter long FEPS on NDCX-II, where effective charge neutralization of the beam was achieved with the optimized FEPS timing. This work was supported by the Office of Science of the US Department of Energy under contracts DE-AC0209CH11466 (PPPL) and DE-AC0205CH11231 (LBNL).

  10. Polarized Electron Source for the MOLLER Experiment

    Science.gov (United States)

    Palatchi, Caryn

    2017-01-01

    The MOLLER experiment at Jefferson Laboratory will be part of a new generation of ultra high precision electroweak experiments. It will measure the Moller (electron-electron scattering) parity-violating asymmetry, providing an unprecedented precision on the electroweak mixing angle. To achieve such small uncertainties, innovative techniques in the electron source are required to switch the beam helicity more quickly than previously achievable. The key technology is the Pockels cell in the laser optics of the polarized electron source. RTP crystals, which do not suffer from piezo-electric ringing, have been demonstrated to achieve almost an order of magnitude faster transition times than commonly used KD*P crystal cells. This talk will detail the design modifications made to the RTP cell in order to achieve beam quality which is comparable to traditional KD*P controlled accelerator beams. The specific challenges for this use of the RTP system, including laser and crystal constraints, will be discussed.

  11. Generation of anomalously energetic suprathermal electrons by an electron beam interacting with a nonuniform plasma

    CERN Document Server

    Sydorenko, D; Chen, L; Ventzek, P L G

    2015-01-01

    Generation of anomalously energetic suprathermal electrons was observed in simulation of a high- voltage dc discharge with electron emission from the cathode. An electron beam produced by the emission interacts with the nonuniform plasma in the discharge via a two-stream instability. Efficient energy transfer from the beam to the plasma electrons is ensured by the plasma nonuniformity. The electron beam excites plasma waves whose wavelength and phase speed gradually decrease towards anode. The short waves near the anode accelerate plasma bulk electrons to suprathermal energies. The sheath near the anode reflects some of the accelerated electrons back into the plasma. These electrons travel through the plasma, reflect near the cathode, and enter the accelerating area again but with a higher energy than before. Such particles are accelerated to energies much higher than after the first acceleration. This mechanism plays a role in explaining earlier experimental observations of energetic suprathermal electrons i...

  12. The MAMI source of polarized electrons

    Energy Technology Data Exchange (ETDEWEB)

    Aulenbacher, K. [Johannes Gutenberg Univ., Mainz (Germany). Inst. fur Kernphys.; Nachtigall, C.; Andresen, H.G.; Bermuth, J.; Dombo, T.; Drescher, P.; Euteneuer, H.; Fischer, H.; Harrach, D. v.; Hartmann, P.; Hoffmann, J.; Jennewein, P.; Kaiser, K.H.; Koebis, S.; Kreidel, H.J.; Langbein, J.; Petri, M.; Pluetzer, S.; Reichert, E.; Schemies, M.; Schoepe, H.-J.; Steffens, K.-H.; Steigerwald, M.; Trautner, H.; Weis, T.

    1997-06-11

    The present work describes the source of polarized electrons that is run at the 855 MeV race track microtron MAMI at the Johannes Gutenberg Universitaet in Mainz. The source is based on photoelectron emission from (III-V)-semiconductors. Presently strained layer InGaP- or GaAsP-cathodes are used, which are processed to negative electron affinity by coverage of the surface with a submonolayer of caesium and oxygen. Electron beams spin-polarized up to a degree of P=55% at a quantum efficiency of QE=2% or P=75% at QE=0.4%, respectively, are obtained. The well-known but hitherto unsolved problem of limited cathode lifetime has been sidestepped by the attachment of an UHV load lock system to the source electron gun. It allows quick replacement of cathodes without breaking the gun vacuum. Availabilities in excess of 85% are obtained regularly in beamtimes longer than 100 h. The source was mainly applied in measurements of nucleon form factors via the reactions {sup 1}H(vector e,e` vector p), {sup 2}D(vector e,e` vector p), {sup 2}D(vector e,e` vector n), and {sup 3} vector He(vector e,e`n). More than 1600 h beamtime have been accomplished in physics experiments with polarized electron beams at MAMI up to now. (orig.).

  13. Electron Cyclotron Resonance Heating of a High-Density Plasma

    DEFF Research Database (Denmark)

    Hansen, F. Ramskov

    1986-01-01

    Various schemes for electron cyclotron resonance heating of tokamak plasmas with the ratio of electron plasma frequency to electron cyclotron frequency, "»pe/^ce* larger than 1 on axis, are investigated. In particular, a mode conversion scheme is investigated using ordinary waves at the fundamental...

  14. Electron Heating in a Relativistic, Weibel-unstable Plasma

    Science.gov (United States)

    Kumar, Rahul; Eichler, David; Gedalin, Michael

    2015-06-01

    The dynamics of two initially unmagnetized relativistic counter-streaming homogeneous ion-electron plasma beams are simulated in two dimensions (2D) using the particle-in-cell (PIC) method. It is shown that current filaments, which form due to the Weibel instability, develop a large-scale longitudinal electric field in the direction opposite to the current carried by the filaments as predicted by theory. This field, which is partially inductive and partially electrostatic, is identified as the main source of net electron acceleration, greatly exceeding that due to magnetic field decay at later stages. The transverse electric field, although larger than the longitudinal field, is shown to play a smaller role in heating electrons, contrary to previous claims. It is found that in one dimension, the electrons become strongly magnetized and are not accelerated beyond their initial kinetic energy. Rather, the heating of the electrons is enhanced by the bending and break up of the filaments, which releases electrons that would otherwise be trapped within a single filament and slow the development of the Weibel instability (i.e., the magnetic field growth) via induction as per Lenz’s law. In 2D simulations, electrons are heated to about one quarter of the initial kinetic energy of ions. The magnetic energy at maximum is about 4%, decaying to less than 1% by the end of the simulation. The ions are found to gradually decelerate until the end of the simulation, by which time they retain a residual anisotropy of less than 10%.

  15. ELECTRON HEATING IN A RELATIVISTIC, WEIBEL-UNSTABLE PLASMA

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rahul; Eichler, David; Gedalin, Michael [Physics Department, Ben-Gurion University, Be’er-Sheba 84105 (Israel)

    2015-06-20

    The dynamics of two initially unmagnetized relativistic counter-streaming homogeneous ion–electron plasma beams are simulated in two dimensions (2D) using the particle-in-cell (PIC) method. It is shown that current filaments, which form due to the Weibel instability, develop a large-scale longitudinal electric field in the direction opposite to the current carried by the filaments as predicted by theory. This field, which is partially inductive and partially electrostatic, is identified as the main source of net electron acceleration, greatly exceeding that due to magnetic field decay at later stages. The transverse electric field, although larger than the longitudinal field, is shown to play a smaller role in heating electrons, contrary to previous claims. It is found that in one dimension, the electrons become strongly magnetized and are not accelerated beyond their initial kinetic energy. Rather, the heating of the electrons is enhanced by the bending and break up of the filaments, which releases electrons that would otherwise be trapped within a single filament and slow the development of the Weibel instability (i.e., the magnetic field growth) via induction as per Lenz’s law. In 2D simulations, electrons are heated to about one quarter of the initial kinetic energy of ions. The magnetic energy at maximum is about 4%, decaying to less than 1% by the end of the simulation. The ions are found to gradually decelerate until the end of the simulation, by which time they retain a residual anisotropy of less than 10%.

  16. Plasma heating via electron Bernstein wave heating using ordinary and extraodinary mode

    Directory of Open Access Journals (Sweden)

    A. Parvazian

    2008-03-01

    Full Text Available Magnetically confined plasma can be heated with high power microwave sources. In spherical torus the electron plasma frequency exeeds the electron cyclotron frequency (EC and, as a consequence, electromagnetic waves at fundamental and low harmonic EC cannot propagate within the plasma. In contrast, electron Bernstein waves (EBWs readily propagate in spherical torus plasma and are absorbed strongly at the electron cyclotron resonances. In order to proagate EBWs beyond the upper hybrid resonance (UHR, that surrounds the plasma, the EBWs must convert via one of two processes to either ordinary (O-mode or extraordinary (X-mode electromagnetic waves. O-mode and X-mode electromagnetic waves lunched at the plasma edge can convert to the electron Bernstein waves (EBWs which can propagate without and cut-off into the core of the plasma and damp on electrons. Since the electron Bernstein wave (EBW has no cut-off limits, it is well suited to heat an over-dense plasma by resonant absorption. An important problem is to calculate mode conversion coefficient that is very sensitive to density. Mode conversion coefficient depends on Budden parameter ( ñ and density scale length (Ln in upper hybrid resonance (UHR. In Mega Ampere Spherical Tokamak (MAST, the optimized conversion efficiency approached 72.5% when Ln was 4.94 cm and the magnetic field was 0.475 Tesla in the core of the plasma.

  17. Electronic Structure of Dense Plasmas by X-Ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Gregori, G; Glenzer, S H; Rogers, F J; Pollaine, S M; Froula, D H; Blancard, C; Faussurier, G; Renaudin, P; Kuhlbrodt, S; Redmer, R; Landen, O L

    2003-10-07

    We present an improved analytical expression for the x-ray dynamic structure factor from a dense plasma which includes the effects of weakly bound electrons. This result can be applied to describe scattering from low to moderate Z plasmas, and it covers the entire range of plasma conditions that can be found in inertial confinement fusion experiments, from ideal to degenerate up to moderately coupled systems. We use our theory to interpret x-ray scattering experiments from solid density carbon plasma and to extract accurate measurements of electron temperature, electron density and charge state. We use our experimental results to validate various equation-of-state models for carbon plasmas.

  18. Induced Compton Scattering by Relativistic Electrons in Magnetized Astrophysical Plasmas.

    Science.gov (United States)

    Sincell, Mark William

    1994-01-01

    The effects of stimulated scattering on high brightness temperature radiation are studied in two important contexts. In the first case, we assume that the radiation is confined to a collimated beam traversing a relativistically streaming magnetized plasma. When the plasma is cold in the bulk frame, stimulated scattering is only significant if the angle between the photon motion and the plasma velocity is less than gamma^{-1} , where gamma is the bulk Lorentz factor. Under the assumption that the center of the photon beam is parallel to the bulk motion, we calculate the scattering rate as a function of the angular spread of the beam and gamma. Magnetization changes the photon recoil, without which stimulated scattering has no effect. It also introduces a strong dependence on frequency and polarization: if the photon frequency matches the electron cyclotron frequency, the scattering rate of photons polarized perpendicular to the magnetic field can be substantially enhanced relative to Thomson, and if the photon frequency is much less than the cyclotron frequency the scattering is suppressed. Applying these calculations to pulsars, we find that stimulated scattering of the radio beam in the magnetized wind believed to exist outside the light cylinder can substantially alter the spectrum and polarization state of the radio signal. We suggest that the scattering rate is so high in some pulsars that the ability of the radio signal to penetrate the pulsar magnetosphere requires modification of either the conventional model of the magnetosphere or assumptions about the effects of stimulated scattering upon a beam. In the second case, we present a model of the radio emission from synchrotron self-absorbed sources, including the effects of induced Compton scattering by the relativistic electrons in the source. Order of magnitude estimates show that stimulated scattering becomes the dominant absorption process when (kTB/m ec^2)tau_{T }_sp{~}> 0.1. Numerical simulations

  19. Behaviors of Electron Heat Transportation in HT-7 Sawtoothing Plasma

    Institute of Scientific and Technical Information of China (English)

    Hu Liqun; Xu Yi; Wan Baonian; Shi Yuejiang; Zhen Xiangjun; Chen Zhongyong; Lin Shiyao; HT-7 Team

    2005-01-01

    It is found that in HT-7 ohmic plasma, main energy loss comes from electron heat conduction, hence quantitative data of electron heat diffusivity is a very important issue for investigation of electron heat transportation behavior in different target plasmas so as to get high performance plasma. A time-to-peak method of the heat pulse propagation originating from the sawtooth activity on the soft x-ray intensity signal has been adopted to experimentally determine electron heat diffusivity XHPe on the HT-7 tokamak. Aiming to improve the signal-to-noise (S/N)ratio of the original signal to get a stable and reasonable electron heat diffusivity XHDe value, some data processing methods, including average of tens of sawteeth, is discussed. The electron heat diffusivity XHPe is larger than XPBe which is determined from the balance of background plasma power. Based on variation of the measured electron heat diffusivity XHPe, performances of different high confinement plasmas are analyzed.

  20. Washer-Gun Plasma Source for Magnetic Reconnection Experiments on VTF

    Science.gov (United States)

    Vrublevskis, A.; Egedal, J.; Fox, W.; Katz, N.; Le, A.; Porkolab, M.

    2009-11-01

    We present a recently built electrostatic washer-gun plasma source for the Versatile Toroidal Facility (VTF). The source produces plasmas with estimated densities of ˜10^19 m^- 3 and electron temperatures of ˜5-20 eV. The present plasma source for VTF is microwave-induced electron cyclotron resonant breakdown and requires a strong toroidal magnetic field, which acts as a guide field in reconnection experiments. The gun will allow reconnection experiments with no guide field. The source is based on the design developed by Sterling Scientific [1, 2]. To operate, gas is injected into a channel formed by a stack of alternating molybdenum and boron nitride washers with a molybdenum electrode washer at each end. A capacitor bank is discharged through these electrodes and the gas. The resulting plasma escapes the channel into the main chamber of the experiment. If available, we will present data on argon plasma produced by the gun inside the VTF. [1ex] [1] G. Fiksel, et al., Plasma Sources Sci. Technol., 5, 78 (1996)[0ex] [2] D. Hartog et al., Plasma Sources Sci. Technol., 6, 492 (1997)

  1. Quasi-steady carbon plasma source for neutral beam injector.

    Science.gov (United States)

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2014-02-01

    Carbon plasma is successfully sustained during 1000 s without any carrier gas in the bucket type ionization chamber with cusp magnetic field. Every several seconds, seed plasmas having ∼3 ms duration time are injected into the ionization chamber by a shunting arch plasma gun. The weakly ionized carbon plasma ejected from the shunting arch is also ionized by 2.45 GHz microwave at the electron cyclotron resonance surface and the plasma can be sustained even in the interval of gun discharges. Control of the gun discharge interval allows to keep high pressure and to sustain the plasma for long duration.

  2. Neutron Source from Laser Plasma Acceleration

    Science.gov (United States)

    Jiao, Xuejing; Shaw, Joseph; McCary, Eddie; Downer, Mike; Hegelich, Bjorn

    2016-10-01

    Laser driven electron beams and ion beams were utilized to produce neutron sources via different mechanism. On the Texas Petawatt laser, deuterized plastic, gold and DLC foil targets of varying thickness were shot with 150 J , 150 fs laser pulses at a peak intensity of 2 ×1021W /cm2 . Ions were accelerated by either target normal sheath acceleration or Breakout Afterburner acceleration. Neutrons were produced via the 9Be(d,n) and 9Be(p,n) reactions when accelerated ions impinged on a Beryllium converter as well as by deuteron breakup reactions. We observed 2 ×1010 neutron per shot in average, corresponding to 5 ×1018n /s . The efficiencies for different targets are comparable. In another experiment, 38fs , 0.3 J UT3 laser pulse interacted with mixed gas target. Electrons with energy 40MeV were produced via laser wakefield acceleration. Neutron flux of 2 ×106 per shot was generated through bremsstrahlung and subsequent photoneutron reactions on a Copper converter.

  3. H- extraction from electron-cyclotron-resonance-driven multicusp volume source operated in pulsed mode

    Science.gov (United States)

    Svarnas, P.; Bacal, M.; Auvray, P.; Béchu, S.; Pelletier, J.

    2006-03-01

    H2 microwave (2.45GHz) pulsed plasma is produced from seven elementary electron cyclotron resonance sources installed into the magnetic multipole chamber "Camembert III" (École Polytechnique—Palaiseau) from which H- extraction takes place. The negative-ion and electron extracted currents are studied through electrical measurements and the plasma parameters by means of electrostatic probe under various experimental conditions. The role of the plasma electrode bias and the discharge duty cycle in the extraction process is emphasized. The gas breakdown at the beginning of every pulse gives rise to variations of the plasma characteristic parameters in comparison with those established at the later time of the pulse, where the electron temperature, the plasma potential, and the floating potential converge to the values obtained for a continuous plasma. The electron density is significantly enhanced in the pulsed mode.

  4. An Electrothermal Plasma Source Developed for Simulation of Transient Heat Loads in Future Large Fusion Devices

    Science.gov (United States)

    Gebhart, Trey; Baylor, Larry; Winfrey, Leigh

    2016-10-01

    The realization of fusion energy requires materials that can withstand high heat and particle fluxes at the plasma material interface. In this work, an electrothermal (ET) plasma source has been designed as a possible transient heat flux source for a linear plasma material interaction device. An ET plasma source operates in the ablative arc regime, which is driven by a DC capacitive discharge. The current travels through the 4mm bore of a boron nitride liner and subsequently ablates and ionizes the liner material. This results in a high density plasma with a large unidirectional bulk flow out of the source exit. The pulse length for the ET source has been optimized using a pulse forming network to have a duration of 1ms at full-width half maximum. The peak currents and maximum source energies seen in this system are 2kA and 5kJ. The goal of this work is to show that the ET source produces electron densities and heat fluxes that are comparable to transient events in future large magnetic confinement fusion devices. Heat flux, plasma temperature, and plasma density were determined for each test shot using infrared imaging and optical spectroscopy techniques. This work will compare the ET source output (heat flux, temperature, and density) with and without an applied magnetic field. Research sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U. S. Department of Energy.

  5. The HelCat dual-source plasma device.

    Science.gov (United States)

    Lynn, Alan G; Gilmore, Mark; Watts, Christopher; Herrea, Janis; Kelly, Ralph; Will, Steve; Xie, Shuangwei; Yan, Lincan; Zhang, Yue

    2009-10-01

    The HelCat (Helicon-Cathode) device has been constructed to support a broad range of basic plasma science experiments relevant to the areas of solar physics, laboratory astrophysics, plasma nonlinear dynamics, and turbulence. These research topics require a relatively large plasma source capable of operating over a broad region of parameter space with a plasma duration up to at least several milliseconds. To achieve these parameters a novel dual-source system was developed utilizing both helicon and thermionic cathode sources. Plasma parameters of n(e) approximately 0.5-50 x 10(18) m(-3) and T(e) approximately 3-12 eV allow access to a wide range of collisionalities important to the research. The HelCat device and initial characterization of plasma behavior during dual-source operation are described.

  6. Single Crystal Diamond Needle as Point Electron Source

    Science.gov (United States)

    Kleshch, Victor I.; Purcell, Stephen T.; Obraztsov, Alexander N.

    2016-10-01

    Diamond has been considered to be one of the most attractive materials for cold-cathode applications during past two decades. However, its real application is hampered by the necessity to provide appropriate amount and transport of electrons to emitter surface which is usually achieved by using nanometer size or highly defective crystallites having much lower physical characteristics than the ideal diamond. Here, for the first time the use of single crystal diamond emitter with high aspect ratio as a point electron source is reported. Single crystal diamond needles were obtained by selective oxidation of polycrystalline diamond films produced by plasma enhanced chemical vapor deposition. Field emission currents and total electron energy distributions were measured for individual diamond needles as functions of extraction voltage and temperature. The needles demonstrate current saturation phenomenon and sensitivity of emission to temperature. The analysis of the voltage drops measured via electron energy analyzer shows that the conduction is provided by the surface of the diamond needles and is governed by Poole-Frenkel transport mechanism with characteristic trap energy of 0.2-0.3 eV. The temperature-sensitive FE characteristics of the diamond needles are of great interest for production of the point electron beam sources and sensors for vacuum electronics.

  7. Improved Nonambipolar Electron Source Operation with Permanent Magnets

    Science.gov (United States)

    Gudmundson, Jesse; Hershkowitz, Noah

    2008-11-01

    The Nonambipolar Electron Source (NES) is a Radio Frequency (rf) plasma-based electron source that does not rely on electron emission at a cathode surface. All electrons are extracted at an electron sheath through a biased ring and all ions are lost radially to a biased Faraday shield. An electromagnet in the original NES has been replaced by a NdFeB permanent magnet array. A portion of the magnet array consists of a ring of radially aligned magnets followed by a ring of axially aligned magnets that produce a peak field of approximately 800 Gauss. Axial magnetic field strength at the extraction ring was increased using an additional ring of axially aligned magnets. Measurement of the magnetic field was in good agreement with field predicted by the FEMM (Finite Element Method Magnetics) code. Optimization of the single turn antenna and biased ring position in the magnetic field will be discussed. At least 15 A of electron current was extracted using a flow rate of 15 sccm Ar at 600 W of rf power at 13.56 MHz. For comparison, the original NES required 1200 W of power to achieve 15 A of extracted current. Compared to the previous coil design, the NdFeB magnets are lighter weight and require no power.

  8. Positron source position sensing detector and electronics

    Science.gov (United States)

    Burnham, Charles A.; Bradshaw, Jr., John F.; Kaufman, David E.; Chesler, David A.; Brownell, Gordon L.

    1985-01-01

    A positron source, position sensing device, particularly with medical applications, in which positron induced gamma radiation is detected using a ring of stacked, individual scintillation crystals, a plurality of photodetectors, separated from the scintillation crystals by a light guide, and high resolution position interpolation electronics. Preferably the scintillation crystals are several times more numerous than the photodetectors with each crystal being responsible for a single scintillation event from a received gamma ray. The light guide will disperse the light emitted from gamma ray absorption over several photodetectors. Processing electronics for the output of the photodetectors resolves the location of the scintillation event to a fraction of the dimension of each photodetector. Because each positron absorption results in two 180.degree. oppositely traveling gamma rays, the detection of scintillation in pairs permits location of the positron source in a manner useful for diagnostic purposes. The processing electronics simultaneously responds to the outputs of the photodetectors to locate the scintillations to the source crystal. While it is preferable that the scintillation crystal include a plurality of stacked crystal elements, the resolving power of the processing electronics is also applicable to continuous crystal scintillators.

  9. Antitumor action of non thermal plasma sources, DBD and Plasma Gun, alone or in combined protocols

    Science.gov (United States)

    Robert, Eric; Brullé, Laura; Vandamme, Marc; Riès, Delphine; Le Pape, Alain; Pouvesle, Jean-Michel

    2012-10-01

    The presentation deals with the assessment on two non thermal plasma sources developed and optimized for oncology applications. The first plasma source is a floating-electrode dielectric barrier discharge powered at a few hundreds of Hz which deliver air-plasma directly on the surface of cell culture medium in dishes or on the skin or organs of mice bearing cancer tumors. The second plasma source, so called Plasma Gun, is a plasma jet source triggered in noble gas, transferred in high aspect ratio and flexible capillaries, on targeting cells or tumors after plasma transfer in air through the ``plasma plume'' generated at the capillary outlet. In vitro evidence for massive cancer cell destruction and in vivo tumor activity and growth rate reductions have been measured with both plasma sources. DNA damages, cell cycle arrests and apoptosis induction were also demonstrated following the application of any of the two plasma source both in vitro and in vivo. The comparison of plasma treatment with state of the art chemotherapeutic alternatives has been performed and last but not least the benefit of combined protocols involving plasma and chemotherapeutic treatments has been evidenced for mice bearing orthotopic pancreas cancer and is under evaluation for the colon tumors.

  10. Kinetic modelling of runaway electron avalanches in tokamak plasmas

    CERN Document Server

    Nilsson, E; Peysson, Y; Granetz, R S; Saint-Laurent, F; Vlainic, M

    2015-01-01

    Runaway electrons (REs) can be generated in tokamak plasmas if the accelerating force from the toroidal electric field exceeds the collisional drag force due to Coulomb collisions with the background plasma. In ITER, disruptions are expected to generate REs mainly through knock-on collisions, where enough momentum can be transferred from existing runaways to slow electrons to transport the latter beyond a critical momentum, setting off an avalanche of REs. Since knock-on runaways are usually scattered off with a significant perpendicular component of the momentum with respect to the local magnetic field direction, these particles are highly magnetized. Consequently, the momentum dynamics require a full 3-D kinetic description, since these electrons are highly sensitive to the magnetic non-uniformity of a toroidal configuration. A bounce-averaged knock-on source term is derived. The generation of REs from the combined effect of Dreicer mechanism and knock-on collision process is studied with the code LUKE, a s...

  11. Breaking of Large Amplitude Electron Plasma Wave in a Maxwellian Plasma

    CERN Document Server

    Mukherjee, Arghya

    2016-01-01

    The determination of maximum possible amplitude of a coherent longitudinal plasma oscillation/wave is a topic of fundamental importance in non-linear plasma physics. The amplitudes of these large amplitude plasma waves is limited by a phenomena called wave breaking which may be induced by several non-linear processes. It was shown by Coffey [T. P. Coffey, Phys. Fluids 14, 1402 (1971)] using a "water-bag" distribution for electrons that, in a warm plasma the maximum electric field amplitude and density amplitude implicitly depend on the electron temperature, known as Coffey's limit. In this paper, the breaking of large amplitude freely running electron plasma wave in a homogeneous warm plasma where electron's velocity distribution is Maxwellian has been studied numerically using 1D Particle in Cell (PIC) simulation method. It is found that Coffey's propagating wave solutions, which was derived using a "water-bag" distribution for electrons, also represent propagating waves in a Maxwellian plasma. Coffey's wave...

  12. Droplet-free high-density metal ion source for plasma immersion ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Keiji [Department of Electrical Engineering, College of Engineering, Chubu University, 1200 Matsumoto, Kasugai, Aichi 487-8501 (Japan)]. E-mail: nakamura@solan.chubu.ac.jp; Yoshinaga, Hiroaki [Department of Electrical Engineering, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Yukimura, Ken [Department of Electrical Engineering, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe, Kyoto 610-0321 (Japan)

    2006-01-15

    This paper reports on plasma parameters and ion composition of droplet-free Zr ion source for plasma immersion ion implantation and deposition (PIII and D). Zirconium (Zr) ions were obtained by ionizing sputtered Zr atoms in inductively-coupled argon discharge. The characteristics of plasma density, plasma potential and electron temperature were typical ones of such a inductive discharge, and the plasma parameters were not significantly influenced by mixing the sputtered Zr atoms into the plasma. Actually, the main ionic component was still Ar{sup +} ions, and the ion density ratio of [Zr{sup +}]/[Ar{sup +}] was as low as {approx}8%. Increase in sputtering rate of the Zr source will be necessary to improve the ion density ratio.

  13. Optimum plasma grid bias for a negative hydrogen ion source operation with Cs

    Energy Technology Data Exchange (ETDEWEB)

    Bacal, Marthe, E-mail: marthe.bacal@lpp.polytechnique.fr [UPMC, LPP, Ecole Polytechnique, UMR CNRS 7648, Palaiseau (France); Sasao, Mamiko [R& D Promotion Organization, Doshisha University, Kamigyoku, Kyoto 602-8580 (Japan); Wada, Motoi [School of Science and Engineering, Doshisha University, Kyotonabe, Kyoto 610-0321 (Japan); McAdams, Roy [CCFE, Culham Science Center, Abingdon, Oxfordshire 0X14 3DB (United Kingdom)

    2016-02-15

    The functions of a biased plasma grid of a negative hydrogen (H{sup −}) ion source for both pure volume and Cs seeded operations are reexamined. Proper control of the plasma grid bias in pure volume sources yields: enhancement of the extracted negative ion current, reduction of the co-extracted electron current, flattening of the spatial distribution of plasma potential across the filter magnetic field, change in recycling from hydrogen atomic/molecular ions to atomic/molecular neutrals, and enhanced concentration of H{sup −} ions near the plasma grid. These functions are maintained in the sources seeded with Cs with additional direct emission of negative ions under positive ion and neutral hydrogen bombardment onto the plasma electrode.

  14. Interaction of ultrarelativistic electron and proton bunches with dense plasmas

    CERN Document Server

    Rukhadze, A A

    2012-01-01

    Here we discuss the possibility of employment of ultrarelativistic electron and proton bunches for generation of high plasma wakefields in dense plasmas due to the Cherenkov resonance plasma-bunch interaction. We estimate the maximum amplitude of such a wake and minimum system length at which the maximum amplitude can be generated at the given bunch parameters.

  15. Vortex stabilized electron beam compressed fusion grade plasma

    Energy Technology Data Exchange (ETDEWEB)

    Hershcovitch, Ady [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-03-19

    Most inertial confinement fusion schemes are comprised of highly compressed dense plasmas. Those schemes involve short, extremely high power, short pulses of beams (lasers, particles) applied to lower density plasmas or solid pellets. An alternative approach could be to shoot an intense electron beam through very dense, atmospheric pressure, vortex stabilized plasma.

  16. Diagnosis of Hydrogen Plasma in a Miniature Penning Ion Source by Double Probes

    Institute of Scientific and Technical Information of China (English)

    JIN Dazhi; YANG Zhonghai; XIAO Kunxiang; DAI Jingyi

    2009-01-01

    Parameters of hydrogen plasma in a miniature Penning discharge ion source,including the electron temperature and the electron density,were measured by using double probes.The results indicate that the electron density increases and the electron temperature decreases with the increase in gas pressure and the discharge current.The electron temperature is about 5~9 eV and the electron density is 6.0x1013~1.2×1014 m-3 while the discharge current is in a range of 50~12μA.

  17. Diagnosis of Unmagnetized Plasma Electron Number Density and Electron-neutral Collision Frequency by Using Microwave

    Institute of Scientific and Technical Information of China (English)

    Yuan Zhongcai; Shi Jiaming; Xu Bo

    2005-01-01

    The plasma diagnostic method using the transmission attenuation of microwaves at double frequencies (PDMUTAMDF) indicates that the frequency and the electron-neutral collision frequency of the plasma can be deduced by utilizing the transmission attenuation of microwaves at two neighboring frequencies in a non-magnetized plasma. Then the electron density can be obtained from the plasma frequency. The PDMUTAMDF is a simple method to diagnose the plasma indirectly. In this paper, the interaction of electromagnetic waves and the plasma is analyzed. Then, based on the attenuation and the phase shift of a microwave in the plasma, the principle of the PDMUTAMDF is presented. With the diagnostic method, the spatially mean electron density and electron collision frequency of the plasma can be obtained. This method is suitable for the elementary diagnosis of the atmospheric-pressure plasma.

  18. Electron Source based on Superconducting RF

    Science.gov (United States)

    Xin, Tianmu

    High-bunch-charge photoemission electron-sources operating in a Continuous Wave (CW) mode can provide high peak current as well as the high average current which are required for many advanced applications of accelerators facilities, for example, electron coolers for hadron beams, electron-ion colliders, and Free-Electron Lasers (FELs). Superconducting Radio Frequency (SRF) has many advantages over other electron-injector technologies, especially when it is working in CW mode as it offers higher repetition rate. An 112 MHz SRF electron photo-injector (gun) was developed at Brookhaven National Laboratory (BNL) to produce high-brightness and high-bunch-charge bunches for electron cooling experiments. The gun utilizes a Quarter-Wave Resonator (QWR) geometry for a compact structure and improved electron beam dynamics. The detailed RF design of the cavity, fundamental coupler and cathode stalk are presented in this work. A GPU accelerated code was written to improve the speed of simulation of multipacting, an important hurdle the SRF structure has to overcome in various locations. The injector utilizes high Quantum Efficiency (QE) multi-alkali photocathodes (K2CsSb) for generating electrons. The cathode fabrication system and procedure are also included in the thesis. Beam dynamic simulation of the injector was done with the code ASTRA. To find the optimized parameters of the cavities and beam optics, the author wrote a genetic algorithm Python script to search for the best solution in this high-dimensional parameter space. The gun was successfully commissioned and produced world record bunch charge and average current in an SRF photo-injector.

  19. Whistler Solitons in Plasma with Anisotropic Hot Electron Admixture

    Science.gov (United States)

    Khazanov, G. V.; Krivorutsky, E. N.; Gallagher, D. L.

    1999-01-01

    The longitudinal and transverse modulation instability of whistler waves in plasma, with a small admixture of hot anisotropic electrons, is discussed. If the hot particles temperature anisotropy is positive, it is found that, in such plasma, longitudinal perturbations can lead to soliton formation for frequencies forbidden in cold plasma. The soliton is enriched by hot particles. The frequency region unstable to transverse modulation in cold plasma in the presence of hot electrons is divided by stable domains. For both cases the role of hot electrons is more significant for whistlers with smaller frequencies.

  20. Electron Plasmas Cooled by Cyclotron-Cavity Resonance

    CERN Document Server

    Povilus, A P; Evans, L T; Evetts, N; Fajans, J; Hardy, W N; Hunter, E D; Martens, I; Robicheaux, F; Shanman, S; So, C; Wang, X; Wurtele, J S

    2016-01-01

    We observe that high-Q electromagnetic cavity resonances increase the cyclotron cooling rate of pure electron plasmas held in a Penning-Malmberg trap when the electron cyclotron frequency, controlled by tuning the magnetic field, matches the frequency of standing wave modes in the cavity. For certain modes and trapping configurations, this can increase the cooling rate by factors of ten or more. In this paper, we investigate the variation of the cooling rate and equilibrium plasma temperatures over a wide range of parameters, including the plasma density, plasma position, electron number, and magnetic field.

  1. Tip-based electron source for femtosecond electron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Jan-Paul; Hoffrogge, Johannes; Schenk, Markus; Krueger, Michael; Baum, Peter; Hommelhoff, Peter [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching bei Muenchen (Germany)

    2012-07-01

    Illumination of a sharp tungsten tip with femtosecond laser pulses leads to the emission of ultrashort, high brightness electron pulses that are ideally suited for ultrafast electron diffraction (UED) experiments [1]. The tip's small virtual source size ({proportional_to}5 nm) results in a large transverse coherence length of the electron pulse and therefore better spatial resolution as compared to a conventional flat cathode design. The enhanced electric field at the tip apex (2 GV/m) is about two orders of magnitude larger than the maximum electric field applicable in a plate capacitor based setup (20 MV/m). This reduces the influence of the initial energy distribution on the pulse duration at the target and improves the timing jitter. Simulations show that a setup with a sharp tip as the cathode in combination with two anodes yields an electron pulse duration of about 50 fs at the sample. The electron energy is 30 keV and the gun to sample distance is 3 cm. We implemented the two anode setup with the tip experimentally. We present the experimental characteristics of the emitted electron beam both in static field emission and in laser triggered emission.

  2. ATLAS 10 GHz electron cyclotron resonance ion source upgrade project

    Energy Technology Data Exchange (ETDEWEB)

    Moehs, D. P. [Argonne National Laboratory, Physics Division, Argonne, Illinois 60439 (United States); Vondrasek, R. [Argonne National Laboratory, Physics Division, Argonne, Illinois 60439 (United States); Pardo, R. C. [Argonne National Laboratory, Physics Division, Argonne, Illinois 60439 (United States); Xie, D. [Berkeley Ion Equipment Inc., Santa Clara, California 95054 (United States)

    2000-02-01

    A major upgrade of the first ATLAS 10 GHz electron cyclotron resonance (ECR) ion source, which began operations in 1987, is in the planning and procurement phase. The new design will convert the old two-stage source into a single-stage source with an electron donor disk and high gradient magnetic field that preserves radial access for solid material feeds and pumping of the plasma chamber. The new magnetic-field profile allows for the possibility of a second ECR zone at a frequency of 14 GHz. An open hexapole configuration, using a high-energy-product Nd-Fe-B magnet material, having an inner diameter of 8.8 cm and pole gaps of 2.4 cm, has been adopted. Models indicate that the field strengths at the chamber wall, 4 cm in radius, will be 9.3 kG along the magnet poles and 5.6 kG along the pole gaps. The individual magnet bars will be housed in austenitic stainless steel, allowing the magnet housing within the aluminum plasma chamber to be used as a water channel for direct cooling of the magnets. Eight solenoid coils from the existing ECR will be enclosed in an iron yoke to produce the axial mirror. Based on a current of 500 A, the final model predicts a minimum B field of 3 kG with injection and extraction mirror ratios of 4.4 and 2.9, respectively. (c) 2000 American Institute of Physics.

  3. ATLAS 10 GHz electron cyclotron resonance ion source upgrade project

    CERN Document Server

    Moehs, D P; Pardo, R C; Xie, D

    2000-01-01

    A major upgrade of the first ATLAS 10 GHz electron cyclotron resonance (ECR) ion source, which began operations in 1987, is in the planning and procurement phase. The new design will convert the old two-stage source into a single-stage source with an electron donor disk and high gradient magnetic field that preserves radial access for solid material feeds and pumping of the plasma chamber. The new magnetic-field profile allows for the possibility of a second ECR zone at a frequency of 14 GHz. An open hexapole configuration, using a high-energy-product Nd-Fe-B magnet material, having an inner diameter of 8.8 cm and pole gaps of 2.4 cm, has been adopted. Models indicate that the field strengths at the chamber wall, 4 cm in radius, will be 9.3 kG along the magnet poles and 5.6 kG along the pole gaps. The individual magnet bars will be housed in austenitic stainless steel, allowing the magnet housing within the aluminum plasma chamber to be used as a water channel for direct cooling of the magnets. Eight solenoid...

  4. High-resolution VUV spectrometer/detector investigations of rare-earth pulsed plasma source (abstract)

    Science.gov (United States)

    Roberts, J. R.; Cromer, C. L.; Bridges, J. M.; Lucatorto, T. B.

