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Sample records for ghz electron cyclotron

  1. Results of RIKEN superconducting electron cyclotron resonance ion source with 28 GHz.

    PubMed

    Higurashi, Y; Ohnishi, J; Nakagawa, T; Haba, H; Tamura, M; Aihara, T; Fujimaki, M; Komiyama, M; Uchiyama, A; Kamigaito, O

    2012-02-01

    We measured the beam intensity of highly charged heavy ions and x-ray heat load for RIKEN superconducting electron cyclotron resonance ion source with 28 GHz microwaves under the various conditions. The beam intensity of Xe(20+) became maximum at B(min) ∼ 0.65 T, which was ∼65% of the magnetic field strength of electron cyclotron resonance (B(ECR)) for 28 GHz microwaves. We observed that the heat load of x-ray increased with decreasing gas pressure and field gradient at resonance zone. It seems that the beam intensity of highly charged heavy ions with 28 GHz is higher than that with 18 GHz at same RF power.

  2. Control system renewal for efficient operation in RIKEN 18 GHz electron cyclotron resonance ion source

    SciTech Connect

    Uchiyama, A. Ozeki, K.; Higurashi, Y.; Kidera, M.; Komiyama, M.; Nakagawa, T.

    2016-02-15

    A RIKEN 18 GHz electron cyclotron resonance ion source (18 GHz ECRIS) is used as an external ion source at the Radioactive Ion Beam Factory (RIBF) accelerator complex to produce an intense beam of medium-mass heavy ions (e.g., Ca and Ar). In most components that comprise the RIBF, the control systems (CSs) are integrated by the Experimental Physics and Industrial Control System (EPICS). On the other hand, a non-EPICS-based system has hardwired controllers, and it is used in the 18 GHz ECRIS CS as an independent system. In terms of efficient and effective operation, the 18 GHz ECRIS CS as well as the RIBF CS should be renewed using EPICS. Therefore, we constructed an 18 GHz ECRIS CS by using programmable logic controllers with embedded EPICS technology. In the renewed system, an operational log system was developed as a new feature, for supporting of the 18 GHz ECRIS operation.

  3. Control system renewal for efficient operation in RIKEN 18 GHz electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Uchiyama, A.; Ozeki, K.; Higurashi, Y.; Kidera, M.; Komiyama, M.; Nakagawa, T.

    2016-02-01

    A RIKEN 18 GHz electron cyclotron resonance ion source (18 GHz ECRIS) is used as an external ion source at the Radioactive Ion Beam Factory (RIBF) accelerator complex to produce an intense beam of medium-mass heavy ions (e.g., Ca and Ar). In most components that comprise the RIBF, the control systems (CSs) are integrated by the Experimental Physics and Industrial Control System (EPICS). On the other hand, a non-EPICS-based system has hardwired controllers, and it is used in the 18 GHz ECRIS CS as an independent system. In terms of efficient and effective operation, the 18 GHz ECRIS CS as well as the RIBF CS should be renewed using EPICS. Therefore, we constructed an 18 GHz ECRIS CS by using programmable logic controllers with embedded EPICS technology. In the renewed system, an operational log system was developed as a new feature, for supporting of the 18 GHz ECRIS operation.

  4. Kinetic instabilities in pulsed operation mode of a 14 GHz electron cyclotron resonance ion source

    SciTech Connect

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

    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.

  5. Development of an 18 GHz superconducting electron cyclotron resonance ion source at RCNP.

    PubMed

    Yorita, Tetsuhiko; Hatanaka, Kichiji; Fukuda, Mitsuhiro; Kibayashi, Mitsuru; Morinobu, Shunpei; Okamura, Hiroyuki; Tamii, Atsushi

    2008-02-01

    An 18 GHz superconducting electron cyclotron resonance ion source has recently been developed and installed in order to extend the variety and the intensity of ions at the RCNP coupled cyclotron facility. Production of several ions such as O, N, Ar, Kr, etc., is now under development and some of them have already been used for user experiments. For example, highly charged heavy ion beams like (86)Kr(21+,23+) and intense (16)O(5+,6+) and (15)N(6+) ion beams have been provided for experiments. The metal ion from volatile compounds method for boron ions has been developed as well.

  6. First results of the 2.45 GHz Oshima electron cyclotron resonance ion source

    SciTech Connect

    Asaji, T.; Nakamura, T.; Furuse, M.; Hitobo, T.; Uchida, T.; Muramatsu, M.; Kato, Y.

    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.

  7. Electron heating and superthermal electron enhancement due to electron cyclotron heating in ISX-B at 28 GHz

    SciTech Connect

    Elder, G.B.; Hsuan, H.; England, A.C.

    1983-05-01

    A series of electron cyclotron heating (ECH) experiments was performed with a 28-GHz gyrotron on the Impurity Study Experiment (ISX-B) tokamak at Oak Ridge National Laboratory. Up to 70 kW of microwave power was injected into ISX-B from the high field side. Bulk heating was observed with a central temperature rise of approx. 370 eV from an original temperature of approx. 600 eV, as measured by Thomson scattering. With ECH and under low density conditions, large nonthermal signals were observed on electron cyclotron emission diagnostics at the first, second, and third harmonics. These signals sometimes became quite large after the end of the ECH pulse. The effects observed can be attributed to relatively small changes in the electron distribution function. The temporal behavior of the enhanced emission is tentatively attributed to the pitch angle scattering of superthermal electrons.

  8. The third generation superconducting 28 GHz electron cyclotron resonance ion source VENUS (invited)

    SciTech Connect

    Lyneis, C.; Leitner, D.; Leitner, M.; Taylor, C.; Abbott, S.

    2010-02-15

    VENUS is a third generation electron cyclotron resonance (ECR) ion source, which incorporates a high field superconducting NbTi magnet structure, a 28 GHz gryotron microwave source and a state of the art closed cycle cryosystem. During the decade from initial concept to regular operation, it has demonstrated both the feasibility and the performance levels of this new generation of ECR ion sources and required innovation on magnet construction, plasma chamber design, and beam transport. In this paper, the development, performance, and major innovations are described as well as a look to the potential to construct a fourth generation ECR ion source.

  9. Remote-Steering Antennas for 140 GHz Electron Cyclotron Heating of the Stellarator W7-X

    NASA Astrophysics Data System (ADS)

    Lechte, C.; Kasparek, W.; Plaum, B.; Zeitler, A.; Erckmann, V.; Laqua, H.; Schneider, N.; Weissgerber, M.; Bechtold, A.; Busch, M.; Szepaniak, B.

    2017-07-01

    For electron cyclotron resonance heating of the stellarator W7-X at IPP Greifswald, a 140 GHz/10 MW cw millimeter wave system has been built. Two out of 12 launchers will employ a remote-steering design. This paper describes the overall design of the two launchers, and design issues like input coupling structures, manufacturing of corrugated waveguides, optimization of the steering range, integration of vacuum windows, mitrebends and vacuum valves into the launchers, as well as low power tests of the finished waveguides.

  10. Ray Tracing Study of 170GHZ Electron Cyclotron Waves in Kstar Plasmas

    NASA Astrophysics Data System (ADS)

    Bae, Young-Soon; Joung, M.; Yang, H. L.; Namkung, W.; Cho, M. H.; Park, H.; Prater, R.; Ellis, R. A.; Hosea, J.

    2011-02-01

    The electron cyclotron heating/current drive (ECH/ECCD) system has become an essential tool for the fusion plasma research in toroidal devices. In Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak, development of high power and multi-frequency ECH/ECCD system is in progress. The frequencies employed in KSTAR are 84 GHz, 110 GHz, and 170 GHz. Multiple frequency sources can easily support the wide range of operating regimes from 1.5 T to 3.5 T in KSTAR tokamak. In particular, the 170 GHz source, that will be adapted to the ITER, corresponds to the second harmonic frequency of the KSTAR operating range from 2.6 T to 3.5 T. This frequency will be mainly used for the control of the local plasma current profile to manipulate the internal MHD instabilities such as the neoclassical tearing mode (NTM) critical in high-beta plasma operation. This paper presents simulated ray tracings of the 170 GHz EC waves for a various plasma conditions in KSTAR. The TORAY-GA ray tracing code is used, along with Interactive Data Language (IDL) procedures that create the input files, to study the effect of ECH/ECCD on the plasma equilibrium profiles as a function of the initial density and temperature profiles and of toroidal field.

  11. Status of KSTAR 170 GHz, 1 MW Electron Cyclotron Heating and Current Drive System

    SciTech Connect

    Joung, M.; Bae, Y. S.; Jeong, J. H.; Park, S.; Kim, H. J.; Yang, H. L.; Park, H.; Cho, M. H.; Namkung, W.; Hosea, J.; Ellis, R.; Sakamoto, K.; Kajiwara, K.; Doane, J.

    2011-12-23

    A 170 GHz Electron Cyclotron Heating and Current Drive (ECH/CD) system on KSTAR is designed to launch total 2.4 MW of power for up to 300 sec into the plasma. At present the first 1 MW ECH/CD system is under installation and commissioning for 2011 KSTAR campaign. The 170 GHz, 1 MW, 300 sec gyrotron and the matching optics unit (MOU) will be provided from JAEA under collaboration between NFRI and JAEA. The transmission line consists of MOU and 70 m long 63.5 mm ID corrugated waveguides with the eight miter bends. The 1 MW, 10 sec launcher is developed based on the existing two-mirror front-end launcher in collaboration with Princeton Plasma Physics Laboratory and Pohang University of Science and Technology, and is installed on the low field side in the KSTAR equatorial plane. The mirror pivot is located at 30 cm below from the equatorial plane. 3.6 MVA power supply system is manufactured and now is under commissioning to meet the triode gun operation of JAEA gyrotron. The power supply consists of 66 kV/55 A cathode power supply, mode-anode system, and 50 kV/160 mA body power supply. In this paper, the current status of KSTAR 170 GHz, 1 MW ECH/CD system will be presented as well as the experimental plan utilizing 170 GHz new ECH/CD system.

  12. Status report of the 28 GHz superconducting electron cyclotron resonance ion source VENUS (invited)

    SciTech Connect

    Leitner, D.; Lyneis, C.M.; Loew, T.; Todd, D.S.; Virostek, S.; Tarvainen, O.

    2006-03-15

    The superconducting versatile electron cyclotron resonance (ECR) ion source for nuclear science (VENUS) is a next generation superconducting ECR ion source designed to produce high-current, high-charge-state ions for the 88-Inch Cyclotron at the Lawrence Berkeley National Laboratory. VENUS also serves as the prototype ion source for the rare isotope accelerator (RIA) front end, where the goal is to produce intense beams of medium-charge-state ions. Example beams for the RIA accelerator are 15 p {mu}A of Kr{sup 17+}(260 e {mu}A), 12 p {mu}A of Xe{sup 20+} (240 e {mu}A of Xe{sup 20+}), and 8 p {mu}A of U{sup 28+}(230 e {mu}A). To achieve these high currents, VENUS has been optimized for operation at 28 GHz, reaching maximal confinement fields of 4 and 3 T axially and over 2.2 T on the plasma chamber wall radially. After a commissioning phase at 18 GHz, the source started the 28 GHz operation in the summer of 2004. During that ongoing 28 GHz commissioning process, record ion-beam intensities have been extracted. For instance, measured extracted currents for the low to medium charge states were 270 e {mu}A of Xe{sup 27+} and 245 e {mu}A of Bi{sup 29+}, while for the higher charge states 15 e {mu}A of Xe{sup 34+}, 15 e {mu}A of Bi{sup 41+}, and 0.5 e {mu}A of Bi{sup 50+} could be produced. Results from the ongoing 28 GHz commissioning as well as results using double-frequency heating with 18 and 28 GHz for oxygen and xenon are presented. The effect of the minimum B field on the ion source performance has been systematically measured for 18 and 28 GHz. In both cases the performance peaked at a minimum B field of about 80% of the resonance field. In addition, a strong dependence of the x-ray flux and energy on the minimum B field value was found.

  13. Progress in high-temperature oven development for 28 GHz electron cyclotron resonance ion source

    SciTech Connect

    Ohnishi, J. Higurashi, Y.; Nakagawa, T.

    2016-02-15

    We have been developing a high-temperature oven using UO{sub 2} in the 28 GHz superconducting electron cyclotron resonance ion source at RIKEN since 2013. A total of eleven on-line tests were performed. The longest operation time in a single test was 411 h, and the consumption rate of UO{sub 2} was approximately 2.4 mg/h. In these tests, we experienced several problems: the ejection hole of a crucible was blocked with UO{sub 2} and a crucible was damaged because of the reduction of tungsten strength at high temperature. In order to solve these problems, improvements to the crucible shape were made by simulations using ANSYS.

  14. Nitrogen ion implantation into various materials using 28 GHz electron cyclotron resonance ion source

    SciTech Connect

    Shin, Chang Seouk; Lee, Byoung-Seob; Choi, Seyong; Yoon, Jang-Hee; Kim, Hyun Gyu; Ok, Jung-Woo; Park, Jin Yong; Kim, Seong Jun; Bahng, Jungbae; Hong, Jonggi; Won, Mi-Sook; Lee, Seung Wook

    2016-02-15

    The installation of the 28 GHz electron cyclotron resonance ion source (ECRIS) ion implantation beamline was recently completed at the Korea Basic Science Institute. The apparatus contains a beam monitoring system and a sample holder for the ion implantation process. The new implantation system can function as a multipurpose tool since it can implant a variety of ions, ranging hydrogen to uranium, into different materials with precise control and with implantation areas as large as 1–10 mm{sup 2}. The implantation chamber was designed to measure the beam properties with a diagnostic system as well as to perform ion implantation with an in situ system including a mass spectrometer. This advanced implantation system can be employed in novel applications, including the production of a variety of new materials such as metals, polymers, and ceramics and the irradiation testing and fabrication of structural and functional materials to be used in future nuclear fusion reactors. In this investigation, the first nitrogen ion implantation experiments were conducted using the new system. The 28 GHz ECRIS implanted low-energy, multi-charged nitrogen ions into copper, zinc, and cobalt substrates, and the ion implantation depth profiles were obtained. SRIM 2013 code was used to calculate the profiles under identical conditions, and the experimental and simulation results are presented and compared in this report. The depths and ranges of the ion distributions in the experimental and simulation results agree closely and demonstrate that the new system will enable the treatment of various substrates for advanced materials research.

  15. Nitrogen ion implantation into various materials using 28 GHz electron cyclotron resonance ion source.

    PubMed

    Shin, Chang Seouk; Lee, Byoung-Seob; Choi, Seyong; Yoon, Jang-Hee; Kim, Hyun Gyu; Ok, Jung-Woo; Park, Jin Yong; Kim, Seong Jun; Bahng, Jungbae; Hong, Jonggi; Lee, Seung Wook; Won, Mi-Sook

    2016-02-01

    The installation of the 28 GHz electron cyclotron resonance ion source (ECRIS) ion implantation beamline was recently completed at the Korea Basic Science Institute. The apparatus contains a beam monitoring system and a sample holder for the ion implantation process. The new implantation system can function as a multipurpose tool since it can implant a variety of ions, ranging hydrogen to uranium, into different materials with precise control and with implantation areas as large as 1-10 mm(2). The implantation chamber was designed to measure the beam properties with a diagnostic system as well as to perform ion implantation with an in situ system including a mass spectrometer. This advanced implantation system can be employed in novel applications, including the production of a variety of new materials such as metals, polymers, and ceramics and the irradiation testing and fabrication of structural and functional materials to be used in future nuclear fusion reactors. In this investigation, the first nitrogen ion implantation experiments were conducted using the new system. The 28 GHz ECRIS implanted low-energy, multi-charged nitrogen ions into copper, zinc, and cobalt substrates, and the ion implantation depth profiles were obtained. SRIM 2013 code was used to calculate the profiles under identical conditions, and the experimental and simulation results are presented and compared in this report. The depths and ranges of the ion distributions in the experimental and simulation results agree closely and demonstrate that the new system will enable the treatment of various substrates for advanced materials research.

  16. Nitrogen ion implantation into various materials using 28 GHz electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Shin, Chang Seouk; Lee, Byoung-Seob; Choi, Seyong; Yoon, Jang-Hee; Kim, Hyun Gyu; Ok, Jung-Woo; Park, Jin Yong; Kim, Seong Jun; Bahng, Jungbae; Hong, Jonggi; Lee, Seung Wook; Won, Mi-Sook

    2016-02-01

    The installation of the 28 GHz electron cyclotron resonance ion source (ECRIS) ion implantation beamline was recently completed at the Korea Basic Science Institute. The apparatus contains a beam monitoring system and a sample holder for the ion implantation process. The new implantation system can function as a multipurpose tool since it can implant a variety of ions, ranging hydrogen to uranium, into different materials with precise control and with implantation areas as large as 1-10 mm2. The implantation chamber was designed to measure the beam properties with a diagnostic system as well as to perform ion implantation with an in situ system including a mass spectrometer. This advanced implantation system can be employed in novel applications, including the production of a variety of new materials such as metals, polymers, and ceramics and the irradiation testing and fabrication of structural and functional materials to be used in future nuclear fusion reactors. In this investigation, the first nitrogen ion implantation experiments were conducted using the new system. The 28 GHz ECRIS implanted low-energy, multi-charged nitrogen ions into copper, zinc, and cobalt substrates, and the ion implantation depth profiles were obtained. SRIM 2013 code was used to calculate the profiles under identical conditions, and the experimental and simulation results are presented and compared in this report. The depths and ranges of the ion distributions in the experimental and simulation results agree closely and demonstrate that the new system will enable the treatment of various substrates for advanced materials research.

  17. First results of 28 GHz superconducting electron cyclotron resonance ion source for KBSI accelerator

    NASA Astrophysics Data System (ADS)

    Park, Jin Yong; Lee, Byoung-Seob; Choi, Seyong; Kim, Seong Jun; Ok, Jung-Woo; Yoon, Jang-Hee; Kim, Hyun Gyu; Shin, Chang Seouk; Hong, Jonggi; Bahng, Jungbae; Won, Mi-Sook

    2016-02-01

    The 28 GHz superconducting electron cyclotron resonance (ECR) ion source has been developed to produce a high current heavy ion for the linear accelerator at KBSI (Korea Basic Science Institute). The objective of this study is to generate fast neutrons with a proton target via a p(Li,n)Be reaction. The design and fabrication of the essential components of the ECR ion source, which include a superconducting magnet with a liquid helium re-condensed cryostat and a 10 kW high-power microwave, were completed. The waveguide components were connected with a plasma chamber including a gas supply system. The plasma chamber was inserted into the warm bore of the superconducting magnet. A high voltage system was also installed for the ion beam extraction. After the installation of the ECR ion source, we reported the results for ECR plasma ignition at ECRIS 2014 in Russia. Following plasma ignition, we successfully extracted multi-charged ions and obtained the first results in terms of ion beam spectra from various species. This was verified by a beam diagnostic system for a low energy beam transport system. In this article, we present the first results and report on the current status of the KBSI accelerator project.

  18. First results of 28 GHz superconducting electron cyclotron resonance ion source for KBSI accelerator

    SciTech Connect

    Park, Jin Yong; Lee, Byoung-Seob; Choi, Seyong; Kim, Seong Jun; Ok, Jung-Woo; Yoon, Jang-Hee; Kim, Hyun Gyu; Shin, Chang Seouk; Hong, Jonggi; Bahng, Jungbae; Won, Mi-Sook

    2016-02-15

    The 28 GHz superconducting electron cyclotron resonance (ECR) ion source has been developed to produce a high current heavy ion for the linear accelerator at KBSI (Korea Basic Science Institute). The objective of this study is to generate fast neutrons with a proton target via a p(Li,n)Be reaction. The design and fabrication of the essential components of the ECR ion source, which include a superconducting magnet with a liquid helium re-condensed cryostat and a 10 kW high-power microwave, were completed. The waveguide components were connected with a plasma chamber including a gas supply system. The plasma chamber was inserted into the warm bore of the superconducting magnet. A high voltage system was also installed for the ion beam extraction. After the installation of the ECR ion source, we reported the results for ECR plasma ignition at ECRIS 2014 in Russia. Following plasma ignition, we successfully extracted multi-charged ions and obtained the first results in terms of ion beam spectra from various species. This was verified by a beam diagnostic system for a low energy beam transport system. In this article, we present the first results and report on the current status of the KBSI accelerator project.