    1985-05-01

    A 1.5-m grazing incidence spectrometer with a channel electron multiplier (CEMA) and electronic readout detector has been incorporated with a rare-earth target, pulsed plasma, continuum source. The spectrometer is compact and portable while maintaining high resolution. The CEMA detector consists of a single multichannel plate (MCP) with coned-shaped input pores which are cut at a 15-degree bias to improve efficiency at grazing angles. The source is a rare-earth plasma generated by a 10-J ruby laser producing intense continuum emission for wavelengths from 170 to 5 nm. This system will be used for both stationary and transient high-resolution atomic photoabsorption spectroscopy. The pulsed plasma source itself will be investigated for suitability as a radiometric transfer standard source. Preliminary results obtained with this integrated system will be discussed.

  5. Numerical model of electron cyclotron resonance ion source

    Directory of Open Access Journals (Sweden)

    V. Mironov

    2015-12-01

    Full Text Available Important features of the electron cyclotron resonance ion source (ECRIS operation are accurately reproduced with a numerical code. The code uses the particle-in-cell technique to model the dynamics of ions in ECRIS plasma. It is shown that a gas dynamical ion confinement mechanism is sufficient to provide the ion production rates in ECRIS close to the experimentally observed values. Extracted ion currents are calculated and compared to the experiment for a few sources. Changes in the simulated extracted ion currents are obtained with varying the gas flow into the source chamber and the microwave power. Empirical scaling laws for ECRIS design are studied and the underlying physical effects are discussed.

  6. Capillary plasma jet: A low volume plasma source for life science applications

    Energy Technology Data Exchange (ETDEWEB)

    Topala, I., E-mail: ionut.topala@uaic.ro, E-mail: tmnagat@ipc.shizuoka.ac.jp [Alexandru Ioan Cuza University of Iasi, Faculty of Physics, Iasi Plasma Advanced Research Center (IPARC), Bd. Carol I No. 11, Iasi 700506 (Romania); Nagatsu, M., E-mail: ionut.topala@uaic.ro, E-mail: tmnagat@ipc.shizuoka.ac.jp [Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561 (Japan)

    2015-02-02

    In this letter, we present results from multispectroscopic analysis of protein films, after exposure to a peculiar plasma source, i.e., the capillary plasma jet. This plasma source is able to generate very small pulsed plasma volumes, in kilohertz range, with characteristic dimensions smaller than 1 mm. This leads to specific microscale generation and transport of all plasma species. Plasma diagnosis was realized using general electrical and optical methods. Depending on power level and exposure duration, this miniature plasma jet can induce controllable modifications to soft matter targets. Detailed discussions on protein film oxidation and chemical etching are supported by results from absorption, X-ray photoelectron spectroscopy, and microscopy techniques. Further exploitation of principles presented here may consolidate research interests involving plasmas in biotechnologies and plasma medicine, especially in patterning technologies, modified biomolecule arrays, and local chemical functionalization.

  7. Charge, density and electron temperature in a molecular ultracold plasma

    CERN Document Server

    Rennick, C J; Ortega-Arroyo, J; Godin, P J; Grant, E R

    2009-01-01

    A Rydberg gas of NO entrained in a supersonic molecular beam releases electrons as it evolves to form an ultracold plasma. The size of this signal, compared with that extracted by the subsequent application of a pulsed electric field, determines the absolute magnitude of the plasma charge. This information, combined with the number density of ions, supports a simple thermochemical model that explains the evolution of the plasma to an ultracold electron temperature.

  8. Waves in relativistic electron beam in low-density plasma

    Science.gov (United States)

    Sheinman, I.; Sheinman (Chernenco, J.

    2016-11-01

    Waves in electron beam in low-density plasma are analyzed. The analysis is based on complete electrodynamics consideration. Dependencies of dispersion laws from system parameters are investigated. It is shown that when relativistic electron beam is passed through low-density plasma surface waves of two types may exist. The first type is a high frequency wave on a boundary between the beam and neutralization area and the second type wave is on the boundary between neutralization area and stationary plasma.

  9. Investigation of electron heating in laser-plasma interaction

    Directory of Open Access Journals (Sweden)

    A Parvazian

    2013-03-01

    Full Text Available  In this paper, stimulated Raman scattering (SRS and electron heating in laser plasma propagating along the plasma fusion is investigated by particle-in cell simulation. Applying an external magnetic field to plasma, production of whistler waves and electron heating associated with whistler waves in the direction perpendicular to external magnetic field was observed in this simulation. The plasma waves with low phase velocities, generated in backward-SRS and dominateing initially in time and space, accelerated the backward electrons by trapping them. Then these electrons promoted to higher energies by the forward-SRS plasma waves with high phase velocities. This tow-stage electron acceleration is more efficient due to the coexistence of these two instabilities.

  10. Plasma instability in the afterglow of electron cyclotron resonance discharge sustained in a mirror trap

    Energy Technology Data Exchange (ETDEWEB)

    Izotov, I.; Mansfeld, D.; Skalyga, V.; Zorin, V. [Institute of Applied Physics, RAS, 46 Ulyanova St., 603950 Nizhny Novgorod (Russian Federation); Grahn, T.; Kalvas, T.; Koivisto, H.; Komppula, J.; Peura, P.; Tarvainen, O.; Toivanen, V. [Department of Physics, University of Jyvaeskylae, P.O. Box 35 (YFL), 40500 Jyvaeskylae (Finland)

    2012-12-15

    The work presented in this article is devoted to time-resolved diagnostics of non-linear effects observed during the afterglow plasma decay of a 14 GHz electron cyclotron resonance ion source operated in pulsed mode. Plasma instabilities that cause perturbations of the extracted ion current during the decay were observed and studied. It is shown that these perturbations are associated with precipitation of high energy electrons along the magnetic field lines and strong bursts of bremsstrahlung emission. The effect of ion source settings on the onset of the observed instabilities was investigated. Based on the experimental data and estimated plasma properties, it is assumed that the instabilities are of cyclotron type. The conclusion is supported by a comparison to other types of plasma devices which exhibit similar characteristics but which operate in a different plasma confinement regime.

  11. Non-thermal atmospheric pressure HF plasma source: generation of nitric oxide and ozone for bio-medical applications

    Science.gov (United States)

    Kühn, S.; Bibinov, N.; Gesche, R.; Awakowicz, P.

    2010-01-01

    A new miniature high-frequency (HF) plasma source intended for bio-medical applications is studied using nitrogen/oxygen mixture at atmospheric pressure. This plasma source can be used as an element of a plasma source array for applications in dermatology and surgery. Nitric oxide and ozone which are produced in this plasma source are well-known agents for proliferation of the cells, inhalation therapy for newborn infants, disinfection of wounds and blood ozonation. Using optical emission spectroscopy, microphotography and numerical simulation, the gas temperature in the active plasma region and plasma parameters (electron density and electron distribution function) are determined for varied nitrogen/oxygen flows. The influence of the gas flows on the plasma conditions is studied. Ozone and nitric oxide concentrations in the effluent of the plasma source are measured using absorption spectroscopy and electro-chemical NO-detector at variable gas flows. Correlations between plasma parameters and concentrations of the particles in the effluent of the plasma source are discussed. By varying the gas flows, the HF plasma source can be optimized for nitric oxide or ozone production. Maximum concentrations of 2750 ppm and 400 ppm of NO and O3, correspondingly, are generated.

  12. A plasma source driven predator-prey like mechanism as a potential cause of spiraling intermittencies in linear plasma devices

    Energy Technology Data Exchange (ETDEWEB)

    Reiser, D. [Research Center Jülich GmbH, Institute for Energy and Climate Research—Plasma Physics, D-52425 Jülich (Germany); Ohno, N. [Department of Energy Engineering and Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Tanaka, H. [National Institute for Fusion Science, Toki 509-5292 (Japan); Vela, L. [Physics Department, Universidad Carlos III de Madrid, Avda de la Universidad 30, 28911-Leganés, Madrid (Spain)

    2014-03-15

    Three-dimensional global drift fluid simulations are carried out to analyze coherent plasma structures appearing in the NAGDIS-II linear device (nagoya divertor plasma Simulator-II). The numerical simulations reproduce several features of the intermittent spiraling structures observed, for instance, statistical properties, rotation frequency, and the frequency of plasma expulsion. The detailed inspection of the three-dimensional plasma dynamics allows to identify the key mechanism behind the formation of these intermittent events. The resistive coupling between electron pressure and parallel electric field in the plasma source region gives rise to a quasilinear predator-prey like dynamics where the axisymmetric mode represents the prey and the spiraling structure with low azimuthal mode number represents the predator. This interpretation is confirmed by a reduced one-dimensional quasilinear model derived on the basis of the findings in the full three-dimensional simulations. The dominant dynamics reveals certain similarities to the classical Lotka-Volterra cycle.

  13. A plasma source driven predator-prey like mechanism as a potential cause of spiraling intermittencies in linear plasma devices

    Science.gov (United States)

    Reiser, D.; Ohno, N.; Tanaka, H.; Vela, L.

    2014-03-01

    Three-dimensional global drift fluid simulations are carried out to analyze coherent plasma structures appearing in the NAGDIS-II linear device (nagoya divertor plasma Simulator-II). The numerical simulations reproduce several features of the intermittent spiraling structures observed, for instance, statistical properties, rotation frequency, and the frequency of plasma expulsion. The detailed inspection of the three-dimensional plasma dynamics allows to identify the key mechanism behind the formation of these intermittent events. The resistive coupling between electron pressure and parallel electric field in the plasma source region gives rise to a quasilinear predator-prey like dynamics where the axisymmetric mode represents the prey and the spiraling structure with low azimuthal mode number represents the predator. This interpretation is confirmed by a reduced one-dimensional quasilinear model derived on the basis of the findings in the full three-dimensional simulations. The dominant dynamics reveals certain similarities to the classical Lotka-Volterra cycle.

  14. Femtosecond electron bunches, source and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Thongbai, C. [FNRF, Department of Physics, Chiang Mai University, Chiangmai 50200 (Thailand)], E-mail: chlada@chiangmai.ac.th; Kusoljariyakul, K. [FNRF, Department of Physics, Chiang Mai University, Chiangmai 50200 (Thailand); Rimjaem, S. [DESY Zeuthen, Platanenallee 6, Zeuthen 15738 (Germany); Rhodes, M.W. [IST, Chiang Mai University, Chiangmai 50200 (Thailand); Saisut, J. [FNRF, Department of Physics, Chiang Mai University, Chiangmai 50200 (Thailand); Thamboon, P.; Wichaisirimongkol, P. [IST, Chiang Mai University, Chiangmai 50200 (Thailand); Vilaithong, T. [FNRF, Department of Physics, Chiang Mai University, Chiangmai 50200 (Thailand)

    2008-03-11

    A femtosecond electron source has been developed at the Fast Neutron Research Facility (FNRF), Chiang Mai University, Thailand. So far, it has produced electron bunches as short as {sigma}{sub z}{approx}180 fs with (1-6)x10{sup 8} electrons per microbunch. The system consists of an RF-gun with a thermionic cathode, an alpha-magnet as a magnetic bunch compressor, and a linear accelerator as a post acceleration section. Coherent transition radiation emitted at wavelengths equal to and longer than the bunch length is used in a Michelson interferometer to determine the bunch length by autocorrelation technique. The experimental setup and results of the bunch length measurement are described.

  15. Note: Triggering behavior of a vacuum arc plasma source.

    Science.gov (United States)

    Lan, C H; Long, J D; Zheng, L; Dong, P; Yang, Z; Li, J; Wang, T; He, J L

    2016-08-01

    Axial symmetry of discharge is very important for application of vacuum arc plasma. It is discovered that the triggering method is a significant factor that would influence the symmetry of arc discharge at the final stable stage. Using high-speed multiframe photography, the transition processes from cathode-trigger discharge to cathode-anode discharge were observed. It is shown that the performances of the two triggering methods investigated are quite different. Arc discharge triggered by independent electric source can be stabilized at the center of anode grid, but it is difficult to achieve such good symmetry through resistance triggering. It is also found that the triggering process is highly correlated to the behavior of emitted electrons.

  16. Note: Triggering behavior of a vacuum arc plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Lan, C. H., E-mail: lanchaohui@163.com; Long, J. D.; Zheng, L.; Dong, P.; Yang, Z.; Li, J.; Wang, T.; He, J. L. [Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900 (China)

    2016-08-15

    Axial symmetry of discharge is very important for application of vacuum arc plasma. It is discovered that the triggering method is a significant factor that would influence the symmetry of arc discharge at the final stable stage. Using high-speed multiframe photography, the transition processes from cathode-trigger discharge to cathode-anode discharge were observed. It is shown that the performances of the two triggering methods investigated are quite different. Arc discharge triggered by independent electric source can be stabilized at the center of anode grid, but it is difficult to achieve such good symmetry through resistance triggering. It is also found that the triggering process is highly correlated to the behavior of emitted electrons.

  17. The effect of seed electrons on the repeatability of atmospheric pressure plasma plume propagation. II. Modeling

    Science.gov (United States)

    Chang, L.; Nie, L.; Xian, Y.; Lu, X.

    2016-12-01

    One of the distinguishable features of plasma jets compared with the traditional streamers is their repeatable propagation. As an initial objective, the effect of seed electrons on the repeatability of plasma plume propagation is investigated numerically. Besides residual electrons left from previous pulses, the electrons detached from O2 - ions could also be a significant source of the seed electrons to affect the repeatability of plasma plume propagation when an electronegative gas admixture is presented. In this investigation, a global plasma chemical kinetics model is developed to investigate the temporal evolution of the electron and O2 - ions in the afterglow of a plasma plume driven by microsecond pulse direct current voltages, at a total gas pressure of 2 × 104 Pa or 4 × 103 Pa in helium or helium-oxygen mixtures with an air impurity of 0.025%. In addition, a Monte Carlo technique has been applied to calculate the O2 - detachment rate coefficient. Accordingly, the seed electron density due to detachment from O2 - ions for different percentages of oxygen is obtained. Finally, the minimum seed electron density required for the plasma bullets to propagate in a repeatable mode is obtained according to the critical frequency from the experiments. It is found that the order of minimum seed electron number density required for repeatable propagation mode is independent of oxygen concentrations in the helium-oxygen mixture. It is 10 8 cm - 3 for 20 kPa and 10 7 cm - 3 for 4 kPa. Furthermore, for the helium with an air impurity of 0.025%, the residual electrons left over from previous discharges are the main source of seed electrons. On the other hand, when 0.5% of O2 is added, the detachment of O2 - is the main source of the seed electrons.

  18. Enhancement of H{sup -}/D{sup -} volume production in a double plasma type negative ion source

    Energy Technology Data Exchange (ETDEWEB)

    Fukumasa, Osamu; Nishimura, Hideki; Sakiyama, Satoshi [Yamaguchi Univ., Ube (Japan). Faculty of Engineering

    1997-02-01

    H{sup -}/D{sup -} production in a pure volume source has been studied. In our double plasma type negative ion source, both energy and density of fast electrons are well controlled. With the use of this source, the enhancement of H{sup -}/D{sup -} production has been observed. Namely, under the same discharge power, the extracted H{sup -}/D{sup -} current in the double plasma operation is higher than that in the single plasma operation. At the same time, measurements of plasma parameters have been made in the source and the extractor regions for these two cases. (author)

  19. Electron Acoustic Waves in Pure Ion Plasmas

    Science.gov (United States)

    Anderegg, F.; Affolter, M.; Driscoll, C. F.; O'Neil, T. M.; Valentini, F.

    2012-10-01

    Electron Acoustic Waves (EAWs) are the low-frequency branch of near-linear Langmuir (plasma) waves: the frequency is such that the complex dielectric function (Dr, Di) has Dr= 0; and ``flattening'' of f(v) near the wave phase velocity vph gives Di=0 and eliminates Landau damping. Here, we observe standing axisymmetric EAWs in a pure ion column.footnotetextF. Anderegg, et al., Phys. Rev. Lett. 102, 095001 (2009). At low excitation amplitudes, the EAWs have vph˜1.4 v, in close agreement with near-linear theory. At moderate excitation strengths, EAW waves are observed over a range of frequencies, with 1.3 v vphvph.footnotetextF. Valentini et al., arXiv:1206.3500v1. Large amplitude EAWs have strong phase-locked harmonic content, and experiments will be compared to same-geometry simulations, and to simulations of KEENfootnotetextB. Afeyan et al., Proc. Inertial Fusion Sci. and Applications 2003, A.N.S. Monterey (2004), p. 213. waves in HEDLP geometries.

  20. Cysteine as a Biological Probe for Comparing Plasma Sources

    Science.gov (United States)

    Lackmann, Jan-Wilm; Golda, Judith; Kogelheide, Friederike; Held, Julian; Schulz-von-der-Gathen, Volker; Stapelmann, Katharina

    2016-09-01

    A large variety of plasma sources are available in the plasma medicine community. While enabling to choose the most promising source for a certain biomedical application, comparison of the different sources with a focus on their effect on biological targets is rather challenging. To allow for better comparison of various sources, the recent European COST action MP1101 was used to design the COST reference microplasma jet. Cysteine is a promising candidate investigate the impact of plasma from various sources on a standardized biological molecule, which is especially relevant for the investigations on a molecular level after plasma treatment. The simple structure of cysteine allows for a more in-depth analysis of each chemical group after plasma treatment and enables a comparison between different plasma sources and treatment parameters on each chemical group. The model itself has already been successfully established using a dielectric barrier discharge. Here, additional plasma sources are compared by the means of their impact on cysteine samples, showing e.g. the influence of feed-gas variations by adding oxygen or nitrogen admixture This work was supported by the German Research Foundation (DFG) with the packet grant PAK816 (PlaCID).

  1. Shunting arc plasma source for pure carbon ion beam.

    Science.gov (United States)

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA∕mm(2) at the peak of the pulse.

  2. Shunting arc plasma source for pure carbon ion beama)

    Science.gov (United States)

    Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y.

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm2 at the peak of the pulse.

  3. Vertical Electron Cyclotron Emission Diagnostic for TCV Plasmas

    Directory of Open Access Journals (Sweden)

    Goodman T. P.

    2012-09-01

    Full Text Available Electron cyclotron resonance heating (ECRH and electron cyclotron current drive (ECCD are used to heat the plasma, to tailor the current profiles and to achieve different operating regimes of tokamak plasmas. Plasmas with ECRH/ECCD are characterized by non-thermal electrons, which cannot be described by a Maxwellian distribution. Non-thermal electrons are also generated during MHD activity, like sawteeth crashes. Quantifying the non-thermal electron distribution is therefore a key for understanding EC heated fusion plasmas. For this purpose a vertical electron cyclotron emission (V-ECE diagnostic is being installed at TCV. The diagnostic layout, the calibration, the analysis technique for data interpretation, the physics potentials and limitations are discussed.

  4. Electron Sheaths: The Outsized Influence of Positive Boundaries on Plasmas

    CERN Document Server

    Yee, Benjamin T; Baalrud, Scott D; Barnat, Edward V; Hopkins, Matthew M

    2015-01-01

    Electron sheaths form near the surface of objects biased more positive than the plasma potential, such as in the electron saturation region of a Langmuir probe trace. They are commonly thought to be local phenomena that collect the random thermal electron current, but do not otherwise perturb a plasma. Here, using experiments, particle-in-cell simulations and theory, it is shown that under low temperature plasma conditions ($T_e \\gg T_i$) electron sheaths are far from local. Instead, a long presheath region extends into the plasma where electrons are accelerated via a pressure gradient to a flow speed exceeding the electron thermal speed at the sheath edge. This fast flow is found to excite instabilities, causing strong fluctuations near the sheath edge.

  5. Catheterized plasma X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Derzon, Mark S.; Robinson, Alex; Galambos, Paul C.

    2017-06-20

    A radiation generator useful for medical applications, among others, is provided. The radiation generator includes a catheter; a plasma discharge chamber situated within a terminal portion of the catheter, a cathode and an anode positioned within the plasma discharge chamber and separated by a gap, and a high-voltage transmission line extensive through the interior of the catheter and terminating on the cathode and anode so as to deliver, in operation, one or more voltage pulses across the gap.

  6. Whistler-mode phenomena in electron MHD plasmas

    Science.gov (United States)

    Stenzel, R. L.

    2003-12-01

    While the linear properties of plane whistler waves are well known, many new phenomena of bounded wavepackets and nonlinear effects are worth to describe. The present talk will review laboratory observations of whistler filaments, whistler vortices, whistler wings, whistler-sound modes in high-beta plasmas, nonlinear whistlers forming magnetic null points, and magnetic reconnection in EMHD plasmas. The time-varying magnetic field of a spatially bounded whistler wave packet consists of 3-D vortices. Each vortex can be decomposed into linked toroidal and poloidal field components. The self-helicity is positive for propagation along the field, negative for opposite propagation. Helicity injection from a suitable source produces unidirectional propagation. Magnetic helicity changes sign, i.e., is not conserved, when the propagation direction along B changes, for example due to reflection or propagation through a magnetic null point. In ideal EMHD the electric and magnetic forces on the electrons are equal, -n e E +J x B=0, i.e., the electron fluid is not compressed. Force-free vortices do not interact during collisions. Vortices are excited with pulsed magnetic antennas or pulsed electrodes. Both transient currents and fields can form vortices that propagate in the whistler mode. Moving dc magnets or dc current systems can also induce whistler modes in a magnetized plasma. These form a Cherenkov-like radiation pattern, a ``whistler wing.'' Nonlinear phenomena arise from wave-induced modifications of the electron temperature, density and magnetic field. In collisional plasmas electrons are heated by strong whistlers. Modifications of the classical conductivity leads to current filamentation. On a slower time scale density modifications arise from ambipolar fields associated with electron heating. In a filamentation instability a strong whistler wave is ducted along a narrow field-aligned density depression. The ion density is also modified by the ac electric field of

  7. PIC simulation of electron acceleration in an underdense plasma

    Directory of Open Access Journals (Sweden)

    S Darvish Molla

    2011-06-01

    Full Text Available One of the interesting Laser-Plasma phenomena, when the laser power is high and ultra intense, is the generation of large amplitude plasma waves (Wakefield and electron acceleration. An intense electromagnetic laser pulse can create plasma oscillations through the action of the nonlinear pondermotive force. electrons trapped in the wake can be accelerated to high energies, more than 1 TW. Of the wide variety of methods for generating a regular electric field in plasmas with strong laser radiation, the most attractive one at the present time is the scheme of the Laser Wake Field Accelerator (LWFA. In this method, a strong Langmuir wave is excited in the plasma. In such a wave, electrons are trapped and can acquire relativistic energies, accelerated to high energies. In this paper the PIC simulation of wakefield generation and electron acceleration in an underdense plasma with a short ultra intense laser pulse is discussed. 2D electromagnetic PIC code is written by FORTRAN 90, are developed, and the propagation of different electromagnetic waves in vacuum and plasma is shown. Next, the accuracy of implementation of 2D electromagnetic code is verified, making it relativistic and simulating the generating of wakefield and electron acceleration in an underdense plasma. It is shown that when a symmetric electromagnetic pulse passes through the plasma, the longitudinal field generated in plasma, at the back of the pulse, is weaker than the one due to an asymmetric electromagnetic pulse, and thus the electrons acquire less energy. About the asymmetric pulse, when front part of the pulse has smaller time rise than the back part of the pulse, a stronger wakefield generates, in plasma, at the back of the pulse, and consequently the electrons acquire more energy. In an inverse case, when the rise time of the back part of the pulse is bigger in comparison with that of the back part, a weaker wakefield generates and this leads to the fact that the electrons

  8. VUV Emission of Microwave Driven Argon Plasma Source

    Science.gov (United States)

    Henriques, Julio; Espinho, Susana; Felizardo, Edgar; Tatarova, Elena; Dias, Francisco; Ferreira, Carlos

    2013-09-01

    An experimental and kinetic modeling investigation of a low-pressure (0.1-1.2 mbar), surface wave (2.45 GHz) induced Ar plasma as a source vacuum ultraviolet (VUV) light is presented, using visible and VUV optical spectroscopy. The electron density and the relative VUV emission intensities of excited Ar atoms (at 104.8 nm and 106.6 nm) and ions (at 92.0 nm and 93.2 nm) were determined as a function of the microwave power and pressure. The experimental results were analyzed using a 2D self-consistent theoretical model based on a set of coupled equations including the electron Boltzmann equation, the rate balance equations for the most important electronic excited species and for charged particles, the gas thermal balance equation, and the wave electrodynamics. The principal collisional and radiative processes for neutral Ar(3p54s) and Ar(3p54p) and ionized Ar(3s3p6 2S1/2) levels are accounted for. Model predictions are in good agreement with the experimental measurements. This study was funded by the Foundation for Science and Technology, Portuguese Ministry of Education and Science, under the research contract PTDC/FIS/108411/2008.

  9. Physical limitations in ferromagnetic inductively coupled plasma sources

    CERN Document Server

    Bliokh, Yury P; Slutsker, Yakov Z

    2012-01-01

    The Ferromagnetic Inductively Coupled Plasma (FICP) source, which is a version of the common inductively coupled plasma sources, has a number of well known advantages such as high efficiency, high level of ionization, low minimal gas pressure, very low required driver frequency, and even a possibility to be driven by single current pulses. We present an experimental study of such an FICP source which showed that above a certain value of the driving pulse power the properties of this device changed rather drastically. Namely, the plasma became non-stationary and non-uniform contrary to the stationary and uniform plasmas typical for this kind of plasma sources. In this case the plasma appeared as a narrow dense spike which was short compared to the driving pulse. The local plasma density could exceed the neutral atoms density by a few orders of magnitude. When that happened, the afterglow plasma decay time after the end of the pulse was long compared to an ordinary case with no plasma spike. Experiments were pe...

  10. Counter-facing plasma guns for efficient extreme ultra-violet plasma light source

    Science.gov (United States)

    Kuroda, Yusuke; Yamamoto, Akiko; Kuwabara, Hajime; Nakajima, Mitsuo; Kawamura, Tohru; Horioka, Kazuhiko

    2013-11-01

    A plasma focus system composed of a pair of counter-facing coaxial guns was proposed as a long-pulse and/or repetitive high energy density plasma source. We applied Li as the source of plasma for improvement of the conversion efficiency, the spectral purity, and the repetition capability. For operation of the system with ideal counter-facing plasma focus mode, we changed the system from simple coaxial geometry to a multi-channel configuration. We applied a laser trigger to make synchronous multi-channel discharges with low jitter. The results indicated that the configuration is promising to make a high energy density plasma with high spectral efficiency.

  11. Collisionless damping of electron waves in non-Maxwellian plasma

    OpenAIRE

    Soshnikov, V. N.

    2007-01-01

    In this paper we have criticized the so-called Landau damping theory. We have analyzed solutions of the standard dispersion equations for longitudinal (electric) and transversal (electromagnetic and electron) waves in half-infinite slab of the uniform collisionless plasmas with non-Maxwellian and Maxwellian-like electron energy distribution functions. One considered the most typical cases of both the delta-function type distribution function (the plasma stream with monochromatic electrons) an...

  12. Electron beam charge diagnostics for laser plasma accelerators

    Directory of Open Access Journals (Sweden)

    K. Nakamura

    2011-06-01

    Full Text Available A comprehensive study of charge diagnostics is conducted to verify their validity for measuring electron beams produced by laser plasma accelerators (LPAs. First, a scintillating screen (Lanex was extensively studied using subnanosecond electron beams from the Advanced Light Source booster synchrotron, at the Lawrence Berkeley National Laboratory. The Lanex was cross calibrated with an integrating current transformer (ICT for up to the electron energy of 1.5 GeV, and the linear response of the screen was confirmed for charge density and intensity up to 160  pC/mm^{2} and 0.4  pC/(ps  mm^{2}, respectively. After the radio-frequency accelerator based cross calibration, a series of measurements was conducted using electron beams from an LPA. Cross calibrations were carried out using an activation-based measurement that is immune to electromagnetic pulse noise, ICT, and Lanex. The diagnostics agreed within ±8%, showing that they all can provide accurate charge measurements for LPAs.

  13. Electron Beam Charge Diagnostics for Laser Plasma Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Kei; Gonsalves, Anthony; Lin, Chen; Smith, Alan; Rodgers, David; Donahue, Rich; Byrne, Warren; Leemans, Wim

    2011-06-27

    A comprehensive study of charge diagnostics is conducted to verify their validity for measuring electron beams produced by laser plasma accelerators (LPAs). First, a scintillating screen (Lanex) was extensively studied using subnanosecond electron beams from the Advanced Light Source booster synchrotron, at the Lawrence Berkeley National Laboratory. The Lanex was cross calibrated with an integrating current transformer (ICT) for up to the electron energy of 1.5 GeV, and the linear response of the screen was confirmed for charge density and intensity up to 160 pC/mm{sup 2} and 0.4 pC/(ps mm{sup 2}), respectively. After the radio-frequency accelerator based cross calibration, a series of measurements was conducted using electron beams from an LPA. Cross calibrations were carried out using an activation-based measurement that is immune to electromagnetic pulse noise, ICT, and Lanex. The diagnostics agreed within {+-}8%, showing that they all can provide accurate charge measurements for LPAs.

  14. Ferroelectric Plasma Source for Heavy Ion Beam Charge Neutralization

    CERN Document Server

    Efthimion, Philip; Gilson, Erik P; Grisham, Larry; Logan, B G; Waldron, William; Yu, Simon

    2005-01-01

    Plasmas are employed as a medium for charge neutralizing heavy ion beams to allow them to focus to a small spot size. Calculations suggest that plasma at a density of 1-100 times the ion beam density and at a length ~ 0.1-1 m would be suitable. To produce 1 meter plasma, large-volume plasma sources based upon ferroelectric ceramics are being considered. These sources have the advantage of being able to increase the length of the plasma and operate at low neutral pressures. The source will utilize the ferroelectric ceramic BaTiO3 to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) will be covered with ceramic. High voltage (~ 1-5 kV) is applied between the drift tube and the front surface of the ceramic by placing a wire grid on the front surface. A prototype ferroelectric source 20 cm long produced plasma densities ~ 5x1011 cm-3. The source was integrated into the experiment and successfully charge neutralized the K ion beam. Presently, the 1 meter source ...

  15. Electron density and temperature in NIO1 RF source operated in oxygen and argon

    Science.gov (United States)

    Barbisan, M.; Zaniol, B.; Cavenago, M.; Pasqualotto, R.; Serianni, G.; Zanini, M.

    2017-08-01

    The NIO1 experiment, built and operated at Consorzio RFX, hosts an RF negative ion source, from which it is possible to produce a beam of maximum 130 mA in H- ions, accelerated up to 60 kV. For the preliminary tests of the extraction system the source has been operated in oxygen, whose high electronegativity allows to reach useful levels of extracted beam current. The efficiency of negative ions extraction is strongly influenced by the electron density and temperature close to the Plasma Grid, i.e. the grid of the acceleration system which faces the source. To support the tests, these parameters have been measured by means of the Optical Emission Spectroscopy diagnostic. This technique has involved the use of an oxygen-argon mixture to produce the plasma in the source. The intensities of specific Ar I and Ar II lines have been measured along lines of sight close to the Plasma Grid, and have been interpreted with the ADAS package to get the desired information. This work will describe the diagnostic hardware, the analysis method and the measured values of electron density and temperature, as function of the main source parameters (RF power, pressure, bias voltage and magnetic filter field). The main results show that not only electron density but also electron temperature increase with RF power; both decrease with increasing magnetic filter field. Variations of source pressure and plasma grid bias voltage appear to affect only electron temperature and electron density, respectively.

  16. Design and Construction of a Microwave Plasma Ion Source

    CERN Document Server

    Çınar, Kamil

    2011-01-01

    This thesis is about the designing and constructing a microwave ion source. The ions are generated in a thermal and dense hydrogen plasma by microwave induction. The plasma is generated by using a microwave source with a frequency of 2.45 GHz and a power of 700 W. The generated microwave is pulsing with a frequency of 50 Hz. The designed and constructed microwave system generates hydrogen plasma in a pyrex plasma chamber. Moreover, an ion extraction unit is designed and constructed in order to extract the ions from the generated hydrogen plasma. The ion beam extraction is achieved and ion currents are measured. The plasma parameters are determined by a double Langmuir probe and the ion current is measured by a Faraday cup. The designed ion extraction unit is simulated by using the dimensions of the designed and constructed ion extraction unit in order to trace out the trajectories of the extracted ions.

  17. Design of a new electron cyclotron resonance ion source at Oshima National College of Maritime Technology

    Energy Technology Data Exchange (ETDEWEB)

    Asaji, T., E-mail: asaji@oshima-k.ac.jp; Hirabara, N.; Izumihara, T.; Nakamizu, T.; Ohba, T.; Nakamura, T.; Furuse, M. [Oshima National College of Maritime Technology (OCMT), 1091-1 Komatsu, Suo-oshima, Yamaguchi 742-2193 (Japan); Hitobo, T. [Tateyama Machine Co., Ltd., 30 Shimonoban, Toyama 930-1305 (Japan); Kato, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2014-02-15

    A new electron cyclotron resonance ion/plasma source has been designed and will be built at Oshima National College of Maritime Technology by early 2014. We have developed an ion source that allows the control of the plasma parameters over a wide range of electron temperatures for material research. A minimum-B magnetic field composed of axial mirror fields and radial cusp fields was designed using mainly Nd-Fe-B permanent magnets. The axial magnetic field can be varied by three solenoid coils. The apparatus has 2.45 GHz magnetron and 2.5–6.0 GHz solid-state microwave sources.

  18. Simulation of Electron Trajectories in the Multicusp Ion Source Using Geantn4 Monte Carlo Code

    Science.gov (United States)

    Khodadadi Azadboni, Fatemeh; Sedaghatizade, Mahmood

    2010-04-01

    To optimize the multicusp ion source, understanding of transport properties of electrons is indispensable. Since the transport of electrons in the multicusp ion source is a three-dimensional problem, we use the 3D computer code Geant4, to model the particle trajectories. The goal is to study the effect of electron injection into a cylindrical gas chamber and the electron trajectories. The role of the magnetic filter in contemporary negative ion sources is analyzed. The conditions in the magnetic filter adjacent to the plasma electrode optimum for the generation, formation, and extraction of an H- ion beam are found. The simulation results are in good agreement with the experimental data.

  19. Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources

    Energy Technology Data Exchange (ETDEWEB)

    Geddes, Cameron G.R.; Cormier-Michel, Estelle; Esarey, Eric H.; Schroeder, Carl B.; Vay, Jean-Luc; Leemans, Wim P.; Bruhwiler, David L.; Cary, John R.; Cowan, Ben; Durant, Marc; Hamill, Paul; Messmer, Peter; Mullowney, Paul; Nieter, Chet; Paul, Kevin; Shasharina, Svetlana; Veitzer, Seth; Weber, Gunther; Rubel, Oliver; Ushizima, Daniela; Bethel, Wes; Wu, John

    2009-03-20

    Compared to conventional particle accelerators, plasmas can sustain accelerating fields that are thousands of times higher. To exploit this ability, massively parallel SciDAC particle simulations provide physical insight into the development of next-generation accelerators that use laser-driven plasma waves. These plasma-based accelerators offer a path to more compact, ultra-fast particle and radiation sources for probing the subatomic world, for studying new materials and new technologies, and for medical applications.

  20. Influence of Electron Evaporative Cooling on Ultracold Plasma Expansion

    CERN Document Server

    Wilson, Truman; Roberts, Jacob

    2013-01-01

    The expansion of ultracold neutral plasmas (UCP) is driven primarily by the thermal pressure of the electron component and is therefore sensitive to the electron temperature. At lower densities (less than 10$^8$ /cm$^3$), evaporative cooling has a significant influence on the UCP expansion rate. We studied the effect of electron evaporation in this density range. Owing to the low density, the effects of three-body recombination were negligible. We modeled the expansion by taking into account the change in electron temperature owing to evaporation as well as adiabatic expansion and found good agreement with our data. We also developed a simple model for initial evaporation over a range of ultracold plasma densities, sizes, and electron temperatures to determine over what parameter range electron evaporation is expected to have a significant effect. We also report on a signal calibration technique, which relates the signal at our detector to the total number of ions and electrons in the ultracold plasma.

  1. Correlation function and electronic spectral line broadening in relativistic plasmas

    Directory of Open Access Journals (Sweden)

    Douis S.

    2013-01-01

    Full Text Available The electrons dynamics and the time autocorrelation function Cee(t for the total electric microfield of the electrons on positive charge impurity embedded in a plasma are considered when the relativistic dynamic of the electrons is taken into account. We have, at first, built the effective potential governing the electrons dynamics. This potential obeys a nonlinear integral equation that we have solved numerically. Regarding the electron broadening of the line in plasma, we have found that when the plasma parameters change, the amplitude of the collision operator changes in the same way as the time integral of Cee(t. The electron-impurity interaction is taken at first time as screened Deutsh interaction and at the second time as Kelbg interaction. Comparisons of all interesting quantities are made with respect to the previous interactions as well as between classical and relativistic dynamics of electrons.

  2. Electronic detection of collective modes of an ultracold plasma

    CERN Document Server

    Twedt, K A

    2011-01-01

    Using a new technique to directly detect current induced on a nearby electrode, we measure plasma oscillations in ultracold plasmas, which are influenced by the inhomogeneous and time-varying density and changing neutrality. Electronic detection avoids heating and evaporation dynamics associated with previous measurements and allows us to test the importance of the plasma neutrality. We apply dc and pulsed electric fields to control the electron loss rate and find the charge imbalance of the plasma has a significant effect on the resonant frequency, in excellent agreement with recent predictions suggesting coupling to an edge mode.