  19. Emittance study of a 28 GHz electron cyclotron resonance ion source for the Rare Isotope Science Project superconducting linear accelerator.

    PubMed

    Park, Bum-Sik; Hong, In-Seok; Jang, Ji-Ho; Jin, Hyunchang; Choi, Sukjin; Kim, Yonghwan

    2016-02-01

    A 28 GHz electron cyclotron resonance (ECR) ion source is being developed for use as an injector for the superconducting linear accelerator of the Rare Isotope Science Project. Beam extraction from the ECR ion source has been simulated using the KOBRA3-INP software. The simulation software can calculate charged particle trajectories in three dimensional complex magnetic field structures, which in this case are formed by the arrangement of five superconducting magnets. In this study, the beam emittance is simulated to understand the effects of plasma potential, mass-to-charge ratio, and spatial distribution. The results of these simulations and their comparison to experimental results are presented in this paper.

  20. Emittance study of a 28 GHz electron cyclotron resonance ion source for the Rare Isotope Science Project superconducting linear accelerator

    SciTech Connect

    Park, Bum-Sik Hong, In-Seok; Jang, Ji-Ho; Jin, Hyunchang; Choi, Sukjin; Kim, Yonghwan

    2016-02-15

    A 28 GHz electron cyclotron resonance (ECR) ion source is being developed for use as an injector for the superconducting linear accelerator of the Rare Isotope Science Project. Beam extraction from the ECR ion source has been simulated using the KOBRA3-INP software. The simulation software can calculate charged particle trajectories in three dimensional complex magnetic field structures, which in this case are formed by the arrangement of five superconducting magnets. In this study, the beam emittance is simulated to understand the effects of plasma potential, mass-to-charge ratio, and spatial distribution. The results of these simulations and their comparison to experimental results are presented in this paper.

  1. Emittance study of a 28 GHz electron cyclotron resonance ion source for the Rare Isotope Science Project superconducting linear accelerator

    NASA Astrophysics Data System (ADS)

    Park, Bum-Sik; Hong, In-Seok; Jang, Ji-Ho; Jin, Hyunchang; Choi, Sukjin; Kim, Yonghwan

    2016-02-01

    A 28 GHz electron cyclotron resonance (ECR) ion source is being developed for use as an injector for the superconducting linear accelerator of the Rare Isotope Science Project. Beam extraction from the ECR ion source has been simulated using the KOBRA3-INP software. The simulation software can calculate charged particle trajectories in three dimensional complex magnetic field structures, which in this case are formed by the arrangement of five superconducting magnets. In this study, the beam emittance is simulated to understand the effects of plasma potential, mass-to-charge ratio, and spatial distribution. The results of these simulations and their comparison to experimental results are presented in this paper.

  2. Production of highly charged heavy ions by 18 GHz superconducting electron cyclotron resonance at Research Center for Nuclear Physics.

    PubMed

    Yorita, Tetsuhiko; Hatanaka, Kichiji; Fukuda, Mitsuhiro; Kibayashi, Mitsuru; Morinobu, Shunpei; Okamura, Hiroyuki; Tamii, Atsushi

    2010-02-01

    An 18 GHz superconducting electron cyclotron resonance ion source has been installed as a subject of the azimuthally varying field cyclotron upgrade project (K. Hatanaka et al., in Proceedings of the 17th International Conference on Cyclotrons and Their Applications, Tokyo, Japan, 18-22 October 2004, pp. 115-117), in order to increase beam currents and to extend the variety of ions. The production development of several ions has been performed since 2006 and some of them have already been used for user experiments [T. Yorita et al., Rev. Sci. Instrum. 79, 02A311 (2008)]. Further optimizations for each component such as the material of plasma electrode, material, and shape of bias probe and mirror field have been continued and more intense ion beams have been obtained for O, N, and Ar. For the purpose of obtaining highly charged Xe with several microamperes, the optimization of position and shape of plasma electrode and bias disk has also been done and highly charged Xe(32+) beam has been obtained successfully.

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

    NASA Astrophysics Data System (ADS)

    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.

  4. Development of a new superconducting electron cyclotron resonance ion source for operations up to 18 GHz at LBNL

    SciTech Connect

    Xie, D. Z. Benitez, J. Y.; Hodgkinson, A.; Lyneis, C. M.; Phair, L. W.; Strohmeier, M. M.; Thuillier, T. P.; Todd, D. S.; Caspi, S.; Prestemon, S. O.

    2014-02-15

    A new superconducting Electron Cyclotron Resonance Ion Source (ECRIS) is under development at LBNL to harness the winding techniques of a closed-loop sextupole coil for the next generation ECRIS and to enhance the capability of the 88-in. cyclotron facility. The proposed ECRIS will use a superconducting closed-loop sextupole coil to produce the radial field and a substantial portion of the axial field. The field strengths of the injection, central and extraction regions are adjusted by a three solenoids outside the closed-loop sextupole coil. In addition to maintaining the typical ECRIS magnetic field configuration, this new source will also be able to produce a dustpan-like minimum-B field to explore possible ECRIS performance enhancement. The dustpan-like minimum-B field configuration has about the same strengths for the maximum axial field at the injection region and the maximum radial pole fields at the plasma chamber walls but it can be substantially lower at the extraction region. The dustpan-like minimum-B will have a field maximum B{sub max} ≥ 2.6 T for operations up to 18 GHz with a ratio of B{sub max}/B{sub res} ≥ 4 and higher ratios for lower frequencies. The field maxima of this new source can reach over 3 T both at the injection and the plasma chamber walls which could also support operation at 28 GHz. The source will be built of cryogen-free with the magnets directly cooled by cryo-coolers to simplify the cryostat structure. The source design features will be presented and discussed.

  5. Development of a new superconducting Electron Cyclotron Resonance Ion Source for operations up to 18 GHz at LBNL.

    PubMed

    Xie, D Z; Benitez, J Y; Caspi, S; Hodgkinson, A; Lyneis, C M; Phair, L W; Prestemon, S O; Strohmeier, M M; Thuillier, T P; Todd, D S

    2014-02-01

    A new superconducting Electron Cyclotron Resonance Ion Source (ECRIS) is under development at LBNL to harness the winding techniques of a closed-loop sextupole coil for the next generation ECRIS and to enhance the capability of the 88-in. cyclotron facility. The proposed ECRIS will use a superconducting closed-loop sextupole coil to produce the radial field and a substantial portion of the axial field. The field strengths of the injection, central and extraction regions are adjusted by a three solenoids outside the closed-loop sextupole coil. In addition to maintaining the typical ECRIS magnetic field configuration, this new source will also be able to produce a dustpan-like minimum-B field to explore possible ECRIS performance enhancement. The dustpan-like minimum-B field configuration has about the same strengths for the maximum axial field at the injection region and the maximum radial pole fields at the plasma chamber walls but it can be substantially lower at the extraction region. The dustpan-like minimum-B will have a field maximum Bmax ≥ 2.6 T for operations up to 18 GHz with a ratio of Bmax/Bres ≥ 4 and higher ratios for lower frequencies. The field maxima of this new source can reach over 3 T both at the injection and the plasma chamber walls which could also support operation at 28 GHz. The source will be built of cryogen-free with the magnets directly cooled by cryo-coolers to simplify the cryostat structure. The source design features will be presented and discussed.

  6. Performance and operation of advanced superconducting electron cyclotron resonance ion source SECRAL at 24 GHz

    SciTech Connect

    Zhao, H. W.; Zhang, X. Z.; Feng, Y. C.; Guo, J. W.; Li, J. Y.; Guo, X. H.; Sha, S.; Sun, L. T.; Xie, D. Z.; Lu, W.; Cao, Y.

    2012-02-15

    SECRAL (superconducting ECR ion source with advanced design in Lanzhou) ion source has been in routine operation for Heavy Ion Research Facility in Lanzhou (HIRFL) accelerator complex since May 2007. To further enhance the SECRAL performance in order to satisfy the increasing demand for intensive highly charged ion beams, 3-5 kW high power 24 GHz single frequency and 24 GHz +18 GHz double frequency with an aluminum plasma chamber were tested, and some exciting results were produced with quite a few new record highly charged ion beam intensities, such as {sup 129}Xe{sup 35+} of 64 e{mu}A, {sup 129}Xe{sup 42+} of 3 e{mu}A, {sup 209}Bi{sup 41+} of 50 e{mu}A, {sup 209}Bi{sup 50+} of 4.3 e{mu}A and {sup 209}Bi{sup 54+} of 0.2 e{mu}A. In most cases SECRAL is operated at 18 GHz to deliver highly charged heavy ion beams for the HIRFL accelerator, only for those very high charge states and very heavy ion beams such as {sup 209}Bi{sup 36+} and {sup 209}Bi{sup 41+}, SECRAL has been operated at 24 GHz. The total operation beam time provided by SECRAL up to July 2011 has exceeded 7720 hours. In this paper, the latest performance, development, and operation status of SECRAL ion source are presented. The latest results and reliable long-term operation for the HIRFL accelerator have demonstrated that SECRAL performance for production of highly charged heavy ion beams remains improving at higher RF power with optimized tuning.

  7. Review on high current 2.45 GHz electron cyclotron resonance sources (invited)

    SciTech Connect

    Gammino, S.; Celona, L.; Ciavola, G.; Maimone, F.; Mascali, D.

    2010-02-15

    The suitable source for the production of intense beams for high power accelerators must obey to the request of high brightness, stability, and reliability. The 2.45 GHz off-resonance microwave discharge sources are the ideal device to generate the requested beams, as they produce multimilliampere beams of protons, deuterons, and monocharged ions, remaining stable for several weeks without maintenance. A description of different technical designs will be given, analyzing their strength, and weakness, with regard to the extraction system and low energy beam transport line, as the presence of beam halo is detrimental for the accelerator.

  8. Development of a high-temperature oven for the 28 GHz electron cyclotron resonance ion source

    SciTech Connect

    Ohnishi, J. Higurashi, Y.; Kidera, M.; Ozeki, K.; Nakagawa, T.

    2014-02-15

    We have been developing the 28 GHz ECR ion source in order to accelerate high-intensity uranium beams at the RIKEN RI-beam Factory. Although we have generated U{sup 35+} beams by the sputtering method thus far, we began developing a high-temperature oven with the aim of increasing and stabilizing the beams. Because the oven method uses UO{sub 2}, a crucible must be heated to a temperature higher than 2000 °C to supply an appropriate amount of UO{sub 2} vapor to the ECR plasma. Our high-temperature oven uses a tungsten crucible joule-heated with DC current of approximately 450 A. Its inside dimensions are ϕ11 mm × 13.5 mm. Since the crucible is placed in a magnetic field of approximately 3 T, it is subject to a magnetic force of approximately 40 N. Therefore, we used ANSYS to carefully design the crucible, which was manufactured by machining a tungsten rod. We could raise the oven up to 1900 °C in the first off-line test. Subsequently, UO{sub 2} was loaded into the crucible, and the oven was installed in the 28 GHz ECR ion source and was tested. As a result, a U{sup 35+} beam current of 150 μA was extracted successfully at a RF power of approximately 3 kW.

  9. Note: Effect of hot liner in producing {sup 40,48}Ca beam from RIKEN 18-GHz electron cyclotron resonance ion source

    SciTech Connect

    Ozeki, K. Higurashi, Y.; Kidera, M.; Nakagawa, T.

    2015-01-15

    In order to produce a high-intensity and stable {sup 48}Ca beam from the RIKEN 18-GHz electron cyclotron resonance ion source, we have begun testing the production of a calcium beam using a micro-oven. To minimize the consumption rate of the material ({sup 48}Ca), we introduced the “hot liner” method and investigated the effect of the liner on the material consumption rate. The micro-oven was first used to produce the {sup 48}Ca beam for experiments in the RIKEN radioisotope beam factory, and a stable beam could be supplied for a long time with low consumption rate.

  10. Temperature and density evolution during decay in a 2.45 GHz hydrogen electron cyclotron resonance plasma: Off-resonant and resonant cases

    NASA Astrophysics Data System (ADS)

    Cortázar, O. D.; Megía-Macías, A.; Vizcaíno-de-Julián, A.

    2013-09-01

    Time resolved electron temperature and density measurements during the decay stage in a hydrogen electron cyclotron resonance (ECR) plasma are presented for a resonance and off-resonance magnetic field configurations. The measurements are conducted on a ECR plasma generator excited at 2.45 GHz denominated test-bench for ion-sources plasma studies at ESS Bilbao. The plasma parameters evolution is studied by Langmuir probe diagnostic with synchronized sample technique developed for repetitive pulsed plasmas with a temporal resolution of 200 ns in typical decay processes of about 40 μs. An afterglow transient is clearly observed in the reflected microwave power signal from the plasma. Simultaneously, the electron temperature evolution shows rebounding peaks that may be related to the interplay between density drop and microwave coupling with deep impact on the Electron Energy Distribution Function. The correlation of such structures with the plasma absorbed power and the coupling quality is also reported.

  11. Temperature and density evolution during decay in a 2.45 GHz hydrogen electron cyclotron resonance plasma: Off-resonant and resonant cases

    SciTech Connect

    Cortázar, O. D.

    2013-09-15

    Time resolved electron temperature and density measurements during the decay stage in a hydrogen electron cyclotron resonance (ECR) plasma are presented for a resonance and off-resonance magnetic field configurations. The measurements are conducted on a ECR plasma generator excited at 2.45 GHz denominated test-bench for ion-sources plasma studies at ESS Bilbao. The plasma parameters evolution is studied by Langmuir probe diagnostic with synchronized sample technique developed for repetitive pulsed plasmas with a temporal resolution of 200 ns in typical decay processes of about 40 μs. An afterglow transient is clearly observed in the reflected microwave power signal from the plasma. Simultaneously, the electron temperature evolution shows rebounding peaks that may be related to the interplay between density drop and microwave coupling with deep impact on the Electron Energy Distribution Function. The correlation of such structures with the plasma absorbed power and the coupling quality is also reported.

  12. Temperature and density evolution during decay in a 2.45 GHz hydrogen electron cyclotron resonance plasma: off-resonant and resonant cases.

    PubMed

    Cortázar, O D; Megía-Macías, A; Vizcaíno-de-Julián, A

    2013-09-01

    Time resolved electron temperature and density measurements during the decay stage in a hydrogen electron cyclotron resonance (ECR) plasma are presented for a resonance and off-resonance magnetic field configurations. The measurements are conducted on a ECR plasma generator excited at 2.45 GHz denominated test-bench for ion-sources plasma studies at ESS Bilbao. The plasma parameters evolution is studied by Langmuir probe diagnostic with synchronized sample technique developed for repetitive pulsed plasmas with a temporal resolution of 200 ns in typical decay processes of about 40 μs. An afterglow transient is clearly observed in the reflected microwave power signal from the plasma. Simultaneously, the electron temperature evolution shows rebounding peaks that may be related to the interplay between density drop and microwave coupling with deep impact on the Electron Energy Distribution Function. The correlation of such structures with the plasma absorbed power and the coupling quality is also reported.

  13. Studies of extraction and transport system for highly charged ion beam of 18 GHz superconducting electron cyclotron resonance ion source at Research Center for Nuclear Physics

    NASA Astrophysics Data System (ADS)

    Yorita, T.; Hatanaka, K.; Fukuda, M.; Ueda, H.; Yasuda, Y.; Morinobu, S.; Tamii, A.; Kamakura, K.

    2014-02-01

    An 18 GHz superconducting electron cyclotron resonance ion source is installed to increase beam currents and to extend the variety of ions especially for highly charged heavy ions which can be accelerated by cyclotrons of Research Center for Nuclear Physics (RCNP), Osaka University. The beam production developments of several ions from B to Xe have been already done [T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 79, 02A311 (2008) and T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 81, 02A332 (2010)] and the further studies for those beam extraction and its transport have been done in order to increase the beam current more. The plasma electrode, extraction electrode, and einzel lens are modified. Especially extraction electrode can be applied minus voltage for the beam extraction and it works well to improve the extracted beam current. The extraction voltage dependences of transmission and emittance also have been studied for beam current improvement which is injected into azimuthally varying field cyclotron at RCNP.

  14. Studies of extraction and transport system for highly charged ion beam of 18 GHz superconducting electron cyclotron resonance ion source at Research Center for Nuclear Physics

    SciTech Connect

    Yorita, T. Hatanaka, K.; Fukuda, M.; Ueda, H.; Yasuda, Y.; Morinobu, S.; Tamii, A.; Kamakura, K.

    2014-02-15

    An 18 GHz superconducting electron cyclotron resonance ion source is installed to increase beam currents and to extend the variety of ions especially for highly charged heavy ions which can be accelerated by cyclotrons of Research Center for Nuclear Physics (RCNP), Osaka University. The beam production developments of several ions from B to Xe have been already done [T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 79, 02A311 (2008) and T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 81, 02A332 (2010)] and the further studies for those beam extraction and its transport have been done in order to increase the beam current more. The plasma electrode, extraction electrode, and einzel lens are modified. Especially extraction electrode can be applied minus voltage for the beam extraction and it works well to improve the extracted beam current. The extraction voltage dependences of transmission and emittance also have been studied for beam current improvement which is injected into azimuthally varying field cyclotron at RCNP.

  15. Studies of extraction and transport system for highly charged ion beam of 18 GHz superconducting electron cyclotron resonance ion source at Research Center for Nuclear Physics.

    PubMed

    Yorita, T; Hatanaka, K; Fukuda, M; Ueda, H; Yasuda, Y; Morinobu, S; Tamii, A; Kamakura, K

    2014-02-01

    An 18 GHz superconducting electron cyclotron resonance ion source is installed to increase beam currents and to extend the variety of ions especially for highly charged heavy ions which can be accelerated by cyclotrons of Research Center for Nuclear Physics (RCNP), Osaka University. The beam production developments of several ions from B to Xe have been already done [T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 79, 02A311 (2008) and T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 81, 02A332 (2010)] and the further studies for those beam extraction and its transport have been done in order to increase the beam current more. The plasma electrode, extraction electrode, and einzel lens are modified. Especially extraction electrode can be applied minus voltage for the beam extraction and it works well to improve the extracted beam current. The extraction voltage dependences of transmission and emittance also have been studied for beam current improvement which is injected into azimuthally varying field cyclotron at RCNP.

  16. Superconducting magnet performance for 28 GHz electron cyclotron resonance ion source developed at the Korea Basic Science Institute

    SciTech Connect

    Park, Jin Yong; Choi, Seyong; Lee, Byoung-Seob; Yoon, Jang-Hee; Ok, Jung-Woo; Shin, Chang Seouk; Won, Mi-Sook; Kim, Byoung Chul; Ahn, Jung Keun

    2014-02-15

    A superconducting magnet for use in an electron cyclotron resonance ion source was developed at the Korea Basic Science Institute. The superconducting magnet is comprised of three solenoids and a hexapole magnet. According to the design value, the solenoid magnets can generate a mirror field, resulting in axial magnetic fields of 3.6 T at the injection area and 2.2 T at the extraction region. A radial field strength of 2.1 T can also be achieved by hexapole magnet on the plasma chamber wall. NbTi superconducting wire was used in the winding process following appropriate techniques for magnet structure. The final assembly of the each magnet involved it being vertically inserted into the cryostat to cool down the temperature using liquid helium. The performance of each solenoid and hexapole magnet was separately verified experimentally. The construction of the superconducting coil, the entire magnet assembly for performance testing and experimental results are reported herein.

  17. Superconducting magnet performance for 28 GHz electron cyclotron resonance ion source developed at the Korea Basic Science Institute.

    PubMed

    Park, Jin Yong; Choi, Seyong; Lee, Byoung-Seob; Yoon, Jang-Hee; Ok, Jung-Woo; Kim, Byoung Chul; Shin, Chang Seouk; Ahn, Jung Keun; Won, Mi-Sook

    2014-02-01

    A superconducting magnet for use in an electron cyclotron resonance ion source was developed at the Korea Basic Science Institute. The superconducting magnet is comprised of three solenoids and a hexapole magnet. According to the design value, the solenoid magnets can generate a mirror field, resulting in axial magnetic fields of 3.6 T at the injection area and 2.2 T at the extraction region. A radial field strength of 2.1 T can also be achieved by hexapole magnet on the plasma chamber wall. NbTi superconducting wire was used in the winding process following appropriate techniques for magnet structure. The final assembly of the each magnet involved it being vertically inserted into the cryostat to cool down the temperature using liquid helium. The performance of each solenoid and hexapole magnet was separately verified experimentally. The construction of the superconducting coil, the entire magnet assembly for performance testing and experimental results are reported herein.

  18. Effect of a metal-dielectric structure introduced in the plasma chamber of the Frankfurt 14 GHz electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Schächter, L.; Stiebing, K. E.; Dobrescu, S.; Badescu-Singureanu, Al. I.; Schmidt, L.; Hohn, O.; Runkel, S.

    1999-02-01

    A new approach of the possibility to significantly increase the high charge state ion beams delivered by electron cyclotron resonance (ECR) ion sources by using metal-dielectric (MD) structures characterized by high secondary electron emission properties is presented. The intensities of argon ion beams extracted from the 14 GHz electron cyclotron resonance ion source of the Institut für Kernphysik (IKF) der Johann Wolfgang Goethe-Universität in Frankfurt/Main were measured when a 26 mm diam disk of a specially treated MD structure (Al-Al2O3) was introduced axially close to the ECR plasma. The Ar beam intensities and charge-state distributions obtained with this disk are compared to measurements with disks of iron and pure aluminum at the same position relative to the plasma. All measurements were performed with the disk at the plasma chamber potential. The results with the MD structure show a net shift of the beam intensity towards higher charge states as compared with the other disk materials. Enhancement factors of the beam current of up to 10 (for Ar12+) when using a MD disk compared to the output when using an aluminum disk and up to 40 (for Ar11+) when using an iron disk were measured.

  19. Photoelectron emission from metal surfaces induced by radiation emitted by a 14 GHz electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    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.

  20. Photoelectron emission from metal surfaces induced by radiation emitted by a 14 GHz electron cyclotron resonance ion source

    SciTech Connect

    Laulainen, Janne Kalvas, Taneli; Koivisto, Hannu; Komppula, Jani; Kronholm, Risto; Tarvainen, Olli

    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.

  1. Non-inductive current built-up by local electron cyclotron heating and current drive with a 28 GHz focused beam on QUEST

    NASA Astrophysics Data System (ADS)

    Onchi, Takumi; Idei, Hiroshi; Hasegawa, Makoto; Ohwada, Hiroaki; Zushi, Hideki; Hanada, Kazuaki; Kariya, Tsuyoshi; Mishra, Kishore; Shikama, Taichi; Quest Team

    2016-10-01

    The plasma current can be driven solely by injecting electron cyclotron waves (ECWs) in spherical tokamak (ST) configuration. A system of 28 GHz gyrotron (maximum power: 270 kW) is renewed and reinstalled on QUEST. A focused ECW beam, whose diameter is about 5 cm at the second harmonic resonance, is injected for local ECW heating and current drive. The local power density at resonance exceeds 75 MW/m2 at an injection power of 150 kW. The incident ECW polarization can be adjusted employing the phase shifter consisting of two corrugated plates. During 1.25 second pulse of ECH, plasma current is built up to Ip = 70 kA fully non-inductively with a core electron density of ne > 1018 m-3. The closed flux in such ST plasma is determined at the inboard limiter on the center stack. Energetic electrons are also responsible for the pressure and equilibrium. This work is supported by JSPS KAKENHI (15H04231, 15K17800), NIFS Collaboration Research program (NIFS13KUTR085, NIFS11KUTR069, NIFS16KUTR114).

  2. 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

    NASA Astrophysics Data System (ADS)

    Megía-Macías, A.; Cortázar, O. D.; Vizcaíno-de-Julián, A.

    2014-03-01

    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.

  3. 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.

    PubMed

    Megía-Macías, A; Cortázar, O D; Vizcaíno-de-Julián, A

    2014-03-01

    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.

  4. The effect of cavity tuning on oxygen beam currents of an A-ECR type 14 GHz electron cyclotron resonance ion source

    SciTech Connect

    Tarvainen, O. Orpana, J.; Kronholm, R.; Kalvas, T.; Laulainen, J.; Koivisto, H.; Izotov, I.; Skalyga, V.; Toivanen, V.

    2016-09-15

    The efficiency of the microwave-plasma coupling plays a significant role in the production of highly charged ion beams with electron cyclotron resonance ion sources (ECRISs). The coupling properties are affected by the mechanical design of the ion source plasma chamber and microwave launching system, as well as damping of the microwave electric field by the plasma. Several experiments attempting to optimize the microwave-plasma coupling characteristics by fine-tuning the frequency of the injected microwaves have been conducted with varying degrees of success. The inherent difficulty in interpretation of the frequency tuning results is that the effects of microwave coupling system and the cavity behavior of the plasma chamber cannot be separated. A preferable approach to study the effect of the cavity properties of the plasma chamber on extracted beam currents is to adjust the cavity dimensions. The results of such cavity tuning experiments conducted with the JYFL 14 GHz ECRIS are reported here. The cavity properties were adjusted by inserting a conducting tuner rod axially into the plasma chamber. The extracted beam currents of oxygen charge states O{sup 3+}–O{sup 7+} were recorded at various tuner positions and frequencies in the range of 14.00–14.15 GHz. It was observed that the tuner position affects the beam currents of high charge state ions up to several tens of percent. In particular, it was found that at some tuner position / frequency combinations the plasma exhibited “mode-hopping” between two operating regimes. The results improve the understanding of the role of plasma chamber cavity properties on ECRIS performances.

  5. The effect of cavity tuning on oxygen beam currents of an A-ECR type 14 GHz electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Tarvainen, O.; Orpana, J.; Kronholm, R.; Kalvas, T.; Laulainen, J.; Koivisto, H.; Izotov, I.; Skalyga, V.; Toivanen, V.

    2016-09-01

    The efficiency of the microwave-plasma coupling plays a significant role in the production of highly charged ion beams with electron cyclotron resonance ion sources (ECRISs). The coupling properties are affected by the mechanical design of the ion source plasma chamber and microwave launching system, as well as damping of the microwave electric field by the plasma. Several experiments attempting to optimize the microwave-plasma coupling characteristics by fine-tuning the frequency of the injected microwaves have been conducted with varying degrees of success. The inherent difficulty in interpretation of the frequency tuning results is that the effects of microwave coupling system and the cavity behavior of the plasma chamber cannot be separated. A preferable approach to study the effect of the cavity properties of the plasma chamber on extracted beam currents is to adjust the cavity dimensions. The results of such cavity tuning experiments conducted with the JYFL 14 GHz ECRIS are reported here. The cavity properties were adjusted by inserting a conducting tuner rod axially into the plasma chamber. The extracted beam currents of oxygen charge states O3+-O7+ were recorded at various tuner positions and frequencies in the range of 14.00-14.15 GHz. It was observed that the tuner position affects the beam currents of high charge state ions up to several tens of percent. In particular, it was found that at some tuner position / frequency combinations the plasma exhibited "mode-hopping" between two operating regimes. The results improve the understanding of the role of plasma chamber cavity properties on ECRIS performances.

  6. The effect of cavity tuning on oxygen beam currents of an A-ECR type 14 GHz electron cyclotron resonance ion source.

    PubMed

    Tarvainen, O; Orpana, J; Kronholm, R; Kalvas, T; Laulainen, J; Koivisto, H; Izotov, I; Skalyga, V; Toivanen, V

    2016-09-01

    The efficiency of the microwave-plasma coupling plays a significant role in the production of highly charged ion beams with electron cyclotron resonance ion sources (ECRISs). The coupling properties are affected by the mechanical design of the ion source plasma chamber and microwave launching system, as well as damping of the microwave electric field by the plasma. Several experiments attempting to optimize the microwave-plasma coupling characteristics by fine-tuning the frequency of the injected microwaves have been conducted with varying degrees of success. The inherent difficulty in interpretation of the frequency tuning results is that the effects of microwave coupling system and the cavity behavior of the plasma chamber cannot be separated. A preferable approach to study the effect of the cavity properties of the plasma chamber on extracted beam currents is to adjust the cavity dimensions. The results of such cavity tuning experiments conducted with the JYFL 14 GHz ECRIS are reported here. The cavity properties were adjusted by inserting a conducting tuner rod axially into the plasma chamber. The extracted beam currents of oxygen charge states O(3+)-O(7+) were recorded at various tuner positions and frequencies in the range of 14.00-14.15 GHz. It was observed that the tuner position affects the beam currents of high charge state ions up to several tens of percent. In particular, it was found that at some tuner position / frequency combinations the plasma exhibited "mode-hopping" between two operating regimes. The results improve the understanding of the role of plasma chamber cavity properties on ECRIS performances.

  7. A 2.45 GHz electron cyclotron resonance proton ion source and a dual-lens low energy beam transporta)

    NASA Astrophysics Data System (ADS)

    Zhang, W. H.; Ma, H. Y.; Yang, Y.; Wu, Q.; Zhang, X. Z.; Wang, H.; Ma, B. H.; Feng, Y. C.; Fang, X.; Guo, J. W.; Cao, Y.; Li, X. X.; Zhu, Y. H.; Li, J. Y.; Sha, S.; Lu, W.; Lin, S. H.; Guo, X. H.; Zhao, H. Y.; Sun, L. T.; Xie, D. Z.; Peng, S. X.; Liu, Z. W.; Zhao, H. W.

    2012-02-01

    The structure and preliminary commissioning results of a new 2.45 GHz ECR proton ion source and a dual-lens low energy beam transport (LEBT) system are presented in this paper. The main magnetic field of the ion source is provided by a set of permanent magnets with two small electro-solenoid magnets at the injection and the extraction to fine tune the magnetic field for better microwave coupling. A 50 keV pulsed proton beam extracted by a three-electrode mechanism passes through the LEBT system of length of 1183 mm. This LEBT consists of a diagnosis chamber, two Glaser lenses, two steering magnets, and a final beam defining cone. A set of inner permanent magnetic rings is embedded in each of the two Glaser lenses to produce a flatter axial-field to reduce the lens aberrations.

  8. A 2.45 GHz electron cyclotron resonance proton ion source and a dual-lens low energy beam transport

    SciTech Connect

    Zhang, W. H.; Ma, H. Y.; Wu, Q.; Zhang, X. Z.; Wang, H.; Ma, B. H.; Feng, Y. C.; Fang, X.; Guo, J. W.; Li, X. X.; Zhu, Y. H.; Li, J. Y.; Guo, X. H.; Zhao, H. Y.; Sun, L. T.; Xie, D. Z.; Liu, Z. W.; Zhao, H. W.; Yang, Y.; Cao, Y.; and others

    2012-02-15

    The structure and preliminary commissioning results of a new 2.45 GHz ECR proton ion source and a dual-lens low energy beam transport (LEBT) system are presented in this paper. The main magnetic field of the ion source is provided by a set of permanent magnets with two small electro-solenoid magnets at the injection and the extraction to fine tune the magnetic field for better microwave coupling. A 50 keV pulsed proton beam extracted by a three-electrode mechanism passes through the LEBT system of length of 1183 mm. This LEBT consists of a diagnosis chamber, two Glaser lenses, two steering magnets, and a final beam defining cone. A set of inner permanent magnetic rings is embedded in each of the two Glaser lenses to produce a flatter axial-field to reduce the lens aberrations.

  9. Effect of the gas mixing technique on the plasma potential and emittance of the JYFL 14 GHz electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Tarvainen, O.; Suominen, P.; Ropponen, T.; Kalvas, T.; Heikkinen, P.; Koivisto, H.

    2005-09-01

    The effect of the gas mixing technique on the plasma potential, energy spread, and emittance of ion beams extracted from the JYFL 14 GHz electron cyclotron resonance ion source has been studied under various gas mixing conditions. The plasma potential and energy spread of the ion beams were studied with a plasma potential instrument developed at the Department of Physics, University of Jyväskylä (JYFL). With the instrument the effects of the gas mixing on different plasma parameters such as plasma potential and the energy distribution of the ions can be studied. The purpose of this work was to confirm that ion cooling can explain the beneficial effect of the gas mixing on the production of highly charged ion beams. This was done by measuring the ion-beam current as a function of a stopping voltage in conjunction with emittance measurements. It was observed that gas mixing affects the shape of the beam current decay curves measured with low charge-state ion beams indicating that the temperature and/or the spatial distribution of these ions is affected by the mixing gas. The results obtained in the emittance measurements support the conclusion that the ion temperature changes due to the gas mixing. The effect of the energy spread on the emittance of different ion beams was also studied theoretically. It was observed that the emittance depends considerably on the dispersive matrix elements of the beam line transfer matrix. This effect is due to the fact that the dipole magnet is a dispersive ion optical component. The effect of the energy spread on the measured emittance in the bending plane of the magnet can be several tens of percent.

  10. Pulse-Periodic Regimes of Kinetic Instabilities in the Non-Equilibrium Plasma of an Electron Cyclotron Resonance Discharge Maintained by Continuous-Wave Radiation of a 24 GHz Gyrotron

    NASA Astrophysics Data System (ADS)

    Mansfeld, D. A.; Viktorov, M. E.; Vodopyanov, A. V.

    2017-01-01

    We have experimentally discovered an instability, which manifests itself as precipitations of hot electrons occurring synchronously with generation of bursts of electromagnetic radiation, in the plasma of an electron cyclotron resonance discharge maintained by a high-power, continuous-wave radiation of a 24 GHz gyrotron, for the first time. The observed instability has the kinetic nature and is determined by the formation of the non-equilibrium velocity distribution of hot particles. Two possible explanations are proposed for the mechanism of wave excitation in a two-component plasma with a stationary source of non-equilibrium particles. The results of the studies performed are of interest for modeling of the dynamics of magnetospheric cyclotron masers.

  11. Electron cyclotron heating in TMX-Upgrade

    SciTech Connect

    Stallard, B.W.; Hooper, E.B. Jr.

    1981-01-01

    TMX-Upgrade, an improved tandem mirror experiment under construction at LLNL, will use electron cyclotron resonance heating (ECRH) to create thermal barriers and to increase the center cell ion confining potential. Gyrotron oscillators (200 kW, 28 GHz) supply the heating power for the potential confined electron (fundamental heating) and the mirror-confined electrons (harmonic heating) in the thermal barriers. Important issues are temperature limitation and microstability for the hot electrons. Off-midplane heating can control anisotropy-driven microstability. Spacially restricting heating offers the possibility of temperature control by limiting the energy for resonant interaction.

  12. EC-5 fifth international workshop on electron cyclotron emission and electron cyclotron heating

    SciTech Connect

    Prater, R.; Lohr, J.

    1985-12-31

    This report contains papers on the following topics: electron cyclotron emission measurements; electron cyclotron emission theory; electron cyclotron heating; gyrotron development; and ECH systems and waveguide development. These paper have been indexed separately elsewhere. (LSP).

  13. Electron cyclotron harmonic wave acceleration

    NASA Technical Reports Server (NTRS)

    Karimabadi, H.; Menyuk, C. R.; Sprangle, P.; Vlahos, L.

    1987-01-01

    A nonlinear analysis of particle acceleration in a finite bandwidth, obliquely propagating electromagnetic cyclotron wave is presented. It has been suggested by Sprangle and Vlahos in 1983 that the narrow bandwidth cyclotron radiation emitted by the unstable electron distribution inside a flaring solar loop can accelerate electrons outside the loop by the interaction of a monochromatic wave propagating along the ambient magnetic field with the ambient electrons. It is shown here that electrons gyrating and streaming along a uniform, static magnetic field can be accelerated by interacting with the fundamental or second harmonic of a monochromatic, obliquely propagating cyclotron wave. It is also shown that the acceleration is virtually unchanged when a wave with finite bandwidth is considered. This acceleration mechanism can explain the observed high-energy electrons in type III bursts.

  14. Electron cyclotron harmonic wave acceleration

    NASA Technical Reports Server (NTRS)

    Karimabadi, H.; Menyuk, C. R.; Sprangle, P.; Vlahos, L.

    1987-01-01

    A nonlinear analysis of particle acceleration in a finite bandwidth, obliquely propagating electromagnetic cyclotron wave is presented. It has been suggested by Sprangle and Vlahos in 1983 that the narrow bandwidth cyclotron radiation emitted by the unstable electron distribution inside a flaring solar loop can accelerate electrons outside the loop by the interaction of a monochromatic wave propagating along the ambient magnetic field with the ambient electrons. It is shown here that electrons gyrating and streaming along a uniform, static magnetic field can be accelerated by interacting with the fundamental or second harmonic of a monochromatic, obliquely propagating cyclotron wave. It is also shown that the acceleration is virtually unchanged when a wave with finite bandwidth is considered. This acceleration mechanism can explain the observed high-energy electrons in type III bursts.

  15. Electron cyclotron emission diagnostics on KSTAR tokamak

    SciTech Connect

    Jeong, S. H.; Lee, K. D.; Kwon, M.; Kogi, Y.; Kawahata, K.; Nagayama, Y.; Mase, A.

    2010-10-15

    A new electron cyclotron emission (ECE) diagnostics system was installed for the Second Korea Superconducting Tokamak Advanced Research (KSTAR) campaign. The new ECE system consists of an ECE collecting optics system, an overmode circular corrugated waveguide system, and 48 channel heterodyne radiometer with the frequency range of 110-162 GHz. During the 2 T operation of the KSTAR tokamak, the electron temperatures as well as its radial profiles at the high field side were measured and sawtooth phenomena were also observed. We also discuss the effect of a window on in situ calibration.

  16. Effect of frequency tuning on bremsstrahlung spectra, beam intensity, and shape in the 10 GHz NANOGAN electron cyclotron resonance ion source

    SciTech Connect

    Rodrigues, G. Mal, Kedar; Kumar, Narender; Lakshmy, P. S.; Mathur, Y.; Kumar, P.; Kanjilal, D.; Roy, A.; Baskaran, R.

    2014-02-15

    Studies on the effect of the frequency tuning on the bremsstrahlung spectra, beam intensities, and beam shape of various ions have been carried out in the 10 GHz NANOGAN ECR ion source. The warm and cold components of the electrons were found to be directly correlated with beam intensity enhancement in case of Ar{sup 9+} but not so for O{sup 5+}. The warm electron component was, however, much smaller compared to the cold component. The effect of the fine tuning of the frequency on the bremsstrahlung spectrum, beam intensities and beam shape is presented.

  17. Hydrogen negative ion production in a 14 GHz electron cyclotron resonance compact ion source with a cone-shaped magnetic filter.

    PubMed

    Ichikawa, T; Kasuya, T; Kenmotsu, T; Maeno, S; Nishiura, M; Shimozuma, T; Yamaoka, H; Wada, M

    2014-02-01

    The plasma electrode structure of a 14 GHz ECR ion source was modified to enlarge the plasma volume of low electron temperature region. The result shows that the extracted beam current reached about 0.6 mA/cm(2) with about 40 W microwave power. To investigate the correlation between the volume of the low electron temperature region and the H(-) current, a vacuum ultraviolet (VUV) spectrometer had been installed to observe light emission in the VUV wavelength range from the plasma. From the results of the negative ion beam current and that from VUV spectrometry, production rate of vibrationally excited hydrogen molecule seems to be enhanced by increasing the volume of low electron temperature region.

  18. A 250-GHz CARM (Cyclotron Auto Resonance Maser) oscillator experiment driven by an induction linac

    SciTech Connect

    Caplan, M.; Kulke, B.; Bubp, D.G. ); McDermott, D.; Luhmann, N. )

    1990-09-14

    A 250-GHz Cyclotron Auto Resonance Maser (CARM) oscillator has been designed and constructed and will be tested using a 1-kA, 2-MeV electron beam produced by the induction linac at the Accelerator Research Center (ARC) facility of Lawrence Livermore National Laboratory (LLNL). The oscillator circuit was made to operate in the TE{sub 11} mode at ten times cutoff using waveguide Bragg reflectors to create an external cavity Q of 8000. Theory predicts cavity fill times of less than 30 ns (pulse length) and efficiencies approaching 20% is sufficiently low transverse electron velocity spreads are maintained (2%).

  19. Electron cyclotron heating experiments on the DIII-D tokamak

    SciTech Connect

    Prater, R.; Austin, M.E.; Bernabei, S.