  3. Tungsten transport and sources control in JET ITER-like wall H-mode plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Fedorczak, N., E-mail: nicolas.fedorczak@cea.fr [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Monier-Garbet, P. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Pütterich, T. [MPI für Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, 85748 Garching (Germany); Brezinsek, S. [Institute of Energy and Climate Research, Forschungszentrum Jlich, Assoc EURATOM-FZJ, Jlich (Germany); Devynck, P.; Dumont, R.; Goniche, M.; Joffrin, E. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Lerche, E. [Association EURATOM-Belgian State, LPP-ERM-KMS, TEC partner, Brussels (Belgium); Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Lipschultz, B. [York Plasma Institute, University of York, Heslington, York YO10 5DD (United Kingdom); Luna, E. de la [Laboratorio Nacional de Fusin, Asociacin EURATOM/CIEMAT, 28040 Madrid (Spain); Maddison, G. [Culham Centre for Fusion Energy, EURATOM-CCFE Association, Abingdon (United Kingdom); Maggi, C. [MPI für Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, 85748 Garching (Germany); Matthews, G. [Culham Centre for Fusion Energy, EURATOM-CCFE Association, Abingdon (United Kingdom); Nunes, I. [Istituto de plasmas e fusao nuclear, Lisboa (Portugal); Rimini, F. [Culham Centre for Fusion Energy, EURATOM-CCFE Association, Abingdon (United Kingdom); Solano, E.R. [Laboratorio Nacional de Fusin, Asociacin EURATOM/CIEMAT, 28040 Madrid (Spain); Tamain, P. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Tsalas, M. [Association EURATOM-Hellenic Republic, NCSR Demokritos 153 10, Attica (Greece); Vries, P. de [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2015-08-15

    A set of discharges performed with the JET ITER-like wall is investigated with respect to control capabilities on tungsten sources and transport. In attached divertor regimes, increasing fueling by gas puff results in higher divertor recycling ion flux, lower divertor tungsten source, higher ELM frequency and lower core plasma radiation, dominated by tungsten ions. Both pedestal flushing by ELMs and divertor screening (including redeposition) are possibly responsible. For specific scenarios, kicks in plasma vertical position can be employed to increase the ELM frequency, which results in slightly lower core radiation. The application of ion cyclotron radio frequency heating at the very center of the plasma is efficient to increase the core electron temperature gradient and flatten electron density profile, resulting in a significantly lower central tungsten peaking. Beryllium evaporation in the main chamber did not reduce the local divertor tungsten source whereas core radiation was reduced by approximately 50%.

  4. Laser-Produced Plasmas and Radiation Sources.

    Science.gov (United States)

    1980-01-31

    Vlases, H. Rutkowski, A. Hertzberg, A. Hoffman, L. Steinhauer, J. Dawson, D.R. Cohn, W. Halverson, B. Lax, J.D. Daugherty, J.E. Eninger , E.R. Pugh, T.K...Meeting, Albuquerque (October 1974). J.D. Daugherty, J.E. Eninger , D.R. Cohn, and W. Halverson, "Scaling of Laser Heated Plasmas Confined in Long Solenoids...Cohn, H.E. Eninger , W. Halverson, and D.J. Rose, "Stress, Dissipation, and Neutronics Constraints on ’fagnets for Laser-Solenoid Reactors," APS Plasma

  5. Matching network for RF plasma source

    Science.gov (United States)

    Pickard, Daniel S.; Leung, Ka-Ngo

    2007-11-20

    A compact matching network couples an RF power supply to an RF antenna in a plasma generator. The simple and compact impedance matching network matches the plasma load to the impedance of a coaxial transmission line and the output impedance of an RF amplifier at radio frequencies. The matching network is formed of a resonantly tuned circuit formed of a variable capacitor and an inductor in a series resonance configuration, and a ferrite core transformer coupled to the resonantly tuned circuit. This matching network is compact enough to fit in existing compact focused ion beam systems.

  6. Acceleration of injected electrons by the plasma beat wave accelerator

    Science.gov (United States)

    Joshi, C.; Clayton, C. E.; Marsh, K. A.; Dyson, A.; Everett, M.; Lal, A.; Leemans, W. P.; Williams, R.; Katsouleas, T.; Mori, W. B.

    1992-07-01

    In this paper we describe the recent work at UCLA on the acceleration of externally injected electrons by a relativistic plasma wave. A two frequency laser was used to excite a plasma wave over a narrow range of static gas pressures close to resonance. Electrons with energies up to our detection limit of 9.1 MeV were observed when 2.1 MeV electrons were injected in the plasma wave. No accelerated electrons above the detection threshold were observed when the laser was operated on a single frequency or when no electrons were injected. Experimental results are compared with theoretical predictions, and future prospects for the plasma beat wave accelerator are discussed.

  7. Transport and Non-Invasive Position Detection of Electron Beams from Laser-Plasma Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Osterhoff, Jens; Sokollik, Thomas; Nakamura, Kei; Bakeman, Michael; Weingartner, R; Gonsalves, Anthony; Shiraishi, Satomi; Lin, Chen; vanTilborg, Jeroen; Geddes, Cameron; Schroeder, Carl; Esarey, Eric; Toth, Csaba; DeSantis, Stefano; Byrd, John; Gruner, F; Leemans, Wim

    2011-07-20

    The controlled imaging and transport of ultra-relativistic electrons from laser-plasma accelerators is of crucial importance to further use of these beams, e.g. in high peak-brightness light sources. We present our plans to realize beam transport with miniature permanent quadrupole magnets from the electron source through our THUNDER undulator. Simulation results demonstrate the importance of beam imaging by investigating the generated XUV-photon flux. In addition, first experimental findings of utilizing cavity-based monitors for non-invasive beam-position measurements in a noisy electromagnetic laser-plasma environment are discussed.

  8. Rare-earth plasma light source for VUV applications.

    Science.gov (United States)

    O'Sullivan, G; Carroll, P K; McLlrath, T J; Ginter, M L

    1981-09-01

    A compact versatile light source for producing VUV radiation from laser produced plasmas is described. Measurements of the spectral irradiance from CO(2) laser-produced plasmas on targets of gadolinium and ytterbium in the 115-220-nm range are given, and a comparison is made with analogous results obtained using a ruby laser.

  9. Modelling the plasma plume of an assist source in PIAD

    Science.gov (United States)

    Wauer, Jochen; Harhausen, Jens; Foest, Rüdiger; Loffhagen, Detlef

    2016-09-01

    Plasma ion assisted deposition (PIAD) is a technique commonly used to produce high-precision optical interference coatings. Knowledge regarding plasma properties is most often limited to dedicated scenarios without film deposition. Approaches have been made to gather information on the process plasma in situ to detect drifts which are suspected to cause limits in repeatability of resulting layer properties. Present efforts focus on radiance monitoring of the plasma plume of an Advanced Plasma Source (APSpro, Bühler) by optical emission spectroscopy to provide the basis for an advanced plasma control. In this contribution modelling results of the plume region are presented to interpret these experimental data. In the framework of the collisional radiative model used, 15 excited neutral argon states in the plasma are considered. Results of the species densities show good consistency with the measured optical emission of various argon 2 p - 1 s transitions. This work was funded by BMBF under grant 13N13213.

  10. Detection of solvated electrons at a plasma-liquid interface

    Science.gov (United States)

    Go, David B.; Rumbach, Paul; Bartels, David; Sankaran, R. Mohan

    2014-10-01

    We have recently shown that charge can be transferred from a DC microplasma jet into an aqueous solution to promote electrolytic reduction reactions [1,2]. However, the precise nature of these charge transfer reactions remains poorly understood---in particular, it is not known if plasma electrons solvate and solvated electrons are responsible for the reduction of solution species. To address these questions, we have designed and built an optical absorption spectroscopy system to directly detect solvated electrons at a plasma-liquid interface, which only have a lifetime of ~1 μs. Our preliminary results reveal that plasma electrons do indeed solvate, and survive up to depths of approximately 0.5 nm beneath the plasma-liquid interface. Adding electron scavengers such as nitrite and nitrate salts to the solution causes a decrease in optical absorption, indicating a decrease in the average lifetime of the solvated electrons, further confirming their existence. Measuring optical absorption as a function of scavenger concentration, we extrapolate rate constants that agree well with prior radiolysis experiments. These preliminary findings are consistent with the hypothesis that free electrons from atmospheric pressure plasmas solvate in aqueous solutions, and open potential applications of plasmas for solvated electron chemistry.

  11. Plasma interferometry and how the bound electron contribution can bend fringes in unexpected ways

    Energy Technology Data Exchange (ETDEWEB)

    Nilsen, J; Johnson, W R

    2005-02-11

    For decades the measurement of the electron density in plasmas by interferometers has relied on the approximation that the index of refraction in a plasma is due solely to the free electrons and therefore is less than one. Recent measurements of Al plasmas using X-ray laser interferometers have observed anomalous results with the fringes bending the opposite way than expected due to the index of refraction being larger than one. Subsequent analysis showed that the bound electrons have a larger contribution to the index of refraction with the opposite sign than the free electrons. This effect extends far from the absorption edges and lines of the bound electrons. Utilizing a new average atom code we calculate the index of refraction in C, Al, Ti and Pd plasmas and show that there are many conditions over which the bound electron contribution dominates as we explore photon energies from the optical to 100 eV (12 nm) soft X-rays. During the next decade X-ray free electron lasers and other sources will be available to probe a wider variety of plasmas at higher densities and shorter wavelengths so understanding the index of refraction in plasmas will be even more essential.

  12. Runaway electrons as a diagnostic of plasma internal magnetic fluctuations

    Institute of Scientific and Technical Information of China (English)

    Zheng Yong-Zhen; Ding Xuan-Tong; Li Wen-Zhong

    2006-01-01

    The transport of runaway electrons in a high-temperature plasma is relatively easy to measure in a steady state experiment and a perturbation experiment, which provides runaway electron diffusion coefficient Dr. This diffusion coefficient is determined by internal magnetic fluctuations, so it can be interpreted in terms of a magnetic fluctuation level. The internal magnetic fluctuation level (br/BT) is estimated to be about (2-4)×-4 in the HL-1M plasma. The results presented here demonstrate the effectiveness of using runaway electron transport techniques to determine internal magnetic fluctuations. A profile of magnetic fluctuation level in the HL-1M plasma can be estimated from Dr.

  13. Electron temperature dynamics of TEXTOR plasmas

    NARCIS (Netherlands)

    Udintsev, Victor Sergeevich

    2003-01-01

    To study plasma properties in the presence of large and small MHD modes, new high-resolution ECE diagnostics have been installed at TEXTOR tokamak, and some of the already existing systems have been upgraded. Two models for the plasma transport properties inside large m/n = 2/1 MHD islands have been

  14. A Plasma Ion Source for ISOLTRAP

    CERN Document Server

    Skov, Thomas Guldager

    2016-01-01

    In this report, my work testing the new Penning ion source as a summer student at ISOLTRAP is described. The project was composed of three stages: (1) Setting up a test laboratory in building 275, (2) characterizing the ion source, and (3) implementing and testing the source in the ISOLTRAP setup. After setting up the test laboratory, the ion source was tested in a constant pressure environment with produced ion currents in the range of nA . An extensive scan of the source ion current versus operating parameters (pressure, voltage) was performed. A setup with pulsed gas flow was also tested, allowing a reduction of the gas load on the vacuum system. The behavior of the ion source together with the ISOLTRAP setup was also investigated, allowing to understand current limitations and future directions of improvement.

  15. Electron Temperature and Plasma Flow Measurements of NIF Hohlraum Plasmas

    Science.gov (United States)

    Barrios, M. A.; Liedahl, D. A.; Schneider, M. B.; Jones, O.; Brow, G. V.; Regan, S. P.; Fournier, K. B.; Moore, A. S.; Ross, J. S.; Eder, D.; Landen, O.; Kauffman, R. L.; Nikroo, A.; Kroll, J.; Jaquez, J.; Huang, H.; Hansen, S. B.; Callahan, D. A.; Hinkel, D. E.; Bradley, D.; Moody, J. D.; LLNL Collaboration; LLE Collaboration; GA Collaboration; SNL Collaboration

    2016-10-01

    Characterizing the plasma conditions inside NIF hohlraums, in particular mapping the plasma Te, is critical to gaining insight into mechanisms that affect energy coupling and transport in the hohlraum. The dot spectroscopy platform provides a temporal history of the localized Te and plasma flow inside a NIF hohlraum, by introducing a Mn-Co tracer dot, at strategic locations inside the hohlraum, that comes to equilibrium with the local plasma. K-shell X-ray spectroscopy of the tracer dot is recorded onto an absolutely calibrated X-ray streak spectrometer. Isoelectronic and interstage line ratios are used to infer localized Te through comparison with atomic physics calculations using SCRAM. Time resolved X-ray images are simultaneously taken of the expanding dot, providing plasma (ion) flow information. We present recent results provided by this platform and compare with simulations using HYDRA. This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.

  16. Radio Emissions from Plasma with Electron Kappa-Distributions

    Science.gov (United States)

    Fleishman, G. D.; Kuznetsov, A. A.

    2015-12-01

    Gregory Fleishman (New Jersey Institute of Technology, Newark, USA)Alexey Kuznetsov (Institute of Solar-Terrestrial Physics, Irkutsk, Russia), Currently there is a concern about the ability of the classical thermal (Maxwellian) distribution to describe quasisteady-state plasma in the solar atmosphere, including active regions. In particular, other distributions have been proposed to better fit observations, for example, kappa-distributions. If present, these distributions will generate radio emissions with different observable properties compared with the classical gyroresonance (GR) or free-free emission, which implies a way of remotely detecting these kappa distributions in the radio observations. Here we present analytically derived GR and free-free emissivities and absorption coefficients for the kappa-distribution, and discuss their properties, which are in fact remarkably different from the classical Maxwellian plasma. In particular, the radio brightness temperature from a gyrolayer increases with the optical depth τ for kappa-distribution. This property has a remarkable consequence allowing a straightforward observational test: the GR radio emission from the non-Maxwellian distributions is supposed to be noticeably polarized even in the optically thick case, where the emission would have strictly zero polarization in the case of Maxwellian plasma. This offers a way of remote probing the plasma distribution in astrophysical sources, including solar active regions as a vivid example. In this report, we present analytical formulae and computer codes to calculate the emission parameters. We simulate the gyroresonance emission under the conditions typical of the solar active regions and compare the results for different electron distributions. We discuss the implications of our findings for interpretation of radio observations. This work was supported in part by NSF grants AGS-1250374 and AGS-1262772, NASA grant NNX14AC87G to New Jersey Institute of Technology

  17. Characterisation of Plasma Filled Rod Pinch electron beam diode operation

    Science.gov (United States)

    MacDonald, James; Bland, Simon; Chittenden, Jeremy

    2016-10-01

    The plasma filled rod pinch diode (aka PFRP) offers a small radiographic spot size and a high brightness source. It operates in a very similar to plasma opening switches and dense plasma focus devices - with a plasma prefill, supplied via a number of simple coaxial plasma guns, being snowploughed along a thin rod cathode, before detaching at the end. The aim of this study is to model the PFRP and understand the factors that affect its performance, potentially improving future output. Given the dependence on the PFRP on the prefill, we are making detailed measurements of the density (1015-1018 cm-3), velocity, ionisation and temperature of the plasma emitted from a plasma gun/set of plasma guns. This will then be used to provide initial conditions to the Gorgon 3D MHD code, and the dynamics of the entire rod pinch process studied.

  18. Plasma scale-length effects on electron energy spectra in high-irradiance laser plasmas

    Science.gov (United States)

    Culfa, O.; Tallents, G. J.; Rossall, A. K.; Wagenaars, E.; Ridgers, C. P.; Murphy, C. D.; Dance, R. J.; Gray, R. J.; McKenna, P.; Brown, C. D. R.; James, S. F.; Hoarty, D. J.; Booth, N.; Robinson, A. P. L.; Lancaster, K. L.; Pikuz, S. A.; Faenov, A. Ya.; Kampfer, T.; Schulze, K. S.; Uschmann, I.; Woolsey, N. C.

    2016-04-01

    An analysis of an electron spectrometer used to characterize fast electrons generated by ultraintense (1020W cm-2 ) laser interaction with a preformed plasma of scale length measured by shadowgraphy is presented. The effects of fringing magnetic fields on the electron spectral measurements and the accuracy of density scale-length measurements are evaluated. 2D EPOCH PIC code simulations are found to be in agreement with measurements of the electron energy spectra showing that laser filamentation in plasma preformed by a prepulse is important with longer plasma scale lengths (>8 μ m ).

  19. The CLIC electron and positron polarized sources

    CERN Document Server

    Rinolfi, Louis; Bulyak, Eugene; Chehab, Robert; Dadoun, Olivier; Gai, Wei; Gladkikh, Peter; Kamitani, Takuya; Kuriki, Masao; Liu, Wanming; Maryuama, Takashi; Omori, Tsunehiko; Poelker, Matt; Sheppard, John; Urakawa, Junji; Variola, Alessandro; Vivoli, Alessandro; Yakimenko, Vitaly; Zhou, Feng; Zimmermann, Frank

    2010-01-01

    The CLIC polarized electron source is based on a DC gun where the photocathode is illuminated by a laser beam. Each micro-bunch has a charge of 6x109 e−, a width of 100 ps and a repetition rate of 2 GHz. A peak current of 10 A in the micro-bunch is a challenge for the surface charge limit of the photo-cathode. Two options are feasible to generate the 2 GHz e− bunch train: 100 ps micro-bunches can be extracted from the photo-cathode either by a 2 GHz laser system or by generating a macro-bunch using a ~200 ns laser pulse and a subsequent RF bunching system to produce the appropriate micro-bunch structure. Recent results obtained by SLAC, for the latter case, are presented. The polarized positron source is based on a positron production scheme in which polarized photons are produced by a laser Compton scattering process. The resulting circularly-polarized gamma photons are sent onto a target, producing pairs of longitudinally polarized electrons and positrons. The Compton backscattering process occurs eithe...

  20. An electromagnetically focused electron beam line source

    Science.gov (United States)

    Iqbal, Munawar; Masood, Khalid; Rafiq, Mohammad; Chaudhary, Maqbool A.; Aleem, Fazal-e.-

    2003-11-01

    A directly heated thermionic electron beam source was constructed. A tungsten wire of length 140 mm with diameter 0.9 mm was used as a cathode. An emission current of 5000 mA was achieved at an input heating power of 600 W. Cathode to anode distance of 6 mm with acceleration voltage of 10 kV was used. A uniform external magnetic field of 50 G was employed to obtain a well-focused electron beam at a deflection of 180°, with cathode to work site distance of 130 mm. Dimensions of the beam (1.25×120 mm) recorded at the work site were found to be in good agreement with the designed length of cathode. The deformation of the cathode was overcome by introducing a spring action mechanism, which gives uniform emission current density throughout the emission surface. We have achieved the saturation limit of the designed source resulting in smooth and swift operation of the gun for many hours (10-15 h continuously). The design of gun is so simple that it can accommodate longer cathodes for obtaining higher emission values. This gun has made it possible to coat large substrate surfaces at much faster evaporation rate at lower cost. It can also be useful in large-scale vacuum metallurgy plants for melting, welding and heat treatment.

  1. Relativistic electromagnetic waves in an electron-ion plasma

    Science.gov (United States)

    Chian, Abraham C.-L.; Kennel, Charles F.

    1987-01-01

    High power laser beams can drive plasma particles to relativistic energies. An accurate description of strong waves requires the inclusion of ion dynamics in the analysis. The equations governing the propagation of relativistic electromagnetic waves in a cold electron-ion plasma can be reduced to two equations expressing conservation of energy-momentum of the system. The two conservation constants are functions of the plasma stream velocity, the wave velocity, the wave amplitude, and the electron-ion mass ratio. The dynamic parameter, expressing electron-ion momentum conversation in the laboratory frame, can be regarded as an adjustable quantity, a suitable choice of which will yield self-consistent solutions when other plasma parameters were specified. Circularly polarized electromagnetic waves and electrostatic plasma waves are used as illustrations.

  2. Hot-electron refluxing enhanced relativistic transparency of overdense plasmas

    CERN Document Server

    Yu, Yong; Chen, Zi-Yu; Wang, Jia-Xiang; Zhu, Wen-Jun

    2013-01-01

    A new phenomenon of enhancing the relativistic transparency of overdense plasmas by the influence of hot-electron refluxing has been found via particle-in-cell simulations. When a p-polarized laser pulse, with intensity below the self-induced-transparency (SIT) threshold, obliquely irradiates a thin overdense plasma, the initially opaque plasma would become transparent after a time interval which linearly relies on the thickness of the plasma. This phenomenon can be interpreted by the influence of hot-electron refluxing. As the laser intensity is higher than the SIT threshold, the penetration velocity of the laser in the plasma is enhanced when the refluxing is presented. Simulation data with ion motion considered is also consistent with the assumption that hot-electron refluxing enhances transparency. These results have potential applications in laser shaping.

  3. Nonlinear magnetosonic waves in dense plasmas with non-relativistic and ultra-relativistic degenerate electrons

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, S.; Mahmood, S.; Rehman, Aman-ur- [Theoretical Physics Division (TPD), PINSTECH, P.O. Nilore, Islamabad 44000, Pakistan and Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad 44000 (Pakistan)

    2014-11-15

    Linear and nonlinear propagation of magnetosonic waves in the perpendicular direction to the ambient magnetic field is studied in dense plasmas for non-relativistic and ultra-relativistic degenerate electrons pressure. The sources of nonlinearities are the divergence of the ions and electrons fluxes, Lorentz forces on ions and electrons fluids and the plasma current density in the system. The Korteweg-de Vries equation for magnetosonic waves propagating in the perpendicular direction of the magnetic field is derived by employing reductive perturbation method for non-relativistic as well as ultra-relativistic degenerate electrons pressure cases in dense plasmas. The plots of the magnetosonic wave solitons are also shown using numerical values of the plasma parameters such a plasma density and magnetic field intensity of the white dwarfs from literature. The dependence of plasma density and magnetic field intensity on the magnetosonic wave propagation is also pointed out in dense plasmas for both non-relativistic and ultra-relativistic degenerate electrons pressure cases.

  4. Generation of anomalously energetic suprathermal electrons by an electron beam interacting with a nonuniform plasma

    Science.gov (United States)

    Sydorenko, Dmytro; Kaganovich, Igor D.; Ventzek, Peter L. G.

    2016-10-01

    Electrons emitted from electrodes are accelerated by the sheath electric field and become the electron beams penetrating the plasma. The electron beam can interact with the plasma in collisionless manner via two-stream instability and produce suprathermal electrons. In order to understand the mechanism of suprathermal electrons acceleration, a beam-plasma system was simulated using a 1D3V particle-in-cell code EDIPIC. These simulation results show that the acceleration may be caused by the effects related to the plasma nonuniformity. The electron beam excites plasma waves whose wavelength and phase speed gradually decrease towards anode. The short waves near the anode accelerate plasma bulk electrons to suprathermal energies. Rich complexity of beam- plasma interaction phenomena was also observed: intermittency and multiple regimes of two-stream instability in a dc discharge, band structure of the growth rate of the two-stream instability of an electron beam propagating in a bounded plasma, multi-stage acceleration of electrons in a finite system.

  5. Combined Gas-Liquid Plasma Source for Nanoparticle Synthesis

    Science.gov (United States)

    Burakov, V. S.; Kiris, V. V.; Nevar, A. A.; Nedelko, M. I.; Tarasenko, N. V.

    2016-09-01

    A gas-liquid plasma source for the synthesis of colloidal nanoparticles by spark erosion of the electrode material was developed and allowed the particle synthesis regime to be varied over a wide range. The source parameters were analyzed in detail for the electrical discharge conditions in water. The temperature, particle concentration, and pressure in the discharge plasma were estimated based on spectroscopic analysis of the plasma. It was found that the plasma parameters did not change signifi cantly if the condenser capacitance was increased from 5 to 20 nF. Purging the electrode gap with argon reduced substantially the pressure and particle concentration. Signifi cant amounts of water decomposition products in addition to electrode elements were found in the plasma in all discharge regimes. This favored the synthesis of oxide nanoparticles.

  6. A microwave plasma source for VUV atmospheric photochemistry

    Science.gov (United States)

    Tigrine, S.; Carrasco, N.; Vettier, L.; Cernogora, G.

    2016-10-01

    Microwave plasma discharges working at low pressure are nowadays a well-developed technique mainly used to provide radiation at different wavelengths. The aim of this work is to show that those discharges are an efficient windowless vacuum ultra-violet (VUV) photon source for planetary atmospheric photochemistry experiments. To do this, we use a surfatron-type discharge with a neon gas flow in the mbar pressure range coupled to a photochemical reactor. Working in the VUV range allows nitrogen-dominated atmospheres to be focused on (λ  <  100 nm). The experimental setup makes sure that no energy sources (electrons, metastable atoms) other than the VUV photons interact with the reactive medium. Neon has two resonance lines at 73.6 and 74.3 nm that behave differently depending on the pressure or power conditions. In parallel, the VUV photon flux emitted at 73.6 nm has been experimentally estimated in different pressure and power conditions, and varies in a large range between 2  ×  1013 ph s-1 cm-2 and 4  ×  1014 ph s-1 cm-2, which is comparable to a VUV synchrotron photon flux. Our first case study is the atmosphere of Titan and its N2-CH4 atmosphere. With this VUV source, the production of HCN and C2N2, two major Titan compounds, is detected, ensuring the suitability of the source for atmospheric photochemistry experiments.

  7. Multidimensional electron beam-plasma instabilities in the relativistic regime

    OpenAIRE

    BRET, ANTOINE; Gremillet, Laurent; Dieckmann, Mark Eric

    2010-01-01

    The interest in relativistic beam-plasma instabilities has been greatly rejuvenated over the past two decades by novel concepts in laboratory and space plasmas. Recent advances in this long-standing field are here reviewed from both theoretical and numerical points of view. The primary focus is on the two-dimensional spectrum of unstable electromagnetic waves growing within relativistic, unmagnetized, and uniform electron beam-plasma systems. Although the goal is to provide a unified picture ...

  8. Plasma actuator electron density measurement using microwave perturbation method

    Energy Technology Data Exchange (ETDEWEB)

    Mirhosseini, Farid; Colpitts, Bruce [Electrical and Computer Engineering, University of New Brunswick, Fredericton, New Brunswick E3B 5A3 (Canada)

    2014-07-21

    A cylindrical dielectric barrier discharge plasma under five different pressures is generated in an evacuated glass tube. This plasma volume is located at the center of a rectangular copper waveguide cavity, where the electric field is maximum for the first mode and the magnetic field is very close to zero. The microwave perturbation method is used to measure electron density and plasma frequency for these five pressures. Simulations by a commercial microwave simulator are comparable to the experimental results.

  9. The solvation of electrons by an atmospheric-pressure plasma

    Science.gov (United States)

    Rumbach, Paul; Bartels, David M.; Sankaran, R. Mohan; Go, David B.

    2015-06-01

    Solvated electrons are typically generated by radiolysis or photoionization of solutes. While plasmas containing free electrons have been brought into contact with liquids in studies dating back centuries, there has been little evidence that electrons are solvated by this approach. Here we report direct measurements of solvated electrons generated by an atmospheric-pressure plasma in contact with the surface of an aqueous solution. The electrons are measured by their optical absorbance using a total internal reflection geometry. The measured absorption spectrum is unexpectedly blue shifted, which is potentially due to the intense electric field in the interfacial Debye layer. We estimate an average penetration depth of 2.5+/-1.0 nm, indicating that the electrons fully solvate before reacting through second-order recombination. Reactions with various electron scavengers including H+, NO2-, NO3- and H2O2 show that the kinetics are similar, but not identical, to those for solvated electrons formed in bulk water by radiolysis.

  10. 77 FR 6463 - Revisions to Labeling Requirements for Blood and Blood Components, Including Source Plasma...

    Science.gov (United States)

    2012-02-08

    ... Requirements for Blood and Blood Components, Including Source Plasma; Correction AGENCY: Food and Drug... Blood Components, Including Source Plasma,'' which provided incorrect publication information...

  11. Ab-initio calculations on two-electron ions in strongly coupled plasma environment

    CERN Document Server

    Bhattacharyya, S; Mukherjee, T K

    2015-01-01

    In this work, the controversy between the interpretations of recent measurements on dense aluminum plasma created with Linac coherent light sources (LCLS) X-ray free electron laser (FEL) and Orion laser has been addressed. In both kind of experiments, helium-like and hydrogen-like spectral lines are used for plasma diagnostics . However, there exist no precise theoretical calculations for He-like ions within dense plasma environment. The strong need for an accurate theoretical estimates for spectral properties of He-like ions in strongly coupled plasma environment leads us to perform ab initio calculations in the framework of Rayleigh-Ritz variation principle in Hylleraas coordinates where ion-sphere potential is used. An approach to resolve the long-drawn problem of numerical instability for evaluating two-electron integrals with extended basis inside a finite domain is presented here. The present values of electron densities corresponding to disappearance of different spectral lines obtained within the fram...

  12. Low temperature plasmas created by photoionization of gases with intense radiation pulses from laser-produced plasma sources

    Science.gov (United States)

    Bartnik, A.; Pisarczyk, T.; Wachulak, P.; Chodukowski, T.; Fok, T.; Wegrzyński, Ł.; Kalinowska, Z.; Fiedorowicz, H.

    2016-12-01

    A comparative study of photoionized plasmas created by soft X-ray (SXR) and extreme ultraviolet (EUV) laser plasma sources was performed. The sources, employing high or low energy laser systems, utilized double-stream Xe/He gas-puff targets irradiated with laser pulses of different parameters. The SXR/EUV beams were used for irradiation of a gas stream, injected into a vacuum chamber synchronously with the radiation pulse. Photoionized plasmas produced this way in Ne gas emitted radiation in the SXR/EUV range. The corresponding spectra were dominated by emission lines originating from singly charged ions. Significant differences between spectra obtained in different experimental conditions concern specific transitions in Ne II ions. Creation of photoionized plasmas by SXR or EUV irradiation resulted in K-shell or L-shell emissions respectively. In case of the low energy system absorption spectra were measured additionally. In case of the high energy system, the electron density measurements were performed by laser interferometry, employing a femtosecond laser system. A maximum electron density reached the value of 2·1018cm-3. For the low energy system, a detection limit was too high for the interferometric measurements, thus only an upper estimation for electron density could be made.

  13. Multicomponent plasma expansion into vacuum with non-Maxwellian electrons

    Science.gov (United States)

    Elkamash, Ibrahem; Kourakis, Ioannis

    2016-10-01

    The expansion of a collisionless plasma into vacuum has been widely studied since the early works of Gurevich et al and Allen and coworkers. It has received momentum in recent years, in particular in the context of ultraintense laser pulse interaction with a solid target, in an effort to elucidate the generation of high energy ion beams. In most present day experiments, laser produced plasmas contain several ion species, due to increasingly complicated composite targets. Anderson et al have studied the isothermal expansion of a two-ion-species plasma. As in most earlier works, the electrons were assumed to be isothermal throughout the expansion. However, in more realistic situations, the evolution of laser produced plasmas into vacuum is mainly governed by nonthermal electrons. These electrons are characterized by particle distribution functions with high energy tails, which may significantly deviate from the Maxwellian distribution. In this paper, we present a theoretical model for plasma expansion of two component plasma with nonthermal electrons, modelled by a kappa-type distribution. The superthermal effect on the ion density, velocity and the electric field is investigated. It is shown that energetic electrons have a significant effecton the expansion dynamics of the plasma. This work was supported from CPP/QUB funding. One of us (I.S. Elkamash) acknowledges financial support by an Egyptian Government fellowship.

  14. Research on EBEP (Electron Beam Excited Plasma) applications; EBEP (denshi beam reiki plasma) no tekiyo gijutsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Yanase, E.; Ryoji, M.; Mori, Y.; Tokai, M. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1996-04-20

    Research and development is actively conducted on machining technologies using plasma in various fields, with studies energetically pursued on etching techniques or those of forming a thin film by the use of high frequency and microwave plasma. The EBEP system jointly developed by Kawasaki Heavy Industries Ltd. and Institute of Physical and Chemical Research is a plasma source for forming a high density plasma by implanting into a plasma chamber from the outside a high-current electron beam accelerated to an energy of approximately 60 to 100eV where the collision cross-section of gas ionization is maximized. The characteristics of the system are such as (1) it enables electron energy distribution to be controlled from outside by varying acceleration voltage, (2) it excels in the controllability of ion energy and (3) it allows to form a steady high-density plasma in a nonmagnetic field. This paper presents the generating principle of EBEP, its plasma characteristics, etching technique using EBEP, thin film forming technique by EBEP-CVD method, and multipurpose apparatus for research and development. 6 refs., 7 figs., 1 tab.

  15. Collimation of fast electrons in critical density plasma channel

    OpenAIRE

    2015-01-01

    Significantly collimated fast electron beam with a divergence angle 10° (FWHM) is generated through the interaction of ultra-intense laser light with a uniform critical density plasma in experiments and 2D PIC simulations. In the experiment, the uniform critical density plasma is created by ionizing an ultra-low density foam target. The spacial distribution of the fast electron is observed by Imaging Plate. 2D PIC simulation and post process analysis reveal magnetic collimation of energetic e...

  16. Ion Acoustic Waves in the Presence of Electron Plasma Waves

    DEFF Research Database (Denmark)

    Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens

    1977-01-01

    Long-wavelength ion acoustic waves in the presence of propagating short-wavelength electron plasma waves are examined. The influence of the high frequency oscillations is to decrease the phase velocity and the damping distance of the ion wave.......Long-wavelength ion acoustic waves in the presence of propagating short-wavelength electron plasma waves are examined. The influence of the high frequency oscillations is to decrease the phase velocity and the damping distance of the ion wave....

  17. 2-D studies of Relativistic electron beam plasma instabilities in an inhomogeneous plasma

    CERN Document Server

    Shukla, Chandrashekhar; Patel, Kartik

    2015-01-01

    Relativistic electron beam propagation in plasma is fraught with several micro instabilities like two stream, filamentation etc., in plasma. This results in severe limitation of the electron transport through a plasma medium. Recently, however, there has been an experimental demonstration of improved transport of Mega Ampere of electron currents (generated by the interaction of intense laser with solid target) in a carbon nanotube structured solid target [Phys. Rev Letts. 108, 235005 (2012)]. This then suggests that the inhomogeneous plasma (created by the ionization of carbon nano tube structured target) helps in containing the growth of the beam plasma instabilities. This manuscript addresses this issue with the help of a detailed analytical study and simulations with the help of 2-D Particle - In - Cell code. The study conclusively demonstrates that the growth rate of the dominant instability in the 2-D geometry decreases when the plasma density is chosen to be inhomogeneous, provided the scale length 1/ks...

  18. Electron beam manipulation, injection and acceleration in plasma wakefield accelerators by optically generated plasma density spikes

    Energy Technology Data Exchange (ETDEWEB)

    Wittig, Georg; Karger, Oliver S.; Knetsch, Alexander [Institute of Experimental Physics, University of Hamburg, 22761 Hamburg (Germany); Xi, Yunfeng; Deng, Aihua; Rosenzweig, James B. [Particle Beam Physics Laboratory, UCLA, Los Angeles, CA 90095 (United States); Bruhwiler, David L. [RadiaSoft LLC, Boulder, CO 80304 (United States); RadiaBeam Technologies LLC (United States); Smith, Jonathan [Tech-X UK Ltd, Daresbury, Cheshire WA4 4FS (United Kingdom); Sheng, Zheng-Ming; Jaroszynski, Dino A.; Manahan, Grace G. [Physics Department, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Hidding, Bernhard [Institute of Experimental Physics, University of Hamburg, 22761 Hamburg (Germany); Physics Department, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2016-09-01

    We discuss considerations regarding a novel and robust scheme for optically triggered electron bunch generation in plasma wakefield accelerators [1]. In this technique, a transversely propagating focused laser pulse ignites a quasi-stationary plasma column before the arrival of the plasma wake. This localized plasma density enhancement or optical “plasma torch” distorts the blowout during the arrival of the electron drive bunch and modifies the electron trajectories, resulting in controlled injection. By changing the gas density, and the laser pulse parameters such as beam waist and intensity, and by moving the focal point of the laser pulse, the shape of the plasma torch, and therefore the generated trailing beam, can be tuned easily. The proposed method is much more flexible and faster in generating gas density transitions when compared to hydrodynamics-based methods, and it accommodates experimentalists needs as it is a purely optical process and straightforward to implement.

  19. Plasma characterization using ultraviolet Thomson scattering from ion-acoustic and electron plasma waves (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Follett, R. K., E-mail: rfollett@lle.rochester.edu; Delettrez, J. A.; Edgell, D. H.; Henchen, R. J.; Katz, J.; Myatt, J. F.; Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 (United States)

    2016-11-15

    Collective Thomson scattering is a technique for measuring the plasma conditions in laser-plasma experiments. Simultaneous measurements of ion-acoustic and electron plasma-wave spectra were obtained using a 263.25-nm Thomson-scattering probe beam. A fully reflective collection system was used to record light scattered from electron plasma waves at electron densities greater than 10{sup 21} cm{sup −3}, which produced scattering peaks near 200 nm. An accurate analysis of the experimental Thomson-scattering spectra required accounting for plasma gradients, instrument sensitivity, optical effects, and background radiation. Practical techniques for including these effects when fitting Thomson-scattering spectra are presented and applied to the measured spectra to show the improvements in plasma characterization.

  20. Electron beam manipulation, injection and acceleration in plasma wakefield accelerators by optically generated plasma density spikes

    Science.gov (United States)

    Wittig, Georg; Karger, Oliver S.; Knetsch, Alexander; Xi, Yunfeng; Deng, Aihua; Rosenzweig, James B.; Bruhwiler, David L.; Smith, Jonathan; Sheng, Zheng-Ming; Jaroszynski, Dino A.; Manahan, Grace G.; Hidding, Bernhard

    2016-09-01

    We discuss considerations regarding a novel and robust scheme for optically triggered electron bunch generation in plasma wakefield accelerators [1]. In this technique, a transversely propagating focused laser pulse ignites a quasi-stationary plasma column before the arrival of the plasma wake. This localized plasma density enhancement or optical "plasma torch" distorts the blowout during the arrival of the electron drive bunch and modifies the electron trajectories, resulting in controlled injection. By changing the gas density, and the laser pulse parameters such as beam waist and intensity, and by moving the focal point of the laser pulse, the shape of the plasma torch, and therefore the generated trailing beam, can be tuned easily. The proposed method is much more flexible and faster in generating gas density transitions when compared to hydrodynamics-based methods, and it accommodates experimentalists needs as it is a purely optical process and straightforward to implement.

  1. Plasma characterization using ultraviolet Thomson scattering from ion-acoustic and electron plasma waves (invited)

    Science.gov (United States)

    Follett, R. K.; Delettrez, J. A.; Edgell, D. H.; Henchen, R. J.; Katz, J.; Myatt, J. F.; Froula, D. H.

    2016-11-01

    Collective Thomson scattering is a technique for measuring the plasma conditions in laser-plasma experiments. Simultaneous measurements of ion-acoustic and electron plasma-wave spectra were obtained using a 263.25-nm Thomson-scattering probe beam. A fully reflective collection system was used to record light scattered from electron plasma waves at electron densities greater than 1021 cm-3, which produced scattering peaks near 200 nm. An accurate analysis of the experimental Thomson-scattering spectra required accounting for plasma gradients, instrument sensitivity, optical effects, and background radiation. Practical techniques for including these effects when fitting Thomson-scattering spectra are presented and applied to the measured spectra to show the improvements in plasma characterization.

  2. Electron acoustic solitary waves in a magnetized plasma with nonthermal electrons and an electron beam

    Science.gov (United States)

    Singh, S. V.; Devanandhan, S.; Lakhina, G. S.; Bharuthram, R.

    2016-08-01

    A theoretical investigation is carried out to study the obliquely propagating electron acoustic solitary waves having nonthermal hot electrons, cold and beam electrons, and ions in a magnetized plasma. We have employed reductive perturbation theory to derive the Korteweg-de-Vries-Zakharov-Kuznetsov (KdV-ZK) equation describing the nonlinear evolution of these waves. The two-dimensional plane wave solution of KdV-ZK equation is analyzed to study the effects of nonthermal and beam electrons on the characteristics of the solitons. Theoretical results predict negative potential solitary structures. We emphasize that the inclusion of finite temperature effects reduces the soliton amplitudes and the width of the solitons increases by an increase in the obliquity of the wave propagation. The numerical analysis is presented for the parameters corresponding to the observations of "burst a" event by Viking satellite on the auroral field lines.

  3. Hot electron stabilization of a helically symmetric plasma

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R.L.

    1986-04-01

    Furth and Boozer (private communication; Proceedings of the Advanced Bumpy Torus Concepts Workshop, CONF-830758, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 1983, p. 161) have suggested the use of relativistic electrons to achieve the second stability regime in a helical axis stellarator (Heliac). The hot electrons would only be required until the background plasma reached the second stability regime; the heating power maintaining the hot electron layer would then be turned off. The basic correctness of Furth and Boozer's suggestion is confirmed numerically by a localized stability analysis of helically symmetric plasma equilibria, with anisotropic pressure profiles. Stability is evaluated using the localized interchange criterion in which the hot electrons, because of their large drift speeds, are treated as rigid. A hot electron pressure profile is exhibited; it provides a stable path to the second stability regime for the background plasma.

  4. Hybrid Simulation of Laser-Plasma Interactions and Fast Electron Transport in Inhomogeneous Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, B I; Kemp, A; Divol, L

    2009-05-27

    A new framework is introduced for kinetic simulation of laser-plasma interactions in an inhomogenous plasma motivated by the goal of performing integrated kinetic simulations of fast-ignition laser fusion. The algorithm addresses the propagation and absorption of an intense electromagnetic wave in an ionized plasma leading to the generation and transport of an energetic electron component. The energetic electrons propagate farther into the plasma to much higher densities where Coulomb collisions become important. The high-density plasma supports an energetic electron current, return currents, self-consistent electric fields associated with maintaining quasi-neutrality, and self-consistent magnetic fields due to the currents. Collisions of the electrons and ions are calculated accurately to track the energetic electrons and model their interactions with the background plasma. Up to a density well above critical density, where the laser electromagnetic field is evanescent, Maxwell's equations are solved with a conventional particle-based, finite-difference scheme. In the higher-density plasma, Maxwell's equations are solved using an Ohm's law neglecting the inertia of the background electrons with the option of omitting the displacement current in Ampere's law. Particle equations of motion with binary collisions are solved for all electrons and ions throughout the system using weighted particles to resolve the density gradient efficiently. The algorithm is analyzed and demonstrated in simulation examples. The simulation scheme introduced here achieves significantly improved efficiencies.

  5. Radiofrequency and 2.45 GHz electron cyclotron resonance H- volume production ion sources

    Science.gov (United States)

    Tarvainen, O.; Peng, S. X.

    2016-10-01

    The volume production of negative hydrogen ions ({{{H}}}-) in plasma ion sources is based on dissociative electron attachment (DEA) to rovibrationally excited hydrogen molecules (H2), which is a two-step process requiring both, hot electrons for ionization, and vibrational excitation of the H2 and cold electrons for the {{{H}}}- formation through DEA. Traditionally {{{H}}}- ion sources relying on the volume production have been tandem-type arc discharge sources equipped with biased filament cathodes sustaining the plasma by thermionic electron emission and with a magnetic filter separating the main discharge from the {{{H}}}- formation volume. The main motivation to develop ion sources based on radiofrequency (RF) or electron cyclotron resonance (ECR) plasma discharges is to eliminate the apparent limitation of the cathode lifetime. In this paper we summarize the principles of {{{H}}}- volume production dictating the ion source design and highlight the differences between the arc discharge and RF/ECR ion sources from both, physics and technology point-of-view. Furthermore, we introduce the state-of-the-art RF and ECR {{{H}}}- volume production ion sources and review the challenges and future prospects of these yet developing technologies.

  6. Hydrogen Ionic Plasma and Particle Dynamics in Negative Ion Source for NBI

    Science.gov (United States)

    Tsumori, Katsuyoshi

    2013-10-01

    Three negative-ion-based neutral beam injectors (NBIs) have been developed for plasma heating in the Large Helical Device. The NBIs achieve successfully the nominal injection power and beam energy, and understanding of the production and transport mechanisms of H- ion is required to obtain more stable high power beam. In the ion source development, we have found hydrogen ionic plasmas with extremely low electron density are produced in the beam extraction region. The plasma is measured with a combination of an electrostatic probe, millimeter-wave interferometer and cavity ring down (CRD). It has been observed for the first time that the charge neutrality of the ionic plasma is broken with H- extraction and electrons compensate the extracted H- charge. The influence of the extraction field widely affects to the ionic plasma in the extraction region. Two-dimensional particle-in-cell simulation (2D-PIC) has been applied to investigate the particle transport and reproduces the production of the ionic plasma and electron compensation due to H- extraction. In particle model, produced H- ions leave from the Cs covered PG surface in opposite direction to beam extraction. The direction can be changed with the electric field and collective effect due to the presence of plasma. A new technique using CCD camera with H α filter applied to measure the two-dimensional distribution of H- density. In the ionic plasma, H α light is emitted via electron-impact excitation and mutual neutralization processes with H- ion and proton. Comparing the results obtained with optical emission spectroscopy, electrostatic probe and CRD, it is shown the H α emission is dominated with the mutual neutralization. By subtracting the CCD images with and without beam extraction, it becomes clear that H- ions are extracted not directly from the PG surface but from the bulk of the ionic plasma. The result suggests the initial energy of H- ion is dumped rapidly in the ionic plasma.

  7. Interaction of energetic electrons with dust whistler-mode waves in magnetospheric dusty plasmas

    Science.gov (United States)

    Jafari, S.

    2016-04-01

    In this Letter, a new conceptual approach has been presented to investigate the interaction of energetic electrons with dust whistler-mode waves in magnetospheric dusty (complex) plasmas. Dust whistler-mode waves generated in the presence of charged dust grains in the magnetized dusty plasma, can scatter the launched electrons into the loss-cone leading to precipitation into the upper atmosphere which is an important loss process in the radiation belts and provides a major source of energy for the diffuse and pulsating aurora. To study the scattered electrons and chaotic regions, a Hamiltonian model of the electron-dust wave interaction has been employed in the magnetospheric plasma by considering the launched electron beam self-fields. Numerical simulations indicate that an electron beam interacting with the whistler-mode wave can easily trigger chaos in the dust-free plasma, while in the presence of dust charged grains in the plasma, the chaotic regions are quenched to some extent in the magnetosphere. Consequently, the rate of scattered electrons into the loss-cone reduces for the regions that the dust grains are present.

  8. Imperative function of electron beams in low-energy plasma focus device

    Indian Academy of Sciences (India)

    M Z Khan; L K Lim; S L Yap; C S Wong

    2015-12-01

    A 2.2 kJ plasma focus device was analysed as an electron beam and an X-ray source that operates with argon gas refilled at a specific pressure. Time-resolved X-ray signals were observed using an array of PIN diode detectors, and the electron beam energy was detected using a scintillator-assisted photomultiplier tube. The resultant X-rays were investigated by plasma focus discharge for pressures ranging from 1.5 mbar to 2.0 mbar. This range corresponded to the significant values of X-ray yields and electron beam energies from the argon plasma. The electron temperature of argon plasma at an optimum pressure range was achieved by an indirect method using five-channel BPX65 PIN diodes of aluminum foils with different thicknesses. X-ray yield, electron beam energy, and electron temperature of argon plasma were achieved at 1.5–2.0 mbar because of the strong bombardment of the energetic electron beam.

  9. A Simulator for Producing of High Flux Atomic Oxygen Beam by Using ECR Plasma Source

    Institute of Scientific and Technical Information of China (English)

    Shuwang DUO; Meishuan LI; Yaming ZHANG

    2004-01-01

    In order to study the atomic oxygen corrosion of spacecraft materials in low earth orbit environment, an atomic oxygen simulator was established. In the simulator, a 2.45 GHz microwave source with maximum power of 600 W was launched into the circular cavity to generate ECR (electron cyclotron resonance) plasma. The oxygen ion beam moved onto a negatively biased Mo plate under the condition of symmetry magnetic mirror field confine, then was neutralized and reflected to form oxygen atom beam. The properties of plasma density, electron temperature, plasma space potential and ion incident energy were characterized. The atomic oxygen beam flux was calibrated by measuring the mass loss rate of Kapton during the atomic 5~30 eV and a cross section of φ80 mm could be obtained under the operating pressure of 10-1~10-3 Pa. Such a high flux source can provide accelerated simulation tests of materials and coatings for space applications.

  10. Measurements and modeling of the impact of weak magnetic fields on the plasma properties of a planar slot antenna driven plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Jun, E-mail: jun.yoshikawa@tel.com; Susa, Yoshio; Ventzek, Peter L. G. [Tokyo Electron Ltd., Akasaka Biz Tower, 3-1 Akasaka 5-chome, Minato-ku, Tokyo 107-6325 (Japan)

    2015-05-15

    The radial line slot antenna plasma source is a type of surface wave plasma source driven by a planar slot antenna. Microwave power is transmitted through a slot antenna structure and dielectric window to a plasma characterized by a generation zone adjacent to the window and a diffusion zone that contacts a substrate. The diffusion zone is characterized by a very low electron temperature. This renders the source useful for soft etch applications and thin film deposition processes requiring low ion energy. Another property of the diffusion zone is that the plasma density tends to decrease from the axis to the walls under the action of ambipolar diffusion at distances far from where the plasma is generated. A previous simulation study [Yoshikawa and. Ventzek, J. Vac. Sci. Technol. A 31, 031306 (2013)] predicted that the anisotropy in transport parameters due to weak static magnetic fields less than 50 G could be leveraged to manipulate the plasma profile in the radial direction. These simulations motivated experimental tests in which weak magnetic fields were applied to a radial line slot antenna source. Plasma absorption probe measurements of electron density and etch rate showed that the magnetic fields remote from the wafer were able to manipulate both parameters. A summary of these results is presented in this paper. Argon plasma simulation trends are compared with experimental plasma and etch rate measurements. A test of the impact of magnetic fields on charge up damage showed no perceptible negative effect.

  11. An open-source laser electronics suite

    Science.gov (United States)

    Pisenti, Neal C.; Reschovsky, Benjamin J.; Barker, Daniel S.; Restelli, Alessandro; Campbell, Gretchen K.

    2016-05-01

    We present an integrated set of open-source electronics for controlling external-cavity diode lasers and other instruments in the laboratory. The complete package includes a low-noise circuit for driving high-voltage piezoelectric actuators, an ultra-stable current controller based on the design of, and a high-performance, multi-channel temperature controller capable of driving thermo-electric coolers or resistive heaters. Each circuit (with the exception of the temperature controller) is designed to fit in a Eurocard rack equipped with a low-noise linear power supply capable of driving up to 5 A at +/- 15 V. A custom backplane allows signals to be shared between modules, and a digital communication bus makes the entire rack addressable by external control software over TCP/IP. The modular architecture makes it easy for additional circuits to be designed and integrated with existing electronics, providing a low-cost, customizable alternative to commercial systems without sacrificing performance.

  12. Thomson scattering off a pair (electron-positron) plasma

    Institute of Scientific and Technical Information of China (English)

    Zheng Jian

    2006-01-01

    Thomson scattering off a pair (electron-positron) plasma is theoretically investigated in the collisionless and collisional limits respectively. Our calculations show that the power spectrum of the Thomson scattering offa collisionless pair plasma is just proportional to the velocity distribution function of the particles in the plasma. Collective modes in the plasma do not have any effects on the Thomson scattering spectrum because of the correlation between the negatively- and positively-charged particles. In the collisional limit, the power spectrum of the Thomson scattering presents three spikes: two peaks correspond to two contra-propagating sound waves and one peak corresponds to an entropy wave.

  13. Secondary electron emission from plasma-generated nanostructured tungsten fuzz

    Science.gov (United States)

    Patino, M.; Raitses, Y.; Wirz, R.

    2016-11-01

    Recently, several researchers [e.g., Yang et al., Sci. Rep. 5, 10959 (2015)] have shown that tungsten fuzz can grow on a hot tungsten surface under bombardment by energetic helium ions in different plasma discharges and applications, including magnetic fusion devices with plasma facing tungsten components. This work reports the direct measurements of the total effective secondary electron emission (SEE) from tungsten fuzz. Using dedicated material surface diagnostics and in-situ characterization, we find two important results: (1) SEE values for tungsten fuzz are 40%-63% lower than for smooth tungsten and (2) the SEE values for tungsten fuzz are independent of the angle of the incident electron. The reduction in SEE from tungsten fuzz is most pronounced at high incident angles, which has important implications for many plasma devices since in a negative-going sheath the potential structure leads to relatively high incident angles for the electrons at the plasma confining walls. Overall, low SEE will create a relatively higher sheath potential difference that reduces plasma electron energy loss to the confining wall. Thus, the presence or self-generation in a plasma of a low SEE surface such as tungsten fuzz can be desirable for improved performance of many plasma devices.

  14. Nonrelativistic structure calculations of two-electron ions in a strongly coupled plasma environment

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharyya, S.; Saha, J. K.; Mukherjee, T. K.

    2015-04-01

    In this work, the controversy between the interpretations of recent measurements on dense aluminum plasma created with the Linac coherent light source (LCLS) x-ray free electron laser (FEL) and the Orion laser has been addressed. In both kinds of experiments, heliumlike and hydrogenlike spectral lines are used for plasma diagnostics. However, there exist no precise theoretical calculations for He-like ions within a dense plasma environment. The strong need for an accurate theoretical estimate for spectral properties of He-like ions in a strongly coupled plasma environment leads us to perform ab initio calculations in the framework of the Rayleigh-Ritz variation principle in Hylleraas coordinates where an ion-sphere potential is used. An approach to resolve the long-drawn problem of numerical instability for evaluating two-electron integrals with an extended basis inside a finite domain is presented here. The present values of electron densities corresponding to the disappearance of different spectral lines obtained within the framework of an ion-sphere potential show excellent agreement with Orion laser experiments in Al plasma and with recent theories. Moreover, this method is extended to predict the critical plasma densities at which the spectral lines of H-like and He-like carbon and argon ions disappear. Incidental degeneracy and level-crossing phenomena are being reported for two-electron ions embedded in strongly coupled plasma. Thermodynamic pressure experienced by the ions in their respective ground states inside the ion spheres is also reported.

  15. Ambipolar and non-ambipolar diffusion in an rf plasma source containing a magnetic filter

    Energy Technology Data Exchange (ETDEWEB)

    Lafleur, T., E-mail: trevor.lafleur@lpp.polytechnique.fr [Laboratoire de Physique des Plasmas, CNRS, Sorbonne Universités, UPMC Univ Paris 06, Univ Paris-Sud, Ecole Polytechnique, 91128 Palaiseau (France); ONERA-The French Aerospace Lab, 91120 Palaiseau (France); Aanesland, A. [Laboratoire de Physique des Plasmas, CNRS, Sorbonne Universités, UPMC Univ Paris 06, Univ Paris-Sud, Ecole Polytechnique, 91128 Palaiseau (France)

    2014-06-15

    By placing a magnetic filter across a rectangular plasma source (closed at one end with a ceramic plate and an rf antenna, and terminated at the opposite end by a grounded grid), we experimentally investigate the effect of conducting and insulating source walls on the nature of the plasma diffusion phenomena. The use of a magnetic filter creates a unique plasma, characterized by a high upstream electron temperature (T{sub e{sub u}}∼5 eV) near the rf antenna and a low downstream electron temperature (T{sub e{sub d}}∼1 eV) near the grid, which more clearly demonstrates the role of the source wall materials. For conducting walls a net ion current to ground is measured on the grid, and the plasma potential is determined by a mean electron temperature within the source. For insulating walls the plasma potential is determined by the downstream electron temperature (i.e., V{sub p}∼5.2T{sub e{sub d}} in argon), and the net current to the grid is exactly zero. Furthermore, by inserting a small additional upstream conductor (that can be made floating or grounded through an external circuit switch), we demonstrate that the plasma potential can be controlled and set to a low (V{sub p}∼5.2T{sub e{sub d}}), or high (V{sub p}∼5.2T{sub e{sub u}}) value.

  16. Shock Formation in Electron-Ion Plasmas: Mechanism and Timing

    Science.gov (United States)

    Bret, Antoine; Stockem Novo, Anne; Ricardo, Fonseca; Luis, Silva

    2016-10-01

    We analyze the formation of a collisionless shock in electron-ion plasmas in theory and simulations. In initially un-magnetized relativistic plasmas, such shocks are triggered by the Weibel instability. While in pair plasmas the shock starts forming right after the instability saturates, it is not so in electron-ion plasmas because the Weibel filaments at saturation are too small. An additional merging phase is therefore necessary for them to efficiently stop the flow. We derive a theoretical model for the shock formation time, taking into account filament merging in the nonlinear phase of the Weibel instability. This process is much slower than in electron-positron pair shocks, and so the shock formation is longer by a factor proportional to √{mi /me } ln(mi /me).

  17. Candidate plasma-facing materials for EUV lithography source components

    Science.gov (United States)

    Hassanein, Ahmed; Burtseva, Tatiana; Brooks, Jeff N.; Konkashbaev, Isak K.; Rice, Bryan J.

    2003-06-01

    Material selection and lifetime issues for extreme ultraviolet (EUV) lithography are of critical importance to the success of this technology for commercial applications. This paper reviews current trends in production and use of plasma-facing electrodes, insulators, and wall materials for EUV type sources. Ideal candidate materials should be able to: withstand high thermal shock from the short pulsed plasma; withstand high thermal loads without structural failure; reduce debris generation during discharge; and be machined accurately. We reviewed the literature on current and proposed fusion plasma-facing materials as well as current experience with plasma gun and other simulation devices. Both fusion and EUV source materials involve issues of surface erosion by particle sputtering and heat-induced evaporation/melting. These materials are either bare structural materials or surface coatings. EUV materials can be divided into four categories: wall, electrode, optical, and insulator materials. For electric discharge sources, all four types are required, whereas laser-produced plasma EUV sources do not require electrode and insulator materials. Several types of candidate alloy and other materials and methods of manufacture are recommended for each component of EUV lithography light sources.

  18. Electron-acoustic solitary waves in a beam plasma with electron trapping and nonextensivity effects

    Science.gov (United States)

    Ali Shan, S.; Aman-ur-Rehman, Mushtaq, A.

    2016-09-01

    A theoretical investigation is carried out for understanding the properties of electron-acoustic solitary waves (EASWs) in a beam plasma whose constituents are a cold beam electron fluid, hot nonextensive electrons obeying a vortex-like distribution with nonextensive factor q, and stationary ions. An energy integral (Schamel KdV) equation is derived by employing pseudo-potential (reductive perturbation) approach. The presence of nonextensive q-distributed hot trapped electrons and cold electron beam has been shown to influence the soliton structure quite significantly. The nonlinear dispersion relation is derived to analyze the dependency of the electron acoustic solitary wave quantities. From the analysis of our results, it is shown that the present plasma model supports the compressive EASWs. As the real plasma situations are observed with plasma species having a relative flow, so our present analysis should be useful for understanding the electrostatic solitary structures observed in the dayside auroral zone and other regions of the magnetosphere.

  19. Controlled Electron Injection into Plasma Accelerators and SpaceCharge Estimates

    Energy Technology Data Exchange (ETDEWEB)

    Fubiani, Gwenael G.J. [Univ. of California, Berkeley, CA (United States)

    2005-09-01

    Plasma based accelerators are capable of producing electron sources which are ultra-compact (a few microns) and high energies (up to hundreds of MeVs) in much shorter distances than conventional accelerators. This is due to the large longitudinal electric field that can be excited without the limitation of breakdown as in RF structures.The characteristic scale length of the accelerating field is the plasma wavelength and for typical densities ranging from 1018 - 1019 cm-3, the accelerating fields and scale length can hence be on the order of 10-100GV/m and 10-40 μm, respectively. The production of quasimonoenergetic beams was recently obtained in a regime relying on self-trapping of background plasma electrons, using a single laser pulse for wakefield generation. In this dissertation, we study the controlled injection via the beating of two lasers (the pump laser pulse creating the plasma wave and a second beam being propagated in opposite direction) which induce a localized injection of background plasma electrons. The aim of this dissertation is to describe in detail the physics of optical injection using two lasers, the characteristics of the electron beams produced (the micrometer scale plasma wavelength can result in femtosecond and even attosecond bunches) as well as a concise estimate of the effects of space charge on the dynamics of an ultra-dense electron bunch with a large energy spread.

  20. Behavior of moving plasma in solenoidal magnetic field in a laser ion source

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, S., E-mail: ikeda.s.ae@m.titech.ac.jp [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8502 (Japan); Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0108 (Japan); Takahashi, K. [Department of Electrical Engineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2137 (Japan); Okamura, M. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Horioka, K. [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8502 (Japan)

    2016-02-15

    In a laser ion source, a solenoidal magnetic field is useful to guide the plasma and to control the extracted beam current. However, the behavior of the plasma drifting in the magnetic field has not been well understood. Therefore, to investigate the behavior, we measured the plasma ion current and the total charge within a single pulse in the solenoid by changing the distance from the entrance of the solenoid to a detector. We observed that the decrease of the total charge along the distance became smaller as the magnetic field became larger and then the charge became almost constant with a certain magnetic flux density. The results indicate that the transverse spreading speed of the plasma decreased with increasing the field and the plasma was confined transversely with the magnetic flux density. We found that the reason of the confinement was not magnetization of ions but an influence induced by electrons.

  1. Behavior of moving plasma in solenoidal magnetic field in a laser ion source

    Science.gov (United States)

    Ikeda, S.; Takahashi, K.; Okamura, M.; Horioka, K.

    2016-02-01

    In a laser ion source, a solenoidal magnetic field is useful to guide the plasma and to control the extracted beam current. However, the behavior of the plasma drifting in the magnetic field has not been well understood. Therefore, to investigate the behavior, we measured the plasma ion current and the total charge within a single pulse in the solenoid by changing the distance from the entrance of the solenoid to a detector. We observed that the decrease of the total charge along the distance became smaller as the magnetic field became larger and then the charge became almost constant with a certain magnetic flux density. The results indicate that the transverse spreading speed of the plasma decreased with increasing the field and the plasma was confined transversely with the magnetic flux density. We found that the reason of the confinement was not magnetization of ions but an influence induced by electrons.

  2. Electron-vibration relaxation in oxygen plasmas

    Science.gov (United States)

    Laporta, V.; Heritier, K. L.; Panesi, M.

    2016-06-01

    An ideal chemical reactor model is used to study the vibrational relaxation of oxygen molecules in their ground electronic state, X3Σg-, in presence of free electrons. The model accounts for vibrational non-equilibrium between the translational energy mode of the gas and the vibrational energy mode of individual molecules. The vibrational levels of the molecules are treated as separate species, allowing for non-Boltzmann distributions of their population. The electron and vibrational temperatures are varied in the range [0-20,000] K. Numerical results show a fast energy transfer between oxygen molecules and free electron, which causes strong deviation of the vibrational distribution function from Boltzmann distribution, both in heating and cooling conditions. Comparison with Landau-Teller model is considered showing a good agreement for electron temperature range [2000-12,000] K. Finally analytical fit of the vibrational relaxation time is given.

  3. A highly reliable trigger for vacuum ARC plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Bernardet, H.; Godechot, X.; Jarjat, F. [SODERN, Limeil-Brevannes (France)

    1996-08-01

    The authors have developed a reliable electrical trigger and its associated circuitry to fire vacuum arc plasma or ion source. They tested different embodiments of the trigger device in order to get a highly reliable one, which is able to perform more than 1.2 x 10{sup 6} shots at 60 A and 6.5 ps pulse length. The evolution of the ion current emitted has been recorded as a function of the number of shots. They have also investigated in which direction the plasma jet is emitted : axially or radially. This device can be used to fire a vacuum arc plasma or ion source by plasma injection. It has obvious advantage to be placed outside the cathode and therefore would ease maintenance of vacuum arc devices.

  4. Revisiting plasma hysteresis with an electronically compensated Langmuir probe

    Science.gov (United States)

    Srivastava, P. K.; Singh, S. K.; Awasthi, L. M.; Mattoo, S. K.

    2012-09-01

    The measurement of electron temperature in plasma by Langmuir probes, using ramped bias voltage, is seriously affected by the capacitive current of capacitance of the cable between the probe tip and data acquisition system. In earlier works a dummy cable was used to balance the capacitive currents. Under these conditions, the measured capacitive current was kept less than a few mA. Such probes are suitable for measurements in plasma where measured ion saturation current is of the order of hundreds of mA. This paper reports that controlled balancing of capacitive current can be minimized to less than 20 μA, allowing plasma measurements to be done with ion saturation current of the order of hundreds of μA. The electron temperature measurement made by using probe compensation technique becomes independent of sweep frequency. A correction of ≤45% is observed in measured electron temperature values when compared with uncompensated probe. This also enhances accuracy in the measurement of fluctuation in electron temperature as δTpk-pk changes by ˜30%. The developed technique with swept rate ≤100 kHz is found accurate enough to measure both the electron temperature and its fluctuating counterpart. This shows its usefulness in measuring accurately the temperature fluctuations because of electron temperature gradient in large volume plasma device plasma with frequency ordering ≤50 kHz.

  5. Are Spicules the Primary Source of Hot Coronal Plasma?

    Science.gov (United States)

    Klimchuk, James A.

    2011-01-01

    The recent discovery of Type II spicules has generated considerable excitement. It has even been suggested that these ejections can account for a majority of the hot plasma observed in the corona, thus obviating the need for "coronal" heating. If this is the case, however, then there should be observational consequences. We have begun to examine some of these consequences and find reason to question the idea that spicules are the primary source of hot coronal plasma.

  6. Photoionization of an aluminum plasma by a tantalum X source

    Science.gov (United States)

    Renaudin, Patrick; Back, Christina A.; Chenais-Popovics, Claude; Audebert, Patrick; Geindre, Jean-Paul; Gauthier, Jean-Claude

    1991-05-01

    Photoionization of a helium like aliminum plasma is carried out by an external x-source. The laser beam used corresponds to the 3d to 4F transition level of tantalum. The experimental spectrum of tantalum is shown superimposed over the emission spectrum of aluminum on diagrammatic form. Good correspondence is seen between the 3d to 4F emissions of tantalum and helium like aluminum. Plasma pumping is obtained by exposure of a tantalum target to laser rays.

  7. Electron cyclotron resonance breakdown studies in a linear plasma system

    Indian Academy of Sciences (India)

    Vipin K Yadav; K Sathyanarayana; D Bora

    2008-03-01

    Electron cyclotron resonance (ECR) plasma breakdown is studied in a small linear cylindrical system with four different gases - hydrogen, helium, argon and nitrogen. Microwave power in the experimental system is delivered by a magnetron at 2.45 ± 0.02 GHz in TE10 mode and launched radially to have extra-ordinary (X) wave in plasma. The axial magnetic field required for ECR in the system is such that the fundamental ECR surface ( = 875.0 G) resides at the geometrical centre of the plasma system. ECR breakdown parameters such as plasma delay time and plasma decay time from plasma density measurements are carried out at the centre using a Langmuir probe. The operating parameters such as working gas pressure (1 × 10-5 -1 × 10-2 mbar) and input microwave power (160{800 W) are varied and the corresponding effect on the breakdown parameters is studied. The experimental results obtained are presented in this paper.

  8. Fluid echoes in a pure electron plasma.

    Science.gov (United States)

    Yu, J H; O'Neil, T M; Driscoll, C F

    2005-01-21

    Experimental observations of diocotron wave echoes on a magnetized electron column are reported, representing Kelvin wave echoes on a rotating near-ideal fluid. The echoes occur by reversal of an inviscid wave damping process, and the phase-space mixing and unmixing are directly imaged. The basic echo characteristics agree with a simple nonlinear ballistic theory. At late times, the echo is degraded, and the maximal observed echo times agree with a theory of electron-electron collisions acting on separately evolving velocity classes.

  9. Simple filtered repetitively pulsed vacuum arc plasma source

    Science.gov (United States)

    Chekh, Yu.; Zhirkov, I. S.; Delplancke-Ogletree, M. P.

    2010-02-01

    A very simple design of cathodic filtered vacuum arc plasma source is proposed. The source without filter has only four components and none of them require precise machining. The source operates in a repetitively pulsed regime, and for laboratory experiments it can be used without water cooling. Despite the simple construction, the source provides high ion current at the filter outlet reaching 2.5% of 400 A arc current, revealing stable operation in a wide pressure range from high vacuum to oxygen pressure up to more than 10-2 mbar. There is no need in complicated power supply system for this plasma source, only one power supply can be used to ignite the arc, to provide the current for the arc itself, to generate the magnetic field in the filter, and provide its positive electric biasing without any additional high power resistance.

  10. e+e- Plasma Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Hartouni, Ed P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-12-06

    This note addresses the idea of a photon source that is based on an e+e- plasma created by co-propagating beams of e+ and e-. The plasma has a well-defined temperature, and the thermal distribution of the charged particles is used to average over the relative velocity cross section multiplied by the relative velocity. Two relevant cross sections are the direct “free-free” annihilation of e+e- pairs in the plasma, and the radiative recombination of e+e- pairs into positronium (Ps) which subsequently undergoes annihilation.

  11. Evolution of plasma parameters in a He - N2/Ar magnetic pole enhanced inductive plasma source

    Science.gov (United States)

    Younus, Maria; Rehman, N. U.; Shafiq, M.; Zakaullah, M.; Abrar, M.

    2016-02-01

    A magnetic pole enhanced inductively coupled H e - N2/A r plasma is studied at low pressure, to monitor the effects of helium mixing on plasma parameters like electron number density (ne) , electron temperature (Te) , plasma potential (Vp ) , and electron energy probability functions (EEPFs). An RF compensated Langmuir probe is employed to measure these plasma parameters. It is noted that electron number density increases with increasing RF power and helium concentration in the mixture, while it decreases with increase in filling gas pressure. On the other hand, electron temperature shows an increasing trend with helium concentration in the mixture. At low RF powers and low helium concentration in the mixture, EEPFs show a "bi-Maxwellian" distribution with pressure. While at RF powers greater than 50 W and higher helium concentration in the mixture, EEPFs evolve into "Maxwellian" distribution. The variation of skin depth with RF power and helium concentration in the mixture, and its relation with EEPF are also studied. The effect of helium concentrations on the temperatures of two electron groups ( Tb u l k and Tt a i l ) in the "bi-Maxwellian" EEPFs is also observed. The temperature of low energy electron group ( Tb u l k) shows significant increase with helium addition, while the temperature of tail electrons ( Tt a i l) increases smoothly as compared to ( Tb u l k).

  12. Ion source research and development at University of Jyväskylä: Studies of different plasma processes and towards the higher beam intensities

    Energy Technology Data Exchange (ETDEWEB)

    Koivisto, H., E-mail: hannu.koivisto@phys.jyu.fi; Kalvas, T.; Tarvainen, O.; Komppula, J.; Laulainen, J.; Kronholm, R.; Ranttila, K.; Tuunanen, J. [Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä (Finland); Thuillier, T. [LPSC, CNRS/IN2P3, Université Grenoble-Alpes1, 53 Rue des Martyrs, 38026 Grenoble Cedex (France); Xie, D. [Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720 (United States); Machicoane, G. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States)

    2016-02-15

    Several ion source related research and development projects are in progress at the Department of Physics, University of Jyväskylä (JYFL). The work can be divided into investigation of the ion source plasma and development of ion sources, ion beams, and diagnostics. The investigation covers the Electron Cyclotron Resonance Ion Source (ECRIS) plasma instabilities, vacuum ultraviolet (VUV) and visible light emission, photon induced electron emission, and the development of plasma diagnostics. The ion source development covers the work performed for radiofrequency-driven negative ion source, RADIS, beam line upgrade of the JYFL 14 GHz ECRIS, and the development of a new room-temperature-magnet 18 GHz ECRIS, HIISI.

  13. Laser ion source with solenoid for Brookhaven National Laboratory-electron beam ion sourcea)

    Science.gov (United States)

    Kondo, K.; Yamamoto, T.; Sekine, M.; Okamura, M.

    2012-02-01

    The electron beam ion source (EBIS) preinjector at Brookhaven National Laboratory (BNL) is a new heavy ion-preinjector for relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Laser ion source (LIS) is a primary ion source provider for the BNL-EBIS. LIS with solenoid at the plasma drift section can realize the low peak current (˜100 μA) with high charge (˜10 nC) which is the BNL-EBIS requirement. The gap between two solenoids does not cause serious plasma current decay, which helps us to make up the BNL-EBIS beamline.

  14. Evolution of plasma parameters in an Ar-N2/He inductive plasma source with magnetic pole enhancement

    Science.gov (United States)

    Maria, Younus; N, U. Rehman; M, Shafiq; M, Naeem; M, Zaka-Ul-Islam; M, Zakaullah

    2017-02-01

    Magnetic pole enhanced inductively coupled plasmas (MaPE-ICPs) are a promising source for plasma-based etching and have a wide range of material processing applications. In the present study Langmuir probe and optical emission spectroscopy were used to monitor the evolution of plasma parameters in a MaPE-ICP Ar-N2/He mixture plasma. Electron density ({n}{{e}}) and temperature ({T}{{e}}), excitation temperature ({T}{{exc}}), plasma potential ({V}{{p}}), skin depth (δ ) and the evolution of the electron energy probability function (EEPF) are reported as a function of radiofrequency (RF) power, pressure and argon concentration in the mixture. It is observed that {n}{{e}} increases while {T}{{e}} decreases with increase in RF power and argon concentration in the mixture. The emission intensity of the argon line at 750.4 nm is also used to monitor the variation of the ‘high-energy tail’ of the EEPF with RF power and gas pressure. The EEPF has a ‘bi-Maxwellian’ distribution at low RF powers and higher pressure in a pure {{{N}}}2 discharge. However, it evolves into a ‘Maxwellian’ distribution at RF powers greater than 70 W for pure {{{N}}}2, and at 50 W for higher argon concentrations in the mixture. The effect of argon concentration on the temperatures of two electron groups in the ‘bi-Maxwellian’ EEPF is examined. The temperature of the low-energy electron group {T}{{L}} shows a decreasing trend with argon addition until the ‘thermalization’ of the two temperatures occurs, while the temperature of high-energy electrons {T}{{H}} decreases continuously.

  15. A compact tunable polarized X-ray source based on laser-plasma helical undulators

    CERN Document Server

    Luo, Ji; Zeng, Ming; Vieira, Jorge; Yu, Lu-Le; Weng, Su-Ming; Silva, Luis O; Jaroszynski, Dino A; Sheng, Zheng-Ming; Zhang, Jie

    2016-01-01

    Laser wakefield accelerators have great potential as the basis for next generation compact radiation sources because their accelerating gradients are three orders of magnitude larger than traditional accelerators. However, X-ray radiation from such devices still lacks of tunability, especially the intensity and polarization distribution. Here we propose a tunable polarized radiation source from a helical plasma undulator based on plasma channel guided wakefield accelerator. When a laser pulse is initially incident with a skew angle relative to the channel axis, the laser and accelerated electrons experience collective spiral motions, which leads to elliptically polarized synchrotron-like radiation with flexible tunability on radiation intensity, spectra and polarization. We demonstrate that a radiation source with millimeter size and peak brilliance of $2\\times10^{19} photons/s/mm^{2}/mrad^{2}/0.1%$ bandwidth can be made with moderate laser and electron beam parameters. This brilliance is comparable with the ...