    1998-01-01

    Initial experiments on heating and current drive using second harmonic electron cyclotron heating (ECH) are being performed on the DIII-D tokamak using the new 110 GHz ECH system. Modulation of the ECH power in the frequency range 50 to 300 Hz and detection of the temperature perturbation by ECE diagnostics is used to validate the location of the heating. This technique also determines an upper bound on the width of the deposition profile. Analysis of electron cyclotron current drive indicates that up to 0.17 MA of central current is driven, resulting in a negative loop voltage near the axis.

  20. A simple electron cyclotron resonance ion sourcea)

    NASA Astrophysics Data System (ADS)

    Welton, R. F.; Moran, T. F.; Feeney, R. K.; Thomas, E. W.

    1996-04-01

    A simple, all permanent magnet, 2.45 GHz electron cyclotron resonance ion source has been developed for the production of stable beams of low charge state ions from gaseous feed materials. The source can produce ˜1 mA of low energy (3 kV) singly charged ion current in the 10-4 Torr pressure range. The source can also be operated in a more efficient low-pressure mode at an order of magnitude lower pressure. In this latter range, for example, the ionization efficiency of Ar is estimated to be 1% with charge states up to Ar8+ present. Operation in the low-pressure mode requires low power input (˜20 W). These features make the source especially suited for use with small accelerator systems for a number of applications including ion implantation, mass spectrometry, and atomic collision experiments where multiply charged ions are desirable. Design details and performance characteristics of the source are presented.

  1. ECR (Electron Cyclotron Resonance) ion sources for cyclotrons

    SciTech Connect

    Lyneis, C.M.

    1986-10-01

    In the last decade ECR (Electron Cyclotron Resonance) ion sources have evolved from a single large, power consuming, complex prototype into a variety of compact, simple, reliable, efficient, high performance sources of high charge state ions for accelerators and atomic physics. The coupling of ECR sources to cyclotrons has resulted in significant performance gains in energy, intensity, reliability, and variety of ion species. Seven ECR sources are in regular operation with cyclotrons and numerous other projects are under development or in the planning stag. At least four laboratories have ECR sources dedicated for atomic physics research and other atomic physics programs share ECR sources with cyclotrons. An ECR source is now installed on the injector for the CERN SPS synchrotron to accelerate O/sup 8 +/ to relativistic energies. A project is underway at Argonne to couple an ECR source to a superconducting heavy-ion linac. Although tremendous progress has been made, the field of ECR sources is still a relatively young technology and there is still the potential for further advances both in source development and understanding of the plasma physics. The development of ECR sources is reviewed. The important physics mechanisms which come into play in the operation of ECR Sources are discussed, along with various models for charge state distributions (CSD). The design and performance of several ECR sources are compared. The 88-Inch Cyclotron and the LBL ECR is used as an example of cyclotron+ECR operation. The future of ECR sources is considered.

  2. Two-frequency heating technique at the 18 GHz electron cyclotron resonance ion source of the National Institute of Radiological Sciences

    SciTech Connect

    Biri, S.; Rácz, R.; Sasaki, N.; Takasugi, W.

    2014-02-15

    The two-frequency heating technique was studied to increase the beam intensities of highly charged ions provided by the high-voltage extraction configuration (HEC) ion source at the National Institute of Radiological Sciences (NIRS). The observed dependences on microwave power and frequency suggested that this technique improved plasma stability but it required precise frequency tuning and more microwave power than was available before 2013. Recently, a new, high-power (1200 W) wide band-width (17.1–18.5 GHz) travelling-wave-tube amplifier (TWTA) was installed. After some single tests with klystron and TWT amplifiers the simultaneous injection of the two microwaves has been successfully realized. The dependence of highly charged ions (HCI) currents on the superposed microwave power was studied by changing only the output power of one of the two amplifiers, alternatively. While operating the klystron on its fixed 18.0 GHz, the frequency of the TWTA was swept within its full limits (17.1–18.5 GHz), and the effect of this frequency on the HCI-production rate was examined under several operation conditions. As an overall result, new beam records of highly charged argon, krypton, and xenon beams were obtained at the NIRS-HEC ion source by this high-power two-frequency operation mode.

  3. Two-frequency heating technique at the 18 GHz electron cyclotron resonance ion source of the National Institute of Radiological Sciences

    NASA Astrophysics Data System (ADS)

    Biri, S.; Kitagawa, A.; Muramatsu, M.; Drentje, A. G.; Rácz, R.; Yano, K.; Kato, Y.; Sasaki, N.; Takasugi, W.

    2014-02-01

    The two-frequency heating technique was studied to increase the beam intensities of highly charged ions provided by the high-voltage extraction configuration (HEC) ion source at the National Institute of Radiological Sciences (NIRS). The observed dependences on microwave power and frequency suggested that this technique improved plasma stability but it required precise frequency tuning and more microwave power than was available before 2013. Recently, a new, high-power (1200 W) wide band-width (17.1-18.5 GHz) travelling-wave-tube amplifier (TWTA) was installed. After some single tests with klystron and TWT amplifiers the simultaneous injection of the two microwaves has been successfully realized. The dependence of highly charged ions (HCI) currents on the superposed microwave power was studied by changing only the output power of one of the two amplifiers, alternatively. While operating the klystron on its fixed 18.0 GHz, the frequency of the TWTA was swept within its full limits (17.1-18.5 GHz), and the effect of this frequency on the HCI-production rate was examined under several operation conditions. As an overall result, new beam records of highly charged argon, krypton, and xenon beams were obtained at the NIRS-HEC ion source by this high-power two-frequency operation mode.

  4. Fourth generation electron cyclotron resonance ion sources.

    PubMed

    Lyneis, Claude M; Leitner, D; Todd, D S; Sabbi, G; Prestemon, S; Caspi, S; Ferracin, P

    2008-02-01

    The concepts and technical challenges related to developing a fourth generation electron cyclotron resonance (ECR) ion source with a rf frequency greater than 40 GHz and magnetic confinement fields greater than twice B(ECR) will be explored in this article. Based on the semiempirical frequency scaling of ECR plasma density with the square of operating frequency, there should be significant gains in performance over current third generation ECR ion sources, which operate at rf frequencies between 20 and 30 GHz. While the third generation ECR ion sources use NbTi superconducting solenoid and sextupole coils, the new sources will need to use different superconducting materials, such as Nb(3)Sn, to reach the required magnetic confinement, which scales linearly with rf frequency. Additional technical challenges include increased bremsstrahlung production, which may increase faster than the plasma density, bremsstrahlung heating of the cold mass, and the availability of high power continuous wave microwave sources at these frequencies. With each generation of ECR ion sources, there are new challenges to be mastered, but the potential for higher performance and reduced cost of the associated accelerator continues to make this a promising avenue for development.

  5. Electron cyclotron emissions from an electron cyclotron heated discharge in ISX-B

    SciTech Connect

    Elder, G.B.

    1983-01-01

    Observation of the electron cyclotron emissions (ECE) is especially effective when studying the effects of electron cyclotron heating (ECH). Two detectors were built to observe the optically thin third harmonic radiation from ISX B during the recent 28 GHz ECH experiments carried on at Oak Ridge National Laboratory. These detectors supplemented existing detectors at the fundamental frequency and at the second harmonic frequency. Observations of the three frequencies during and after the ECH was pulsed into the plasma showed an unexpected rise in their intensity, occurring after the ECH pulse was over. This rise lasted for many tens of milliseconds, well beyond estimates of the electron energy confinement time. The rise in the third harmonic intensity was frequently to an intensity 100 times greater than the pre-ECH intensity. The fundamental frequency and the second harmonic had a much milder change in their intensities. The rises were seen to depend critically on the density of the plasma and the length of the ECH pulse but only weakly on the pre-ECH temperature. A computer code that predicts the ECE from an electron distribution in ISX-B, taking into a account the effect of the plasma's dielectric response to the emissions from a single electron, was developed.

  6. Electron cyclotron resonance plasma photosa)

    NASA Astrophysics Data System (ADS)

    Rácz, R.; Biri, S.; Pálinkás, J.

    2010-02-01

    In order to observe and study systematically the plasma of electron cyclotron resonance (ECR) ion sources (ECRIS) we made a high number of high-resolution visible light plasma photos and movies in the ATOMKI ECRIS Laboratory. This required building the ECR ion source into an open ECR plasma device, temporarily. An 8MP digital camera was used to record photos of plasmas made from Ne, Ar, and Kr gases and from their mixtures. We studied and recorded the effect of ion source setting parameters (gas pressure, gas composition, magnetic field, and microwave power) to the shape, color, and structure of the plasma. The analysis of the photo series gave us many qualitative and numerous valuable physical information on the nature of ECR plasmas.

  7. Electron cyclotron resonance plasma photos.

    PubMed

    Rácz, R; Biri, S; Pálinkás, J

    2010-02-01

    In order to observe and study systematically the plasma of electron cyclotron resonance (ECR) ion sources (ECRIS) we made a high number of high-resolution visible light plasma photos and movies in the ATOMKI ECRIS Laboratory. This required building the ECR ion source into an open ECR plasma device, temporarily. An 8MP digital camera was used to record photos of plasmas made from Ne, Ar, and Kr gases and from their mixtures. We studied and recorded the effect of ion source setting parameters (gas pressure, gas composition, magnetic field, and microwave power) to the shape, color, and structure of the plasma. The analysis of the photo series gave us many qualitative and numerous valuable physical information on the nature of ECR plasmas.

  8. Electron cyclotron resonance plasma photos

    SciTech Connect

    Racz, R.; Palinkas, J.; Biri, S.

    2010-02-15

    In order to observe and study systematically the plasma of electron cyclotron resonance (ECR) ion sources (ECRIS) we made a high number of high-resolution visible light plasma photos and movies in the ATOMKI ECRIS Laboratory. This required building the ECR ion source into an open ECR plasma device, temporarily. An 8MP digital camera was used to record photos of plasmas made from Ne, Ar, and Kr gases and from their mixtures. We studied and recorded the effect of ion source setting parameters (gas pressure, gas composition, magnetic field, and microwave power) to the shape, color, and structure of the plasma. The analysis of the photo series gave us many qualitative and numerous valuable physical information on the nature of ECR plasmas.

  9. Ultra-fast intensified frame images from an electron cyclotron resonance hydrogen plasma at 2.45 GHz: Some space distributions of visible and monochromatic emissions

    NASA Astrophysics Data System (ADS)

    Cortázar, O. D.; Megía-Macías, A.; Vizcaíno-de-Julián, A.; Tarvainen, O.; Komppula, J.; Koivisto, H.

    2014-02-01

    First results from an ultra-fast frame image acquisition diagnostic coupled to a 2.45 GHz microwave hydrogen discharge are presented. The plasma reactor has been modified to include a transparent doubled shielded quartz window allowing to viewing the full plasma volume. Pictures describing the breakdown process at 1 μs exposure time have been obtained for integrated visible light signal, Balmer-alpha, Balmer-beta lines, and Fulcher-band. Several different plasma emission distributions are reported. The distribution depends on the magnetic field configuration, incident microwave power, and neutral gas pressure.

  10. Ultra-fast intensified frame images from an electron cyclotron resonance hydrogen plasma at 2.45 GHz: some space distributions of visible and monochromatic emissions.

    PubMed

    Cortázar, O D; Megía-Macías, A; Vizcaíno-de-Julián, A; Tarvainen, O; Komppula, J; Koivisto, H

    2014-02-01

    First results from an ultra-fast frame image acquisition diagnostic coupled to a 2.45 GHz microwave hydrogen discharge are presented. The plasma reactor has been modified to include a transparent doubled shielded quartz window allowing to viewing the full plasma volume. Pictures describing the breakdown process at 1 μs exposure time have been obtained for integrated visible light signal, Balmer-alpha, Balmer-beta lines, and Fulcher-band. Several different plasma emission distributions are reported. The distribution depends on the magnetic field configuration, incident microwave power, and neutral gas pressure.

  11. GHz-THz Electronics

    DTIC Science & Technology

    2013-03-07

    Schlom & Kyle Shen (Cornell) Tight coupling of molecular-beam epitaxy (MBE) and angle-resolved photoelectron spectroscopy (ARPES) reveals metal...electronics • Paul Maki – nitride electronics • Chagaan Baatar – 2D materials • Marc Ulrich – topological insulators • Pani Varanasi – 2D materials • Mike

  12. 30-cm electron cyclotron plasma generator

    NASA Technical Reports Server (NTRS)

    Goede, Hank

    1987-01-01

    Experimental results on the development of a 30-cm-diam electron cyclotron resonance plasma generator are presented. This plasma source utilizes samarium-cobalt magnets and microwave power at a frequency of 4.9 GHz to produce a uniform plasma with densities of up to 3 x 10 to the 11th/cu cm in a continuous fashion. The plasma generator contains no internal structures, and is thus inherently simple in construction and operation and inherently durable. The generator was operated with two different magnetic geometries. One used the rare-earth magnets arranged in an axial line cusp configuration, which directly showed plasma production taking place near the walls of the generator where the electron temperature was highest but with the plasma density peaking in the central low B-field regions. The second configuration had magnets arranged to form azimuthal line cusps with approximately closed electron drift surfaces; this configuration showed an improved electrical efficiency of about 135 eV/ion.

  13. Electron Cyclotron Emissions from AN Electron Cyclotron Heated Discharge in Isx-B

    NASA Astrophysics Data System (ADS)

    Elder, Gerald Blaine

    1983-09-01

    Observation of the electron cyclotron emissions (ECE) at both optically thick and optically thin frequencies can be a very useful tool in studying the behavior of the electron distribution. It is especially effective when studying the effects of electron cyclotron heating (ECH). Two detectors were built to observe the optically thin third harmonic radiation from ISX-B during the recent 28 GHz ECH experiments carried on at Oak Ridge National Laboratory. These detectors supplemented existing detectors at the fundamental frequency and at the second harmonic frequency. Observations of the three frequencies during and after the ECH was pulsed into the plasma showed an unexpected rise in their intensity, occurring after the ECH pulse was over. This rise lasted for many tens of milliseconds, well beyond estimates of the electron energy confinement time. The rise in the third harmonic intensity was frequently to an intensity 100 times greater than the pre-ECH intensity. The fundamental frequency and the second harmonic had a much milder change in their intensities. The rises were seen to depend critically on the density of the plasma and the length of the ECH pulse but only weakly on the pre-ECH temperature. A computer code which predicts the ECE from an electron distribution in ISX-B, taking into account the effect of the plasma's dielectric response to the emissions from a single electron, is developed. This code is the result of combining a ray tracing technique with the emissions from a single dressed test particle and summing over the electron distribution. The code confirms the sensitivity of the third harmonic emissions to small changes in the electron distribution. A Fokker-Planck code is combined with the emission code to predict the evolution of the ECE from a perturbed electron distribution. The codes clearly show that the rises in the emissions observed by the three detectors can be reasonably explained by consideration of the effect of pitch angle scattering

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

    NASA Astrophysics Data System (ADS)

    Cortázar, O. D.; Megía-Macías, A.; Vizcaíno-de-Julián, A.

    2012-10-01

    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 μs 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.

  15. Design and fabrication of a superconducting magnet for an 18 GHz electron cyclotron resonance ion∕photon source NFRI-ECRIPS.

    PubMed

    You, H-J; Jang, S-W; Jung, Y-H; Lho, T-H; Lee, S-J

    2012-02-01

    A superconducting magnet was designed and fabricated for an 18 GHz ECR ion∕photon source, which will be installed at National Fusion Research Institute (NFRI) in South Korea. The magnetic system consists of a set of four superconducting coils for axial mirror field and 36 pieces of permanent magnets for hexapolar field. The superconducting coils with a cryocooler (1.5 W @ 4.2 K) allow one to reach peak mirror fields of 2.2 T in the injection and those of 1.5 T in the extraction regions on the source axis, and the resultant hexapolar field gives 1.35 T on the plasma chamber wall. The unbalanced magnetic force between the coils and surrounding yoke has been minimized to 16 ton by a coil arrangement and their electrical connection, and then was successfully suspended by 12 strong thermal insulating supports made of large numbers of carbon fibers. In order to block radiative thermal losses, multilayer thermal insulations are covered on the coil windings as well as 40-K aluminum thermal shield. Also new schemes of quench detection and safety system (coil divisions, quench detection coils, and heaters) were employed. For impregnation of the windings a special epoxy has been selected and treated to have a higher breaking strength and a higher thermal conductivity, which enables the superconductors to be uniformly and rapidly cooled down or heated during a quench.

  16. Design and fabrication of a superconducting magnet for an 18 GHz electron cyclotron resonance ion/photon source NFRI-ECRIPS

    SciTech Connect

    You, H.-J.; Jang, S.-W.; Jung, Y.-H.; Lho, T.-H.; Lee, S.-J.

    2012-02-15

    A superconducting magnet was designed and fabricated for an 18 GHz ECR ion/photon source, which will be installed at National Fusion Research Institute (NFRI) in South Korea. The magnetic system consists of a set of four superconducting coils for axial mirror field and 36 pieces of permanent magnets for hexapolar field. The superconducting coils with a cryocooler (1.5 W - 4.2 K) allow one to reach peak mirror fields of 2.2 T in the injection and those of 1.5 T in the extraction regions on the source axis, and the resultant hexapolar field gives 1.35 T on the plasma chamber wall. The unbalanced magnetic force between the coils and surrounding yoke has been minimized to 16 ton by a coil arrangement and their electrical connection, and then was successfully suspended by 12 strong thermal insulating supports made of large numbers of carbon fibers. In order to block radiative thermal losses, multilayer thermal insulations are covered on the coil windings as well as 40-K aluminum thermal shield. Also new schemes of quench detection and safety system (coil divisions, quench detection coils, and heaters) were employed. For impregnation of the windings a special epoxy has been selected and treated to have a higher breaking strength and a higher thermal conductivity, which enables the superconductors to be uniformly and rapidly cooled down or heated during a quench.

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

    SciTech Connect

    Cortazar, O. D.

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

    PubMed

    Cortázar, O D; Megía-Macías, A; Vizcaíno-de-Julián, A

    2012-10-01

    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 μs 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.

  19. Electron Cyclotron Resonances in Electron Cloud Dynamics

    SciTech Connect

    Celata, Christine; Celata, C.M.; Furman, Miguel A.; Vay, J.-L.; Yu, Jennifer W.

    2008-06-25

    We report a previously unknown resonance for electron cloud dynamics. The 2D simulation code"POSINST" was used to study the electron cloud buildup at different z positions in the International Linear Collider positron damping ring wiggler. An electron equilibrium density enhancement of up to a factor of 3 was found at magnetic field values for which the bunch frequency is an integral multiple of the electron cyclotron frequency. At low magnetic fields the effects of the resonance are prominent, but when B exceeds ~;;(2 pi mec/(elb)), with lb = bunch length, effects of the resonance disappear. Thus short bunches and low B fields are required for observing the effect. The reason for the B field dependence, an explanation of the dynamics, and the results of the 2D simulations and of a single-particle tracking code used to elucidate details of the dynamics are discussed.

  20. Effect of source tuning parameters on the plasma potential of heavy ions in the 18 GHz high temperature superconducting electron cyclotron resonance ion source.

    PubMed

    Rodrigues, G; Baskaran, R; Kukrety, S; Mathur, Y; Kumar, Sarvesh; Mandal, A; Kanjilal, D; Roy, A

    2012-03-01

    Plasma potentials for various heavy ions have been measured using the retarding field technique in the 18 GHz high temperature superconducting ECR ion source, PKDELIS [C. Bieth, S. Kantas, P. Sortais, D. Kanjilal, G. Rodrigues, S. Milward, S. Harrison, and R. McMahon, Nucl. Instrum. Methods B 235, 498 (2005); D. Kanjilal, G. Rodrigues, P. Kumar, A. Mandal, A. Roy, C. Bieth, S. Kantas, and P. Sortais, Rev. Sci. Instrum. 77, 03A317 (2006)]. The ion beam extracted from the source is decelerated close to the location of a mesh which is polarized to the source potential and beams having different plasma potentials are measured on a Faraday cup located downstream of the mesh. The influence of various source parameters, viz., RF power, gas pressure, magnetic field, negative dc bias, and gas mixing on the plasma potential is studied. The study helped to find an upper limit of the energy spread of the heavy ions, which can influence the design of the longitudinal optics of the high current injector being developed at the Inter University Accelerator Centre. It is observed that the plasma potentials are decreasing for increasing charge states and a mass effect is clearly observed for the ions with similar operating gas pressures. In the case of gas mixing, it is observed that the plasma potential minimizes at an optimum value of the gas pressure of the mixing gas and the mean charge state maximizes at this value. Details of the measurements carried out as a function of various source parameters and its impact on the longitudinal optics are presented.