  16. Non-thermal plasma mills bacteria: Scanning electron microscopy observations

    Energy Technology Data Exchange (ETDEWEB)

    Lunov, O., E-mail: lunov@fzu.cz; Churpita, O.; Zablotskii, V.; Jäger, A.; Dejneka, A. [Institute of Physics AS CR, Prague 18221 (Czech Republic); Deyneka, I. G.; Meshkovskii, I. K. [St. Petersburg State University of Information Technologies, Mechanics and Optics, St. Petersburg 197101 (Russian Federation); Syková, E. [Institute of Experimental Medicine AS CR, Prague 14220 (Czech Republic); Kubinová, Š. [Institute of Physics AS CR, Prague 18221 (Czech Republic); Institute of Experimental Medicine AS CR, Prague 14220 (Czech Republic)

    2015-02-02

    Non-thermal plasmas hold great promise for a variety of biomedical applications. To ensure safe clinical application of plasma, a rigorous analysis of plasma-induced effects on cell functions is required. Yet mechanisms of bacteria deactivation by non-thermal plasma remain largely unknown. We therefore analyzed the influence of low-temperature atmospheric plasma on Gram-positive and Gram-negative bacteria. Using scanning electron microscopy, we demonstrate that both Gram-positive and Gram-negative bacteria strains in a minute were completely destroyed by helium plasma. In contrast, mesenchymal stem cells (MSCs) were not affected by the same treatment. Furthermore, histopathological analysis of hematoxylin and eosin–stained rat skin sections from plasma–treated animals did not reveal any abnormalities in comparison to control ones. We discuss possible physical mechanisms leading to the shred of bacteria under non-thermal plasma irradiation. Our findings disclose how helium plasma destroys bacteria and demonstrates the safe use of plasma treatment for MSCs and skin cells, highlighting the favorability of plasma applications for chronic wound therapy.

  17. Laser-driven electron beam and radiation sources for basic, medical and industrial sciences.

    Science.gov (United States)

    Nakajima, Kazuhisa

    2015-01-01

    To date active research on laser-driven plasma-based accelerators have achieved great progress on production of high-energy, high-quality electron and photon beams in a compact scale. Such laser plasma accelerators have been envisaged bringing a wide range of applications in basic, medical and industrial sciences. Here inheriting the groundbreaker's review article on "Laser Acceleration and its future" [Toshiki Tajima, (2010)],(1)) we would like to review recent progress of producing such electron beams due to relativistic laser-plasma interactions followed by laser wakefield acceleration and lead to the scaling formulas that are useful to design laser plasma accelerators with controllability of beam energy and charge. Lastly specific examples of such laser-driven electron/photon beam sources are illustrated.

  18. Energy distributions of electrons in electron beam produced nitrogen plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Suhre, D.R.

    1976-01-01

    A theory was developed which predicts the equilibrium electron energy distributions resulting from the injection of an electron beam into molecular nitrogen. The results were highly non-Maxwellian with a depletion region existing near 2.5 eV. Using these distributions, fractional power transfers to various excitation processes were calculated. The theory was verified experimentally by using Langmuir probes to measure the electron energy distributions produced by a beam generated by a cold cathode discharge in low pressure nitrogen. The distributions were measured in absolute units and compared directly with theory. All of the major features of the theory were found to be present in the measurements.

  19. Plasma ion sources and ion beam technology inmicrofabrications

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Lili [Univ. of California, Berkeley, CA (United States)

    2007-01-01

    For over decades, focused ion beam (FIB) has been playing a very important role in microscale technology and research, among which, semiconductor microfabrication is one of its biggest application area. As the dimensions of IC devices are scaled down, it has shown the need for new ion beam tools and new approaches to the fabrication of small-scale devices. In the meanwhile, nanotechnology has also deeply involved in material science research and bioresearch in recent years. The conventional FIB systems which utilize liquid gallium ion sources to achieve nanometer scale resolution can no longer meet the various requirements raised from such a wide application area such as low contamination, high throughput and so on. The drive towards controlling materials properties at nanometer length scales relies on the availability of efficient tools. In this thesis, three novel ion beam tools have been developed and investigated as the alternatives for the conventional FIB systems in some particular applications. An integrated focused ion beam (FIB) and scanning electron microscope (SEM) system has been developed for direct doping or surface modification. This new instrument employs a mini-RF driven plasma source to generate focused ion beam with various ion species, a FEI two-lens electron (2LE) column for SEM imaging, and a five-axis manipulator system for sample positioning. An all-electrostatic two-lens column has been designed to focus the ion beam extracted from the source. Based on the Munro ion optics simulation, beam spot sizes as small as 100 nm can be achieved at beam energies between 5 to 35 keV if a 5 μm-diameter extraction aperture is used. Smaller beam spot sizes can be obtained with smaller apertures at sacrifice of some beam current. The FEI 2LE column, which utilizes Schottky emission, electrostatic focusing optics, and stacked-disk column construction, can provide high-resolution (as small as 20 nm) imaging capability, with fairly long working distance (25

  20. 21 CFR 640.64 - Collection of blood for Source Plasma.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Collection of blood for Source Plasma. 640.64... (CONTINUED) BIOLOGICS ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.64 Collection of blood for Source Plasma. (a) Supervision. All blood for the collection of Source Plasma shall...

  1. Auroral electron distributions within and close to the Saturn kilometric radiation source region

    Science.gov (United States)

    Schippers, P.; Arridge, C. S.; Menietti, J. D.; Gurnett, D. A.; Lamy, L.; Cecconi, B.; Mitchell, D. G.; André, N.; Kurth, W. S.; Grimald, S.; Dougherty, M. K.; Coates, A. J.; Krupp, N.; Young, D. T.

    2011-05-01

    On 17 October 2008, Cassini observed for the first time the electron populations associated with the crossing of a Saturn kilometric radiation source region and its surroundings. These observations allow for the first time the constraint and quantification of the high-latitude acceleration processes, the current systems, and the origin of the low-frequency electromagnetic waves. Enhanced fluxes of field-aligned energetic electrons were measured by the Cassini electron plasma spectrometer in conjunction with unusual intense field-aligned current systems identified using the magnetometer instrument. In the region where downward field-aligned currents were measured, electron data show evidence of two types of upward accelerated electron beams: a broadband energetic (1-100 keV) electron population that is observed throughout the region and a narrow-banded (0.1-1 keV) electron population that is observed sporadically. In the regions where the magnetic field signatures showed evidence for upward field-aligned currents, we observe electron loss cone distributions and some evidence of shell-like distributions. Such nonthermal electron populations are commonly known as a potential free energy source to drive plasma instabilities. In the downward current region, the low-energy and energetic beams are likely the source of the very low frequency emissions. In the upward current region, the shell distribution is identified as a potential source for Saturn kilometric radiation generation via the cyclotron maser instability.

  2. Counter-facing plasma guns for efficient extreme ultra-violet plasma light source

    Directory of Open Access Journals (Sweden)

    Kuroda Yusuke

    2013-11-01

    Full Text Available A plasma focus system composed of a pair of counter-facing coaxial guns was proposed as a long-pulse and/or repetitive high energy density plasma source. We applied Li as the source of plasma for improvement of the conversion efficiency, the spectral purity, and the repetition capability. For operation of the system with ideal counter-facing plasma focus mode, we changed the system from simple coaxial geometry to a multi-channel configuration. We applied a laser trigger to make synchronous multi-channel discharges with low jitter. The results indicated that the configuration is promising to make a high energy density plasma with high spectral efficiency.

  3. Kinetic simulation of the electron-cyclotron maser instability: effect of a finite source size

    CERN Document Server

    Kuznetsov, A A

    2012-01-01

    The electron-cyclotron maser instability is widespread in the Universe, producing, e.g., radio emission of the magnetized planets and cool substellar objects. Diagnosing the parameters of astrophysical radio sources requires comprehensive nonlinear simulations of the radiation process. We simulate the electron-cyclotron maser instability in a very low-beta plasma. The model used takes into account the radiation escape from the source region and the particle flow through this region. We developed a kinetic code to simulate the time evolution of an electron distribution in a radio emission source. The model includes the terms describing the particle injection to and escape from the emission source region. The spatial escape of the emission from the source is taken into account by using a finite amplification time. The unstable electron distribution of the horseshoe type is considered. A number of simulations were performed for different parameter sets typical of the magnetospheres of planets and ultracool dwarf...

  4. Electron acceleration in preformed plasma channels with terawatt CO{sub 2} laser

    Energy Technology Data Exchange (ETDEWEB)

    Pogorelsky, I.V.

    1995-02-01

    Extended cylindrical plasma channels produced under gas breakdown by axicon-focused laser beams may be used as optical waveguides in laser-driven electron accelerators. Plasma channeling of the laser beams will help to maintain a high acceleration gradient over many Rayleigh lengths. In addition, the rarefied gas density channel produced after the optical gas breakdown, and followed by a plasma column expansion, reduces multiple scattering of the electron beam. A high-power picosecond C0{sub 2}laser operational at the ATF and being further upgraded to the 1 TW level is considered as the source for a plasma channel formation and as the laser accelerator driver. We show how various laser accelerator schemes including beat wave, wake field, and Inverse Cherenkov accelerator benefit from using a channeled short-pulse C0{sub 2}laser as a driver.

  5. Separation of finite electron temperature effect on plasma polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Imazawa, Ryota; Kawano, Yasunori; Kusama, Yoshinori [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki (Japan)

    2012-12-15

    This study demonstrates the separation of the finite electron temperature on the plasma polarimetry in the magnetic confined fusion plasma for the first time. Approximate solutions of the transformed Stokes equation, including the relativistic effect, suggest that the orientation angle, {theta}, and ellipticity angle, {epsilon}, of polarization state have different dependency on the electron density, n{sub e}, and the electron temperature, T{sub e}, and that the separation of n{sub e} and T{sub e} from {theta} and {epsilon} is possible in principle. We carry out the equilibrium and kinetic reconstruction of tokamak plasma when the central electron density was 10{sup 20} m{sup -3}, and the central electron temperatures were 5, 10, 20, and 30 keV. For both cases when a total plasma current, I{sub p}, is known and when I{sub p} is unknown, the profiles of plasma current density, j{sub {phi}}, n{sub e}, and T{sub e} are successfully reconstructed. The reconstruction of j{sub {phi}} without the information of I{sub p} indicates the new method of I{sub p} measurement applicable to steady state operation of tokamak.

  6. Separation of finite electron temperature effect on plasma polarimetry.

    Science.gov (United States)

    Imazawa, Ryota; Kawano, Yasunori; Kusama, Yoshinori

    2012-12-01

    This study demonstrates the separation of the finite electron temperature on the plasma polarimetry in the magnetic confined fusion plasma for the first time. Approximate solutions of the transformed Stokes equation, including the relativistic effect, suggest that the orientation angle, θ, and ellipticity angle, ε, of polarization state have different dependency on the electron density, n(e), and the electron temperature, T(e), and that the separation of n(e) and T(e) from θ and ε is possible in principle. We carry out the equilibrium and kinetic reconstruction of tokamak plasma when the central electron density was 10(20) m(-3), and the central electron temperatures were 5, 10, 20, and 30 keV. For both cases when a total plasma current, I(p), is known and when I(p) is unknown, the profiles of plasma current density, j(φ), n(e), and T(e) are successfully reconstructed. The reconstruction of j(φ) without the information of I(p) indicates the new method of I(p) measurement applicable to steady state operation of tokamak.

  7. A Mirror-like ECR Plasma Source for Ionosphere Environment Simulator

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A compact mirror-like ECR (electron cyclotron resonance) plasma source for the ionosphere environment simulator was described for the first time in China. The overall sources system was composed of a 200 W 2.45 GHz microwave source, a coaxial 3λo/4 TEM-mode microwave resonance applicator, column and cylindrical Nd-Fe-P magnets, a quartz bell-shaped discharge chamber, a gas inlet system and a plasma-diffusing bore. The preliminary experiment demonstrated that ambi-polar diffusion plasma stream into the simulator (~500 mm long) formed an environment with following parameters: a plasma density ne of 104 cm-3 ~ 106cm-3, an electron temperature Te < 5 eV at a pressure P of 10-1 Pa~10-3 Pa, a plasma uniformity of > 80% over the experimental target with a 160-mm-in-diameter, satisfying primarily the requirement of simulating in a severe ionosphere environment.

  8. L-shell spectroscopic diagnostics of radiation from krypton HED plasma sources

    Science.gov (United States)

    Petkov, E. E.; Safronova, A. S.; Kantsyrev, V. L.; Shlyaptseva, V. V.; Rawat, R. S.; Tan, K. S.; Beiersdorfer, P.; Hell, N.; Brown, G. V.

    2016-11-01

    X-ray spectroscopy is a useful tool for diagnosing plasma sources due to its non-invasive nature. One such source is the dense plasma focus (DPF). Recent interest has developed to demonstrate its potential application as a soft x-ray source. We present the first spectroscopic studies of krypton high energy density plasmas produced on a 3 kJ DPF device in Singapore. In order to diagnose spectral features, and to obtain a more comprehensive understanding of plasma parameters, a new non-local thermodynamic equilibrium L-shell kinetic model for krypton was developed. It has the capability of incorporating hot electrons, with different electron distribution functions, in order to examine the effects that they have on emission spectra. To further substantiate the validity of this model, it is also benchmarked with data gathered from experiments on the electron beam ion trap (EBIT) at Lawrence Livermore National Laboratory, where data were collected using the high resolution EBIT calorimeter spectrometer.

  9. L-shell spectroscopic diagnostics of radiation from krypton HED plasma sources

    Energy Technology Data Exchange (ETDEWEB)

    Petkov, E. E., E-mail: emilp@unr.edu; Safronova, A. S.; Kantsyrev, V. L.; Shlyaptseva, V. V. [University of Nevada, Reno, Nevada 89557 (United States); Rawat, R. S.; Tan, K. S. [National Institute of Education, Nanyang Technological University, Singapore 637616 (Singapore); Beiersdorfer, P.; Brown, G. V. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Hell, N. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Dr. Remeis-Sternwarte and ECAP, Universität Erlangen-Nürnberg, 96049 Bamberg (Germany)

    2016-11-15

    X-ray spectroscopy is a useful tool for diagnosing plasma sources due to its non-invasive nature. One such source is the dense plasma focus (DPF). Recent interest has developed to demonstrate its potential application as a soft x-ray source. We present the first spectroscopic studies of krypton high energy density plasmas produced on a 3 kJ DPF device in Singapore. In order to diagnose spectral features, and to obtain a more comprehensive understanding of plasma parameters, a new non-local thermodynamic equilibrium L-shell kinetic model for krypton was developed. It has the capability of incorporating hot electrons, with different electron distribution functions, in order to examine the effects that they have on emission spectra. To further substantiate the validity of this model, it is also benchmarked with data gathered from experiments on the electron beam ion trap (EBIT) at Lawrence Livermore National Laboratory, where data were collected using the high resolution EBIT calorimeter spectrometer.

  10. Self-effect in expanding electron beam plasma

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, M

    1999-05-07

    An analytical model of plasma flow from a metal plate hit by an intense, pulsed, electron beam aims to bridge the gap between radiation-hydrodynamics simulations and experiments, and to quantify the self-effect of the electron beam penetrating the flow. Does the flow disrupt the tight focus of the initial electron bunch, or later pulses in a train? This work aims to model the spatial distribution of plasma speed, density, degree of ionization, and magnetization to inquire. The initial solid density, several eV plasma expands to 1 cm and 10{sup {minus}4} relative density by 2 {micro}s, beyond which numerical simulations are imprecise. Yet, a Faraday cup detector at the ETA-II facility is at 25 cm from the target and observes the flow after 50 {micro}s. The model helps bridge this gap. The expansion of the target plasma into vacuum is so rapid that the ionized portion of the flow departs from local thermodynamic equilibrium. When the temperature (in eV) in a parcel of fluid drops below V{sub i} x [(2{gamma} - 2)/(5{gamma} + 17)], where V{sub i} is the ionization potential of the target metal (7.8 eV for tantalum), and {gamma} is the ratio of specific heats (5/3 for atoms), then the fractional ionization and electron temperature in that parcel remain fixed during subsequent expansion. The freezing temperature as defined here is V{sub i}/19. The balance between the self-pinching force and the space charge repulsion of an electron beam changes on penetrating a flow: (i) the target plasma cancels the space-charge field, (ii) internal eddy currents arise to counter the magnetization of relativistic electrons, and (iii) electron beam heating alters the flow magnetization by changing the plasma density gradient and the magnitude of the conductivity.

  11. Comparison of Plasma Activation of Thin Water Layers by Direct and Remote Plasma Sources

    Science.gov (United States)

    Kushner, Mark

    2014-10-01

    Plasma activation of liquids is now being investigated for a variety of biomedical applications. The plasma sources used for this activation can be generally classified as direct (the plasma is in contact with the surface of the liquid) or remote (the plasma does not directly touch the liquid). The direct plasma source may be a dielectric barrier discharge (DBD) where the surface of the liquid is a floating electrode or a plasma jet in which the ionization wave forming the plasma plume reaches the liquid. The remote plasma source may be a DBD with electrodes electrically isolated from the liquid or a plasma jet in which the ionization wave in the plume does not reach the liquid. In this paper, a comparison of activation of thin water layers on top of tissue, as might be encountered in wound healing, will be discussed using results from numerical investigations. We used the modeling platform nonPDPSIM to simulate direct plasma activation of thin water layers using DBDs and remote activation using plasma jets using up to hundreds of pulses. The DBDs are sustained in humid air while the plasma jets consist of He/O2 mixtures flowed into humid air. For similar number of pulses and energy deposition, the direct DBD plasma sources produce more acidification and higher production of nitrates/nitrites in the liquid. This is due to the accumulation of NxOy plasma jets, the convective flow removes many of these species prior to their diffusing into the water or reacting to form higher nitrogen oxides. This latter effect is sensitive to the repetition rate which determines whether reactive species formed during prior pulses overlap with newly produced reactive species. in the gas phase. In the plasma jets, the convective flow removes many of these species prior to their diffusing into the water or reacting to form higher nitrogen oxides. This latter effect is sensitive to the repetition rate which determines whether reactive species formed during prior pulses overlap with

  12. Parametric study of transport beam lines for electron beams accelerated by laser-plasma interaction

    Science.gov (United States)

    Scisciò, M.; Lancia, L.; Migliorati, M.; Mostacci, A.; Palumbo, L.; Papaphilippou, Y.; Antici, P.

    2016-03-01

    In the last decade, laser-plasma acceleration of high-energy electrons has attracted strong attention in different fields. Electrons with maximum energies in the GeV range can be laser-accelerated within a few cm using multi-hundreds terawatt (TW) lasers, yielding to very high beam currents at the source (electron bunches with up to tens-hundreds of pC in a few fs). While initially the challenge was to increase the maximum achievable electron energy, today strong effort is put in the control and usability of these laser-generated beams that still lack of some features in order to be used for applications where currently conventional, radio-frequency (RF) based, electron beam lines represent the most common and efficient solution. Several improvements have been suggested for this purpose, some of them acting directly on the plasma source, some using beam shaping tools located downstream. Concerning the latter, several studies have suggested the use of conventional accelerator magnetic devices (such as quadrupoles and solenoids) as an easy implementable solution when the laser-plasma accelerated beam requires optimization. In this paper, we report on a parametric study related to the transport of electron beams accelerated by laser-plasma interaction, using conventional accelerator elements and tools. We focus on both, high energy electron beams in the GeV range, as produced on petawatt (PW) class laser systems, and on lower energy electron beams in the hundreds of MeV range, as nowadays routinely obtained on commercially available multi-hundred TW laser systems. For both scenarios, our study allows understanding what are the crucial parameters that enable laser-plasma accelerators to compete with conventional ones and allow for a beam transport. We show that suitable working points require a tradeoff-combination between low beam divergence and narrow energy spread.

  13. Parametric study of transport beam lines for electron beams accelerated by laser-plasma interaction

    Energy Technology Data Exchange (ETDEWEB)

    Scisciò, M.; Antici, P., E-mail: patrizio.antici@polytechnique.edu [INFN-RM1 and SBAI, Università di Roma “La Sapienza,” Via Scarpa 16, 00161 Roma (Italy); INRS-EMT, Université du Québec, 1650 Lionel Boulet, Varennes, Québec J3X 1S2 (Canada); Lancia, L.; Migliorati, M.; Mostacci, A.; Palumbo, L. [INFN-RM1 and SBAI, Università di Roma “La Sapienza,” Via Scarpa 16, 00161 Roma (Italy); Papaphilippou, Y. [CERN, CH 1211 Geneva 23 (Switzerland)

    2016-03-07

    In the last decade, laser-plasma acceleration of high-energy electrons has attracted strong attention in different fields. Electrons with maximum energies in the GeV range can be laser-accelerated within a few cm using multi-hundreds terawatt (TW) lasers, yielding to very high beam currents at the source (electron bunches with up to tens-hundreds of pC in a few fs). While initially the challenge was to increase the maximum achievable electron energy, today strong effort is put in the control and usability of these laser-generated beams that still lack of some features in order to be used for applications where currently conventional, radio-frequency (RF) based, electron beam lines represent the most common and efficient solution. Several improvements have been suggested for this purpose, some of them acting directly on the plasma source, some using beam shaping tools located downstream. Concerning the latter, several studies have suggested the use of conventional accelerator magnetic devices (such as quadrupoles and solenoids) as an easy implementable solution when the laser-plasma accelerated beam requires optimization. In this paper, we report on a parametric study related to the transport of electron beams accelerated by laser-plasma interaction, using conventional accelerator elements and tools. We focus on both, high energy electron beams in the GeV range, as produced on petawatt (PW) class laser systems, and on lower energy electron beams in the hundreds of MeV range, as nowadays routinely obtained on commercially available multi-hundred TW laser systems. For both scenarios, our study allows understanding what are the crucial parameters that enable laser-plasma accelerators to compete with conventional ones and allow for a beam transport. We show that suitable working points require a tradeoff-combination between low beam divergence and narrow energy spread.

  14. Femtosecond probing of light-speed plasma wakefields by using a relativistic electron bunch

    CERN Document Server

    Zhang, C J; Wan, Y; Guo, B; Wu, Y P; Pai, C -H; Li, F; Chu, H -H; Gu, Y Q; Xu, X L; Mori, W B; Joshi, C; Wang, J; Lu, W

    2016-01-01

    Relativistic wakes produced by intense laser or particle beams propagating through plasmas are being considered as accelerators for next generation of colliders and coherent light sources. Such wakes have been shown to accelerate electrons and positrons to several gigaelectronvolts (GeV), with a few percent energy spread and a high wake-to-beam energy transfer efficiency. However, complete mapping of electric field structure of the wakes has proven elusive. Here we show that a high-energy electron bunch can be used to probe the fields of such light-speed wakes with femtosecond resolution. The highly transient, microscopic wakefield is reconstructed from the density modulated ultra-short probe bunch after it has traversed the wake. This technique enables visualization of linear wakefields in low-density plasmas that can accelerate electrons and positrons beams. It also allows characterization of wakes in plasma density ramps critical for maintaining the beam emittance, improving the energy transfer efficiency ...

  15. Electron vortex magnetic holes: a nonlinear coherent plasma structure

    CERN Document Server

    Haynes, Christopher T; Camporeale, Enrico; Sundberg, Torbjorn

    2014-01-01

    We report the properties of a novel type of sub-proton scale magnetic hole found in two dimensional PIC simulations of decaying turbulence with a guide field. The simulations were performed with a realistic value for ion to electron mass ratio. These structures, electron vortex magnetic holes (EVMHs), have circular cross-section. The magnetic field depression is associated with a diamagnetic azimuthal current provided by a population of trapped electrons in petal-like orbits. The trapped electron population provides a mean azimuthal velocity and since trapping preferentially selects high pitch angles, a perpendicular temperature anisotropy. The structures arise out of initial perturbations in the course of the turbulent evolution of the plasma, and are stable over at least 100 electron gyroperiods. We have verified the model for the EVMH by carrying out test particle and PIC simulations of isolated structures in a uniform plasma. It is found that (quasi-)stable structures can be formed provided that there is ...

  16. On the effect of runaway electrons in dense plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ramazanov, T.S.; Turekhanova, K.M. [IETP, Al Farabi Kazakh National University, Tole Bi 96, 480012 Almaty (Kazakhstan)

    2003-10-01

    The effect of runaway electrons has been studied in this work. There were derived the conditions runaway electrons, the influence of electric field on the electron velocity distribution is considered for nonideal classical plasma models. The dependence of friction force on electrons on their velocities,electron-ion collision frequency as a function of the coupling parameter and the strength of critical electric field on particle density and temperature are determined. The results are compared with the asymptotic theory. It has been shown that for the definite density and temperature ranges the difference between critical electric field values is essential for various plasma models. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Generation of attosecond electron bunches in a laser-plasma accelerator using a plasma density upramp

    Energy Technology Data Exchange (ETDEWEB)

    Weikum, M.K., E-mail: maria.weikum@desy.de [Deutsches Elektronensynchrotron (DESY), Bdg. 30b, Notkestr. 85, 22607 Hamburg (Germany); Department of Physics, University of Strathclyde, G4 0NG Glasgow (United Kingdom); Li, F.Y. [Department of Physics, University of Strathclyde, G4 0NG Glasgow (United Kingdom); Assmann, R.W. [Deutsches Elektronensynchrotron (DESY), Bdg. 30b, Notkestr. 85, 22607 Hamburg (Germany); Sheng, Z.M. [Department of Physics, University of Strathclyde, G4 0NG Glasgow (United Kingdom); Laboratory for Laser Plasmas and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Jaroszynski, D. [Department of Physics, University of Strathclyde, G4 0NG Glasgow (United Kingdom)

    2016-09-01

    Attosecond electron bunches and attosecond radiation pulses enable the study of ultrafast dynamics of matter in an unprecedented regime. In this paper, the suitability for the experimental realization of a novel scheme producing sub-femtosecond duration electron bunches from laser-wakefield acceleration in plasma with self-injection in a plasma upramp profile has been investigated. While it has previously been predicted that this requires laser power above a few hundred terawatts typically, here we show that the scheme can be extended with reduced driving laser powers down to tens of terawatts, generating accelerated electron pulses with minimum length of around 166 attoseconds and picocoulombs charge. Using particle-in-cell simulations and theoretical models, the evolution of the accelerated electron bunch within the plasma as well as simple scalings of the bunch properties with initial laser and plasma parameters are presented. - Highlights: • LWFA with an upramp density profile can trap and accelerate sub-fs electron beams. • A reduction of the necessary threshold laser intensity by a factor 4 is presented. • Electron properties are tuned by varying initial laser and plasma parameters. • Simulations predict electron bunch lengths below 200 attoseconds with pC charge. • Strong bunch evolution effects and a large energy spread still need to be improved.

  18. Assistant Anode in a Cathodic Arc Plasma Source

    Institute of Scientific and Technical Information of China (English)

    张涛; Paul K. Chu; 张荟星; Ian G. Brown

    2001-01-01

    The performance and characteristics of a cathodic arc plasma source, consisting of a titanium cathode, an anode with and without a tungsten mesh, and a coil producing a focusing magnetic field between the anode and cathode,are investigated. The high transparency and large area of the mesh allow a high plasma flux to penetrate the anode from the cathodic arc. The mesh helps to decrease the arc resistance and the ignition voltage of the cathodic arc in the focusing magnetic field, and to increase the life of the source, which means that the source makes the cathodic arc easily and greatly stabilized during the operation when a focusing magnetic field exists in the source.

  19. Dense plasma focus (DPF) accelerated non radio isotopic radiological source

    Energy Technology Data Exchange (ETDEWEB)

    Rusnak, Brian; Tang, Vincent

    2017-01-31

    A non-radio-isotopic radiological source using a dense plasma focus (DPF) to produce an intense z-pinch plasma from a gas, such as helium, and which accelerates charged particles, such as generated from the gas or injected from an external source, into a target positioned along an acceleration axis and of a type known to emit ionizing radiation when impinged by the type of accelerated charged particles. In a preferred embodiment, helium gas is used to produce a DPF-accelerated He2+ ion beam to a beryllium target, to produce neutron emission having a similar energy spectrum as a radio-isotopic AmBe neutron source. Furthermore, multiple DPFs may be stacked to provide staged acceleration of charged particles for enhancing energy, tunability, and control of the source.

  20. Computer Model for Electrode Plasma Generation by Electron and Ion Flows

    Science.gov (United States)

    Ryzhov, Victor V.; Bespalov, Valeri I.; Kirikov, Alexander V.; Turchanovskii, Igor. Yu.; Tarakanov, Vladimir P.

    2002-12-01

    A model is proposed for computer simulation of the electrode plasma generation by electron and ion flows. The distribution of the absorbed energy of particles in the electrode material is calculated by the Monte-Carlo codes. This provides a possibility to control the electrode temperature by solving the heat conductivity equation for specified distributions of thermal sources and to calculate the rate of plasma generation. The behavior of the plasma in the gap can be modeled based on simple model where the velocity, the density, and the temperature of the plasma can be given by some dependence. Within the framework of the model proposed, numerical study is performed on the effect of the plasma flows in Rod Pinch Diodes and in the Insulator Stack of the Z-accelerator.

  1. VUV diagnostic of electron impact processes in low temperature molecular hydrogen plasma

    CERN Document Server

    Komppula, J

    2015-01-01

    Novel methods for diagnostics of molecular hydrogen plasma processes, such as ionization, production of high vibrational levels, dissociation of molecules via excitation to singlet and triplet states and production of metastable states, are presented for molecular hydrogen plasmas in corona equilibrium. The methods are based on comparison of rate coefficients of plasma processes and optical emission spectroscopy of lowest singlet and triplet transitions, i.e. Lyman-band ($B^1\\Sigma^+_u \\rightarrow X^1\\Sigma^+_g$) and molecular continuum ($a^3\\Sigma^+_g \\rightarrow b^3\\Sigma^+_u$), of the hydrogen molecule in VUV wavelength range. Comparison of rate coefficients of spin-allowed and/or spin-forbidden excitations reduces the uncertainty caused by the non-equilibrium distributions of electron energy and molecular vibrational level, which are typically known poorly in plasma sources. The described methods are applied to estimate the rates of various plasma processes in a filament arc discharge.

  2. Relativistic effects on the modulational instability of electron plasma waves in quantum plasma

    Indian Academy of Sciences (India)

    Basudev Ghosh; Swarniv Chandra; Sailendra Nath Paul

    2012-05-01

    Relativistic effects on the linear and nonlinear properties of electron plasma waves are investigated using the one-dimensional quantum hydrodynamic (QHD) model for a twocomponent electron–ion dense quantum plasma. Using standard perturbation technique, a nonlinear Schrödinger equation (NLSE) containing both relativistic and quantum effects has been derived. This equation has been used to discuss the modulational instability of the wave. Through numerical calculations it is shown that relativistic effects significantly change the linear dispersion character of the wave. Unlike quantum effects, relativistic effects are shown to reduce the instability growth rate of electron plasma waves.

  3. Electron plasma wave filamentation in the kinetic regime

    Science.gov (United States)

    Lushnikov, Pavel; Rose, Harvey; Silantyev, Denis

    2016-10-01

    We consider nonlinear electron plasma wave (EPW) dynamics in the kinetic wavenumber regime, 0.25 Bernstein-Greene-Kruskal (BGK) mode. Transverse perturbations of any of these initial conditions grow with time eventually producing strongly nonlinear filamentation followed by plasma turbulence. We compared these simulations with the theoretical results on growth rates of the transverse instability BGK mode showing the satisfactory agreement. Supported by the New Mexico Consortium and NSF DMS-1412140.

  4. Electron cyclotron plasma startup in the GDT experiment

    Science.gov (United States)

    Yakovlev, D. V.; Shalashov, A. G.; Gospodchikov, E. D.; Solomakhin, A. L.; Savkin, V. Ya.; Bagryansky, P. A.

    2017-01-01

    We report on a new plasma startup scenario in the gas dynamic trap (GDT) magnetic mirror device. The primary 5 MW neutral beam injection (NBI) plasma heating system fires into a sufficiently dense plasma target (‘seed plasma’), which is commonly supplied by an arc plasma generator. In the reported experiments, a different approach to seed plasma generation is explored. One of the channels of the electron cyclotron resonance (ECR) heating system is used to ionize the neutral gas and build up the density of plasma to a level suitable for NBI capture. After a short transition of approximately 1 ms the discharge becomes essentially similar to a standard one initiated by the plasma gun. This paper presents the discharge scenario and experimental data on the seed plasma evolution during ECRH, along with the dependencies on incident microwave power, magnetic configuration and pressure of a neutral gas. The characteristics of the consequent high-power NBI discharge are studied and differences from the conventional scenario are discussed. A theoretical model describing the ECR breakdown and the seed plasma accumulation in a large-scale mirror trap is developed on the basis of the GDT experiment.

  5. Electron-cyclotron plasma startup in the GDT experiment

    CERN Document Server

    Yakovlev, D V; Gospodchikov, E D; Solomakhin, A L; Savkin, V Ya; Bagryansky, P A

    2016-01-01

    The paper reports on a new plasma startup scenario in the Gas Dynamic Trap (GDT) magnetic mirror device. The primary 5 MW neutral beam injection (NBI) plasma heating system fires into a sufficiently dense plasma target ("seed plasma"), which is commonly supplied by an arc plasma generator. In the reported experiments, a different approach to seed plasma generation is explored. One of the channels of the electron cyclotron resonance (ECR) heating system is used to ionize the neutral gas and build up the density of plasma to a level suitable for NBI capture. After a short transition (about 1 ms) the discharge becomes essentially similar to a standard one initiated by the plasma gun. The paper presents the discharge scenario and experimental data on the seed plasma evolution during ECR heating, along with the dependencies on incident microwave power, magnetic configuration and pressure of a neutral gas. The characteristics of consequent high-power NBI discharge are studied and differences to the conventional sce...

  6. A low-energy linear oxygen plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre; Yushkov, Georgy Yu.

    2007-01-08

    A new version of a Constricted Plasma Source is described,characterized by all metal-ceramic construction, a linear slit exit of180 mm length, and cw-operation (typically 50 kHz) at an average power of1.5 kW. The plasma source is here operated with oxygen gas, producingstreaming plasma that contains mainly positive molecular and atomic ions,and to a much lesser degree, negative ions. The maximum total ion currentobtained was about 0.5 A. The fraction of atomic ions reached more than10 percent of all ions when the flow rate was less then 10 sccm O2,corresponding to a chamber pressure of about 0.5 Pa for the selectedpumping speed. The energy distribution functions of the different ionspecies were measured with a combinedmass spectrometer and energyanalyzer. The time-averaged distribution functions were broad and rangedfrom about 30eV to 90 eV at 200 kHz and higher frequencies, while theywere only several eV broad at 50 kHz and lower frequencies, with themaximum located at about 40 eV for the grounded anode case. This maximumwas shifted down to about 7 eV when the anode was floating, indicatingthe important role of the plasma potential for the ion energy for a givensubstrate potential. The source could be scaled to greater length and maybe useful for functionalization of surfaces and plasma-assisteddeposition of compound films.

  7. Characteristics of surface sterilization using electron cyclotron resonance plasma

    Science.gov (United States)

    Yonesu, Akira; Hara, Kazufumi; Nishikawa, Tatsuya; Hayashi, Nobuya

    2016-07-01

    The characteristics of surface sterilization using electron cyclotron resonance (ECR) plasma were investigated. High-energy electrons and oxygen radicals were observed in the ECR zone using electric probe and optical emission spectroscopic methods. A biological indicator (BI), Geobacillus stearothermophilus, containing 1 × 106 spores was sterilized in 120 s by exposure to oxygen discharges while maintaining a temperature of approximately 55 °C at the BI installation position. Oxygen radicals and high-energy electrons were found to be the sterilizing species in the ECR region. It was demonstrated that the ECR plasma could be produced in narrow tubes with an inner diameter of 5 mm. Moreover, sterilization tests confirmed that the spores present inside the narrow tube were successfully inactivated by ECR plasma irradiation.

  8. Ultra short electron beam bunches from a laser plasma cathode

    Energy Technology Data Exchange (ETDEWEB)

    Maekawa, Akira [Nuclear Professional School, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan)]. E-mail: maekawa@nuclear.jp; Tsujii, Ryosuke [Nuclear Professional School, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Kinoshita, Kennichi [Nuclear Professional School, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Atsushi, Yamazaki [Nuclear Professional School, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Kobayashi, Kazuyuki [Nuclear Professional School, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Uesaka, Mitsuru [Nuclear Professional School, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Shibata, Yukio [Nuclear Professional School, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Kondo, Yasuhiro [Nuclear Professional School, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Ohkubo, Takeru [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma (Japan); Hosokai, Tomonao [Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo (Japan); Zhidkov, Alexei [Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa (Japan); Takahashi, Toshiharu [Kyoto University Research Reactor Institute, Asahiro-nishi2, Kumatori, Sennan, Osaka (Japan)

    2007-08-15

    The fluctuation of the electron bunch duration due to energy spectrum instability in a laser plasma cathode has been examined. Previous experiments clearly proved that a laser plasma cathode can generate ultrashort electron bunches with a bunch duration of 130 fs (FWHM) and a geometrical emittance 0.07{pi} mm mrad. The effect of temporal elongation of electron bunches due to their energy spread is estimated and the results are in good agreement with previous experiments. It is also clarified that the instability of the energy spectrum not only leads to a fluctuation of the bunch shape but also to a time-of-flight jitter, affecting possible future applications of a laser plasma cathode.

  9. Magnetoacoustic solitons in dense astrophysical electron-positron-ion plasmas

    Science.gov (United States)

    Hussain, S.; Mahmood, S.; Mushtaq, A.

    2013-08-01

    Nonlinear magnetoacoustic waves in dense electron-positron-ion plasmas are investigated by using three fluid quantum magnetohydrodynamic model. The quantum mechanical effects of electrons and positrons are taken into account due to their Fermionic nature (to obey Fermi statistics) and quantum diffraction effects (Bohm diffusion term) in the model. The reductive perturbation method is employed to derive the Korteweg-de Vries (KdV) equation for low amplitude magnetoacoustic soliton in dense electron-positron-ion plasmas. It is found that positron concentration has significant impact on the phase velocity of magnetoacoustic wave and on the formation of single pulse nonlinear structure. The numerical results are also illustrated by taking into account the plasma parameters of the outside layers of white dwarfs and neutron stars/pulsars.

  10. Ion transport from plasma ion source at ISOLTRAP

    CERN Document Server

    Steinsberger, Timo Pascal

    2017-01-01

    In this report, my work as CERN Summer Student at the ISOLTRAP experiment at ISOLDE is described. A new plasma ion source used as oine source for calibration and implemented before my arrival was commissioned and transportation settings for the produced ions to the ion traps were found. The cyclotron frequencies of 40Ar and the xenon isotopes 129-132Xe were measured using time-of-flight and phase-imaging ion-cyclotron-resonance mass spectroscopy.

  11. VUV SOURCE FROM PULSED-LASER GENERATED PLASMA

    OpenAIRE

    Laporte, P.; Damany, N.; Damany, H.

    1987-01-01

    We describe a pulsed vacuum ultraviolet (VUV) source consisting of a plasma created by focusing a NdYAG laser beam into rare gases under moderate pressure, and we report on spectral and time properties of that source. Main features are : continuum emission in a large spectral range, with only few lines superimposed, good time characteristics of the pulses, stability, cleanliness, and relatively high repetition rate (20 Hz).

  12. Two-dimensional studies of relativistic electron beam plasma instabilities in an inhomogeneous plasma

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, Chandrasekhar; Das, Amita, E-mail: amita@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Patel, Kartik [Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2015-11-15

    Relativistic electron beam propagation in plasma is fraught with several micro instabilities like two stream, filamentation, etc., in plasma. This results in severe limitation of the electron transport through a plasma medium. Recently, however, there has been an experimental demonstration of improved transport of Mega Ampere of electron currents (generated by the interaction of intense laser with solid target) in a carbon nanotube structured solid target [G. Chatterjee et al., Phys. Rev. Lett. 108, 235005 (2012)]. This then suggests that the inhomogeneous plasma (created by the ionization of carbon nanotube structured target) helps in containing the growth of the beam plasma instabilities. This manuscript addresses this issue with the help of a detailed analytical study and 2-D Particle-In-Cell simulations. The study conclusively demonstrates that the growth rate of the dominant instability in the 2-D geometry decreases when the plasma density is chosen to be inhomogeneous, provided the scale length 1/k{sub s} of the inhomogeneous plasma is less than the typical plasma skin depth (c/ω{sub 0}) scale. At such small scale lengths channelization of currents is also observed in simulation.

  13. Modeling of plasma transport and negative ion extraction in a magnetized radio-frequency plasma source

    Science.gov (United States)

    Fubiani, G.; Garrigues, L.; Hagelaar, G.; Kohen, N.; Boeuf, J. P.

    2017-01-01

    Negative ion sources for fusion are high densities plasma sources in large discharge volumes. There are many challenges in the modeling of these sources, due to numerical constraints associated with the high plasma density, to the coupling between plasma and neutral transport and chemistry, the presence of a magnetic filter, and the extraction of negative ions. In this paper we present recent results concerning these different aspects. Emphasis is put on the modeling approach and on the methods and approximations. The models are not fully predictive and not complete as would be engineering codes but they are used to identify the basic principles and to better understand the physics of the negative ion sources.

  14. Evaluation of high-energy brachytherapy source electronic disequilibrium and dose from emitted electrons

    Energy Technology Data Exchange (ETDEWEB)

    Ballester, Facundo; Granero, Domingo; Perez-Calatayud, Jose; Melhus, Christopher S.; Rivard, Mark J. [Department of Atomic, Molecular and Nuclear Physics, University of Valencia, C/Dr. Moliner 50, E-46100 Burjassot (Spain) and IFIC, CSIC-University of Valencia, C/Dr. Moliner 50, E-46100 Burjassot (Spain); Department of Radiation Physics, ERESA, Hospital General Universitario, Avenida Tres Cruces, 2, E-46014 Valencia (Spain); Department of Radiation Oncology, La Fe University Hospital, Avenida Campanar 21, E-46009 Valencia (Spain); Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)

    2009-09-15

    Purpose: The region of electronic disequilibrium near photon-emitting brachytherapy sources of high-energy radionuclides ({sup 60}Co, {sup 137}Cs, {sup 192}Ir, and {sup 169}Yb) and contributions to total dose from emitted electrons were studied using the GEANT4 and PENELOPE Monte Carlo codes. Methods: Hypothetical sources with active and capsule materials mimicking those of actual sources but with spherical shape were examined. Dose contributions due to source photons, x rays, and bremsstrahlung; source {beta}{sup -}, Auger electrons, and internal conversion electrons; and water collisional kerma were scored. To determine if conclusions obtained for electronic equilibrium conditions and electron dose contribution to total dose for the representative spherical sources could be applied to actual sources, the {sup 192}Ir mHDR-v2 source model (Nucletron B.V., Veenendaal, The Netherlands) was simulated for comparison to spherical source results and to published data. Results: Electronic equilibrium within 1% is reached for {sup 60}Co, {sup 137}Cs, {sup 192}Ir, and {sup 169}Yb at distances greater than 7, 3.5, 2, and 1 mm from the source center, respectively, in agreement with other published studies. At 1 mm from the source center, the electron contributions to total dose are 1.9% and 9.4% for {sup 60}Co and {sup 192}Ir, respectively. Electron emissions become important (i.e., >0.5%) within 3.3 mm of {sup 60}Co and 1.7 mm of {sup 192}Ir sources, yet are negligible over all distances for {sup 137}Cs and {sup 169}Yb. Electronic equilibrium conditions along the transversal source axis for the mHDR-v2 source are comparable to those of the spherical sources while electron dose to total dose contribution are quite different. Conclusions: Electronic equilibrium conditions obtained for spherical sources could be generalized to actual sources while electron contribution to total dose depends strongly on source dimensions, material composition, and electron spectra.

  15. Electron-suppression experiments in a small multicusp H sup minus source

    Energy Technology Data Exchange (ETDEWEB)

    Leung, K.N.; Hauck, C.A.; Kunkel, W.B.; Walther, S.R. (Accelerator Research Division Fusion Research Division, Lawrence Berkeley Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (US))

    1990-03-01

    Several techniques for suppressing the electrons before they form part of the extracted beam have been studied in a small multicusp H{sup {minus}} source. It is found that some schemes reduce both the electron and the H{sup {minus}} output currents. Other approaches, such as the installation of a collar at the extraction aperture, the addition of xenon or cesium to the hydrogen discharge, or the reduction of the source plasma potential, not only can reduce the electron current substantially, but bring about an enhancement in the extracted H{sup {minus}} current.

  16. Suppression of cyclotron instability in Electron Cyclotron Resonance ion sources by two-frequency heating

    Energy Technology Data Exchange (ETDEWEB)

    Skalyga, V. [Institute of Applied Physics of Russian Academy of Sciences, 46 Ulyanova st., Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., Nizhny Novgorod (Russian Federation); Izotov, I.; Mansfeld, D. [Institute of Applied Physics of Russian Academy of Sciences, 46 Ulyanova st., Nizhny Novgorod (Russian Federation); Kalvas, T.; Koivisto, H.; Komppula, J.; Kronholm, R.; Laulainen, J.; Tarvainen, O. [Department of Physics, University of Jyväskylä, Jyväskylä (Finland)

    2015-08-15

    Multiple frequency heating is one of the most effective techniques to improve the performance of Electron Cyclotron Resonance (ECR) ion sources. The method increases the beam current and average charge state of the extracted ions and enhances the temporal stability of the ion beams. It is demonstrated in this paper that the stabilizing effect of two-frequency heating is connected with the suppression of electron cyclotron instability. Experimental data show that the interaction between the secondary microwave radiation and the hot electron component of ECR ion source plasmas plays a crucial role in mitigation of the instabilities.

  17. Requirements on the LWFA electron beam for the user-oriented photon source

    Science.gov (United States)

    Molodozhentsev, Alexander; Přibyl, Lukáš; Korn, Georg; Winkler, Paul; Maier, Andreas R.

    2017-05-01

    The laser-driven Undulator X-ray source (LUX) is designed to be a user beamline providing ultra-short EUV photon pulses with a central wavelength tuneable in the range of 0.4 to 4.5 nm and a peak brilliance of up to 1021 photons/(s.mrad2.mm2.0.1% B.W.), which makes this source comparable with modern synchrotron sources. The source shall provide a focal spot size well below 10 μm and a range of auxiliary beams for complex pump-and-probe experiments and it is also an important experimental milestone towards a future laser driven Free Electron Laser. Unique femtosecond nature of the laser-plasma electron acceleration in combination with extremely small transverse emittance of the electron beam is the major advantage of the LWFA technique. Preservation of the electron beam quality is a complicated task for a dedicated electron beam line, which has to be designed to transport the electron beam from the LWFA source up to the undulator. In this report we discuss main requirements on the LWFA source and the electron beam optics of the LUX source and solutions to produce required quality photon beam in the undulator and we also discuss the effect of realistic setup parameters on the quality of the electron beam in the undulator within the range of systematic errors.

  18. On thermalization of electron-positron-photon plasma

    Energy Technology Data Exchange (ETDEWEB)

    Siutsou, I. A., E-mail: siutsou@icranet.org [CAPES–ICRANet program, ICRANet–Rio, CBPF 22290-180, Rua Dr. Xavier Sigaud, 150, Urca, Rio de Janeiro, RJ (Brazil); Aksenov, A. G. [Institute for Computer-Aided Design, Russian Academy of Sciences 123056, 2nd Brestskaya st., 19/18, Moscow (Russian Federation); Vereshchagin, G. V. [ICRANet 65122, p.le della Republica, 10, Pescara (Italy)

    2015-12-17

    Recently a progress has been made in understanding thermalization mechanism of relativistic plasma starting from a non-equilibrium state. Relativistic Boltzmann equations were solved numerically for homogeneous isotropic plasma with collision integrals for two- and three-particle interactions calculated from the first principles by means of QED matrix elements. All particles were assumed to fulfill Boltzmann statistics. In this work we follow plasma thermalization by accounting for Bose enhancement and Pauli blocking in particle interactions. Our results show that particle in equilibrium reach Bose-Einstein distribution for photons, and Fermi-Dirac one for electrons, respectively.

  19. Three Filtered Vacuum Arc Plasma Sources Deposition & Implantation System

    Institute of Scientific and Technical Information of China (English)

    WU Xian-ying; ZHANG Hui-xing; LI Qiang

    2004-01-01

    A deposition & implantation system, which includes three filtered vacuum arc plasma sources, has been built. Vacuum arc discharge is used to produce high-density metal plasma; Curved magnetic filtering technique is used to transfer the plasma into out-of-sight vacuum chamber and reduce macro-particles from the vacuum arc plasma in order to drastically reduce the macro-particles contamination of the films. The up to 30 kV negative bias applied to the target can be used for ion implantation in order to improve the film adhesion; or for ion sputtering to clear the substrate surface. The 0 to 300 V negative bias can be used to adjust the ion energy which forming films. The system is designed for various thin films synthesizing, such as single-layer, compound layer, multi-layer films. It's principle, components and applications are described in the literature.

  20. Nonlinear interactions between electromagnetic waves and electron plasma oscillations in quantum plasmas.

    Science.gov (United States)

    Shukla, P K; Eliasson, B

    2007-08-31

    We consider nonlinear interactions between intense circularly polarized electromagnetic (CPEM) waves and electron plasma oscillations (EPOs) in a dense quantum plasma, taking into account the electron density response in the presence of the relativistic ponderomotive force and mass increase in the CPEM wave fields. The dynamics of the CPEM waves and EPOs is governed by the two coupled nonlinear Schrödinger equations and Poisson's equation. The nonlinear equations admit the modulational instability of an intense CPEM pump wave against EPOs, leading to the formation and trapping of localized CPEM wave pipes in the electron density hole that is associated with a positive potential distribution in our dense plasma. The relevance of our investigation to the next generation intense laser-solid density plasma interaction experiments is discussed.

  1. Monte Carlo simulation of electron beam air plasma characteristics

    Institute of Scientific and Technical Information of China (English)

    Deng Yong-Feng; Han Xian-Wei; Tan Chang

    2009-01-01

    A high-energy electron beam generator is used to generate a plasma in atmosphere. Based on a Monte Carlo toolkit named GEANT4,a model including complete physics processes is established to simulate the passage of the electron beam in air. Based on the model,the characteristics of the electron beam air plasma are calculated. The energy distribution of beam electrons (BEs) indicates that high-energy electrons almost reside in the centre region of the beam,but low-energy electrons always live in the fringe area. The energy deposition is calculated in two cases,i.e.,with and without secondary electrons (SEs). Analysis indicates that the energy deposition of Ses accounts for a large part of the total energy deposition. The results of the energy spectrum show that the electrons in the inlet layer of the low-pressure chamber (LPC) are monoenergetic,but the energy spectrum of the electrons in the outlet layer is not pure. The SEs are largely generated at the outlet of the LPC. Moreover,both the energy distribution of Bes and the magnitude of the density of SEs are closely related to the pressure of LPC. Thus,a conclusion is drawn that a low magnitude of LPC pressure is helpful for reducing the energy loss in the LPC and also useful for greatly increasing the secondary electron density in dense air.

  2. Detailed beam and plasma measurements on the vessel for extraction and source plasma analyses (VESPA) Penning H{sup −} ion source

    Energy Technology Data Exchange (ETDEWEB)

    Lawrie, S. R., E-mail: scott.lawrie@stfc.ac.uk [STFC ISIS Pulsed Spallation Neutron and Muon Facility, Rutherford Appleton Laboratory, Harwell, Oxford (United Kingdom); John Adams Institute of Accelerator Science, University of Oxford, Oxford (United Kingdom); Faircloth, D. C.; Letchford, A. P.; Whitehead, M. O.; Wood, T. [STFC ISIS Pulsed Spallation Neutron and Muon Facility, Rutherford Appleton Laboratory, Harwell, Oxford (United Kingdom)

    2016-02-15

    A vessel for extraction and source plasma analyses (VESPA) is operational at the Rutherford Appleton Laboratory (RAL). This project supports and guides the overall ion source R&D effort for the ISIS spallation neutron and muon facility at RAL. The VESPA produces 100 mA of pulsed H{sup −} beam, but perveance scans indicate that the source is production-limited at extraction voltages above 12 kV unless the arc current is increased. A high resolution optical monochromator is used to measure plasma properties using argon as a diagnostic gas. The atomic hydrogen temperature increases linearly with arc current, up to 2.8 eV for 50 A; whereas the electron temperature has a slight linear decrease toward 2.2 eV. The gas density is 10{sup 21} m{sup −3}, whilst the electron density is two orders of magnitude lower. Densities follow square root relationships with arc current, with gas density decreasing whilst electron (and hence ion) density increases. Stopping and range of ions in matter calculations prove that operating a high current arc with an argon admixture is extremely difficult because cathode-coated cesium is heavily sputtered by argon.

  3. Electron cyclotron resonance heating in a short cylindrical plasma system

    Indian Academy of Sciences (India)

    Vipin K Yadav; D Bora

    2004-09-01

    Electron cyclotron resonance (ECR) plasma is produced and studied in a small cylindrical system. Microwave power is delivered by a CW magnetron at 2.45 GHz in TE10 mode and launched radially to have extraordinary (X) wave in plasma. The axial magnetic field required for ECR in the system is such that the first two ECR surfaces ( = 875.0 G and = 437.5 G) reside in the system. ECR plasma is produced with hydrogen with typical plasma density e as 3.2 × 1010 cm-3 and plasma temperature e between 9 and 15 eV. Various cut-off and resonance positions are identified in the plasma system. ECR heating (ECRH) of the plasma is observed experimentally. This heating is because of the mode conversion of X-wave to electron Bernstein wave (EBW) at the upper hybrid resonance (UHR) layer. The power mode conversion efficiency is estimated to be 0.85 for this system. The experimental results are presented in this paper.

  4. Study on Performance Parameters of the Plasma Source for a Short-Conduction-Time Plasma Opening Switch

    Institute of Scientific and Technical Information of China (English)

    LUO Weixi; ZENG Zhengzhong; WANG Liangping; LEI Tianshi; HU Yixiang; HUANG Tao; SUN Tieping

    2012-01-01

    Plasma source performance parameters, including plasma ejection density and velocity, greatly affect the operation of a short-conduction-time plasma opening switch (POS). In this paper, the plasma source used in the POS of Qiangguang I generator is chosen as the study object. At first the POS working process is analyzed. The result shows that the opening performance of the POS can be improved by increasing the plasma ejection velocity and decreasing the plasma density. The influence of the cable plasma gun structure and number on the plasma ejection parameters is experimentally investigated with two charge collectors. Finally a semi-empirical model is proposed to describe the experimental phenomenon.

  5. Modeling of negative ion transport in a plasma source

    Science.gov (United States)

    Riz, David; Paméla, Jérôme

    1998-08-01

    A code called NIETZSCHE has been developed to simulate the negative ion transport in a plasma source, from their birth place to the extraction holes. The ion trajectory is calculated by numerically solving the 3-D motion equation, while the atomic processes of destruction, of elastic collision H-/H+ and of charge exchange H-/H0 are handled at each time step by a Monte-Carlo procedure. This code can be used to calculate the extraction probability of a negative ion produced at any location inside the source. Calculations performed with NIETZSCHE have allowed to explain, either quantitatively or qualitatively, several phenomena observed in negative ion sources, such as the isotopic H-/D- effect, and the influence of the plasma grid bias or of the magnetic filter on the negative ion extraction. The code has also shown that in the type of sources contemplated for ITER, which operate at large arc power densities (>1 W cm-3), negative ions can reach the extraction region provided if they are produced at a distance lower than 2 cm from the plasma grid in the case of «volume production» (dissociative attachment processes), or if they are produced at the plasma grid surface, in the vicinity of the extraction holes.

  6. Modeling of negative ion transport in a plasma source (invited)

    Science.gov (United States)

    Riz, David; Paméla, Jérôme

    1998-02-01

    A code called NIETZSCHE has been developed to simulate the negative ion transport in a plasma source, from their birth place to the extraction holes. The H-/D- trajectory is calculated by numerically solving the 3D motion equation, while the atomic processes of destruction, of elastic collision with H+/D+ and of charge exchange with H0/D0 are handled at each time step by a Monte Carlo procedure. This code can be used to calculate the extraction probability of a negative ion produced at any location inside the source. Calculations performed with NIETZSCHE have been allowed to explain, either quantitatively or qualitatively, several phenomena observed in negative ion sources, such as the isotopic H-/D- effect, and the influence of the plasma grid bias or of the magnetic filter on the negative ion extraction. The code has also shown that, in the type of sources contemplated for ITER, which operate at large arc power densities (>1 W cm-3), negative ions can reach the extraction region provided they are produced at a distance lower than 2 cm from the plasma grid in the case of volume production (dissociative attachment processes), or if they are produced at the plasma grid surface, in the vicinity of the extraction holes.

  7. Influence of electron injection into 27 cm audio plasma cell on the plasma diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Haleem, N. A.; Ragheb, M. S.; Zakhary, S. G. [Accelerators Department, Nuclear Research Center, AEA, Cairo 13759 (Egypt); El Fiki, S. A.; Nouh, S. A. [Faculty of Science, Ain Shams University, Cairo 11566 (Egypt); El Disoki, T. M. [Faculty of Girls, Ain Shams University, Cairo 11566 (Egypt)

    2013-08-15

    In this article, the plasma is created in a Pyrex tube (L = 27 cm, φ= 4 cm) as a single cell, by a capacitive audio frequency (AF) discharge (f = 10–100 kHz), at a definite pressure of ∼0.2 Torr. A couple of tube linear and deviating arrangements show plasma characteristic conformity. The applied AF plasma and the injection of electrons into two gas mediums Ar and N{sub 2} revealed the increase of electron density at distinct tube regions by one order to attain 10{sup 13}/cm{sup 3}. The electrons temperature and density strengths are in contrast to each other. While their distributions differ along the plasma tube length, they show a decaying sinusoidal shape where their peaks position varies by the gas type. The electrons injection moderates electron temperature and expands their density. The later highest peak holds for the N{sub 2} gas, at electrons injection it changes to hold for the Ar. The sinusoidal decaying density behavior generates electric fields depending on the gas used and independent of tube geometry. The effect of the injected electrons performs a responsive impact on electrons density not attributed to the gas discharge. Analytical tools investigate the interaction of the plasma, the discharge current, and the gas used on the electrodes. It points to the emigration of atoms from each one but for greater majority they behave to a preferred direction. Meanwhile, only in the linear regime, small percentage of atoms still moves in reverse direction. Traces of gas atoms revealed on both electrodes due to sheath regions denote lack of their participation in the discharge current. In addition, atoms travel from one electrode to the other by overcoming the sheaths regions occurring transportation of particles agglomeration from one electrode to the other. The electrons injection has contributed to increase the plasma electron density peaks. These electrons populations have raised the generated electrostatic fields assisting the elemental ions

  8. Vacuum nanoelectronic devices novel electron sources and applications

    CERN Document Server

    Evtukh, Anatoliy; Yilmazoglu, Oktay; Mimura, Hidenori; Pavlidis, Dimitris

    2015-01-01

    Introducing up-to-date coverage of research in electron field emission from nanostructures, Vacuum Nanoelectronic Devices outlines the physics of quantum nanostructures, basic principles of electron field emission, and vacuum nanoelectronic devices operation, and offers as insight state-of-the-art and future researches and developments.  This book also evaluates the results of research and development of novel quantum electron sources that will determine the future development of vacuum nanoelectronics. Further to this, the influence of quantum mechanical effects on high frequency vacuum nanoelectronic devices is also assessed. Key features: In-depth description and analysis of the fundamentals of Quantum Electron effects in novel electron sources. Comprehensive and up-to-date summary of the physics and technologies for THz sources for students of physical and engineering specialties and electronics engineers. Unique coverage of quantum physical results for electron-field emission and novel electron sourc...

  9. A "slingshot" laser-driven acceleration mechanism of plasma electrons

    CERN Document Server

    Fiore, Gaetano; Fedele, Renato

    2016-01-01

    We briefly report on the recently proposed [G. Fiore, R. Fedele, U. de Angelis, Phys. Plasmas 21 (2014), 113105], [G. Fiore, S. De Nicola, arXiv:1509.04656] electron acceleration mechanism named "slingshot effect": under suitable conditions the impact of an ultra-short and ultra-intense laser pulse against the surface of a low-density plasma is expected to cause the expulsion of a bunch of superficial electrons with high energy in the direction opposite to that of the pulse propagation; this is due to the interplay of the huge ponderomotive force, huge longitudinal field arising from charge separation, and the finite size of the laser spot.

  10. Plasma membrane electron transport in frog blood vessels

    Indian Academy of Sciences (India)

    Rashmi P Rao; K Nalini; J Prakasa Rao

    2009-12-01

    In an attempt to see if frog blood vessels possess a plasma membrane electron transport system, the postcaval vein and aorta isolated from Rana tigrina were tested for their ability to reduce ferricyanide, methylene blue, and 2,6-dichloroindophenol. While the dyes remained unchanged, ferricyanide was reduced to ferrocyanide. This reduction was resistant to inhibition by cyanide and azide. Heptane extraction or formalin fixation of the tissues markedly reduced the capability to reduce ferricyanide. Denuded aortas retained only 30% of the activity of intact tissue. Our results indicate that the amphibian postcaval vein and aorta exhibit plasma membrane electron transport

  11. 3D electron fluid turbulence at nanoscales in dense plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Shaikh, Dastgeer [Center for Space Plasma and Aeronomy Research, The University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Shukla, P K [Institut fuer Theoretische Physik IV, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)], E-mail: dastgeer@cspar.uah.edu, E-mail: ps@tp4.rub.de

    2008-08-15

    We have performed three-dimensional (3D) nonlinear fluid simulations of electron fluid turbulence at nanoscales in an unmagnetized warm dense plasma in which mode coupling between wave function and electrostatic (ES) potential associated with underlying electron plasma oscillations (EPOs) lead to nonlinear cascades in inertial range. While the wave function cascades towards smaller length scales, ES potential follows an inverse cascade. We find from our simulations that the quantum diffraction effect associated with a Bohm potential plays a critical role in determining the inertial range turbulent spectrum and the subsequent transport level exhibited by the 3D EPOs.

  12. 3D Electron Fluid Turbulence at Nanoscales in Dense Plasmas

    CERN Document Server

    Shaikh, Dastgeer

    2008-01-01

    We have performed three dimensional nonlinear fluid simulations of electron fluid turbulence at nanoscales in an unmagnetized warm dense plasma in which mode coupling between wave function and electrostatic potential associated with underlying electron plasma oscillations (EPOs) lead to nonlinear cascades in inertial range. While the wave function cascades towards smaller length scales, electrostatic potential follows an inverse cascade. We find from our simulations that quantum diffraction effect associated with a Bohm potential plays a critical role in determining the inertial range turbulent spectrum and the subsequent transport level exhibited by the 3D EPOs.

  13. Finite Amplitude Electron Plasma Waves in a Cylindrical Waveguide

    DEFF Research Database (Denmark)

    Juul Rasmussen, Jens

    1978-01-01

    The nonlinear behaviour of the electron plasma wave propagating in a cylindrical plasma waveguide immersed in an infinite axial magnetic field is investigated using the Krylov-Bogoliubov-Mitropolsky perturbation method, by means of which is deduced the nonlinear Schrodinger equation governing...... the long-time slow modulation of the wave amplitude. From this equation the amplitude-dependent frequency and wavenumber shifts are calculated, and it is found that the electron waves with short wavelengths are modulationally unstable with respect to long-wavelength, low-frequency perturbations...

  14. Structures of quantum 2D electron-hole plasmas

    CERN Document Server

    Filinov, V S; Fehske, H; Levashov, P R; Fortov, V E

    2008-01-01

    We investigate structures of 2D quantum electron-hole (e-h) plasmas by the direct path integral Monte Carlo method (PIMC) in a wide range of temperature, density and hole-to-electron mass ratio. Our simulation includes a region of appearance and decay of the bound states (excitons and biexcitons), the Mott transition from the neutral e-h plasma to metallic-like clusters, formation from clusters the hexatic-like liquid and formation of the crystal-like lattice.

  15. Investigation of the electron capture process in semiclassical plasma

    Directory of Open Access Journals (Sweden)

    Seisembayeva Madina M.

    2016-06-01

    Full Text Available In this work, the process of electron capture in partially ionized plasma is considered. Electron-atom interaction was described by the effective interaction potential, which takes into account the screening effect at large distances and the diffraction effect at the small distances. The results of numerical calculations of the electron capture radius, differential cross-section for different values of the coupling and density parameters are presented. The differential cross-section was obtained on the basis of perturbation theory and also by solving of the equation of motion of the projectile electron.

  16. Effect of bremsstrahlung radiation emission on fast electrons in plasmas

    Science.gov (United States)

    Embréus, O.; Stahl, A.; Fülöp, T.

    2016-09-01

    Bremsstrahlung radiation emission is an important energy loss mechanism for energetic electrons in plasmas. In this paper we investigate the effect of spontaneous bremsstrahlung emission on the momentum-space structure of the electron distribution, fully accounting for the emission of finite-energy photons by modeling the bremsstrahlung interactions with a Boltzmann collision operator. We find that electrons accelerated by electric fields can reach significantly higher energies than predicted by the commonly used radiative stopping-power model. Furthermore, we show that the emission of soft photons can contribute significantly to the dynamics of electrons with an anisotropic distribution by causing pitch-angle scattering at a rate that increases with energy.

  17. Effect of bremsstrahlung radiation emission on fast electrons in plasmas

    CERN Document Server

    Embréus, Ola; Fülöp, Tünde

    2016-01-01

    Bremsstrahlung radiation emission is an important energy loss mechanism for energetic electrons in plasmas. In this paper we investigate the effect of spontaneous bremsstrahlung emission on the momentum-space structure of the electron distribution, fully accounting for the emission of finite-energy photons. We find that electrons accelerated by electric fields can reach significantly higher energies than what is expected from energy-loss considerations. Furthermore, we show that the emission of soft photons can contribute significantly to the dynamics of electrons with an anisotropic distribution.

  18. Collisionless stopping of electron current in an inhomogeneous electron magnetohydrodynamics plasma

    Indian Academy of Sciences (India)

    Amita Das; Sharad K Yadav; Predhiman Kaw; Sudip Sengupta

    2011-11-01

    A brief review of a recent work on a novel collisionless scheme for stopping electron current pulse in plasma is presented. This scheme relies on the inhomogeneity of the plasma medium. This mechanism can be used for heating an overdense regime of plasma where lasers cannot penetrate. The method can ensure efficient localized heating at a desired location. The suitability of the scheme to the frontline fast ignition laser fusion experiment has been illustrated.

  19. Influence of electron evaporative cooling on ultracold plasma expansion

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Truman; Chen, Wei-Ting; Roberts, Jacob [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)

    2013-07-15

    The expansion of ultracold neutral plasmas (UCP) is driven primarily by the thermal pressure of the electron component and is therefore sensitive to the electron temperature. For typical UCP spatial extents, evaporative cooling has a significant influence on the UCP expansion rate at lower densities (less than 10{sup 8}/cm{sup 3}). We studied the effect of electron evaporation in this density range. Owing to the low density, the effects of three-body recombination were negligible. We modeled the expansion by taking into account the change in electron temperature owing to evaporation as well as adiabatic expansion and found good agreement with our data. We also developed a simple model for initial evaporation over a range of ultracold plasma densities, sizes, and electron temperatures to determine over what parameter range electron evaporation is expected to have a significant effect. We also report on a signal calibration technique, which relates the signal at our detector to the total number of ions and electrons in the ultracold plasma.

  20. Runaway electron dynamics in tokamak plasmas with high impurity content

    Science.gov (United States)

    Martín-Solís, J. R.; Loarte, A.; Lehnen, M.

    2015-09-01

    The dynamics of high energy runaway electrons is analyzed for plasmas with high impurity content. It is shown that modified collision terms are required in order to account for the collisions of the relativistic runaway electrons with partially stripped impurity ions, including the effect of the collisions with free and bound electrons, as well as the scattering by the full nuclear and the electron-shielded ion charge. The effect of the impurities on the avalanche runaway growth rate is discussed. The results are applied, for illustration, to the interpretation of the runaway electron behavior during disruptions, where large amounts of impurities are expected, particularly during disruption mitigation by massive gas injection. The consequences for the electron synchrotron radiation losses and the resulting runaway electron dynamics are also analyzed.

  1. Time-resolved measurements with streaked diffraction patterns from electrons generated in laser plasma wakefield

    Science.gov (United States)

    He, Zhaohan; Nees, John; Hou, Bixue; Krushelnick, Karl; Thomas, Alec; Beaurepaire, Benoît; Malka, Victor; Faure, Jérôme

    2013-10-01

    Femtosecond bunches of electrons with relativistic to ultra-relativistic energies can be robustly produced in laser plasma wakefield accelerators (LWFA). Scaling the electron energy down to sub-relativistic and MeV level using a millijoule laser system will make such electron source a promising candidate for ultrafast electron diffraction (UED) applications due to the intrinsic short bunch duration and perfect synchronization with the optical pump. Recent results of electron diffraction from a single crystal gold foil, using LWFA electrons driven by 8-mJ, 35-fs laser pulses at 500 Hz, will be presented. The accelerated electrons were collimated with a solenoid magnetic lens. By applying a small-angle tilt to the magnetic lens, the diffraction pattern can be streaked such that the temporal evolution is separated spatially on the detector screen after propagation. The observable time window and achievable temporal resolution are studied in pump-probe measurements of photo-induced heating on the gold foil.

  2. Electron vortex magnetic holes: A nonlinear coherent plasma structure

    Science.gov (United States)

    Haynes, Christopher T.; Burgess, David; Camporeale, Enrico; Sundberg, Torbjorn

    2015-01-01

    We report the properties of a novel type of sub-proton scale magnetic hole found in two dimensional particle-in-cell simulations of decaying turbulence with a guide field. The simulations were performed with a realistic value for ion to electron mass ratio. These structures, electron vortex magnetic holes (EVMHs), have circular cross-section. The magnetic field depression is associated with a diamagnetic azimuthal current provided by a population of trapped electrons in petal-like orbits. The trapped electron population provides a mean azimuthal velocity and since trapping preferentially selects high pitch angles, a perpendicular temperature anisotropy. The structures arise out of initial perturbations in the course of the turbulent evolution of the plasma, and are stable over at least 100 electron gyroperiods. We have verified the model for the EVMH by carrying out test particle and PIC simulations of isolated structures in a uniform plasma. It is found that (quasi-)stable structures can be formed provided that there is some initial perpendicular temperature anisotropy at the structure location. The properties of these structures (scale size, trapped population, etc.) are able to explain the observed properties of magnetic holes in the terrestrial plasma sheet. EVMHs may also contribute to turbulence properties, such as intermittency, at short scale lengths in other astrophysical plasmas.

  3. Electron vortex magnetic holes: A nonlinear coherent plasma structure

    Energy Technology Data Exchange (ETDEWEB)

    Haynes, Christopher T., E-mail: c.t.haynes@qmul.ac.uk; Burgess, David; Sundberg, Torbjorn [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Camporeale, Enrico [Multiscale Dynamics, Centrum Wiskunde and Informatica (CWI), Amsterdam (Netherlands)

    2015-01-15

    We report the properties of a novel type of sub-proton scale magnetic hole found in two dimensional particle-in-cell simulations of decaying turbulence with a guide field. The simulations were performed with a realistic value for ion to electron mass ratio. These structures, electron vortex magnetic holes (EVMHs), have circular cross-section. The magnetic field depression is associated with a diamagnetic azimuthal current provided by a population of trapped electrons in petal-like orbits. The trapped electron population provides a mean azimuthal velocity and since trapping preferentially selects high pitch angles, a perpendicular temperature anisotropy. The structures arise out of initial perturbations in the course of the turbulent evolution of the plasma, and are stable over at least 100 electron gyroperiods. We have verified the model for the EVMH by carrying out test particle and PIC simulations of isolated structures in a uniform plasma. It is found that (quasi-)stable structures can be formed provided that there is some initial perpendicular temperature anisotropy at the structure location. The properties of these structures (scale size, trapped population, etc.) are able to explain the observed properties of magnetic holes in the terrestrial plasma sheet. EVMHs may also contribute to turbulence properties, such as intermittency, at short scale lengths in other astrophysical plasmas.

  4. Mechanisms of plasma disruption and runaway electron losses in tokamaks

    CERN Document Server

    Abdullaev, S S; Wongrach, K; Tokar, M; Koslowski, H R; Willi, O; Zeng, L

    2015-01-01

    Based on the analysis of data from the numerous dedicated experiments on plasma disruptions in the TEXTOR tokamak mechanisms of the formation of runaway electron beams and their losses are proposed. The plasma disruption is caused by strong stochastic magnetic field formed due to nonlinearly excited low-mode number MHD modes. It is hypothesized that the runaway electron beam is formed in the central plasma region confined inside the intact magnetic surface located between $q=1$ and the closest low--order rational [$q=4/3$ or $q=3/2$] magnetic surfaces. The thermal quench time caused by the fast electron transport in a stochastic magnetic field is calculated using the collisional transport model. The current decay stage is due to the ambipolar particle transport in a stochastic magnetic field. The runaway electron beam in the confined plasma region is formed due to their acceleration the inductive toroidal electric field. The runaway electron beam current is modeled as a sum of toroidally symmetric part and a ...

  5. Microwave frequency sweep interferometer for plasma density measurements in ECR ion sources: Design and preliminary results

    Science.gov (United States)

    Torrisi, Giuseppe; Mascali, David; Neri, Lorenzo; Leonardi, Ornella; Sorbello, Gino; Celona, Luigi; Castro, Giuseppe; Agnello, Riccardo; Caruso, Antonio; Passarello, Santi; Longhitano, Alberto; Isernia, Tommaso; Gammino, Santo

    2016-02-01

    The Electron Cyclotron Resonance Ion Sources (ECRISs) development is strictly related to the availability of new diagnostic tools, as the existing ones are not adequate to such compact machines and to their plasma characteristics. Microwave interferometry is a non-invasive method for plasma diagnostics and represents the best candidate for plasma density measurement in hostile environment. Interferometry in ECRISs is a challenging task mainly due to their compact size. The typical density of ECR plasmas is in the range 1011-1013 cm-3 and it needs a probing beam wavelength of the order of few centimetres, comparable to the chamber radius. The paper describes the design of a microwave interferometer developed at the LNS-INFN laboratories based on the so-called "frequency sweep" method to filter out the multipath contribution in the detected signals. The measurement technique and the preliminary results (calibration) obtained during the experimental tests will be presented.