  1. Effect of source tuning parameters on the plasma potential of heavy ions in the 18 GHz high temperature superconducting electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Rodrigues, G.; Baskaran, R.; Kukrety, S.; Mathur, Y.; Kumar, Sarvesh; Mandal, A.; Kanjilal, D.; Roy, A.

    2012-03-01

    Plasma potentials for various heavy ions have been measured using the retarding field technique in the 18 GHz high temperature superconducting ECR ion source, PKDELIS [C. Bieth, S. Kantas, P. Sortais, D. Kanjilal, G. Rodrigues, S. Milward, S. Harrison, and R. McMahon, Nucl. Instrum. Methods B 235, 498 (2005), 10.1016/j.nimb.2005.03.232; D. Kanjilal, G. Rodrigues, P. Kumar, A. Mandal, A. Roy, C. Bieth, S. Kantas, and P. Sortais, Rev. Sci. Instrum. 77, 03A317 (2006), 10.1063/1.2164887]. The ion beam extracted from the source is decelerated close to the location of a mesh which is polarized to the source potential and beams having different plasma potentials are measured on a Faraday cup located downstream of the mesh. The influence of various source parameters, viz., RF power, gas pressure, magnetic field, negative dc bias, and gas mixing on the plasma potential is studied. The study helped to find an upper limit of the energy spread of the heavy ions, which can influence the design of the longitudinal optics of the high current injector being developed at the Inter University Accelerator Centre. It is observed that the plasma potentials are decreasing for increasing charge states and a mass effect is clearly observed for the ions with similar operating gas pressures. In the case of gas mixing, it is observed that the plasma potential minimizes at an optimum value of the gas pressure of the mixing gas and the mean charge state maximizes at this value. Details of the measurements carried out as a function of various source parameters and its impact on the longitudinal optics are presented.

  2. Effect of source tuning parameters on the plasma potential of heavy ions in the 18 GHz high temperature superconducting electron cyclotron resonance ion source

    SciTech Connect

    Rodrigues, G.; Mathur, Y.; Kumar, Sarvesh; Mandal, A.; Kanjilal, D.; Roy, A.; Baskaran, R.; Kukrety, S.

    2012-03-15

    Plasma potentials for various heavy ions have been measured using the retarding field technique in the 18 GHz high temperature superconducting ECR ion source, PKDELIS [C. Bieth, S. Kantas, P. Sortais, D. Kanjilal, G. Rodrigues, S. Milward, S. Harrison, and R. McMahon, Nucl. Instrum. Methods B 235, 498 (2005); D. Kanjilal, G. Rodrigues, P. Kumar, A. Mandal, A. Roy, C. Bieth, S. Kantas, and P. Sortais, Rev. Sci. Instrum. 77, 03A317 (2006)]. The ion beam extracted from the source is decelerated close to the location of a mesh which is polarized to the source potential and beams having different plasma potentials are measured on a Faraday cup located downstream of the mesh. The influence of various source parameters, viz., RF power, gas pressure, magnetic field, negative dc bias, and gas mixing on the plasma potential is studied. The study helped to find an upper limit of the energy spread of the heavy ions, which can influence the design of the longitudinal optics of the high current injector being developed at the Inter University Accelerator Centre. It is observed that the plasma potentials are decreasing for increasing charge states and a mass effect is clearly observed for the ions with similar operating gas pressures. In the case of gas mixing, it is observed that the plasma potential minimizes at an optimum value of the gas pressure of the mixing gas and the mean charge state maximizes at this value. Details of the measurements carried out as a function of various source parameters and its impact on the longitudinal optics are presented.

  3. Development of electron cyclotron emission imaging system on Large Helical Device

    SciTech Connect

    Kuwahara, D.; Tsuji-Iio, S.; Nagayama, Y.; Yoshinaga, T.; Tsuchiya, H.; Sugito, S.; Yamaguchi, S.; Kogi, Y.; Akaki, K.; Mase, A.

    2010-10-15

    A combined system of microwave imaging reflectometry and electron cyclotron emission (ECE) imaging has been developed for the Large Helical Device. This system includes a wide-band two-dimensional horn-antenna mixer array (HMA). The HMA consists of horn antennas, waveguides, mixers, and intermediate frequency circuits. The frequency response of the HMA is between 50 and 110 GHz. The ECE signal is selected using a 95 GHz local oscillator and a 93 GHz high-pass filter.

  4. Production of a highly charged uranium ion beam with RIKEN superconducting electron cyclotron resonance ion source

    SciTech Connect

    Higurashi, Y.; Ohnishi, J.; Nakagawa, T.; Haba, H.; Fujimaki, M.; Komiyama, M.; Kamigaito, O.; Tamura, M.; Aihara, T.; Uchiyama, A.

    2012-02-15

    A highly charged uranium (U) ion beam is produced from the RIKEN superconducting electron cyclotron resonance ion source using 18 and 28 GHz microwaves. The sputtering method is used to produce this U ion beam. The beam intensity is strongly dependent on the rod position and sputtering voltage. We observe that the emittance of U{sup 35+} for 28 GHz microwaves is almost the same as that for 18 GHz microwaves. It seems that the beam intensity of U ions produced using 28 GHz microwaves is higher than that produced using 18 GHz microwaves at the same Radio Frequency (RF) power.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Electron-cyclotron-resonance ion sources (review)

    SciTech Connect

    Golovanivskii, K.S.; Dougar-Jabon, V.D.

    1992-01-01

    The physical principles are described and a brief survey of the present state is given of ion sources based on electron-cyclotron heating of plasma in a mirror trap. The characteristics of ECR sources of positive and negative ions used chiefly in accelerator technology are presented. 20 refs., 10 figs., 3 tabs.

  7. Tokamak startup with electron cyclotron heating

    SciTech Connect

    Holly, D J; Prager, S C; Shepard, D A; Sprott, J C

    1980-04-01

    Experiments are described in which the startup voltage in a tokamak is reduced by approx. 60% by the use of a modest amount of electron cyclotron resonance heating power for preionization. A 50% reduction in volt-second requirement and impurity reflux are also observed.

  8. Stability of the Electron Cyclotron Resonance

    NASA Astrophysics Data System (ADS)

    Asch, Joachim; Bourget, Olivier; Meresse, Cédric

    2015-12-01

    We consider the magnetic AC Stark effect for the quantum dynamics of a single particle in the plane under the influence of an oscillating homogeneous electric and a constant perpendicular magnetic field. We prove that the electron cyclotron resonance is insensitive to impurity potentials.

  9. Currents driven by electron cyclotron waves

    SciTech Connect

    Karney, C.F.F.; Fisch, N.J.

    1981-07-01

    Certain aspects of the generation of steady-state currents by electron cyclotron waves are explored. A numerical solution of the Fokker-Planck equation is used to verify the theory of Fisch and Boozer and to extend their results into the nonlinear regime. Relativistic effects on the current generated are discussed. Applications to steady-state tokamak reactors are considered.

  10. Status of a compact electron cyclotron resonance ion source for National Institute of Radiological Sciences-930 cyclotron.

    PubMed

    Hojo, S; Katagiri, K; Nakao, M; Sugiura, A; Muramatsu, M; Noda, A; Okada, T; Takahashi, Y; Komiyama, A; Honma, T; Noda, K

    2014-02-01

    The Kei-source is a compact electron cyclotron resonance ion source using only permanent magnets and a frequency of 10 GHz. It was developed at the National Institute of Radiological Sciences (NIRS) for producing C(4+) ions oriented for high-energy carbon therapy. It has also been used as an ion source for the NIRS-930 cyclotron. Its microwave band region for the traveling-wave-tube amplifier and maximum output power are 8-10 GHz and 350 W, respectively. Since 2006, it has provided various ion beams such as proton, deuteron, carbon, oxygen, and neon with sufficient intensity (200 μA for proton and deuteron, 50 μA for C(4+), for example) and good stability for radioisotope production, tests of radiation damage, and basic research experiments. Its horizontal and vertical emittances were measured using a screen monitor and waist-scan. The present paper reports the current status of the Kei-source.

  11. Electron cyclotron emission measurements on the Texas Experimental Tokamak

    SciTech Connect

    Austin, M.E. Jr.

    1992-01-01

    A ten-channel grating polychromator was designed, constructed, and installed on the Texas Experimental Tokamak to monitor the second harmonic electron cyclotron emission. Electron temperature profiles were derived from measurements of the optically thick radiation for a variety of plasma confinement experiments. The radial and temporal evolution of T[sub e] has been characterized for electron cyclotron heated discharges with 150 kW of 60 GHz power. Comparisons were made of the heating efficiency of two type of ECH launchers. A focussed launcher was shown to have slightly better heating efficiency than an unfocussed launcher; however, the focussed antenna did not yield significantly higher electron temperatures as expected. A study of the time evolution of the electron temperature indicated that increased sawtooth activity limited the effectiveness of the focussed launcher. A focussing hog-horn antenna was fabricated and installed on the inboard side of the tokamak to measure emission directed towards the high-field side during ECH. Comparison of the radiation temperature profiles from low-field side and high-field side antennas indicates the creation of a nonthermal electron distribution by the heating. The results of the experiment compare favorably with theoretical predictions from a quasi-linear Fokker-Planck code of a 6 keV nonthermal population with a density about 1 percent of the thermal density.

  12. A room temperature electron cyclotron resonance ion source for the DC-110 cyclotron

    SciTech Connect

    Efremov, A. Bogomolov, S.; Lebedev, A.; Loginov, V.; Yazvitsky, N.

    2014-02-15

    The project of the DC-110 cyclotron facility to provide applied research in the nanotechnologies (track pore membranes, surface modification of materials, etc.) has been designed by the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research (Dubna). The facility includes the isochronous cyclotron DC-110 for accelerating the intensive Ar, Kr, Xe ion beams with 2.5 MeV/nucleon fixed energy. The cyclotron is equipped with system of axial injection and ECR ion source DECRIS-5, operating at the frequency of 18 GHz. This article reviews the design and construction of DECRIS-5 ion source along with some initial commissioning results.

  13. Radiation Sources at Electron Cyclotron Harmonic Frequencies.

    DTIC Science & Technology

    1983-01-28

    KEY WORDS (Continue on reverse side it necesear and Identify by block number) Radiation source, electron cyclotron frequency, gyrotron, travelling ...investigation of gyrotron devices operating in cylindrical geometry. Specific topics include an analysis of oscillations in a gyrotron travelling wave...amplifier, the study of the effects of velocity spread and wall resistivity on gain and bandwidth in a gyrotron travell - ing wave amplifier, an

  14. Plans for Electron Bernstein Wave and Electron Cyclotron Heating in NSTX

    SciTech Connect

    Taylor, G.; Diem, S. J.; Ellis, R. A.; Fredd, E. H.; Greenough, N. L.; Hosea, J. C.; Bigelow, T. S.; Caughman, J. B.; Rasmussen, D. A.; Ryan, P. M.; Wilgen, J. B.; Ershov, N. M.; Harvey, R. W.; Smirnov, A. P.; Preinhaelter, J.; Urban, J.; Ram, A. K.

    2007-09-28

    A 200 kW, 28 GHz system for electron cyclotron heating (ECH) and electron Bernstein wave heating (EBWH) is being installed on NSTX to assist solenoid-free startup, high harmonic fast wave heated current ramp up, and to support initial EBW coupling and heating studies. This system will provide on-axis second harmonic ECH/EBWH in NSTX. Fundamental on-axis heating may also be possible at 15.3 GHz by operating the gyrotron in a lower order TE01 cavity mode. Sufficient power supply capability will be provided to provide up to 1 MW of gyrotron power for future proof-of-principle EBWH experiments on NSTX. Initial modeling of an NSTX startup discharge with 28 GHz ECH is presented.

  15. Glow plasma trigger for electron cyclotron resonance ion sources.

    PubMed

    Vodopianov, A V; Golubev, S V; Izotov, I V; Nikolaev, A G; Oks, E M; Savkin, K P; Yushkov, G Yu

    2010-02-01

    Electron cyclotron resonance ion sources (ECRISs) are particularly useful for nuclear, atomic, and high energy physics, as unique high current generators of multicharged ion beams. Plasmas of gas discharges in an open magnetic trap heated by pulsed (100 micros and longer) high power (100 kW and higher) high-frequency (greater than 37.5 GHz) microwaves of gyrotrons is promising in the field of research in the development of electron cyclotron resonance sources for high charge state ion beams. Reaching high ion charge states requires a decrease in gas pressure in the magnetic trap, but this method leads to increases in time, in which the microwave discharge develops. The gas breakdown and microwave discharge duration becomes greater than or equal to the microwave pulse duration when the pressure is decreased. This makes reaching the critical plasma density initiate an electron cyclotron resonance (ECR) discharge during pulse of microwave gyrotron radiation with gas pressure lower than a certain threshold. In order to reduce losses of microwave power, it is necessary to shorten the time of development of the ECR discharge. For fast triggering of ECR discharge under low pressure in an ECRIS, we initially propose to fill the magnetic trap with the plasmas of auxiliary pulsed discharges in crossed ExB fields. The glow plasma trigger of ECR based on a Penning or magnetron discharge has made it possible not only to fill the trap with plasma with density of 10(12) cm(-3), required for a rapid increase in plasma density and finally for ECR discharge ignition, but also to initially heat the plasma electrons to T(e) approximately = 20 eV.

  16. Electron Cyclotron Heating on DIII-D

    SciTech Connect

    Prater, R.; Petty, C.C.

    2005-10-15

    Electron cyclotron heating (ECH) has proved to be a very flexible system for heating applications in DIII-D. The outstanding characteristics of ECH - controllable heating location, a high degree of localization of the power, ability to heat without introducing particles, and ability to heat only the electron fluid - have been used in a wide variety of experiments to study wave physics and transport, to control magnetohydrodynamic activity, and to improve discharges. These characteristics along with relatively easy coupling to the plasma make ECH a valuable resource for both heating and instability control in burning plasmas.

  17. Cyclotron Resonances in Electron Cloud Dynamics

    SciTech Connect

    Celata, C. M.; Furman, Miguel A.; Vay, J.-L.; Ng, J. S.T.; Grote, D. P.; Pivi, M. T. F.; Wang, L. F.

    2009-04-29

    A new set of resonances for electron cloud dynamics in the presence of a magnetic field has been found. For short beam bunch lengths and low magnetic fields where lb<< 2pi c/omega c (with lb = bunch length, omega c = non-relativistic cyclotron frequency) resonances between the bunch frequency and harmonics of the electron cyclotron frequency cause an increase in the electron cloud density in narrow ranges of magnetic field near the resonances. For ILC parameters the increase in the density is up to a factor ~;;3, and the spatial distribution of the electrons is broader near resonances, lacking the well-defined vertical density"stripes" found for non-resonant cases. Simulations with the 2D computer code POSINST, as well as a single-particle tracking code, were used to elucidate the physics of the dynamics. The existence of the resonances has been confirmed in experiments at PEP-II. The resonances are expected to affect the electron cloud dynamics in the fringe fields of conventional lattice magnets and in wigglers, where the magnetic fields are low. Results of the simulations and experimental observations, the reason for the bunch-length dependence, and details of the dynamics are discussed here.

  18. The Design of a 100 GHz CARM (Cyclotron Auto-Resonance Maser) Oscillator Experiment

    DTIC Science & Technology

    1988-09-14

    2364. (Radio Engng. Electron. Phys., 21, 78-73). 5) Ginzburg , N. S., Zarnitsyna, I. G., and Nusinovich, G. S., 1981, Theory of relativistic cyclotron...An efficient Doppler-shifted electron-cyclotron maser oscillator. Int J. Electron., 53, 555-57 1. 7) Bratman, V. L., Ginzburg , N. S., Nusinovich, G...1386-1389. (Sov. Tech. Phys. Lett., 8, 596-597). 12) Botvinnik, I. E., Bratman, V. L., Volkov, A. B., Ginzburg , N. S, Denisov, G. G., Kol’chugin, B

  19. Cyclotron Resonances in Electron Cloud Dynamics

    SciTech Connect

    Celata, C M; Furman, M A; Vay, J L; Grote, D P; Ng, J T; Pivi, M F; Wang, L F

    2009-05-05

    A new set of resonances for electron cloud dynamics in the presence of a magnetic field has been found. For short beam bunch lengths and low magnetic fields where l{sub b} << 2{pi}{omega}{sub c}, (l{sub b} = bunch duration, {omega}{sub c} = non-relativistic cyclotron frequency) resonances between the bunch frequency and harmonics of the cyclotron frequency cause an increase in the electron cloud density in narrow ranges of magnetic field near the resonances. For ILC parameters the increase in the density is up to a factor {approx} 3, and the spatial distribution of the electrons is broader near resonances, lacking the well-defined density 'stripes' of multipactoring found for non-resonant cases. Simulations with the 2D computer code POSINST, as well as a single-particle tracking code, were used to elucidate the physics of the dynamics. The resonances are expected to affect the electron cloud dynamics in the fringe fields of conventional lattice magnets and in wigglers, where the magnetic fields are low. Results of the simulations, the reason for the bunch-length dependence, and details of the dynamics will be discussed.

  20. Alternative optical concept for electron cyclotron emission imaging

    SciTech Connect

    Liu, J. X.; Milbourne, T.; Bitter, M.; Delgado-Aparicio, L.; Dominguez, A.; Efthimion, P. C.; Hill, K. W.; Kramer, G. J.; Kung, C.; Pablant, N. A.; Tobias, B.; Kubota, S.; Kasparek, W.; Lu, J.; Park, H.

    2014-11-15

    The implementation of advanced electron cyclotron emission imaging (ECEI) systems on tokamak experiments has revolutionized the diagnosis of magnetohydrodynamic (MHD) activities and improved our understanding of instabilities, which lead to disruptions. It is therefore desirable to have an ECEI system on the ITER tokamak. However, the large size of optical components in presently used ECEI systems have, up to now, precluded the implementation of an ECEI system on ITER. This paper describes a new optical ECEI concept that employs a single spherical mirror as the only optical component and exploits the astigmatism of such a mirror to produce an image with one-dimensional spatial resolution on the detector. Since this alternative approach would only require a thin slit as the viewing port to the plasma, it would make the implementation of an ECEI system on ITER feasible. The results obtained from proof-of-principle experiments with a 125 GHz microwave system are presented.

  1. A simple electron cyclotron resonance ion source (abstract)a)

    NASA Astrophysics Data System (ADS)

    Welton, R. F.; Moran, T. F.; Feeney, R. K.; Thomas, E. W.

    1996-03-01

    A simple, all permanent magnet, 2.45 GHz electron cyclotron resonance ion source has been developed for the production of stable beams of low charge state ions from gaseous feed materials. The source can produce ˜1 mA of low energy (3 kV) singly charged ion current in the 10-4 Torr pressure range. The source can also be operated in a more efficient low-pressure mode at an order of magnitude lower pressure. In this latter range, for example, the ionization efficiency of Ar is estimated to be 1% with charge states up to Ar8+ present. Operation in the low-pressure mode requires low power input (˜20 W). These features make the source especially suited for use with small accelerator systems for a number of applications including ion implantation, mass spectrometry, and atomic collision experiments where multiply charged ions are desirable. Design details and performance characteristics of the source are presented.

  2. [Electron cyclotron resonance (ECR) plasma film deposition

    SciTech Connect

    1999-04-01

    During the third quarter of 1995, an electron cyclotron resonance (ECR) plasma film deposition facility was constructed at the University of New Mexico. This work was conducted in support of the Los Alamos/Tycom CRADA agreement to pursue methods of improving drill bit lifetime. Work in the fourth quarter will center on the coating of drill bits and the treating and testing of various test samples. New material systems as well as treatment techniques will be attempted during this period. The following is a brief description of the various subsystems of the film deposition facility. Particular emphasis is placed on the slotted waveguide system as requested.

  3. Coherent Cherenkov-Cyclotron Radiation Excited by an Electron Beam in a Metamaterial Waveguide

    NASA Astrophysics Data System (ADS)

    Hummelt, J. S.; Lu, X.; Xu, H.; Mastovsky, I.; Shapiro, M. A.; Temkin, R. J.

    2016-12-01

    An electron beam passing through a metamaterial structure is predicted to generate reversed Cherenkov radiation, an unusual and potentially very useful property. We present an experimental test of this phenomenon using an intense electron beam passing through a metamaterial loaded waveguide. Power levels of up to 5 MW are observed in backward wave modes at a frequency of 2.40 GHz using a one microsecond pulsed electron beam of 490 keV, 84 A in a 400 G magnetic field. Contrary to expectations, the output power is not generated in the Cherenkov mode. Instead, the presence of the magnetic field, which is required to transport the electron beam, induces a Cherenkov-cyclotron (or anomalous Doppler) instability at a frequency equal to the Cherenkov frequency minus the cyclotron frequency. Nonlinear simulations indicate that the Cherenkov-cyclotron mode should dominate over the Cherenkov instability at a lower magnetic field where the highest output power is obtained.

  4. Electron Cyclotron Emission Diagnostics on ITER

    NASA Astrophysics Data System (ADS)

    Ellis, Richard; Austin, Max; Phillips, Perry; Rowan, William; Beno, Joseph; Auroua, Abelhamid; Feder, Russell; Patel, Ashish; Hubbard, Amanda; Pandya, Hitesh

    2010-11-01

    Electron cyclotron emission (ECE) will be employed on ITER to measure the radial profile of electron temperature and non thermal features of the electron distribution as well as measurements of ELMs, magnetic islands, high frequency instabilities, and turbulence. There are two quasioptical systems, designed with Gaussian beam analysis. One view is radial, primarily for temperature profile measurement, the other views at a small angle to radial for measuring non-thermal emission. Radiation is conducted to by a long corrugated waveguide to a multichannel Michelson interferometer which provides wide wavelength coverage but limited time response as well as two microwave radiometers which cover the fundamental and second harmonic ECE and provide excellent time response. Measurements will be made in both X and O mode. In-situ calibration is provided by a novel hot calibration source. We discuss spatial resolution and the implications for physics studies.

  5. Parametric Instabilities of Electron Cyclotron Waves in Plasmas.

    DTIC Science & Technology

    1980-03-01

    tokamaks eg. PLT. In the EBT, the electron cyclotron pump of finite wavenumber 1% decays into two Bernstein modes at the second harmonic cyclotron...convective threshold with finite k, is -200 W/ . For large tokamaks , the convective threshold for various decay channels turns out to be >200 KW/cu 2...efforts on the electron cyclotron heating of large devices, eg., Elmo bumpy torus, tokamak and mirrors. In the Elmo 1bumpy torus (EBT) the microwaves

  6. A Michelson Interferometer for Electron Cyclotron Emission Measurements on EAST

    NASA Astrophysics Data System (ADS)

    Liu, Yong; Stefan, Schmuck; Zhao, Hailin; John, Fessey; Paul, Trimble; Liu, Xiang; Zhu, Zeying; Zang, Qing; Hu, Liqun

    2016-12-01

    A Michelson interferometer, on loan from EFDA-JET (Culham, United Kingdom) has recently been commissioned on the experimental advanced superconducting tokamak (EAST, ASIPP, Hefei, China). Following a successful in-situ absolute calibration the instrument is able to measure the electron cyclotron emission (ECE) spectrum, from 80 GHz to 350 GHz in extraordinary mode (X-mode) polarization, with high accuracy. This allows the independent determination of the electron temperature profile from observation of the second harmonic ECE and the possible identification of non-Maxwellian features by comparing higher harmonic emission with numerical simulations. The in-situ calibration results are presented together with the initial measured temperature profiles. These measurements are then discussed and compared with other independent temperature profile measurements. This paper also describes the main hardware features of the diagnostic and the associated commissioning test results. supported by National Natural Science Foundation of China (Nos. 11405211, 11275233), and the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB106002, 2015GB101000), and the RCUK Energy Programme (No. EP/I501045), partly supported by the JSPS-NRF-NSFC A3 Foresight Program in the Field of Plasma Physics (NSFC: No. 11261140328)

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

    SciTech Connect

    Asaji, T. Hirabara, N.; Izumihara, T.; Nakamizu, T.; Ohba, T.; Nakamura, T.; Furuse, M.; Hitobo, T.; Kato, Y.

    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.

  8. Fourth generation electron cyclotron resonance ion sources (invited)

    SciTech Connect

    Lyneis, Claude M.; Leitner, D.; Todd, D. S.; Sabbi, G.; Prestemon, S.; Caspi, S.; Ferracin, P.

    2008-02-15

    The concepts and technical challenges related to developing a fourth generation electron cyclotron resonance (ECR) ion source with a rf frequency greater than 40 GHz and magnetic confinement fields greater than twice B{sub ECR} will be explored in this article. Based on the semiempirical frequency scaling of ECR plasma density with the square of operating frequency, there should be significant gains in performance over current third generation ECR ion sources, which operate at rf frequencies between 20 and 30 GHz. While the third generation ECR ion sources use NbTi superconducting solenoid and sextupole coils, the new sources will need to use different superconducting materials, such as Nb{sub 3}Sn, to reach the required magnetic confinement, which scales linearly with rf frequency. Additional technical challenges include increased bremsstrahlung production, which may increase faster than the plasma density, bremsstrahlung heating of the cold mass, and the availability of high power continuous wave microwave sources at these frequencies. With each generation of ECR ion sources, there are new challenges to be mastered, but the potential for higher performance and reduced cost of the associated accelerator continues to make this a promising avenue for development.

  9. Two Dimensional Synthetic Electron Cyclotron Emission Imaging

    NASA Astrophysics Data System (ADS)

    Shi, Lei; Valeo, Ernest J.; Tobias, Benjamin J.; Kramer, Gerrit J.; Liu, Chang; Tang, William M.

    2016-10-01

    Electron Cyclotron Emission (ECE) has been widely used as a measurement of the electron temperature profile in magnetically confined plasmas. The ECE Imaging (ECEI) system provides additional vertical resolutions, and is used to measure the electron temperature fluctuations. The vertical resolution is typically a few centi-meters which is sometimes comparable to the vertical wave length of the underlying fluctuations. The ray-tracing technique used in most synthetic ECE codes to determine the origin and spatial extent of the ECE radiations is not accurate when the refraction and diffraction due to the fluctuations are important. In this presentation, we introduce a new synthetic ECEI code which solves the wave propagation up to the 2nd order of the WKB approximation, and provides full 2D information of the ECE source. We'll show that when the ECE frequency is near the cutoff, the refraction due to the fluctuations is important. A ``trapping'' of the ECE source by the density fluctuations is identified, and is potentially useful for determining the cross phase between electron temperature and density fluctuations. The new formalism is also used to study the Runaway Electrons contribution to the ECE signal, and provides insights to the measured ECE spectrum on DIII-D. This work has been funded by the US Department of Energy under Contract Number DE-AC02-09CH11466.

  10. Ionospheric modification at twice the electron cyclotron frequency.

    PubMed

    Djuth, F T; Pedersen, T R; Gerken, E A; Bernhardt, P A; Selcher, C A; Bristow, W A; Kosch, M J

    2005-04-01

    In 2004, a new transmission band was added to the HAARP high-frequency ionospheric modification facility that encompasses the second electron cyclotron harmonic at altitudes between approximately 220 and 330 km. Initial observations indicate that greatly enhanced airglow occurs whenever the transmission frequency approximately matches the second electron cyclotron harmonic at the height of the upper hybrid resonance. This is the reverse of what happens at higher electron cyclotron harmonics. The measured optical emissions confirm the presence of accelerated electrons in the plasma.

  11. DIII-D Electron Cyclotron Heating System Status and Upgrades

    DOE PAGES

    Cengher, Mirela; Lohr, John; Gorelov, Yuri; ...

    2016-06-23

    The DIII-D Electron Cyclotron Heating (ECH) system consists of six 110 GHz gyrotrons with corrugated coaxial 31.75 mm waveguide transmission lines and steerable launching mirrors. The system has been gradually updated, leading to increased experimental flexibility and a high system reliability of 91% in the past year. Operationally, the gyrotrons can generate up to a total of 4.8 MW of rf power for pulses up to 5 seconds. The maximum ECH energy injected into the DIII-D is 16.6 MJ. The HE1,1 mode content is over 85% for all the lines, and the transmission coefficient is better than -1.1 dB formore » all the transmission lines, close to the theoretical value. A new depressed collector gyrotron was recently installed and was injecting up to 640 kW of power into the plasma during 2014-2015 tokamak operations. Four dual waveguide launchers, which can steer the RF beams ±20 degrees poloidally and toroidally, are used for real-time neoclassical tearing mode control and suppression. The launchers now have increased poloidal scanning speed and beam positioning accuracy of ~±2 mm at the plasma center. Two more gyrotrons are expected to be installed and operational in 2015- 2016. The first is a repaired 110 GHz, 1 MW gyrotron that had a gun failure after more than 11 years of operation at DIII-D. The second is a newly designed depressed collector tube in the 1.5 MW class, operating at 117.5 GHz, manufactured by Communications and Power Industries (CPI).« less

  12. DIII-D Electron Cyclotron Heating System Status and Upgrades

    SciTech Connect

    Cengher, Mirela; Lohr, John; Gorelov, Yuri; Torrezan, Antonio; Ponce, Dan; Chen, Xi; Moeller, Charles

    2016-06-23

    The DIII-D Electron Cyclotron Heating (ECH) system consists of six 110 GHz gyrotrons with corrugated coaxial 31.75 mm waveguide transmission lines and steerable launching mirrors. The system has been gradually updated, leading to increased experimental flexibility and a high system reliability of 91% in the past year. Operationally, the gyrotrons can generate up to a total of 4.8 MW of rf power for pulses up to 5 seconds. The maximum ECH energy injected into the DIII-D is 16.6 MJ. The HE1,1 mode content is over 85% for all the lines, and the transmission coefficient is better than -1.1 dB for all the transmission lines, close to the theoretical value. A new depressed collector gyrotron was recently installed and was injecting up to 640 kW of power into the plasma during 2014-2015 tokamak operations. Four dual waveguide launchers, which can steer the RF beams ±20 degrees poloidally and toroidally, are used for real-time neoclassical tearing mode control and suppression. The launchers now have increased poloidal scanning speed and beam positioning accuracy of ~±2 mm at the plasma center. Two more gyrotrons are expected to be installed and operational in 2015- 2016. The first is a repaired 110 GHz, 1 MW gyrotron that had a gun failure after more than 11 years of operation at DIII-D. The second is a newly designed depressed collector tube in the 1.5 MW class, operating at 117.5 GHz, manufactured by Communications and Power Industries (CPI).

  13. Single-electron detection and spectroscopy via relativistic cyclotron radiation

    SciTech Connect

    Asner, D. M.; Bradley, R. F.; de Viveiros, L.; Doe, P. J.; Fernandes, J. L.; Fertl, M.; Finn, E. C.; Formaggio, J. A.; Furse, D.; Jones, A. M.; Kofron, J. N.; LaRoque, B. H.; Leber, M.; McBride, E. L.; Miller, M. L.; Mohanmurthy, P.; Monreal, B.; Oblath, N. S.; Robertson, R. G. H.; Rosenberg, L. J.; Rybka, G.; Rysewyk, D.; Sternberg, M. G.; Tedeschi, J. R.; Thummler, T.; VanDevender, B. A.; Woods, N. L.

    2015-04-20

    Since 1897, we've understood that accelerating charges must emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. We demonstrate single-electron detection in a novel radiofrequency spec- trometer. Here, we observe the cyclotron radiation emitted by individual magnetically-trapped electrons that are produced with mildly-relativistic energies by a gaseous radioactive source. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work demonstrates a fundamentally new approach to precision beta spectroscopy for future neutrino mass experiments.

  14. Single-electron detection and spectroscopy via relativistic cyclotron radiation

    SciTech Connect

    Asner, David M.; Bradley, Rich; De Viveiros Souza Filho, Luiz A.; Doe, Peter J.; Fernandes, Justin L.; Fertl, M.; Finn, Erin C.; Formaggio, Joseph; Furse, Daniel L.; Jones, Anthony M.; Kofron, Jared N.; LaRoque, Benjamin; Leber, Michelle; MCBride, Lisa; Miller, M. L.; Mohanmurthy, Prajwal T.; Monreal, Ben; Oblath, Noah S.; Robertson, R. G. H.; Rosenberg, Leslie; Rybka, Gray; Rysewyk, Devyn M.; Sternberg, Michael G.; Tedeschi, Jonathan R.; Thummler, Thomas; VanDevender, Brent A.; Woods, N. L.

    2015-04-01

    It has been understood since 1897 that accelerating charges should emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. Here we demonstrate single-electron detection in a novel radiofrequency spectrometer. We observe the cyclotron radiation emitted by individual electrons that are produced with mildly-relativistic energies by a gaseous radioactive source and are magnetically trapped. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work is a proof-of-concept for future neutrino mass experiments using this technique.

  15. Single-electron detection and spectroscopy via relativistic cyclotron radiation

    DOE PAGES

    Asner, D. M.; Bradley, R. F.; de Viveiros, L.; ...

    2015-04-20

    Since 1897, we've understood that accelerating charges must emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. We demonstrate single-electron detection in a novel radiofrequency spec- trometer. Here, we observe the cyclotron radiation emitted by individual magnetically-trapped electrons that are produced with mildly-relativistic energies by a gaseous radioactive source. The relativistic shift in the cyclotron frequency permits a precisemore » electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work demonstrates a fundamentally new approach to precision beta spectroscopy for future neutrino mass experiments.« less

  16. Characterization of electron cyclotron resonance hydrogen plasmas

    SciTech Connect

    Outten, C.A. . Dept. of Nuclear Engineering); Barbour, J.C.; Wampler, W.R. )

    1990-01-01

    Electron cyclotron resonance (ECR) plasmas yield low energy and high ion density plasmas. The characteristics downstream of an ECR hydrogen plasma were investigated as a function of microwave power and magnetic field. A fast-injection Langmuir probe and a carbon resistance probe were used to determine plasma potential (V{sub p}), electron density (N{sub e}), electron temperature (T{sub e}), ion energy (T{sub i}), and ion fluence. Langmuir probe results showed that at 17 cm downstream from the ECR chamber the plasma characteristics are approximately constant across the center 7 cm of the plasma for 50 Watts of absorbed power. These results gave V{sub p} = 30 {plus minus} 5 eV, N{sub e} = 1 {times} 10{sup 8} cm{sup {minus}3}, and T{sub e} = 10--13 eV. In good agreement with the Langmuir probe results, carbon resistance probes have shown that T{sub i} {le} 50 eV. Also, based on hydrogen chemical sputtering of carbon, the hydrogen (ion and energetic neutrals) fluence rate was determined to be 1 {times} 10{sup 16}/cm{sup 2}-sec. at a pressure of 1 {times} 10{sup {minus}4} Torr and for 50 Watts of absorbed power. 19 refs.

  17. An upgraded 32-channel heterodyne electron cyclotron emission radiometer on Tore Supra

    SciTech Connect

    Segui, J.L.; Molina, D.; Giruzzi, G.; Goniche, M.; Huysmans, G.; Maget, P.; Ottaviani, M.

    2005-12-15

    A 32-channel, 1 GHz spaced heterodyne radiometer is used on the Tore Supra tokamak to measure electron cyclotron emission (ECE) in the frequency range 78-110 GHz for the ordinary mode (O:E parallel B,k perpendicular B) and 94-126 GHz for the extraordinary mode (X:E perpendicular B,k perpendicular B). The radial resolution is essentially limited by ECE relativistic effects, depending on electron temperature and density, and not by the channels' frequency spacing. The time resolution depends on the acquisition scheme: the system allows for both 1 ms and 10 {mu}s acquisition. For example, this leads to precise electron temperature mapping during MHD activity. First experimental results obtained with this upgraded 32-channel radiometer are presented.

  18. Superthermal electron distribution measurements from polarized electron cyclotron emission

    SciTech Connect

    Luce, T.C.; Efthimion, P.C.; Fisch, N.J.

    1988-06-01

    Measurements of the superthermal electron distribution can be made by observing the polarized electron cyclotron emission. The emission is viewed along a constant magnetic field surface. This simplifies the resonance condition and gives a direct correlation between emission frequency and kinetic energy of the emitting electron. A transformation technique is formulated which determines the anisotropy of the distribution and number density of superthermals at each energy measured. The steady-state distribution during lower hybrid current drive and examples of the superthermal dynamics as the runaway conditions is varied are presented for discharges in the PLT tokamak. 15 refs., 8 figs.

  19. Correlation electron cyclotron emission diagnostic in TCV

    NASA Astrophysics Data System (ADS)

    Fontana, M.; Porte, L.; Molina Cabrera, P.

    2017-08-01

    The correlation electron cyclotron emission diagnostic of tokamak à configuration variable has recently been upgraded. It now has the choice of three lines of sight: two horizontal lines placed on the low field side of the vessel, perpendicular to the magnetic field, and a dual-axis steerable antenna. The polarization of the radiation collected by the latter can be rotated using a universal polarizer situated in the transmission line. This line is also shared with a reflectometry system, allowing simultaneous measurements of temperature and density fluctuations in the same plasma volumes. When using this line, it is possible to choose between two dedicated front ends characterized by different local oscillator frequencies, adding flexibility in the choice of the plasma region to be studied. The intermediate frequency section is now equipped with six frequency tunable YIG filters allowing the study of turbulence properties in a wide range of radial positions. When studying fluctuations over the whole video bandwidth, the minimum detectable fluctuation level is δ Te/Te˜0.5 % . The new system has been used to measure electron temperature fluctuations over a large fraction of the plasma profiles in a series of plasmas with triangularity varying from 0.6 to -0.6 but comparable collisionality profiles.

  20. A line-of-sight electron cyclotron emission receiver for electron cyclotron resonance heating feedback control of tearing modes

    SciTech Connect

    Oosterbeek, J. W.; Buerger, A.; Westerhof, E.; Baar, M. R. de; Berg, M. A. van den; Bongers, W. A.; Graswinckel, M. F.; Hennen, B. A.; Kruijt, O. G.; Thoen, J.; Heidinger, R.; Korsholm, S. B.; Leipold, F.; Nielsen, S. K.

    2008-09-15

    An electron cyclotron emission (ECE) receiver inside the electron cyclotron resonance heating (ECRH) transmission line has been brought into operation. The ECE is extracted by placing a quartz plate acting as a Fabry-Perot interferometer under an angle inside the electron cyclotron wave (ECW) beam. ECE measurements are obtained during high power ECRH operation. This demonstrates the successful operation of the diagnostic and, in particular, a sufficient suppression of the gyrotron component preventing it from interfering with ECE measurements. When integrated into a feedback system for the control of plasma instabilities this line-of-sight ECE diagnostic removes the need to localize the instabilities in absolute coordinates.

  1. Development of a miniature microwave electron cyclotron resonance plasma ion thruster for exospheric micro-propulsion

    SciTech Connect

    Dey, Indranuj; Toyoda, Yuji; Yamamoto, Naoji; Nakashima, Hideki

    2015-12-15

    A miniature microwave electron cyclotron resonance plasma source [(discharge diameter)/(microwave cutoff diameter) < 0.3] has been developed at Kyushu University to be used as an ion thruster in micro-propulsion applications in the exosphere. The discharge source uses both radial and axial magnetostatic field confinement to facilitate electron cyclotron resonance and increase the electron dwell time in the volume, thereby enhancing plasma production efficiency. Performance of the ion thruster is studied at 3 microwave frequencies (1.2 GHz, 1.6 GHz, and 2.45 GHz), for low input powers (<15 W) and small xenon mass flow rates (<40 μg/s), by experimentally measuring the extracted ion beam current through a potential difference of ≅1200 V. The discharge geometry is found to operate most efficiently at an input microwave frequency of 1.6 GHz. At this frequency, for an input power of 8 W, and propellant (xenon) mass flow rate of 21 μg/s, 13.7 mA of ion beam current is obtained, equivalent to an calculated thrust of 0.74 mN.

  2. Development of a miniature microwave electron cyclotron resonance plasma ion thruster for exospheric micro-propulsion.