  6. Microwave frequency sweep interferometer for plasma density measurements in ECR ion sources: Design and preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Torrisi, Giuseppe [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); University Mediterranea of Reggio Calabria, Reggio Calabria (Italy); Mascali, David; Neri, Lorenzo; Leonardi, Ornella; Celona, Luigi; Castro, Giuseppe; Agnello, Riccardo; Caruso, Antonio; Passarello, Santi; Longhitano, Alberto; Gammino, Santo [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Sorbello, Gino [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); University of Catania, Catania, Italy and INFN-LNS, Catania (Italy); Isernia, Tommaso [University Mediterranea of Reggio Calabria, Reggio Calabria (Italy)

    2016-02-15

    The Electron Cyclotron Resonance Ion Sources (ECRISs) development is strictly related to the availability of new diagnostic tools, as the existing ones are not adequate to such compact machines and to their plasma characteristics. Microwave interferometry is a non-invasive method for plasma diagnostics and represents the best candidate for plasma density measurement in hostile environment. Interferometry in ECRISs is a challenging task mainly due to their compact size. The typical density of ECR plasmas is in the range 10{sup 11}–10{sup 13} cm{sup −3} and it needs a probing beam wavelength of the order of few centimetres, comparable to the chamber radius. The paper describes the design of a microwave interferometer developed at the LNS-INFN laboratories based on the so-called “frequency sweep” method to filter out the multipath contribution in the detected signals. The measurement technique and the preliminary results (calibration) obtained during the experimental tests will be presented.

  7. Influences of Uncaptured Electron on Energy Conversion of Photon Compton Scattering in High Power Laser-plasma

    Institute of Scientific and Technical Information of China (English)

    ZHENG Jing-hua; HAO Xiao-fei; HAO Dong-shan

    2004-01-01

    Using the single particle theory and the non-flexibility collision model of electron and photon, the influence of the uncaptured electrons on the energy conversion efficiency of multi-photon nonlinear Compton scattering in the extra stationary laser-plasma is investigated. It shows that in extra stationary laser-plasma,the uncaptured electrons make the Δω of the scattering frequency of the multi-photon Compton fall down with the increases of the incident radiation electron speed,the materials of the incident collision of electron and photon, and the number of the photons which work with the electrons at the same time. Under the modulation of the uncaptured electrons to the laser field, the energy conversion efficiency between electrons and photons will fall down with the increase of the electron incident radiation speed, using the low-power electrons for incident source, the loss can be efficiently reduced.

  8. Dissipative trapped electron modes in stellarator plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Nasim, M.H.; Rafiq, T.; Persson, M. [Department of Electromagnetics and Euratom/VR Association, Chalmers University of Technology, Gothenburg (Sweden)

    2003-07-01

    The objective of the present paper is to study the dissipative trapped electron modes in different stellarator and tokamak configurations with the purpose to contribute to the understanding of the geometrical effects on these instabilities. A three field periods heliac (H1-NF), a five field period helias (W7-X) and a circular tokamak are selected to study the effect of geometrical properties such as local magnetic shear, normal curvature, geodesic curvature and magnetic field, on the mode localisation. The VMEC code is used to obtain the 3-D equilibria. (orig.)

  9. Investigation on the electron flux to the wall in the VENUS ion source

    Science.gov (United States)

    Thuillier, T.; Angot, J.; Benitez, J. Y.; Hodgkinson, A.; Lyneis, C. M.; Todd, D. S.; Xie, D. Z.

    2016-02-01

    The long-term operation of high charge state electron cyclotron resonance ion sources fed with high microwave power has caused damage to the plasma chamber wall in several laboratories. Porosity, or a small hole, can be progressively created in the chamber wall which can destroy the plasma chamber over a few year time scale. A burnout of the VENUS plasma chamber is investigated in which the hole formation in relation to the local hot electron power density is studied. First, the results of a simple model assuming that hot electrons are fully magnetized and strictly following magnetic field lines are presented. The model qualitatively reproduces the experimental traces left by the plasma on the wall. However, it is too crude to reproduce the localized electron power density for creating a hole in the chamber wall. Second, the results of a Monte Carlo simulation, following a population of scattering hot electrons, indicate a localized high power deposited to the chamber wall consistent with the hole formation process. Finally, a hypervapotron cooling scheme is proposed to mitigate the hole formation in electron cyclotron resonance plasma chamber wall.

  10. Investigation on the electron flux to the wall in the VENUS ion source.

    Science.gov (United States)

    Thuillier, T; Angot, J; Benitez, J Y; Hodgkinson, A; Lyneis, C M; Todd, D S; Xie, D Z

    2016-02-01

    The long-term operation of high charge state electron cyclotron resonance ion sources fed with high microwave power has caused damage to the plasma chamber wall in several laboratories. Porosity, or a small hole, can be progressively created in the chamber wall which can destroy the plasma chamber over a few year time scale. A burnout of the VENUS plasma chamber is investigated in which the hole formation in relation to the local hot electron power density is studied. First, the results of a simple model assuming that hot electrons are fully magnetized and strictly following magnetic field lines are presented. The model qualitatively reproduces the experimental traces left by the plasma on the wall. However, it is too crude to reproduce the localized electron power density for creating a hole in the chamber wall. Second, the results of a Monte Carlo simulation, following a population of scattering hot electrons, indicate a localized high power deposited to the chamber wall consistent with the hole formation process. Finally, a hypervapotron cooling scheme is proposed to mitigate the hole formation in electron cyclotron resonance plasma chamber wall.

  11. Investigation on the electron flux to the wall in the VENUS ion source

    Energy Technology Data Exchange (ETDEWEB)

    Thuillier, T., E-mail: thuillier@lpsc.in2p3.fr; Angot, J. [LPSC, Université Grenoble-Alpes, CNRS/IN2P3, 53 rue des Martyrs, 38026 Grenoble Cedex (France); Benitez, J. Y.; Hodgkinson, A.; Lyneis, C. M.; Todd, D. S.; Xie, D. Z. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2016-02-15

    The long-term operation of high charge state electron cyclotron resonance ion sources fed with high microwave power has caused damage to the plasma chamber wall in several laboratories. Porosity, or a small hole, can be progressively created in the chamber wall which can destroy the plasma chamber over a few year time scale. A burnout of the VENUS plasma chamber is investigated in which the hole formation in relation to the local hot electron power density is studied. First, the results of a simple model assuming that hot electrons are fully magnetized and strictly following magnetic field lines are presented. The model qualitatively reproduces the experimental traces left by the plasma on the wall. However, it is too crude to reproduce the localized electron power density for creating a hole in the chamber wall. Second, the results of a Monte Carlo simulation, following a population of scattering hot electrons, indicate a localized high power deposited to the chamber wall consistent with the hole formation process. Finally, a hypervapotron cooling scheme is proposed to mitigate the hole formation in electron cyclotron resonance plasma chamber wall.

  12. Plasma and Ion Sources in Large Area Coatings: A Review

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre

    2005-02-28

    Efficient deposition of high-quality coatings often requires controlled application of excited or ionized particles. These particles are either condensing (film-forming) or assisting by providing energy and momentum to the film growth process, resulting in densification, sputtering/etching, modification of stress, roughness, texture, etc. In this review, the technical means are surveyed enabling large area application of ions and plasmas, with ion energies ranging from a few eV to a few keV. Both semiconductortype large area (single wafer or batch processing with {approx} 1000 cm{sup 2}) and in-line web and glass-coating-type large area (> 10{sup 7} m{sup 2} annually) are considered. Characteristics and differences between plasma and ion sources are explained. The latter include gridded and gridless sources. Many examples are given, including sources based on DC, RF, and microwave discharges, some with special geometries like hollow cathodes and E x B configurations.

  13. DBD plasma source operated in single-filamentary mode for therapeutic use in dermatology

    Science.gov (United States)

    Rajasekaran, Priyadarshini; Mertmann, Philipp; Bibinov, Nikita; Wandke, Dirk; Viöl, Wolfgang; Awakowicz, Peter

    2009-11-01

    Our dielectric barrier discharge (DBD) plasma source for bio-medical application comprises a copper electrode covered with ceramic. Objects of high capacitance such as the human body can be used as the opposite electrode. In this study, the DBD source is operated in single-filamentary mode using an aluminium spike as the opposite electrode, to imitate the conditions when the discharge is ignited on a raised point, such as hair, during therapeutic use on the human body. The single-filamentary discharge thus obtained is characterized using optical emission spectroscopy, numerical simulation, voltage-current measurements and microphotography. For characterization of the discharge, averaged plasma parameters such as electron distribution function and electron density are determined. Fluxes of nitric oxide (NO), ozone (O3) and photons reaching the treated surface are simulated. The calculated fluxes are finally compared with corresponding fluxes used in different bio-medical applications.

  14. Direct acceleration of electrons by a CO2 laser in a curved plasma waveguide

    CERN Document Server

    Yi, Longqing; Shen, Baifei

    2016-01-01

    Laser plasma interaction with micro-engineered targets at relativistic intensities has been greatly promoted by recent progress in the high contrast lasers and the manufacture of advanced micro- and nano-structures. This opens new possibilities for the physics of laser-matter interaction. Here we propose a novel approach that leverages the advantages of high-pressure CO 2 laser, laser-waveguide interaction, as well as micro-engineered plasma structure to accelerate electrons to peak energy greater than 1 GeV with narrow slice energy spread (~1%) and high overall efficiency. The acceleration gradient is 26 GV/m for a 1.3 TW CO2 laser system. The micro-bunching of a long electron beam leads to the generation of a chain of ultrashort electron bunches with the duration roughly equal to half-laser-cycle. These results open a way for developing a compact and economic electron source for diverse applications.

  15. Direct acceleration of electrons by a CO$_{2}$ laser in a curved plasma waveguide

    CERN Document Server

    Yi, Longqing; Shen, Baifei

    2016-01-01

    Laser plasma interaction with micro-engineered targets at relativistic intensities has been greatly promoted by recent progress in the high contrast lasers and the manufacture of advanced micro- and nano-structures. This opens new possibilities for the physics of laser-matter interaction. Here we propose a novel approach that leverages the advantages of high-pressure CO$_{2}$ laser, laser-waveguide interaction, as well as micro-engineered plasma structure to accelerate electrons to peak energy greater than 1 GeV with narrow slice energy spread ($\\sim1\\%$) and high overall efficiency. The acceleration gradient is 26 GV/m for a 1.3 TW CO$_{2}$ laser system. The micro-bunching of a long electron beam leads to the generation of a chain of ultrashort electron bunches with the duration roughly equal to half-laser-cycle. These results open a way for developing a compact and economic electron source for diverse applications.

  16. Demonstration of relativistic electron beam focusing by a laser-plasma lens.

    Science.gov (United States)

    Thaury, C; Guillaume, E; Döpp, A; Lehe, R; Lifschitz, A; Ta Phuoc, K; Gautier, J; Goddet, J-P; Tafzi, A; Flacco, A; Tissandier, F; Sebban, S; Rousse, A; Malka, V

    2015-04-16

    Laser-plasma technology promises a drastic reduction of the size of high-energy electron accelerators. It could make free-electron lasers available to a broad scientific community and push further the limits of electron accelerators for high-energy physics. Furthermore, the unique femtosecond nature of the source makes it a promising tool for the study of ultrafast phenomena. However, applications are hindered by the lack of suitable lens to transport this kind of high-current electron beams mainly due to their divergence. Here we show that this issue can be solved by using a laser-plasma lens in which the field gradients are five order of magnitude larger than in conventional optics. We demonstrate a reduction of the divergence by nearly a factor of three, which should allow for an efficient coupling of the beam with a conventional beam transport line.

  17. Effect of electron inertia on dispersive properties of Alfvén waves in cold plasmas

    Science.gov (United States)

    Jana, Sayanee; Ghosh, Samiran; Chakrabarti, Nikhil

    2017-10-01

    The effect of electron inertia on Alfvén wave propagation is investigated in the framework of the two-fluid theory in a compressible magnetized plasma. The linear analysis of the governing equations manifests the dispersion relation of the circularly polarized Alfvén waves where the electron inertia is found to act as a source of dispersion. In the finite amplitude limit, the nonlinear Alfvén wave may be described by the Derivative Nonlinear Schrödinger equation (DNLSE) modified by third order dispersion arising due to finite electron inertia. The derived equation seems to be novel with respect to what exists in the literature of Alfvén wave dynamics. We have shown that this electron inertia modified DNLSE is completely integrable and an analytical solution is demonstrated with vanishing boundary conditions. The results are expected to be of special importance in the context of space and laboratory plasmas.

  18. Brilliant GeV electron beam with narrow energy spread generated by a laser plasma accelerator

    Science.gov (United States)

    Hu, Ronghao; Lu, Haiyang; Shou, Yinren; Lin, Chen; Zhuo, Hongbin; Chen, Chia-erh; Yan, Xueqing

    2016-09-01

    The production of GeV electron beam with narrow energy spread and high brightness is investigated using particle-in-cell simulations. A controlled electron injection scheme and a method for phase-space manipulation in a laser plasma accelerator are found to be essential. The injection is triggered by the evolution of two copropagating laser pulses near a sharp vacuum-plasma transition. The collection volume is well confined and the injected bunch is isolated in phase space. By tuning the parameters of the laser pulses, the parameters of the injected electron bunch, such as the bunch length, energy spread, emittance and charge, can be adjusted. Manipulating the phase-space rotation with the rephasing technique, the injected electron bunch can be accelerated to GeV level while keeping relative energy spread below 0.5% and transverse emittance below 1.0 μ m . The results present a very promising way to drive coherent x-ray sources.

  19. Demonstration of electron beam focusing by a laser-plasma lens

    CERN Document Server

    Thaury, Cédric; Döpp, Andreas; Lehe, Remi; Lifschitz, Agustin; Phuoc, Kim Ta; Gautier, Julien; Goddet, Jean-Philippe; Tafzi, Amar; Flacco, Alessandro; Tissandier, Fabien; Sebban, Stéphane; Rousse, Antoine; Malka, Victor

    2014-01-01

    Laser-plasma technology promises a drastic reduction of the size of high energy electron accelerators. It could make free electron lasers available to a broad scientific community, and push further the limits of electron accelerators for high energy physics. Furthermore the unique femtosecond nature of the source makes it a promising tool for the study of ultra-fast phenomena. However, applications are hindered by the lack of suitable lens to transport this kind of high-current electron beams, mainly due to their divergence. Here we show that this issue can be solved by using a laser-plasma lens, in which the field gradients are five order of magnitude larger than in conventional optics. We demonstrate a reduction of the divergence by nearly a factor of three, which should allow for an efficient coupling of the beam with a conventional beam transport line.

  20. Photon and electron Landau damping in quantum plasmas

    Science.gov (United States)

    Mendonça, J. T.; Serbeto, A.

    2016-09-01

    Using a quantum kinetic description, we establish a general expression for the dispersion relation of electron plasma waves in the presence of an arbitrary spectrum of electromagnetic waves. This includes both electron and photon Landau damping. The quantum kinetic description allows us to compare directly these two distinct processes, and to show that they are indeed quite similar. The present work also extends previous results on photon Landau damping onto the quantum domain.

  1. Investigation of the dynamics of the Z-pinch imploding plasma for a laser-assisted discharge-produced Sn plasma EUV source

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Q; Yamada, J; Kishi, N; Watanabe, M; Okino, A; Horioka, K; Hotta, E, E-mail: zhu.q.ab@m.titech.ac.jp [Department of Energy Sciences, Tokyo Institute of Technology, Nagatsuta 4259 J2-35, Midori-ku, Yokohama 226-8502 (Japan)

    2011-04-13

    Dynamics of the imploding plasma and its relations to the 13.5 nm EUV emissions have been experimentally investigated for a laser-assisted Sn based discharge-produced plasma EUV source. The behaviours and two-dimensional electron density distributions of the EUV-emitting plasma were obtained using the time-resolved shadowgraph and Nomarski interferometric techniques. Observation of the plasma piston in the prepinch phase justified the validity of the zero-dimensional thin-shell model, from which the ion charge state of the prepinch plasma in the cathode region was estimated. The sausage (m = 0) instability that usually enhances the EUV emission was observed, with the radial electron density distribution that displays a concave shape at the crest of the plasma and a bell shape at the neck; the maximum of the electron density is located at one peak of the concave distribution at the crest instead of the neck. Intense EUV emission was produced by the Z-pinch plasma with the electron density (2.0-3.0) x 10{sup 18} cm{sup -3}. Moreover, the shock waves generated in the anode region can also produce in-band EUV emission with the intensity of 30% of that from the Z-pinch plasma.

  2. Kinetic models for the VASIMR thruster helicon plasma source

    Science.gov (United States)

    Batishchev, Oleg; Molvig, Kim

    2001-10-01

    Helicon gas discharge [1] is widely used by industry because of its remarkable efficiency [2]. High energy and fuel efficiencies make it very attractive for space electrical propulsion applications. For example, helicon plasma source is used in the high specific impulse VASIMR [3] plasma thruster, including experimental prototypes VX-3 and upgraded VX-10 [4] configurations, which operate with hydrogen (deuterium) and helium plasmas. We have developed a set of models for the VASIMR helicon discharge. Firstly, we use zero-dimensional energy and mass balance equations to characterize partially ionized gas condition/composition. Next, we couple it to one-dimensional hybrid model [6] for gas flow in the quartz tube of the helicon. We compare hybrid model results to a purely kinetic simulation of propellant flow in gas feed + helicon source subsystem. Some of the experimental data [3-4] are explained. Lastly, we discuss full-scale kinetic modeling of coupled gas and plasmas [5-6] in the helicon discharge. [1] M.A.Lieberman, A.J.Lihtenberg, 'Principles of ..', Wiley, 1994; [2] F.F.Chen, Plas. Phys. Contr. Fus. 33, 339, 1991; [3] F.Chang-Diaz et al, Bull. APS 45 (7) 129, 2000; [4] J.Squire et al., Bull. APS 45 (7) 130, 2000; [5] O.Batishchev et al, J. Plasma Phys. 61, part II, 347, 1999; [6] O.Batishchev, K.Molvig, AIAA technical paper 2000-3754, -14p, 2001.

  3. Kinetic instabilities in pulsed operation mode of a 14 GHz electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, O., E-mail: olli.tarvainen@jyu.fi; Kalvas, T.; Koivisto, H.; Komppula, J.; Kronholm, R.; Laulainen, J. [Department of Physics, University of Jyväskylä, 40500 Jyväskylä (Finland); Izotov, I.; Mansfeld, D. [Institute of Applied Physics, RAS, 46 Ul‘yanova St., 603950 Nizhny Novgorod (Russian Federation); Skalyga, V. [Institute of Applied Physics, RAS, 46 Ul‘yanova St., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina St., 603950 Nizhny Novgorod (Russian Federation)

    2016-02-15

    The occurrence of kinetic plasma instabilities is studied in pulsed operation mode of a 14 GHz A-electron cyclotron resonance type electron cyclotron resonance ion source. It is shown that the temporal delay between the plasma breakdown and the appearance of the instabilities is on the order of 10-100 ms. The most important parameters affecting the delay are magnetic field strength and neutral gas pressure. It is demonstrated that kinetic instabilities limit the high charge state ion beam production in the unstable operating regime.

  4. Note: Production of a mercury beam with an electron cyclotron resonance ion source.

    Science.gov (United States)

    Vondrasek, R; Pardo, R; Scott, R

    2013-11-01

    An electron cyclotron resonance ion source has been utilized to produce mercury beams with intensities of 4.5 eμA of (202)Hg(29+) and 3.0 eμA of (202)Hg(31+) from natural abundance mercury metal. The production technique relies on the evaporation of liquid mercury into the source plasma vacuum region and utilizes elemental mercury instead of a volatile organic compound as the neutral feed material.

  5. A proposal for a novel H ion source based on electron cyclotron resonance heating and surface ionization

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, Ollie A [Los Alamos National Laboratory; Kurennoy, Sergey [Los Alamos National Laboratory

    2008-01-01

    A design for a novel H{sup -} ion source based on electron cyclotron resonance plasma heating and surface ionization is presented. The plasma chamber of the source is an rf-cavity designed for TE{sub 111} eigenmode at 2.45 GHz. The desired mode is excited with a loop antenna. The ionization process takes place on a cesiated surface of a biased converter electrode. The H{sup -} ion beam is further 'self-extracted' through the plasma region. The magnetic field of the source is optimized for plasma generation by electron cyclotron resonance heating, and beam extraction. The design features of the source are discussed in detail and the attainable H{sup -} ion current, beam emittance and duty factor of the novel source are estimated.

  6. Plasma Dipole Oscillation Excited by Trapped Electrons Leading to Bursts of Coherent Radiation

    CERN Document Server

    Kwon, Kyu Been; Song, Hyung Seon; Kim, Young-Kuk; Ersfeld, Bernhard; Jaroszynski, Dino A; Hur, Min Sup

    2016-01-01

    Plasma dipole oscillation (PDO) depicted as harmonic motion of a spatially localized block of electrons has, until now, been hypothetical. In practice, the plasma oscillation occurs always as a part of a plasma wave. Studies on radiation burst from plasmas have focused only on coupling of the plasma wave and electromagnetic wave. Here we show that a very-high-field PDO can be generated by the electrons trapped in a moving train of potential wells. The electrons riding on the potential train coherently construct a local dipole moment by charge separation. The subsequent PDO is found to persist stably until its energy is emitted entirely via coherent radiation. In our novel method, the moving potentials are provided by two slightly-detuned laser pulses colliding in a non-magnetized plasma. The radiated energy reaches several millijoules in the terahertz spectral region. The proposed method provides a way of realizing the PDO as a new radiation source in the laboratory. PDO as a mechanism of astrophysical radio-...

  7. Spaced resolved analysis of suprathermal electrons in dense plasma

    Directory of Open Access Journals (Sweden)

    Moinard A.

    2013-11-01

    Full Text Available The investigation of the hot electron fraction is a crucial topic for high energy density laser driven plasmas: first, energy losses and radiative properties depend strongly on the hot electron fraction and, second, in ICF hohlraums suprathermal electrons preheat the D-T-capsule and seriously reduce the fusion performance. In the present work we present our first experimental and theoretical studies to analyze single shot space resolved hot electron fractions inside dense plasmas via optically thin X-ray line transitions from autoionizing states. The benchmark experiment has been carried out at an X-pinch in order to create a dense, localized plasma with a well defined symmetry axis of hot electron propagation. Simultaneous high spatial and spectral resolution in the X-ray spectral range has been obtained with a spherically bent quartz Bragg crystal. The high performance of the X-ray diagnostics allowed to identify space resolved hot electron fractions via the X-ray spectral distribution of multiple excited states.

  8. Diagnostic techniques for measuring suprathermal electron dynamics in plasmas (invited).

    Science.gov (United States)

    Coda, S

    2008-10-01

    Plasmas, both in the laboratory and in space, are often not in thermodynamic equilibrium, and the plasma electron distribution function is accordingly non-Maxwellian. Suprathermal electron tails can be generated by external drives, such as rf waves and electric fields, or internal ones, such as instabilities and magnetic reconnection. The variety and importance of the phenomena in which suprathermal electrons play a significant role explains an enduring interest in diagnostic techniques to investigate their properties and dynamics. X-ray bremsstrahlung emission has been studied in hot magnetized plasmas for well over two decades, flanked progressively by electron-cyclotron emission in geometries favoring the high-energy end of the distribution function (high-field-side, vertical, oblique emission), by electron-cyclotron absorption, by spectroscopic techniques, and at lower temperatures, by Langmuir probes and electrostatic analyzers. Continuous progress in detector technology and in measurement and analysis techniques, increasingly sophisticated layouts (multichannel and tomographic systems, imaging geometries), and highly controlled suprathermal generation methods (e.g., perturbative rf modulation) have all been brought to bear in recent years on an increasingly detailed, although far from complete, understanding of suprathermal electron dynamics.

  9. Runaway electrons and mitigation studies in MST tokamak plasmas

    Science.gov (United States)

    Goetz, J. A.; Chapman, B. E.; Almagri, A. F.; Cornille, B. S.; Dubois, A.; McCollam, K. J.; Munaretto, S.; Sovinec, C. R.

    2016-10-01

    Studies of runaway electrons generated in low-density MST tokamak plasmas are being undertaken. The plasmas have Bt resonant magnetic perturbations (RMP's). An m = 3 RMP strongly suppresses the runaway electrons and initial NIMROD modeling shows that this may be due to degradation of flux surfaces. The RMP is produced by a poloidal array of 32 saddle coils at the narrow vertical insulated cut in MST's thick conducting shell, with each RMP having a single m but a broad n spectrum. While a sufficiently strong m = 3 RMP suppresses the runaway electrons, an RMP with m = 1 and comparable amplitude has little effect. The impact of the RMP's on the magnetic topology of these plasmas is being studied with the nonlinear MHD code NIMROD. With an m = 3 RMP, stochasticity is introduced in the outer third of the plasma but no such flux surface degradation is observed with an m = 1 RMP. NIMROD also predicts regularly occurring MHD activity similar to that observed in the experiment. These studies have also been done in q (a) = 2.7 plasmas and analysis and modeling is ongoing. This work supported by USDoE.

  10. Equatorial plasma bubbles with enhanced ion and electron temperatures

    Science.gov (United States)

    Park, Jaeheung; Min, Kyoung Wook; Kim, Vitaly P.; Kil, Hyosub; Su, Shin-Yi; Chao, Chi Kuang; Lee, Jae-Jin

    2008-09-01

    While the ion and electron temperatures inside equatorial plasma bubbles (EPBs) are normally lower than those in an ambient plasma, bubbles with enhanced temperatures (BETs) are found occasionally in the topside ionosphere. Here we report the characteristics of BETs identified from observations of the first Republic of China Satellite (ROCSAT-1), the first Korea Multi-purpose Satellite (KOMPSAT-1), and the Defense Meteorological Satellite Program (DMSP) F15 during the solar maximum period between 2000 and 2001. The oxygen ion fraction inside the BETs, which was no lower than that of the ambient ionosphere, was similar to the case of ordinary low-temperature EPBs. These observations indicate that the BETs and low-temperature EPBs detected on the topside were produced by the upward drift of low-density plasma from lower altitudes. The feature that distinguishes BETs from normal EPBs is the occurrence of an unusually fast poleward field-aligned plasma flow relative to the ambient plasma. The BETs occurred preferentially around geomagnetic latitudes of 10° in the summer hemisphere, where the ambient ion and electron temperatures are lower than those in the conjugate winter hemisphere. The occurrence of BETs did not show any notable dependence on geomagnetic activities. The characteristics of the BETs suggest that the BETs were produced by adiabatic plasma heating associated with a fast poleward oxygen ion transport along magnetic flux tubes.

  11. Kinetics of metastable atoms and non-Maxwellian electrons in two-temperature plasmas

    Science.gov (United States)

    Kunc, J. A.; Soon, W. H.

    1990-01-01

    Numerical and analytical solutions of the electron Boltzmann equation in two-temperature steady-state helium plasma are studied in a broad range of conditions T(a) = 5,000-20,000 K, T(e) = 10,000-20,000 K; N(a) = 10 to the 10th - 10 to the 18th per cu cm. The WKB analytical solution is found to be satisfactory in most situations. The deviation of the electron distribution from Maxwellian and a possibility of raising of the tail of the distribution in presence of sources of fast electrons is also discussed.

  12. Propagation and oblique collision of electron-acoustic solitons in two-electron-populated quantum plasmas

    Indian Academy of Sciences (India)

    M Akbari-Moghanjoughi; N Ahmadzadeh-Khosroshahi

    2011-08-01

    Oblique interaction of small- but finite-amplitude KdV-type electron-acoustic solitary excitations is examined in an unmagnetized two-electron-populated degenerate quantum electron–ion plasma in the framework of quantum hydrodynamics model using the extended Poincaré–Lighthill–Kuo (PLK) perturbation method. Critical plasma parameter is found to distinguish the types of solitons and their interaction phase-shifts. It is shown that, depending on the critical quantum diffraction parameter cr, both compressive and rarefactive solitary excitations may exist in this plasma and their collision phase-shifts can be either positive or negative for the whole range of collision angles 0 < θ < .

  13. Recycling of the Electronic Waste Applying the Plasma Reactor Technology

    Science.gov (United States)

    Lázár, Marián; Jasminská, Natália; Čarnogurská, Mária; Dobáková, Romana

    2016-12-01

    The following paper discusses a high-temperature gasification process and melting of electronic components and computer equipment using plasma reactor technology. It analyses the marginal conditions of batch processing, as well as the formation of solid products which result from the procedure of waste processing. Attention is also paid to the impact of the emerging products on the environment.

  14. Recycling of the Electronic Waste Applying the Plasma Reactor Technology

    Directory of Open Access Journals (Sweden)

    Lázár Marián

    2016-12-01

    Full Text Available The following paper discusses a high-temperature gasification process and melting of electronic components and computer equipment using plasma reactor technology. It analyses the marginal conditions of batch processing, as well as the formation of solid products which result from the procedure of waste processing. Attention is also paid to the impact of the emerging products on the environment.

  15. Electron beam generated plasmas for the processing of graphene

    Science.gov (United States)

    Walton, S. G.; Hernández, S. C.; Boris, D. R.; Petrova, Tz B.; Petrov, G. M.

    2017-09-01

    The Naval Research Laboratory (NRL) has developed a processing system based on an electron beam-generated plasma and applied it to the processing of graphene. Unlike conventional discharges produced by electric fields (DC, RF, microwave, etc), the plasma is driven by a high-energy (~few keV) electron beam, an approach that simplifies the relative production of species while providing comparatively high ion-to-radical production rates. The resulting plasmas are characterized by high charged particle densities (1010-1011 cm-3) and electron temperatures that are typically about 1.0 eV or lower. Accordingly, the flux to adjacent surfaces is generally dominated by ions with kinetic energies in the range of 1-5 eV, a value at or near the bond strength of most materials. This provides the potential for controllably engineering materials with monolayer precision, an attribute attractive for the processing of atomically thin material systems. This work describes the attributes of electron beam driven plasma processing system and its use in modification of graphene.

  16. High current multicharged metal ion source using high power gyrotron heating of vacuum arc plasma.

    Science.gov (United States)

    Vodopyanov, A V; Golubev, S V; Khizhnyak, V I; Mansfeld, D A; Nikolaev, A G; Oks, E M; Savkin, K P; Vizir, A V; Yushkov, G Yu

    2008-02-01

    A high current, multi charged, metal ion source using electron heating of vacuum arc plasma by high power gyrotron radiation has been developed. The plasma is confined in a simple mirror trap with peak magnetic field in the plug up to 2.5 T, mirror ratio of 3-5, and length variable from 15 to 20 cm. Plasma formed by a cathodic vacuum arc is injected into the trap either (i) axially using a compact vacuum arc plasma gun located on axis outside the mirror trap region or (ii) radially using four plasma guns surrounding the trap at midplane. Microwave heating of the mirror-confined, vacuum arc plasma is accomplished by gyrotron microwave radiation of frequency 75 GHz, power up to 200 kW, and pulse duration up to 150 micros, leading to additional stripping of metal ions by electron impact. Pulsed beams of platinum ions with charge state up to 10+, a mean charge state over 6+, and total (all charge states) beam current of a few hundred milliamperes have been formed.

  17. First results of the 2.45 GHz Oshima electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Asaji, T., E-mail: asaji@nc-toyama.ac.jp [National Institute of Technology, Toyama College, 13 Hongo, Toyama 939-8630 (Japan); Nakamura, T.; Furuse, M. [National Institute of Technology, Oshima College, 1091-1 Komatsu, Suouoshima, Oshima, Yamaguchi 742-2193 (Japan); Hitobo, T. [Tateyama Machine Co., Ltd., 30 Shimonoban, Toyama 930-1305 (Japan); Uchida, T. [Graduate School of Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan); Muramatsu, M. [National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kato, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2016-02-15

    A new electron cyclotron resonance ion source has been constructed at Oshima College with a 2.45 GHz magnetron microwave source and permanent magnets employed as the main components. In addition, a solid-state power amplifier with a frequency range of 2.5–6.0 GHz was installed to study two-frequency plasma heating. Three solenoid coils were set up for adjusting the axial magnetic fields. Argon plasma generation and ion beam production have been conducted during the first year of operation. Ion current densities in the ECR plasma were measured using a biased disk. For 2.45 and 4.65 GHz two-frequency plasma heating, the ion density was approximately 1.5 times higher than that of 2.45 GHz single-frequency heating.

  18. Application of atmospheric plasma sources in growth and differentiation of plant and mammalian stem cells

    Science.gov (United States)

    Puac, Nevena

    2014-10-01

    The expansion of the plasma medicine and its demand for in-vivo treatments resulted in fast development of various plasma devices that operate at atmospheric pressure. These sources have to fulfill all demands for application on biological samples. One of the sources that meet all the requirements needed for treatment of biological material is plasma needle. Previously, we have used this device for sterilization of planctonic samples of bacteria, MRSA biofilm, for improved differentiation of human periodontal stem cells into osteogenic line and for treatment of plant meristematic cells. It is well known that plasma generates reactive oxygen species (ROS) and reactive nitrogen species (RNS) that strongly affect metabolism of living cells. One of the open issues is to correlate external plasma products (electrons, ions, RNS, ROS, photons, strong fields etc.) with the immediate internal response which triggers or induces effects in the living cell. For that purpose we have studied the kinetics of enzymes which are typical indicators of the identity of reactive species from the plasma created environment that can trigger signal transduction in the cell and ensue cell activity. In collaboration with Suzana Zivkovicm, Institute for Biological Research ``Sinisa Stankovic,'' University of Belgrade; Nenad Selakovic, Institute of Physics, University of Belgrade; Milica Milutinovic, Jelena Boljevic, Institute for Biological Research ``Sinisa Stankovic,'' University of Belgrade; and Gordana Malovic, Zoran Lj. Petrovic, Institute of Physics, University of Belgrade. Grants III41011, ON171037 and ON173024, MESTD, Serbia.

  19. High power microwave source for a plasma wakefield experiment

    Science.gov (United States)

    Shafir, G.; Shlapakovski, A.; Siman-Tov, M.; Bliokh, Yu.; Leopold, J. G.; Gleizer, S.; Gad, R.; Rostov, V. V.; Krasik, Ya. E.

    2017-01-01

    The results of the generation of a high-power microwave (˜550 MW, 0.5 ns, ˜9.6 GHz) beam and feasibility of wakefield-excitation with this beam in under-dense plasma are presented. The microwave beam is generated by a backward wave oscillator (BWO) operating in the superradiance regime. The BWO is driven by a high-current electron beam (˜250 keV, ˜1.5 kA, ˜5 ns) propagating through a slow-wave structure in a guiding magnetic field of 2.5 T. The microwave beam is focused at the desired location by a dielectric lens. Experimentally obtained parameters of the microwave beam at its waist are used for numerical simulations, the results of which demonstrate the formation of a bubble in the plasma that has almost 100% electron density modulation and longitudinal and transverse electric fields of several kV/cm.

  20. Atomic Layer Deposition Al2O3 Thin Films in Magnetized Radio Frequency Plasma Source

    Science.gov (United States)

    Li, Xingcun; Chen, Qiang; Sang, Lijun; Yang, Lizhen; Liu, Zhongwei; Wang, Zhenduo

    Self-limiting deposition of aluminum oxide (Al2O3) thin films were accomplished by the plasma-enhanced chemical vapor deposition using trimethyl aluminum (TMA) and O2 as precursor and oxidant, respectively, where argon was kept flowing in whole deposition process as discharge and purge gas. In here we present a novel plasma source for the atomic layer deposition technology, magnetized radio frequency (RF) plasma. Difference from the commercial RF source, magnetic coils were amounted above the RF electrode, and the influence of the magnetic field strength on the deposition rate and morphology are investigated in detail. It concludes that a more than 3 Å/ purging cycle deposition rate and the good quality of ALD Al2O3 were achieved in this plasma source even without extra heating. The ultra-thin films were characterized by including Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectric spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The high deposition rates obtained at ambient temperatures were analyzed after in-situ the diagnostic of plasmas by Langmuir probe.

  1. Initial evaluation and comparison of plasma damage to atomic layer carbon materials using conventional and low T{sub e} plasma sources

    Energy Technology Data Exchange (ETDEWEB)

    Jagtiani, Ashish V.; Miyazoe, Hiroyuki; Chang, Josephine; Farmer, Damon B.; Engel, Michael; Neumayer, Deborah; Han, Shu-Jen; Engelmann, Sebastian U., E-mail: suengelm@us.ibm.com; Joseph, Eric A. [IBM, T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Boris, David R.; Hernández, Sandra C.; Walton, Scott G. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Lock, Evgeniya H. [Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2016-01-15

    The ability to achieve atomic layer precision is the utmost goal in the implementation of atomic layer etch technology. Carbon-based materials such as carbon nanotubes (CNTs) and graphene are single atomic layers of carbon with unique properties and, as such, represent the ultimate candidates to study the ability to process with atomic layer precision and assess impact of plasma damage to atomic layer materials. In this work, the authors use these materials to evaluate the atomic layer processing capabilities of electron beam generated plasmas. First, the authors evaluate damage to semiconducting CNTs when exposed to beam-generated plasmas and compare these results against the results using typical plasma used in semiconductor processing. The authors find that the beam generated plasma resulted in significantly lower current degradation in comparison to typical plasmas. Next, the authors evaluated the use of electron beam generated plasmas to process graphene-based devices by functionalizing graphene with fluorine, nitrogen, or oxygen to facilitate atomic layer deposition (ALD). The authors found that all adsorbed species resulted in successful ALD with varying impact on the transconductance of the graphene. Furthermore, the authors compare the ability of both beam generated plasma as well as a conventional low ion energy inductively coupled plasma (ICP) to remove silicon nitride (SiN) deposited on top of the graphene films. Our results indicate that, while both systems can remove SiN, an increase in the D/G ratio from 0.08 for unprocessed graphene to 0.22 to 0.26 for the beam generated plasma, while the ICP yielded values from 0.52 to 1.78. Generally, while some plasma-induced damage was seen for both plasma sources, a much wider process window as well as far less damage to CNTs and graphene was observed when using electron beam generated plasmas.