    PubMed

    Dey, Indranuj; Toyoda, Yuji; Yamamoto, Naoji; Nakashima, Hideki

    2015-12-01

    A miniature microwave electron cyclotron resonance plasma source [(discharge diameter)/(microwave cutoff diameter) < 0.3] has been developed at Kyushu University to be used as an ion thruster in micro-propulsion applications in the exosphere. The discharge source uses both radial and axial magnetostatic field confinement to facilitate electron cyclotron resonance and increase the electron dwell time in the volume, thereby enhancing plasma production efficiency. Performance of the ion thruster is studied at 3 microwave frequencies (1.2 GHz, 1.6 GHz, and 2.45 GHz), for low input powers (<15 W) and small xenon mass flow rates (<40 μg/s), by experimentally measuring the extracted ion beam current through a potential difference of ≅1200 V. The discharge geometry is found to operate most efficiently at an input microwave frequency of 1.6 GHz. At this frequency, for an input power of 8 W, and propellant (xenon) mass flow rate of 21 μg/s, 13.7 mA of ion beam current is obtained, equivalent to an calculated thrust of 0.74 mN.

  3. Development of a miniature microwave electron cyclotron resonance plasma ion thruster for exospheric micro-propulsion

    NASA Astrophysics Data System (ADS)

    Dey, Indranuj; Toyoda, Yuji; Yamamoto, Naoji; Nakashima, Hideki

    2015-12-01

    A miniature microwave electron cyclotron resonance plasma source [(discharge diameter)/(microwave cutoff diameter) < 0.3] has been developed at Kyushu University to be used as an ion thruster in micro-propulsion applications in the exosphere. The discharge source uses both radial and axial magnetostatic field confinement to facilitate electron cyclotron resonance and increase the electron dwell time in the volume, thereby enhancing plasma production efficiency. Performance of the ion thruster is studied at 3 microwave frequencies (1.2 GHz, 1.6 GHz, and 2.45 GHz), for low input powers (<15 W) and small xenon mass flow rates (<40 μg/s), by experimentally measuring the extracted ion beam current through a potential difference of ≅1200 V. The discharge geometry is found to operate most efficiently at an input microwave frequency of 1.6 GHz. At this frequency, for an input power of 8 W, and propellant (xenon) mass flow rate of 21 μg/s, 13.7 mA of ion beam current is obtained, equivalent to an calculated thrust of 0.74 mN.

  4. Electrostatic electron cyclotron harmonic instability near Ganymede

    NASA Astrophysics Data System (ADS)

    Tripathi, A. K.; Singhal, R. P.; Singh, K. P.; Singh, O. N.

    2014-08-01

    Jupiter's moon—Ganymede—is the largest satellite in our solar system. Galileo spacecraft made six close flybys to explore Ganymede. More information was acquired about particle population, magnetic field and plasma waves during these encounters. In this paper, our aim is to study the generation of electrostatic electron cyclotron harmonic (ECH) emissions in the vicinity of Ganymede using the observed particle data. The calculated ECH wave's growth rates are analyzed in the light of observations of plasma waves along the path of Galileo near Ganymede. Dispersion relation for electrostatic mode is solved to obtain the temporal growth rates. A new electron distribution function, fitted to distribution observed near Ganymede, is used in the calculations. A parametric study is performed to evaluate the effect of loss-cone angle and the ratio of plasma to gyro-frequency on growth rates. It is found that ECH waves growth rates generally decrease as the loss-cone angle is increased. However, the ratio plasma to gyro-frequency has almost no effect on the growth rates. These parameters vary considerably along the Galileo trajectory near Ganymede. This is the first study which relates the occurrence of ECH waves with the particle and magnetic field data in the vicinity of Ganymede. The study of ECH wave growth rate near Ganymede is important for the calculation of pitch angle scattering rates of low-energy electrons and their subsequent precipitation into the thin atmosphere of Ganymede producing ultraviolet emissions. Results of the present study may also be relevant for the upcoming JUNO and JUICE missions to Jupiter.

  5. Fullerenes in electron cyclotron resonance ion sources

    SciTech Connect

    Biri, S.; Fekete, E.; Kitagawa, A.; Muramatsu, M.; Janossy, A.; Palinkas, J.

    2006-03-15

    Fullerene plasmas and beams have been produced in our electron cyclotron resonance ion sources (ECRIS) originally designed for other purposes. The ATOMKI-ECRIS is a traditional ion source with solenoid mirror coils to generate highly charged ions. The variable frequencies NIRS-KEI-1 and NIRS-KEI-2 are ECR ion sources built from permanent magnets and specialized for the production of carbon beams. The paper summarizes the experiments and results obtained by these facilities with fullerenes. Continuous effort has been made to get the highest C{sub 60} beam intensities. Surprisingly, the best result was obtained by moving the C{sub 60} oven deep inside the plasma chamber, very close to the resonance zone. Record intensity singly and doubly charged fullerene beams were obtained (600 and 1600 nA, respectively) at lower C{sub 60} material consumption. Fullerene derivatives were also produced. We mixed fullerenes with other plasmas (N, Fe) with the aim of making new materials. Nitrogen encapsulated fullerenes (mass: 720+14=734) were successfully produced. In the case of iron, two methods (ferrocene, oven) were tested. Molecules with mass of 720+56=776 were detected in the extracted beam spectra.

  6. Millimeter-wave radiometer diagnostics of harmonic electron cyclotron emission in the Levitated Dipole Experiment

    SciTech Connect

    Woskov, P. P.; Kesner, J.; Garnier, D. T.; Mauel, M. E.

    2010-10-15

    A 110/137 GHz radiometer pair with collimated antenna pattern is being used to diagnose optically thin harmonic electron cyclotron emission from hot electrons in LDX. Signal levels of 0.1-1 keV and 110/137 ratios of 2-4 stationary with ECRH power have been observed. The large plasma core magnetic field gradient causes all relevant harmonics to be simultaneously viewed over a <(k,B) angular range of 0 deg. - 90 deg. representing a unique geometry for interpretation of ECE in terms of hot electron temperature and density.

  7. Millimeter-wave radiometer diagnostics of harmonic electron cyclotron emission in the Levitated Dipole Experiment.

    PubMed

    Woskov, P P; Kesner, J; Garnier, D T; Mauel, M E

    2010-10-01

    A 110/137 GHz radiometer pair with collimated antenna pattern is being used to diagnose optically thin harmonic electron cyclotron emission from hot electrons in LDX. Signal levels of 0.1-1 keV and 110/137 ratios of 2-4 stationary with ECRH power have been observed. The large plasma core magnetic field gradient causes all relevant harmonics to be simultaneously viewed over a angle(k,B) angular range of 0°-90° representing a unique geometry for interpretation of ECE in terms of hot electron temperature and density.

  8. First results of an auxiliary electron cyclotron resonance heating experiment in the GDT magnetic mirror

    NASA Astrophysics Data System (ADS)

    Bagryansky, P. A.; Kovalenko, Yu. V.; Savkin, V. Ya.; Solomakhin, A. L.; Yakovlev, D. V.

    2014-08-01

    The axially symmetric magnetic mirror device gas-dynamic trap (GDT, Budker Institute, Novosibirsk) has recently demonstrated a tangible increase in plasma electron temperature. According to laser scattering, a value of 0.4 keV has been achieved (a twofold increase). In addition to standard machine operation, utilizing a 5 MW neutral beam injection, a newly installed electron cyclotron resonance heating (ECRH) system was employed (54.5 GHz, 0.4 MW). The reported progress in electron temperature, along with previous experiments, which demonstrated plasma confinement at beta as high as 60%, is a significant advancement towards an energy efficient fusion neutron source based on GDT physics.

  9. Electron cyclotron thruster new modeling results preparation for initial experiments

    NASA Technical Reports Server (NTRS)

    Hooper, E. Bickford

    1993-01-01

    The following topics are discussed: a whistler-based electron cyclotron resonance heating (ECRH) thruster; cross-field coupling in the helicon approximation; wave propagation; wave structure; plasma density; wave absorption; the electron distribution function; isothermal and adiabatic plasma flow; ECRH thruster modeling; a PIC code model; electron temperature; electron energy; and initial experimental tests. The discussion is presented in vugraph form.

  10. Study of the Polarization Strategy for Electron Cyclotron Heating Systems on HL-2M

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Huang, M.; Xia, D. H.; Song, S. D.; Wang, J. Q.; Huang, B.; Wang, H.

    2016-06-01

    As important components integrated in transmission lines of electron cyclotron heating systems, polarizers are mainly used to obtain the desired polarization for highly efficient coupling between electron cyclotron waves and plasma. The polarization strategy for 105-GHz electron cyclotron heating systems of HL-2M tokamak is studied in this paper. Considering the polarizers need high efficiency, stability, and low loss to realize any polarization states, two sinusoidal-grooved polarizers, which include a linear polarizer and an elliptical polarizer, are designed with the coordinate transformation method. The parameters, the period p and the depth d, of two sinusoidal-grooved polarizers are optimized by a phase difference analysis method to achieve an almost arbitrary polarization. Finally, the optimized polarizers are manufactured and their polarization characteristics are tested with a low-power test platform. The experimental results agree well with the numerical calculations, indicating that the designed polarizers can meet the polarization requirements of the electron cyclotron heating systems of HL-2M tokamak.

  11. Initial characterization of electron cyclotron heated plasmas in the Columbia Non-Neutral Torus

    NASA Astrophysics Data System (ADS)

    Hammond, Kenneth; Volpe, Francesco; Lazerson, Samuel

    2014-10-01

    The Columbia Non-Neutral Torus (CNT) is a stellarator at Columbia University recently modified for the study of quasi-neutral plasmas heated by 2.45 GHz electron cyclotron waves. Using a simple configuration of four circular planar coils, it generates magnetic surfaces with the lowest aspect ratios (1.9-2.7) ever attained by a stellarator. The low magnetic field (0.09 T), combined with the possibility of electron Bernstein wave heating above the cutoff density, could make CNT suitable for research of magnetohydrodynamic equilibrium and stability at high beta. Additional plans for future work include novel microwave and magnetic diagnostics, heating with electron cyclotron and helicon waves, and error field studies. Here we present an experimental characterization of the parameters of CNT's first microwave-heated plasmas. We present Langmuir probe measurements of temperature and density profiles, fast camera images, and equilibrium reconstructions computed by the VMEC code.

  12. Lower hybrid current drive favoured by electron cyclotron radiofrequency heating

    NASA Astrophysics Data System (ADS)

    Cesario, R.; Amicucci, L.; Cardinali, A.; Castaldo, C.; Marinucci, M.; Giruzzi, G.; Napoli, F.; Galli, A.; Schettini, G.; Tuccillo, A. A.

    2014-02-01

    The important goal of adding to the bootstrap a fraction of non-inductive plasma current, which would be controlled for obtaining and optimizing steady-state profiles, can be reached by using the Current Drive produced by Lower Hybrid waves (LHCD). FTU (Frascati Tokamak Upgrade) experiments demonstrated, indeed, that LHCD is effective at reactor-graded high plasma density, and the LH spectral broadening is reduced, operating with higher electron temperature in the outer region of plasma column (Te_periphery). This method was obtained following the guidelines of theoretical predictions indicating that the broadening of launched spectrum produced by parametric instability (PI) should be reduced, and the LHCD effect at high density consequently enabled, under higher (Te_periphery). In FTU, the temperature increase in the outer plasma region was obtained by operating with reduced particle recycling, lithized walls and deep gas fuelling by means of fast pellet. Heating plasma periphery with electron cyclotron resonant waves (ECRH) will provide a further tool for achieving steady-state operations. New FTU experimental results are presented here, demonstrating that temperature effect at the plasma periphery, affecting LH penetration, occurs in a range of plasma parameters broader than in previous work. New information is also shown on the modelling assessing frequencies and growth rates of the PI coupled modes responsible of spectral broadening. Finally, we present the design of an experiment scheduled on FTU next campaign, where ECRH power is used to slightly increase the electron temperature in the outer plasma region of a high-density discharge aiming at restoring LHCD. Consequent to model results, by operating with a toroidal magnetic field of 6.3 T, useful for locating the electron cyclotron resonant layer at the periphery of the plasma column (r/a˜0.8, f0=144 GHz), an increase of Te in the outer plasma (from 40 eV to 80 eV at r/a˜0.8) is expected by the JETTO code

  13. Lower hybrid current drive favoured by electron cyclotron radiofrequency heating

    SciTech Connect

    Cesario, R.; Cardinali, A.; Castaldo, C.; Marinucci, M.; Tuccillo, A. A.; Giruzzi, G.; Napoli, F.; Schettini, G.

    2014-02-12

    The important goal of adding to the bootstrap a fraction of non-inductive plasma current, which would be controlled for obtaining and optimizing steady-state profiles, can be reached by using the Current Drive produced by Lower Hybrid waves (LHCD). FTU (Frascati Tokamak Upgrade) experiments demonstrated, indeed, that LHCD is effective at reactor-graded high plasma density, and the LH spectral broadening is reduced, operating with higher electron temperature in the outer region of plasma column (T{sub e-periphery}). This method was obtained following the guidelines of theoretical predictions indicating that the broadening of launched spectrum produced by parametric instability (PI) should be reduced, and the LHCD effect at high density consequently enabled, under higher (T{sub e-periphery}). In FTU, the temperature increase in the outer plasma region was obtained by operating with reduced particle recycling, lithized walls and deep gas fuelling by means of fast pellet. Heating plasma periphery with electron cyclotron resonant waves (ECRH) will provide a further tool for achieving steady-state operations. New FTU experimental results are presented here, demonstrating that temperature effect at the plasma periphery, affecting LH penetration, occurs in a range of plasma parameters broader than in previous work. New information is also shown on the modelling assessing frequencies and growth rates of the PI coupled modes responsible of spectral broadening. Finally, we present the design of an experiment scheduled on FTU next campaign, where ECRH power is used to slightly increase the electron temperature in the outer plasma region of a high-density discharge aiming at restoring LHCD. Consequent to model results, by operating with a toroidal magnetic field of 6.3 T, useful for locating the electron cyclotron resonant layer at the periphery of the plasma column (r/a∼0.8, f{sub 0}=144 GHz), an increase of T{sub e} in the outer plasma (from 40 eV to 80 eV at r/a∼0.8) is

  14. Electron cyclotron emission measurements on JET: Michelson interferometer, new absolute calibration, and determination of electron temperature.

    PubMed

    Schmuck, S; Fessey, J; Gerbaud, T; Alper, B; Beurskens, M N A; de la Luna, E; Sirinelli, A; Zerbini, M

    2012-12-01

    At the fusion experiment JET, a Michelson interferometer is used to measure the spectrum of the electron cyclotron emission in the spectral range 70-500 GHz. The interferometer is absolutely calibrated using the hot/cold technique and, in consequence, the spatial profile of the plasma electron temperature is determined from the measurements. The current state of the interferometer hardware, the calibration setup, and the analysis technique for calibration and plasma operation are described. A new, full-system, absolute calibration employing continuous data acquisition has been performed recently and the calibration method and results are presented. The noise level in the measurement is very low and as a result the electron cyclotron emission spectrum and thus the spatial profile of the electron temperature are determined to within ±5% and in the most relevant region to within ±2%. The new calibration shows that the absolute response of the system has decreased by about 15% compared to that measured previously and possible reasons for this change are presented. Temperature profiles measured with the Michelson interferometer are compared with profiles measured independently using Thomson scattering diagnostics, which have also been recently refurbished and recalibrated, and agreement within experimental uncertainties is obtained.

  15. Broadband terahertz-power extracting by using electron cyclotron maser.

    PubMed

    Pan, Shi; Du, Chao-Hai; Qi, Xiang-Bo; Liu, Pu-Kun

    2017-08-04

    Terahertz applications urgently require high performance and room temperature terahertz sources. The gyrotron based on the principle of electron cyclotron maser is able to generate watt-to-megawatt level terahertz radiation, and becomes an exceptional role in the frontiers of energy, security and biomedicine. However, in normal conditions, a terahertz gyrotron could generate terahertz radiation with high efficiency on a single frequency or with low efficiency in a relatively narrow tuning band. Here a frequency tuning scheme for the terahertz gyrotron utilizing sequentially switching among several whispering-gallery modes is proposed to reach high performance with broadband, coherence and high power simultaneously. Such mode-switching gyrotron has the potential of generating broadband radiation with 100-GHz-level bandwidth. Even wider bandwidth is limited by the frequency-dependent effective electrical length of the cavity. Preliminary investigation applies a pre-bunched circuit to the single-mode wide-band tuning. Then, more broadband sweeping is produced by mode switching in great-range magnetic tuning. The effect of mode competition, as well as critical engineering techniques on frequency tuning is discussed to confirm the feasibility for the case close to reality. This multi-mode-switching scheme could make gyrotron a promising device towards bridging the so-called terahertz gap.

  16. Electron cyclotron emission spectrometry on the Tokamak a Configuration Variable

    SciTech Connect

    Klimanov, I.; Porte, L.; Alberti, S.; Blanchard, P.; Fasoli, A.; Goodman, T.P.

    2005-09-15

    Electron cyclotron emission (ECE) measurements are an important component of the diagnostic suite on the Tokamak a Configuration Variable (TCV) [F. Hoffman et al., Plasma Phys. Controlled Fusion 36, B277 (1994)]. A recently installed, 24-channel dual-conversion heterodyne radiometer covering the radio frequency range 65-100 GHz and viewing from the low-field side (LFS) of the tokamak greatly enhances the system and, in combination with an existing radiometer viewing from the high-field side (HFS), allows simultaneous measurements of emission from the HFS and LFS. In addition, the new radiometer has multiple lines of sight that can receive the emission perpendicular to the toroidal magnetic field as well as with a finite k{sub parallel} (wave vector parallel to magnetic field). Such flexibility allows the LFS radiometer to make standard measurements of thermal emission and nonstandard measurements of nonthermal, anisotropic emission. The toroidal line of sight allows access to overdense plasma via mode converted emission. The enhanced ECE diagnostic is described and examples of measurements made in various configurations are presented.

  17. Single-chip electron spin resonance detectors operating at 50 GHz, 92 GHz, and 146 GHz

    NASA Astrophysics Data System (ADS)

    Matheoud, Alessandro V.; Gualco, Gabriele; Jeong, Minki; Zivkovic, Ivica; Brugger, Jürgen; Rønnow, Henrik M.; Anders, Jens; Boero, Giovanni

    2017-05-01

    We report on the design and characterization of single-chip electron spin resonance (ESR) detectors operating at 50 GHz, 92 GHz, and 146 GHz. The core of the single-chip ESR detectors is an integrated LC-oscillator, formed by a single turn aluminum planar coil, a metal-oxide-metal capacitor, and two metal-oxide semiconductor field effect transistors used as negative resistance network. On the same chip, a second, nominally identical, LC-oscillator together with a mixer and an output buffer are also integrated. Thanks to the slightly asymmetric capacitance of the mixer inputs, a signal at a few hundreds of MHz is obtained at the output of the mixer. The mixer is used for frequency down-conversion, with the aim to obtain an output signal at a frequency easily manageable off-chip. The coil diameters are 120 μm, 70 μm, and 45 μm for the U-band, W-band, and the D-band oscillators, respectively. The experimental frequency noises at 100 kHz offset from the carrier are 90 Hz/Hz1/2, 300 Hz/Hz1/2, and 700 Hz/Hz1/2 at 300 K, respectively. The ESR spectra are obtained by measuring the frequency variations of the single-chip oscillators as a function of the applied magnetic field. The experimental spin sensitivities, as measured with a sample of α,γ-bisdiphenylene-β-phenylallyl (BDPA)/benzene complex, are 1 × 108 spins/Hz1/2, 4 × 107 spins/Hz1/2, 2 × 107 spins/Hz1/2 at 300 K, respectively. We also show the possibility to perform experiments up to 360 GHz by means of the higher harmonics in the microwave field produced by the integrated single-chip LC-oscillators.

  18. 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.

    PubMed

    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.

  19. Single-Electron Detection and Spectroscopy via Relativistic Cyclotron Radiation.

    PubMed

    Asner, D M; Bradley, R F; de Viveiros, L; Doe, P J; Fernandes, J L; Fertl, M; Finn, E C; Formaggio, J A; Furse, D; Jones, A M; Kofron, J N; LaRoque, B H; Leber, M; McBride, E L; Miller, M L; Mohanmurthy, P; Monreal, B; Oblath, N S; Robertson, R G H; Rosenberg, L J; Rybka, G; Rysewyk, D; Sternberg, M G; Tedeschi, J R; Thümmler, T; VanDevender, B A; Woods, N L

    2015-04-24

    It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Although first derived in 1904, cyclotron radiation from a single electron orbiting in a magnetic field has never been observed directly. We demonstrate single-electron detection in a novel radio-frequency spectrometer. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay end point, and this work demonstrates a fundamentally new approach to precision beta spectroscopy for future neutrino mass experiments.