  2. Efficient computation of electron-electron bremsstrahlung emission in a hot thermal plasma

    Science.gov (United States)

    Haug, E.

    1989-07-01

    A formula for the cross section of electron-electron bremsstrahlung (EEB) in the center-of-mass system is used to calculate the spectrum of EEB in a hot thermal plasma as well as the total rate of energy loss due to EEB with a minimum amount of computing time.

  3. Electron beam generated whistler emissions in a laboratory plasma

    Energy Technology Data Exchange (ETDEWEB)

    Van Compernolle, B., E-mail: bvcomper@physics.ucla.edu; Pribyl, P.; Gekelman, W. [Department of Physics, University of California, Los Angeles (United States); An, X.; Bortnik, J.; Thorne, R. M. [Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles (United States)

    2015-12-10

    Naturally occurring whistler mode emissions in the magnetosphere, are important since they are responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. Recently, we reported on the first laboratory experiment where whistler waves exhibiting fast frequency chirping have been artificially produced [1]. A beam of energetic electrons is launched into a cold plasma and excites both chirping whistler waves and broadband waves. Here we extend our previous analysis by comparing the properties of the broadband waves with linear theory.

  4. Electron beam generated whistler emissions in a laboratory plasma

    Science.gov (United States)

    Van Compernolle, B.; An, X.; Bortnik, J.; Thorne, R. M.; Pribyl, P.; Gekelman, W.

    2015-12-01

    Naturally occurring whistler mode emissions in the magnetosphere, are important since they are responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. Recently, we reported on the first laboratory experiment where whistler waves exhibiting fast frequency chirping have been artificially produced [1]. A beam of energetic electrons is launched into a cold plasma and excites both chirping whistler waves and broadband waves. Here we extend our previous analysis by comparing the properties of the broadband waves with linear theory.

  5. Explosion of relativistic electron vortices in laser plasmas

    CERN Document Server

    Lezhnin, K V; Esirkepov, T Zh; Bulanov, S V; Gu, Y; Weber, S; Korn, G

    2016-01-01

    The interaction of high intensity laser radiation with underdense plasma may lead to the formation of electron vortices. Though being quasistationary on an electron timescales, these structures tend to expand on a proton timescale due to Coloumb repulsion of ions. Using a simple analytical model of a stationary vortex as initial condition, 2D PIC simulations are performed. A number of effects are observed such as vortex boundary field intensification, multistream instabilities at the vortex boundary, and bending of the vortex boundary with the subsequent transformation into smaller electron vortices.

  6. The Orsay polarized electron source from a flowing helium afterglow

    Science.gov (United States)

    Arianer, J.; Brissaud, I.; Essabaa, S.; Humblot, H.; Zerhouni, W.

    1993-12-01

    A polarized electron source was designed at Orsay. We have chosen to adapt the flowing helium afterglow source working at Rice University because it provides a very high polarization. We have investigated a new way for the optical pumping of the helium metastables. An 85% electron polarization was reached.

  7. Broadband Single-Shot Electron Spectrometer for GeV-Class Laser Plasma Based Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, K.; Wan, W.; Ybarrolaza, N.; Syversrud, D.; Wallig, J.; Leemans, W.P.

    2008-05-01

    Laser-plasma-based accelerators can provide electrons over a broad energy range and/or with large momentum spread. The electron beam energy distribution can be controlled via accurate control of laser and plasma properties, and beams with energies ranging from'0.5 to 1000 MeV have been observed. Measuring these energy distributions in a single shot requires the use of a diagnostic with large momentum acceptance and, ideally, sufficient resolution to accurately measure energy spread in the case of narrow energy spread. Such a broadband single-shot electron magnetic spectrometer for GeV-class laser-plasma-based accelerators has been developed at Lawrence Berkeley National Laboratory. A detailed description of the hardware and the design concept is presented, as well as a performance evaluation of the spectrometer. The spectrometer covered electron beam energies raging from 0.01 to 1.1 GeV in a single shot, and enabled the simultaneous measurement of the laser properties at the exit of the accelerator through the use of a sufficiently large pole gap. Based on measured field maps and 3rd-order transport analysis, a few percent-level resolution and determination of the absolute energy were achieved over the entire energy range. Laser-plasma-based accelerator experiments demonstrated the capability of the spectrometer as a diagnostic and its suitability for such a broadband electron source.

  8. Beam loading by distributed injection of electrons in a plasma wakefield accelerator.

    Science.gov (United States)

    Vafaei-Najafabadi, N; Marsh, K A; Clayton, C E; An, W; Mori, W B; Joshi, C; Lu, W; Adli, E; Corde, S; Litos, M; Li, S; Gessner, S; Frederico, J; Fisher, A S; Wu, Z; Walz, D; England, R J; Delahaye, J P; Clarke, C I; Hogan, M J; Muggli, P

    2014-01-17

    We show through experiments and supporting simulations that propagation of a highly relativistic and dense electron bunch through a plasma can lead to distributed injection of electrons, which depletes the accelerating field, i.e., beam loads the wake. The source of the injected electrons is ionization of the second electron of rubidium (Rb II) within the wake. This injection of excess charge is large enough to severely beam load the wake, and thereby reduce the transformer ratio T. The reduction of the average T with increasing beam loading is quantified for the first time by measuring the ratio of peak energy gain and loss of electrons while changing the beam emittance. Simulations show that beam loading by Rb II electrons contributes to the reduction of the peak accelerating field from its weakly loaded value of 43  GV/m to a strongly loaded value of 26  GV/m.

  9. Plasma shape control by pulsed solenoid on laser ion source

    Science.gov (United States)

    Sekine, M.; Ikeda, S.; Romanelli, M.; Kumaki, M.; Fuwa, Y.; Kanesue, T.; Hayashizaki, N.; Lambiase, R.; Okamura, M.

    2015-09-01

    A Laser ion source (LIS) provides high current heavy ion beams with a very simple mechanical structure. Plasma is produced by a pulsed laser ablation of a solid state target and ions are extracted by an electric field. However, it was difficult to manipulate the beam parameters of a LIS, since the plasma condition could only be adjusted by the laser irradiation condition. To enhance flexibility of LIS operation, we employed a pulsed solenoid in the plasma drift section and investigated the effect of the solenoid field on singly charged iron beams. The experimentally obtained current profile was satisfactorily controlled by the pulsed magnetic field. This approach may also be useful to reduce beam emittance of a LIS.

  10. Plasma shape control by pulsed solenoid on laser ion source

    Energy Technology Data Exchange (ETDEWEB)

    Sekine, M. [Tokyo Institute of Technology, Meguro-ku, Tokyo 2-12-1 (Japan); RIKEN, Wako, Saitama 351-0198 (Japan); Ikeda, S. [Tokyo Institute of Technology, Yokohama, Kanagawa 226-8502 (Japan); RIKEN, Wako, Saitama 351-0198 (Japan); Romanelli, M. [Cornell University, Ithaca, NY 14850 (United States); Kumaki, M. [RIKEN, Wako, Saitama 351-0198 (Japan); Waseda University, Shinjuku, Tokyo 169-0072 (Japan); Fuwa, Y. [RIKEN, Wako, Saitama 351-0198 (Japan); Kyoto University, Uji, Kyoto 611-0011 (Japan); Kanesue, T. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Hayashizaki, N. [Tokyo Institute of Technology, Meguro-ku, Tokyo 2-12-1 (Japan); Lambiase, R. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Okamura, M. [RIKEN, Wako, Saitama 351-0198 (Japan); Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2015-09-21

    A Laser ion source (LIS) provides high current heavy ion beams with a very simple mechanical structure. Plasma is produced by a pulsed laser ablation of a solid state target and ions are extracted by an electric field. However, it was difficult to manipulate the beam parameters of a LIS, since the plasma condition could only be adjusted by the laser irradiation condition. To enhance flexibility of LIS operation, we employed a pulsed solenoid in the plasma drift section and investigated the effect of the solenoid field on singly charged iron beams. The experimentally obtained current profile was satisfactorily controlled by the pulsed magnetic field. This approach may also be useful to reduce beam emittance of a LIS.

  11. Bright X-ray source from a laser-driven micro-plasma-waveguide

    CERN Document Server

    Yi, Longqing

    2016-01-01

    Bright tunable x-ray sources have a number of applications in basic science, medicine and industry. The most powerful sources are synchrotrons, where relativistic electrons are circling in giant storage rings. In parallel, compact laser-plasma x-ray sources are being developed. Owing to the rapid progress in laser technology, very high-contrast femtosecond laser pulses of relativistic intensities become available. These pulses allow for interaction with micro-structured solid-density plasma without destroying the structure by parasitic pre-pulses. The high-contrast laser pulses as well as the manufacturing of materials at micro- and nano-scales open a new realm of possibilities for laser interaction with photonic materials at the relativistic intensities. Here we demonstrate, via numerical simulations, that when coupling with a readily available 1.8 Joule laser, a micro-plasma-waveguide (MPW) may serve as a novel compact x-ray source. Electrons are extracted from the walls by the laser field and form a dense ...

  12. The evolution of electronic reference sources

    OpenAIRE

    Van Epps, Amy S

    2004-01-01

    Purpose To provide a historical look at the development of web versions of reference materials and discuss what makes an easy-to-use and useful electronic handbook. Design/methodology/approach Electronic reference materials were limited to handbooks available on the web. Observations and assumptions about usability are tested with an information retrieval test for specific tasks in print and online editions of the same texts. Findings Recommended adoption of those elements which create a w...

  13. The evolution of electronic reference sources

    OpenAIRE

    Van Epps, Amy S.

    2004-01-01

    Purpose To provide a historical look at the development of web versions of reference materials and discuss what makes an easy-to-use and useful electronic handbook. Design/methodology/approach Electronic reference materials were limited to handbooks available on the web. Observations and assumptions about usability are tested with an information retrieval test for specific tasks in print and online editions of the same texts. Findings Recommended adoption of those elements which create a w...

  14. Microscopic theory of electron absorption by plasma-facing surfaces

    Science.gov (United States)

    Bronold, F. X.; Fehske, H.

    2017-01-01

    We describe a method for calculating the probability with which the wall of a plasma absorbs an electron at low energy. The method, based on an invariant embedding principle, expresses the electron absorption probability as the probability for transmission through the wall’s long-range surface potential times the probability to stay inside the wall despite of internal backscattering. To illustrate the approach we apply it to a SiO2 surface. Besides emission of optical phonons inside the wall we take elastic scattering at imperfections of the plasma-wall interface into account and obtain absorption probabilities significantly less than unity in accordance with available electron-beam scattering data but in disagreement with the widely used perfect absorber model.

  15. Microscopic theory of electron absorption by plasma-facing surfaces

    CERN Document Server

    Bronold, Franz X

    2016-01-01

    We describe a method for calculating the probability with which the wall of a plasma absorbs an electron at low energy. The method, based on an invariant embedding principle, expresses the electron absorption probability as the probability for transmission through the wall's long-range surface potential times the probability to stay inside the wall despite of internal backscattering. To illustrate the approach we apply it to a \\SiOTwo\\ surface. Besides emission of optical phonons inside the wall we take elastic scattering at imperfections of the plasma-wall interface into account and obtain absorption probabilities significantly less than unity in accordance with available electron-beam scattering data but in disagreement with the widely used perfect absorber model.

  16. [Experimental investigation of laser plasma soft X-ray source with gas target].

    Science.gov (United States)

    Ni, Qi-liang; Gong, Yan; Lin, Jing-quan; Chen, Bo; Cao, Jian-lin

    2003-02-01

    This paper describes a debris-free laser plasma soft X-ray source with a gas target, which has high operating frequency and can produce strong soft X-ray radiation. The valve of this light source is drived by a piezoelectrical ceramic whose operating frequency is up to 400 Hz. In comparison with laser plasma soft X-ray sources using metal target, the light source is debris-free. And it has higher operating frequency than gas target soft X-ray sources whose nozzle is controlled by a solenoid valve. A channel electron multiplier (CEM) operating in analog mode is used to detect the soft X-ray generated by the laser plasma source, and the CEM's output is fed to to a charge-sensitive preamplifier for further amplification purpose. Output charges from the CEM are proportional to the amplitude of the preamplifier's output voltage. Spectra of CO2, Xe and Kr at 8-14 nm wavelength which can be used for soft X-ray projection lithography are measured. The spectrum for CO2 consists of separate spectral lines originate mainly from the transitions in Li-like and Be-like ions. The Xe spectrum originating mainly from 4d-5f, 4d-4f, 4d-6p and 4d-5p transitions in multiply charged xenon ions. The spectrum for Kr consists of separate spectral lines and continuous broad spectra originating mainly from the transitions in Cu-, Ni-, Co- and Fe-like ions.

  17. Hydrogen Plasma Generation with 200 MHz RF Ion Source

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeongtae; Park, Kwangmook; Seo, Dong Hyuk; Kim, Han-Sung; Kwon, Hyeok-Jung; Cho, Yong-Sub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The ion source for the system is required to be rugged with 2000 hours maintenance free operation time because it is installed in the vessel filled with SF6 gas at the pressure of 10 bar. A 200 MHz RF ion source is considered as an ion source. It is a simple construction and provides long life operation. The specifications of the ion source are 5 kV extraction voltage and 1 mA beam current referenced to the proton. RF ion source has been developed and undergone a performance test. Results of the test are presented. 200 MHz RF ion source is designated and manufactured. First of all test stand test of ion source are set up for a performance test of ion source. It includes a RF ion source, a 200-MHz RF system, beam extraction system, vacuum system, beam extraction system, and beam diagnostic system. At pressure of 1.2E-5 torr, hydrogen plasma is generated with net RF power 70 W. Pyrex tube surrounded by an inductive coil takes the role of vessel and discharge is enhanced with field of permanent magnets.

  18. Numerical study of plasma generation process and internal antenna heat loadings in J-PARC RF negative ion source

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, T., E-mail: shibat@post.j-parc.jp; Ueno, A.; Oguri, H.; Ohkoshi, K.; Ikegami, K.; Takagi, A.; Asano, H.; Naito, F. [J-PARC Center, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Nishida, K.; Mochizuki, S.; Hatayama, A. [Keio University, Hiyoshi, Kohoku-ku, Yokohama-shi, Kanagawa-ken 223-8522 (Japan); Mattei, S.; Lettry, J. [European Organization for Nuclear Research (CERN), 1211 Geneva 23 (Switzerland)

    2016-02-15

    A numerical model of plasma transport and electromagnetic field in the J-PARC (Japan Proton Accelerator Research Complex) radio frequency ion source has been developed to understand the relation between antenna coil heat loadings and plasma production/transport processes. From the calculation, the local plasma density increase is observed in the region close to the antenna coil. Electrons are magnetized by the magnetic field line with absolute magnetic flux density 30–120 Gauss which leads to high local ionization rate. The results suggest that modification of magnetic configuration can be made to reduce plasma heat flux onto the antenna.

  19. submitter Numerical study of plasma generation process and internal antenna heat loadings in J-PARC RF negative ion source

    CERN Document Server

    Shibata, T; Mochizuki, S; Mattei, S; Lettry, J; Hatayama, A; Ueno, A; Oguri, H; Ohkoshi, K; Ikegami, K; Takagi, A; Asano, H; Naito, F

    2016-01-01

    A numerical model of plasma transport and electromagnetic field in the J-PARC (Japan Proton Accelerator Research Complex) radio frequency ion source has been developed to understand the relation between antenna coil heat loadings and plasma production/transport processes. From the calculation, the local plasma density increase is observed in the region close to the antenna coil. Electrons are magnetized by the magnetic field line with absolute magnetic flux density 30-120 Gauss which leads to high local ionization rate. The results suggest that modification of magnetic configuration can be made to reduce plasma heat flux onto the antenna.

  20. Plasma expansion across a transverse magnetic field in a negative hydrogen ion source for fusion

    Science.gov (United States)

    Fantz, U.; Schiesko, L.; Wünderlich, D.

    2014-08-01

    High power negative hydrogen ion sources operating at 0.3 Pa are a key component of the neutral beam injection systems for the international fusion experiment ITER. To achieve the required large ion current at a tolerable number of co-extracted electrons the source is equipped with a magnetic filter field (up to 10 mT). The IPP prototype source (1/8 of the area of the ITER source) has been equipped with a flexible magnetic filter frame to perform filter field studies (position, polarity, strength). Axial profiles of the plasma parameters are measured with two Langmuir probes, positioned in the upper and the lower half of the expansion chamber. In addition to the expected decrease in electron temperature and density a vertical drift develops the direction depending on the polarity of the field. Without field no drift is observed. The drift is less pronounced in caesium seeded discharges and almost vanishes in deuterium, indicating an influence of the ion mass on the drift. A comparison with results from a half-size ITER source reveals that the plasma is much more uniform in the large source.

  1. H- ion production in electron cyclotron resonance driven multicusp volume source

    Science.gov (United States)

    Ivanov, A. A.; Rouillé, C.; Bacal, M.; Arnal, Y.; Béchu, S.; Pelletier, J.

    2004-05-01

    We have used the existing magnetic multicusp configuration of the large volume H- source Camembert III to confine the plasma created by seven elementary multidipolar electron cyclotron resonance (ECR) sources, operating at 2.45 GHz. We varied the pressure from 1 to 4 mTorr, while the total power of the microwave generator was varied between 500 W and 1 kW. We studied the plasma created by this system and measured the various plasma parameters, including the density and temperature of the negative hydrogen ions which are compared to the data obtained in a chamber with elementary ECR sources without multicusp magnetic confinement. The electron temperature is lower than that obtained with similar elementary sources in the absence of the magnetic multicusp field. We found that at pressures in the range from 2 to 4 mTorr and microwave power of up to 1 kW, the electron temperature is optimal for H- ion production (0.6-0.8 eV). This could indicate that the multicusp configuration effectively traps the fast electrons produced by the ECR discharge.

  2. A novel plasma source for sterilization of living tissues

    Energy Technology Data Exchange (ETDEWEB)

    Martines, E; Zuin, M; Cavazzana, R; Gazza, E; Serianni, G; Spagnolo, S; Spolaore, M [Consorzio RFX, Associazione Euratom-ENEA sulla Fusione, Padova (Italy); Leonardi, A; Deligianni, V [Department of Neuroscience, Ophthalmology Unit, University of Padova (Italy); Brun, P; Aragona, M [Department of Histology, Microbiology and Medical Biotechnology, Histology Unit, University of Padova (Italy); Castagliuolo, I; Brun, P [Department of Histology, Microbiology and Medical Biotechnology, Microbiology Unit, University of Padova (Italy)], E-mail: emilio.martines@igi.cnr.it

    2009-11-15

    A source for the production of low-power plasmas at atmospheric pressure, to be used for the nondamaging sterilization of living tissues, is presented. The source, powered by radiofrequency and working with a helium flow, has a specific configuration, studied to prevent the formation of electric arcs dangerous to living matter. It is capable of killing different types of bacteria with a decimal reduction time of 1-2 min; on the contrary, human cells such as conjunctival fibroblasts were found to be almost unharmed by the plasma. A high concentration of OH radicals, likely to be the origin of the sterilizing effect, is detected through their UV emission lines. The effect of the UV and the OH radicals on the fibroblasts was analysed and no significant effects were detected.

  3. Applications of plasma sources for nitric oxide medicine

    Science.gov (United States)

    Vasilets, Victor; Shekhter, Anatoly; Pekshev, Alexander

    2013-09-01

    Nitric oxide (NO) has important roles in the function of many tissues and organs. Wound healing processes are always accompanying by the increase of nitric oxide concentration in wound tissue. These facts suggest a possible therapeutic use of various NO donors for the acceleration of the wound healing and treatment of other diseases. Our previous studies indicated that gaseous NO flow produced by air-plasma generators acts beneficially on the wound healing. This beneficial effect could be caused by the mechanism involving peroxynitrite as an intermediate. As a result of mobilization of various antioxidant reactions more endogenous NO molecules become available as signaling molecules. to regulate the metabolic processes in wound tissue. In this paper different air plasma sources generated therapeutic concentrations of NO are discussed. The concentration of NO and other therapeutically important gas products are estimated by thermodynamic simulation. Synergy effects of NO with other plasma components are discussed as a factor enhancing therapeutic results. Some new medical application of plasma devices are presented. Advanced Plasma Therapies Inc.

  4. Tin LPP plasma control in the argon cusp source

    Science.gov (United States)

    McGeoch, Malcolm W.

    2016-03-01

    The argon cusp plasma has been introduced [1,2] for 500W class tin LPP exhaust control in view of its high power handling, predicted low tin back-scatter from a beam dump, and avoidance of hydrogen usage. The physics of tin ion control by a plasma is first discussed. Experimentally, cusp stability and exhaust disc geometry have previously been proved at full scale [2], the equivalent of 300W-500W usable EUV. Here we verify operation of the plasma barrier that maintains a high argon density next to the collector, for its protection, and a low density in the long path toward the intermediate focus, for efficiency. A pressure differential of 2Pa has been demonstrated in initial work. Other aspects of tin LPP plasma control by the cusp have now been demonstrated using tin ions from a low Hz 130mJ CO2 laser pulse onto a solid tin surface at the cusp center. Plasma is rejected at the design to match a specified exhaust power is discussed. In view of this work, argon cusp exhaust control appears to be very promising for 500W class tin LPP sources.

  5. Sheath overlap during very large scale plasma source ion implantation

    Science.gov (United States)

    Cluggish, B. P.; Munson, C. P.

    1998-12-01

    Measurements of plasma source ion implantation have been performed on a large target of complex geometry. The target consists of 1000 aluminum, automotive piston surrogates mounted on four racks; total surface area is over 16 m2. The four racks are positioned parallel to each other, 0.25 m apart, in an 8 m3 vacuum chamber. The racks of pistons are immersed in a capacitive radio frequency plasma, with an argon gas pressure of 20-65 mPa. Langmuir probe measurements indicate that the plasma density profile is highly nonuniform, due to particle losses to the racks of pistons. The plasma ions are implanted into the pistons by pulse biasing the workpiece to negative voltages as low as -18 kV for up to 20 μs. During the voltage pulse, the high-voltage sheaths from adjacent racks of pistons converge towards each other. At plasma densities less than 109 cm-3 the sheaths are observed to overlap. Measurements of the sheath overlap time are compared with standard analytic theory and with simulations run with a two-dimensional particle-in-cell code.

  6. Laboratory Plasma Source as an MHD Model for Astrophysical Jets

    Science.gov (United States)

    Mayo, Robert M.

    1997-01-01

    The significance of the work described herein lies in the demonstration of Magnetized Coaxial Plasma Gun (MCG) devices like CPS-1 to produce energetic laboratory magneto-flows with embedded magnetic fields that can be used as a simulation tool to study flow interaction dynamic of jet flows, to demonstrate the magnetic acceleration and collimation of flows with primarily toroidal fields, and study cross field transport in turbulent accreting flows. Since plasma produced in MCG devices have magnetic topology and MHD flow regime similarity to stellar and extragalactic jets, we expect that careful investigation of these flows in the laboratory will reveal fundamental physical mechanisms influencing astrophysical flows. Discussion in the next section (sec.2) focuses on recent results describing collimation, leading flow surface interaction layers, and turbulent accretion. The primary objectives for a new three year effort would involve the development and deployment of novel electrostatic, magnetic, and visible plasma diagnostic techniques to measure plasma and flow parameters of the CPS-1 device in the flow chamber downstream of the plasma source to study, (1) mass ejection, morphology, and collimation and stability of energetic outflows, (2) the effects of external magnetization on collimation and stability, (3) the interaction of such flows with background neutral gas, the generation of visible emission in such interaction, and effect of neutral clouds on jet flow dynamics, and (4) the cross magnetic field transport of turbulent accreting flows. The applicability of existing laboratory plasma facilities to the study of stellar and extragalactic plasma should be exploited to elucidate underlying physical mechanisms that cannot be ascertained though astrophysical observation, and provide baseline to a wide variety of proposed models, MHD and otherwise. The work proposed herin represents a continued effort on a novel approach in relating laboratory experiments to

  7. Photoelectron Emission from Metal Surfaces Induced by Radiation Emitted by a 14 GHz Electron Cyclotron Resonance Ion Source

    CERN Document Server

    Laulainen, Janne; Koivisto, Hannu; Komppula, Jani; Kronholm, Risto; Tarvainen, Olli

    2015-01-01

    Photoelectron emission measurements have been performed using a room-temperature 14 GHz ECR ion source. It is shown that the photoelectron emission from Al, Cu, and stainless steel (SAE 304) surfaces, which are common plasma chamber materials, is predominantly caused by radiation emitted from plasma with energies between 8 eV and 1 keV. Characteristic X-ray emission and bremsstrahlung from plasma have a negligible contribution to the photoelectron emission. It is estimated from the measured data that the maximum conceivable photoelectron flux from plasma chamber walls is on the order of 10 % of the estimated total electron losses from the plasma.

  8. Photoelectron emission from metal surfaces induced by radiation emitted by a 14 GHz electron cyclotron resonance ion source

    Science.gov (United States)

    Laulainen, Janne; Kalvas, Taneli; Koivisto, Hannu; Komppula, Jani; Kronholm, Risto; Tarvainen, Olli

    2016-02-01

    Photoelectron emission measurements have been performed using a room-temperature 14 GHz ECR ion source. It is shown that the photoelectron emission from Al, Cu, and stainless steel (SAE 304) surfaces, which are common plasma chamber materials, is predominantly caused by radiation emitted from plasma with energies between 8 eV and 1 keV. Characteristic X-ray emission and bremsstrahlung from plasma have a negligible contribution to the photoelectron emission. It is estimated from the measured data that the maximum conceivable photoelectron flux from plasma chamber walls is on the order of 10% of the estimated total electron losses from the plasma.

  9. Photoelectron emission from metal surfaces induced by radiation emitted by a 14 GHz electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Laulainen, Janne, E-mail: janne.p.laulainen@student.jyu.fi; Kalvas, Taneli; Koivisto, Hannu; Komppula, Jani; Kronholm, Risto; Tarvainen, Olli [Department of Physics, University of Jyvaskyla, P.O. Box 35, FI-40014 Jyvaskyla (Finland)

    2016-02-15

    Photoelectron emission measurements have been performed using a room-temperature 14 GHz ECR ion source. It is shown that the photoelectron emission from Al, Cu, and stainless steel (SAE 304) surfaces, which are common plasma chamber materials, is predominantly caused by radiation emitted from plasma with energies between 8 eV and 1 keV. Characteristic X-ray emission and bremsstrahlung from plasma have a negligible contribution to the photoelectron emission. It is estimated from the measured data that the maximum conceivable photoelectron flux from plasma chamber walls is on the order of 10% of the estimated total electron losses from the plasma.

  10. A microwave plasma source for VUV atmospheric photochemistry

    OpenAIRE

    Tigrine, Sarah; Carrasco, Nathalie; Vettier, Ludovic; Cernogora, Guy

    2017-01-01

    International audience; Microwave plasma discharges working at low pressure are nowadays a well-developed technique mainly used to provide radiations at different wavelengths. The aim of this work is to show that those discharges are an efficient windowless VUV photon source for planetary atmospheric photochemistry experiments. To do this, we use a surfatron-type discharge with a neon gas flow in the mbar pressure range coupled to a photochemical reactor. Working in the VUV range allows to fo...

  11. Towards laboratory produced relativistic electron-positron pair plasmas

    Science.gov (United States)

    Chen, Hui; Meyerhofer, D. D.; Wilks, S. C.; Cauble, R.; Dollar, F.; Falk, K.; Gregori, G.; Hazi, A.; Moses, E. I.; Murphy, C. D.; Myatt, J.; Park, J.; Seely, J.; Shepherd, R.; Spitkovsky, A.; Stoeckl, C.; Szabo, C. I.; Tommasini, R.; Zulick, C.; Beiersdorfer, P.

    2011-12-01

    We review recent experimental results on the path to producing electron-positron pair plasmas using lasers. Relativistic pair-plasmas and jets are believed to exist in many astrophysical objects and are often invoked to explain energetic phenomena related to Gamma Ray Bursts and Black Holes. On earth, positrons from radioactive isotopes or accelerators are used extensively at low energies (sub-MeV) in areas related to surface science positron emission tomography and basic antimatter science. Experimental platforms capable of producing the high-temperature pair-plasma and high-flux jets required to simulate astrophysical positron conditions have so far been absent. In the past few years, we performed extensive experiments generating positrons with intense lasers where we found that relativistic electron and positron jets are produced by irradiating a solid gold target with an intense picosecond laser pulse. The positron temperatures in directions parallel and transverse to the beam both exceeded 0.5 MeV, and the density of electrons and positrons in these jets are of order 10 16 cm -3 and 10 13 cm -3, respectively. With the increasing performance of high-energy ultra-short laser pulses, we expect that a high-density, up to 10 18 cm -3, relativistic pair-plasma is achievable, a novel regime of laboratory-produced hot dense matter.

  12. Emittance of a Field Emission Electron Source

    Science.gov (United States)

    2010-01-05

    approximately correct. The gate and switching time A thermionic source is run space-charge limited for which the current varies as a power 3 /2 of the grid...and millimeter-wave power amplifiers that use thermionic cathodes, requiring the sources to produce a current density characteristic of that in the...Rb radius, magnetic field strength B, accelerating voltage Vb, frequency f inversely related to Rb, harmonic number n, and emit- tance via 1− J

  13. Improvement in brightness of multicusp-plasma ion source

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Q.; Jiang, X.; King, T-J.; Leung, K-N.; Standiford, K.; Wilde, S.B.

    2002-05-24

    The beam brightness of a multicusp-plasma ion source has been substantially improved by optimizing the source configuration and extractor geometry. The current density of a 2 keV He{sup +} beam extracted from a 7.5-cm-diameter source operating at 2.5 kW RF power is {approx}100 mA/cm{sup 2}, which is {approx}10 times larger than that of a beam extracted from a 5-cm-diameter source operating at 1 kW RF power. A smaller focused beam spot size is achieved with a counter-bored extractor instead of a conventional (''through-hole'') extractor, resulting another order of magnitude improvement in beam current density. Measured brightness can be as high as 440 A/cm{sup 2}Sr, which represents a 30 times improvement over prior work.

  14. Efficient cesiation in RF driven surface plasma negative ion source

    Energy Technology Data Exchange (ETDEWEB)

    Belchenko, Yu.; Ivanov, A.; Konstantinov, S.; Sanin, A., E-mail: sanin@inp.nsk.su; Sotnikov, O. [Budker Institute of Nuclear Physics, Siberian Branch of Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2016-02-15

    Experiments on hydrogen negative ions production in the large radio-frequency negative ion source with cesium seed are described. The system of directed cesium deposition to the plasma grid periphery was used. The small cesium seed (∼0.5 G) provides an enhanced H{sup −} production during a 2 month long experimental cycle. The gradual increase of negative ion yield during the long-term source runs was observed after cesium addition to the source. The degraded H{sup −} production was recorded after air filling to the source or after the cesium washing away from the driver and plasma chamber walls. The following source conditioning by beam shots produces the gradual recovery of H{sup −} yield to the high value. The effect of H{sup −} yield recovery after cesium coverage passivation by air fill was studied. The concept of cesium coverage replenishment and of H{sup −} yield recovery due to sputtering of cesium from the deteriorated layers is discussed.

  15. Arbitrary amplitude slow electron-acoustic solitons in three-electron temperature space plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Mbuli, L. N. [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200, Republic of South Africa (South Africa); University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa); Maharaj, S. K. [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200, Republic of South Africa (South Africa); Bharuthram, R. [University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa); Singh, S. V.; Lakhina, G. S. [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India)

    2015-06-15

    We examine the characteristics of large amplitude slow electron-acoustic solitons supported in a four-component unmagnetised plasma composed of cool, warm, hot electrons, and cool ions. The inertia and pressure for all the species in this plasma system are retained by assuming that they are adiabatic fluids. Our findings reveal that both positive and negative potential slow electron-acoustic solitons are supported in the four-component plasma system. The polarity switch of the slow electron-acoustic solitons is determined by the number densities of the cool and warm electrons. Negative potential solitons, which are limited by the cool and warm electron number densities becoming unreal and the occurrence of negative potential double layers, are found for low values of the cool electron density, while the positive potential solitons occurring for large values of the cool electron density are only limited by positive potential double layers. Both the lower and upper Mach numbers for the slow electron-acoustic solitons are computed and discussed.

  16. Inductively Coupled Plasma and Electron Cyclotron Resonance Plasma Etching of InGaAlP Compound Semiconductor System

    Energy Technology Data Exchange (ETDEWEB)

    Abernathy, C.R.; Hobson, W.S.; Hong, J.; Lambers, E.S.; Pearton, S.J.; Shul, R.J.

    1998-11-04

    Current and future generations of sophisticated compound semiconductor devices require the ability for submicron scale patterning. The situation is being complicated since some of the new devices are based on a wider diversity of materials to be etched. Conventional IUE (Reactive Ion Etching) has been prevalent across the industry so far, but has limitations for materials with high bond strengths or multiple elements. IrI this paper, we suggest high density plasmas such as ECR (Electron Cyclotron Resonance) and ICP (Inductively Coupled Plasma), for the etching of ternary compound semiconductors (InGaP, AIInP, AlGaP) which are employed for electronic devices like heterojunction bipolar transistors (HBTs) or high electron mobility transistors (HEMTs), and photonic devices such as light-emitting diodes (LEDs) and lasers. High density plasma sources, opeiating at lower pressure, are expected to meet target goals determined in terms of etch rate, surface morphology, surface stoichiometry, selectivity, etc. The etching mechanisms, which are described in this paper, can also be applied to other III-V (GaAs-based, InP-based) as well as III-Nitride since the InGaAIP system shares many of the same properties.

  17. Extended quasiparticle approximation for relativistic electrons in plasmas

    Directory of Open Access Journals (Sweden)

    V.G.Morozov

    2006-01-01

    Full Text Available Starting with Dyson equations for the path-ordered Green's function, it is shown that the correlation functions for relativistic electrons (positrons in a weakly coupled non-equilibrium plasmas can be decomposed into sharply peaked quasiparticle parts and off-shell parts in a rather general form. To leading order in the electromagnetic coupling constant, this decomposition yields the extended quasiparticle approximation for the correlation functions, which can be used for the first principle calculation of the radiation scattering rates in QED plasmas.

  18. The comparison of DNA damage induced by micro DBD plasma and low energy electron for curing human diseases

    Science.gov (United States)

    Park, Yeunsoo

    2015-09-01

    It is well known that low energy electrons (LEE, especially below 10 eV) can generate DNA damage via indirect action named dissociative electron attachment (DEA). We can now explain some parts of the exact mechanism on DNA damage by LEE collision with direct ionization effect when cancer patients get the radiotherapy. It is kind of remarkable information in the field of radiation therapy. However, it is practically very difficult to directly apply this finding to human disease cure due to difficulty of LEE therapy actualization and request of further clinical studies. Recently, there is a novel challenge in plasma application, that is, how we can apply plasma technology to diagnosis and treatment of many serious diseases like cancer. Cold atmospheric pressure plasma (CAPP) is a very good source to apply to plasma medicine and bio-applications because of low temperature, low cost, and easy handling. Some scientists have already reported good results related to clinical plasma application. The purposes of this study are to further find out exact mechanisms of DNA damage by LEE at the molecular level, to verify new DNA damage like structural alteration on DNA subunits and to compare DNA damage by LEE and plasma source. We will keep expanding our study to DNA damage by plasma source to develop plasma-based new medical and biological applications. We will show some recent results, DNA damage by LEE and non-thermal plasma.

  19. Kinetic simulations of ladder climbing by electron plasma waves

    Science.gov (United States)

    Hara, Kentaro; Barth, Ido; Kaminski, Erez; Dodin, I. Y.; Fisch, N. J.

    2017-05-01

    The energy of plasma waves can be moved up and down the spectrum using chirped modulations of plasma parameters, which can be driven by external fields. Depending on whether the wave spectrum is discrete (bounded plasma) or continuous (boundless plasma), this phenomenon is called ladder climbing (LC) or autoresonant acceleration of plasmons. It was first proposed by Barth et al. [Phys. Rev. Lett. 115, 075001 (2015), 10.1103/PhysRevLett.115.075001] based on a linear fluid model. In this paper, LC of electron plasma waves is investigated using fully nonlinear Vlasov-Poisson simulations of collisionless bounded plasma. It is shown that, in agreement with the basic theory, plasmons survive substantial transformations of the spectrum and are destroyed only when their wave numbers become large enough to trigger Landau damping. Since nonlinear effects decrease the damping rate, LC is even more efficient when practiced on structures like quasiperiodic Bernstein-Greene-Kruskal (BGK) waves rather than on Langmuir waves per se.

  20. Highly charged ion X-rays from Electron-Cyclotron Resonance Ion Sources

    OpenAIRE

    Indelicato, Paul; Boucard, S.; Covita, D. S.; Gotta, D.; Gruber, A; Hirtl, A.; Fuhrmann, H.; Le Bigot, E.-O.; Schlesser, S.; dos Santos, J. M. F.; Simons, L.M.; Stingelin, L.; Trassinelli, Martino; Veloso, J.; Wasser, A.

    2006-01-01

    Radiation from the highly-charged ions contained in the plasma of Electron-Cyclotron Resonance Ion Sources constitutes a very bright source of X-rays. Because the ions have a relatively low kinetic energy ($\\approx 1$~eV) transitions can be very narrow, containing only small Doppler broadening. We describe preliminary accurate measurements of two and three-electron ions with $Z=16$--18. We show how these measurement can test sensitively many-body relativistic calculations or can be used as X-...