  20. Wall-loss distribution of charge breeding ions in an electron cyclotron resonance ion source

    SciTech Connect

    Jeong, S. C.; Oyaizu, M.; Imai, N.; Hirayama, Y.; Ishiyama, H.; Miyatake, H.; Niki, K.; Okada, M.; Watanabe, Y. X.; Otokawa, Y.; Osa, A.; Ichikawa, S.

    2012-02-15

    We investigated the ion-loss distribution on the sidewall of an electron cyclotron resonance (ECR) plasma chamber using the 18-GHz ECR charge breeder at the Tokai Radioactive Ion Accelerator Complex (TRIAC). Similarities and differences between the ion-loss distributions (longitudinal and azimuthal) of different ion species (i.e., radioactive {sup 111}In{sup 1+} and {sup 140}Xe{sup 1+} ions that are typical volatile and nonvolatile elements) was qualitatively discussed to understand the element dependence of the charge breeding efficiency. Especially, the similarities represent universal ion loss characteristics in an ECR charge breeder, which are different from the loss patterns of electrons on the ECRIS wall.

  1. Low-noise heterodyne receiver for electron cyclotron emission imaging and microwave imaging reflectometry

    DOE PAGES

    Tobias, B.; Domier, C. W.; Luhmann, Jr., N. C.; ...

    2016-07-25

    The critical component enabling electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR) to resolve 2D and 3D electron temperature and density perturbations is the heterodyne imaging array that collects and downconverts radiated emission and/or reflected signals (50-150 GHz) to an intermediate frequency (IF) band (e.g. 0.1-18 GHz) that can be transmitted by a shielded coaxial cable for further filtering and detection. New circuitry has been developed for this task, integrating gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs) mounted on a liquid crystal polymer (LCP) substrate. The improved topology significantly increases electromagnetic shielding from out-of-band interference, leads tomore » 10x improvement in the signal-to-noise ratio, and dramatic cost savings through integration. The current design, optimized for reflectometry and edge radiometry on mid-sized tokamaks, has demonstrated >20 dB conversion gain in upper V-band (60-75 GHz). As a result, implementation of the circuit in a multi-channel electron cyclotron emission imaging (ECEI) array will improve the diagnosis of edge-localized modes and fluctuations of the high-confinement, or H-mode, pedestal.« less

  2. Low-noise heterodyne receiver for electron cyclotron emission imaging and microwave imaging reflectometry

    SciTech Connect

    Tobias, B.; Domier, C. W.; Luhmann, Jr., N. C.; Luo, C.; Mamidanna, M.; Phan, T.; Pham, A. -V.; Wang, Y.

    2016-07-25

    The critical component enabling electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR) to resolve 2D and 3D electron temperature and density perturbations is the heterodyne imaging array that collects and downconverts radiated emission and/or reflected signals (50-150 GHz) to an intermediate frequency (IF) band (e.g. 0.1-18 GHz) that can be transmitted by a shielded coaxial cable for further filtering and detection. New circuitry has been developed for this task, integrating gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs) mounted on a liquid crystal polymer (LCP) substrate. The improved topology significantly increases electromagnetic shielding from out-of-band interference, leads to 10x improvement in the signal-to-noise ratio, and dramatic cost savings through integration. The current design, optimized for reflectometry and edge radiometry on mid-sized tokamaks, has demonstrated >20 dB conversion gain in upper V-band (60-75 GHz). As a result, implementation of the circuit in a multi-channel electron cyclotron emission imaging (ECEI) array will improve the diagnosis of edge-localized modes and fluctuations of the high-confinement, or H-mode, pedestal.

  3. Low-noise heterodyne receiver for electron cyclotron emission imaging and microwave imaging reflectometry

    SciTech Connect

    Tobias, B.; Domier, C. W.; Luhmann, N. C.; Luo, C.; Mamidanna, M.; Phan, T.; Pham, A.-V.; Wang, Y.

    2016-11-15

    The critical component enabling electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR) to resolve 2D and 3D electron temperature and density perturbations is the heterodyne imaging array that collects and downconverts radiated emission and/or reflected signals (50–150 GHz) to an intermediate frequency (IF) band (e.g. 0.1–18 GHz) that can be transmitted by a shielded coaxial cable for further filtering and detection. New circuitry has been developed for this task, integrating gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs) mounted on a liquid crystal polymer (LCP) substrate. The improved topology significantly increases electromagnetic shielding from out-of-band interference, leads to 10× improvement in the signal-to-noise ratio, and dramatic cost savings through integration. The current design, optimized for reflectometry and edge radiometry on mid-sized tokamaks, has demonstrated >20 dB conversion gain in upper V-band (60-75 GHz). Implementation of the circuit in a multi-channel electron cyclotron emission imaging (ECEI) array will improve the diagnosis of edge-localized modes and fluctuations of the high-confinement, or H-mode, pedestal.

  4. Low-noise heterodyne receiver for electron cyclotron emission imaging and microwave imaging reflectometry

    SciTech Connect

    Tobias, B.; Domier, C. W.; Luhmann, Jr., N. C.; Luo, C.; Mamidanna, M.; Phan, T.; Pham, A. -V.; Wang, Y.

    2016-07-25

    The critical component enabling electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR) to resolve 2D and 3D electron temperature and density perturbations is the heterodyne imaging array that collects and downconverts radiated emission and/or reflected signals (50-150 GHz) to an intermediate frequency (IF) band (e.g. 0.1-18 GHz) that can be transmitted by a shielded coaxial cable for further filtering and detection. New circuitry has been developed for this task, integrating gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs) mounted on a liquid crystal polymer (LCP) substrate. The improved topology significantly increases electromagnetic shielding from out-of-band interference, leads to 10x improvement in the signal-to-noise ratio, and dramatic cost savings through integration. The current design, optimized for reflectometry and edge radiometry on mid-sized tokamaks, has demonstrated >20 dB conversion gain in upper V-band (60-75 GHz). As a result, implementation of the circuit in a multi-channel electron cyclotron emission imaging (ECEI) array will improve the diagnosis of edge-localized modes and fluctuations of the high-confinement, or H-mode, pedestal.

  5. Low-noise heterodyne receiver for electron cyclotron emission imaging and microwave imaging reflectometry

    NASA Astrophysics Data System (ADS)

    Tobias, B.; Domier, C. W.; Luhmann, N. C.; Luo, C.; Mamidanna, M.; Phan, T.; Pham, A.-V.; Wang, Y.

    2016-11-01

    The critical component enabling electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR) to resolve 2D and 3D electron temperature and density perturbations is the heterodyne imaging array that collects and downconverts radiated emission and/or reflected signals (50-150 GHz) to an intermediate frequency (IF) band (e.g. 0.1-18 GHz) that can be transmitted by a shielded coaxial cable for further filtering and detection. New circuitry has been developed for this task, integrating gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs) mounted on a liquid crystal polymer (LCP) substrate. The improved topology significantly increases electromagnetic shielding from out-of-band interference, leads to 10× improvement in the signal-to-noise ratio, and dramatic cost savings through integration. The current design, optimized for reflectometry and edge radiometry on mid-sized tokamaks, has demonstrated >20 dB conversion gain in upper V-band (60-75 GHz). Implementation of the circuit in a multi-channel electron cyclotron emission imaging (ECEI) array will improve the diagnosis of edge-localized modes and fluctuations of the high-confinement, or H-mode, pedestal.

  6. Low-noise heterodyne receiver for electron cyclotron emission imaging and microwave imaging reflectometry.

    PubMed

    Tobias, B; Domier, C W; Luhmann, N C; Luo, C; Mamidanna, M; Phan, T; Pham, A-V; Wang, Y

    2016-11-01

    The critical component enabling electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR) to resolve 2D and 3D electron temperature and density perturbations is the heterodyne imaging array that collects and downconverts radiated emission and/or reflected signals (50-150 GHz) to an intermediate frequency (IF) band (e.g. 0.1-18 GHz) that can be transmitted by a shielded coaxial cable for further filtering and detection. New circuitry has been developed for this task, integrating gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs) mounted on a liquid crystal polymer (LCP) substrate. The improved topology significantly increases electromagnetic shielding from out-of-band interference, leads to 10× improvement in the signal-to-noise ratio, and dramatic cost savings through integration. The current design, optimized for reflectometry and edge radiometry on mid-sized tokamaks, has demonstrated >20 dB conversion gain in upper V-band (60-75 GHz). Implementation of the circuit in a multi-channel electron cyclotron emission imaging (ECEI) array will improve the diagnosis of edge-localized modes and fluctuations of the high-confinement, or H-mode, pedestal.

  7. The electron-cyclotron maser for astrophysical application

    NASA Astrophysics Data System (ADS)

    Treumann, Rudolf A.

    2006-08-01

    The electron-cyclotron maser is a process that generates coherent radiation from plasma. In the last two decades, it has gained increasing attention as a dominant mechanism of producing high-power radiation in natural high-temperature magnetized plasmas. Originally proposed as a somewhat exotic idea and subsequently applied to include non-relativistic plasmas, the electron-cyclotron maser was considered as an alternative to turbulent though coherent wave-wave interaction which results in radio emission. However, when it was recognized that weak relativistic corrections had to be taken into account in the radiation process, the importance of the electron-cyclotron maser rose to the recognition it deserves. Here we review the theory and application of the electron-cyclotron maser to the directly accessible plasmas in our immediate terrestrial and planetary environments. In situ access to the radiating plasmas has turned out to be crucial in identifying the conditions under which the electron-cyclotron maser mechanism is working. Under extreme astrophysical conditions, radiation from plasmas may provide a major energy loss; however, for generating the powerful radiation in which the electron-cyclotron maser mechanism is capable, the plasma must be in a state where release of susceptible amounts of energy in the form of radiation is favorable. Such conditions are realized when the plasma is unable to digest the available free energy that is imposed from outside and stored in its particle distribution. The lack of dissipative processes is a common property of collisionless plasmas. When, in addition, the plasma density becomes so low that the amount of free energy per particle is large, direct emission becomes favorable. This can be expressed as negative absorption of the plasma which, like in conventional masers, leads to coherent emission even though no quantum correlations are involved. The physical basis of this formal analogy between a quantum maser and the

  8. The next generation of electron cyclotron emission imaging diagnostics (invited).

    PubMed

    Zhang, P; Domier, C W; Liang, T; Kong, X; Tobias, B; Shen, Z; Luhmann, N C; Park, H; Classen, I G J; van de Pol, M J; Donné, A J H; Jaspers, R

    2008-10-01

    A 128 channel two-dimensional electron cyclotron emission imaging system collects time-resolved 16x8 images of T(e) profiles and fluctuations on the TEXTOR tokamak. Electron cyclotron emission imaging (ECEI) is undergoing significant changes which promise to revolutionize and extend its capabilities far beyond what has been achieved to date. These include the development of a minilens array configuration with increased sensitivity antennas, a new local oscillator pumping scheme, enhanced electron cyclotron resonance heating shielding, and a highly flexible optical design with vertical zoom capability. Horizontal zoom and spot size (rf bandwidth) capabilities are also being developed with new ECEI electronics. An interface module is under development to remotely control all key features of the new ECEI instrument, many of which can be changed during a plasma discharge for maximum flexibility.

  9. The next generation of electron cyclotron emission imaging diagnostics (invited)

    SciTech Connect

    Zhang, P.; Domier, C. W.; Liang, T.; Kong, X.; Tobias, B.; Shen, Z.; Luhmann, N. C. Jr.; Park, H.; Classen, I. G. J.; Pol, M. J. van de; Donne, A. J. H.; Jaspers, R.

    2008-10-15

    A 128 channel two-dimensional electron cyclotron emission imaging system collects time-resolved 16x8 images of T{sub e} profiles and fluctuations on the TEXTOR tokamak. Electron cyclotron emission imaging (ECEI) is undergoing significant changes which promise to revolutionize and extend its capabilities far beyond what has been achieved to date. These include the development of a minilens array configuration with increased sensitivity antennas, a new local oscillator pumping scheme, enhanced electron cyclotron resonance heating shielding, and a highly flexible optical design with vertical zoom capability. Horizontal zoom and spot size (rf bandwidth) capabilities are also being developed with new ECEI electronics. An interface module is under development to remotely control all key features of the new ECEI instrument, many of which can be changed during a plasma discharge for maximum flexibility.

  10. 600-GHz Electronically Tunable Vector Measurement System

    NASA Technical Reports Server (NTRS)

    Dengler, Robert; Maiwald, Frank; Siegel, Peter

    2007-01-01

    A compact, high-dynamic-range, electronically tunable vector measurement system that operates in the frequency range from approximately 560 to approximately 635 GHz has been developed as a prototype of vector measurement systems that would be suitable for use in nearly-real-time active submillimeter-wave imaging. As used here, 'vector measurement system" signifies an instrumentation system that applies a radio-frequency (RF) excitation to an object of interest and measures the resulting amplitude and phase response, relative to either the applied excitatory signal or another reference signal related in a known way to applied excitatory signal.

  11. New development of advanced superconducting electron cyclotron resonance ion source SECRAL (invited)

    SciTech Connect

    Zhao, H. W.; Sun, L. T.; Zhang, X. Z.; Guo, X. H.; Zhao, H. Y.; Feng, Y. C.; Li, J. Y.; Ma, H. Y.; Ma, B. H.; Wang, H.; Li, X. X.; Xie, D. Z.; Lu, W.; Cao, Y.; Shang, Y.

    2010-02-15

    Superconducting electron cyclotron resonance ion source with advance design in Lanzhou (SECRAL) is an 18-28 GHz fully superconducting electron cyclotron resonance (ECR) ion source dedicated for highly charged heavy ion beam production. SECRAL, with an innovative superconducting magnet structure of solenoid-inside-sextupole and at lower frequency and lower rf power operation, may open a new way for developing compact and reliable high performance superconducting ECR ion source. One of the recent highlights achieved at SECRAL is that some new record beam currents for very high charge states were produced by 18 GHz or 18+14.5 GHz double frequency heating, such as 1 e {mu}A of {sup 129}Xe{sup 43+}, 22 e {mu}A of {sup 209}Bi{sup 41+}, and 1.5 e {mu}A of {sup 209}Bi{sup 50+}. To further enhance the performance of SECRAL, a 24 GHz/7 kW gyrotron microwave generator was installed and SECRAL was tested at 24 GHz. Some promising and exciting results at 24 GHz with new record highly charged ion beam intensities were produced, such as 455 e {mu}A of {sup 129}Xe{sup 27+} and 152 e {mu}A of {sup 129}Xe{sup 30+}, although the commissioning time was limited within 3-4 weeks and rf power only 3-4 kW. Bremsstrahlung measurements at 24 GHz show that x-ray is much stronger with higher rf frequency, higher rf power. and higher minimum mirror magnetic field (minimum B). Preliminary emittance measurements indicate that SECRAL emittance at 24 GHz is slightly higher that at 18 GHz. SECRAL has been put into routine operation at 18 GHz for heavy ion research facility in Lanzhou (HIRFL) accelerator complex since May 2007. The total operation beam time from SECRAL for HIRFL accelerator has been more than 2000 h, and {sup 129}Xe{sup 27+}, {sup 78}Kr{sup 19+}, {sup 209}Bi{sup 31+}, and {sup 58}Ni{sup 19+} beams were delivered. All of these new developments, the latest results, and long-term operation for the accelerator have again demonstrated that SECRAL is one of the best in the performance of

  12. Electron cyclotron current drive efficiency in general tokamak geometry

    SciTech Connect

    Lin-Liu, Y. R.; Chan, V. S.; Prater, R.

    2003-01-01

    Green's-function techniques are used to calculate electron cyclotron current drive (ECCD) efficiency in general tokamak geometry in the low-collisionality regime. Fully relativistic electron dynamics is employed in the theoretical formulation. The high-velocity collision model is used to model Coulomb collisions and a simplified quasi-linear rf diffusion operator describes wave-particle interactions. The approximate analytic solutions which are benchmarked with a widely used ECCD model, facilitate time-dependent simulations of tokamak operational scenarios using the non-inductive current drive of electron cyclotron waves.

  13. Millimeter-wave, megawatt gyrotron development for ECR (electron cyclotron resonance) heating applications

    SciTech Connect

    Jory, H.; Felch, K.; Hess, C.; Huey, H.; Jongewaard, E.; Neilson, J.; Pendleton, R.; Tsirulnikov, M. )

    1990-09-17

    To address the electron cyclotron heating requirements of planned fusion experiments such as the International Thermonuclear Experimental Reactor (ITER) and the Compact Ignition Tokamak (CIT), Varian is developing gyrotrons at frequencies ranging from 100--300 GHz with output power capabilities up to 1 MW CW. Experimental gyrotrons have been built at frequencies between 100--140 GHz, and a study program has addressed the critical elements of designing 280--300 GHz gyrotrons capable of generating CW power levels up to 1 MW. Initial test vehicles at 140 GHz have utilized TE{sub 15,2,1} interaction cavities, and have been designed to generate short-pulse (up to 20 ms) power levels of 1 MW and up to 400 kW CW. Recently, short-pulse power levels of 1040 kW at 38% efficiency have been obtained and average powers of 200 kW have been achieved. Long-pulse operation has been extended to pulse durations of 0.5 seconds at power levels of 400 kW. Gyrotron oscillators capable of generating output powers of 500 kW CW at a frequency of 110 GHz have recently been designed and a prototype is currently being tested. Design work for a 1 MW CW gyrotron at 110 GHz, is in progress. The 1 MW CW tube will employ an output coupling approach where the microwave output is separated from the microwave output. 15 refs., 10 figs., 3 tabs.

  14. Cyclotron Resonance of Electrons Trapped in a Microwave Cavity

    ERIC Educational Resources Information Center

    Elmore, W. C.

    1975-01-01

    Describes an experiment in which the free-electron cyclotron resonance of electrons trapped in a microwave cavity by a Penning trap is observed. The experiment constitutes an attractive alternative to one of the Gardner-Purcell variety. (Author/GS)

  15. Microwave-Excited Microplasma Thrusters Using Surface Wave and Electron Cyclotron Resonance Discharges

    NASA Astrophysics Data System (ADS)

    Mori, Daisuke; Kawanabe, Tetsuo; Takao, Yoshinori; Eriguchi, Koji; Ono, Kouichi

    2012-10-01

    Downsizing spacecrafts has recently been focused on to decrease mission costs and to increase launch rates, and missions with small satellites would bring a great advantage of reducing their risks. Such a concept supports a new approach to developing precise, reliable, and low-cost micropropulsion systems. We have studied two types of microwave-excited microplasma thrusters, using surface wave-excited and electron cyclotron resonance-excited discharges. Microwaves of S-band (4 GHz) and X-band (11 GHz) were employed to excite the plasma in these experiments, with the feed or propellant gases of Ar and He. A microplasma thruster of electrothermal type consisted of a surface wave-excited microplasma source, and a converging-diverging micronozzle to obtain the thrust. For 11-GHz microwaves at a power of 6 W, a thrust of 1.1 mN and a specific impulse of 90 s were obtained at an Ar gas flow rate of 40 sccm, where the plasma electron density was 1.2x10^20 m-3, and the gas temperature was 1.5x10^3 K; under the same conditions for 4-GHz microwaves, the thrust, specific impulse, electron density, and gas temperature were 0.93 mN, 80 s, 7.0x10^19 m-3, and 8.0x10^2 K, respectively. A microplasma thruster of electromagnetic type had a microplasma source excited by electron cyclotron resonance with external magnetic fields, to obtain the thrust through accelerating ions by ambipolar electric fields. Optical emission spectrum was dominated by Ar^+ ion lines in the microplasma thruster of electromagnetic type, owing to higher electron temperatures at lower feed-gas pressures.

  16. Effects of fundamental and second harmonic electron cyclotron resonances on ECRIS.

    PubMed

    Kato, Yushi; Satani, Takashi; Asaji, Toyohisa; Sato, Fuminobu; Iida, Toshiyuki

    2008-02-01

    A new concept on magnetic field of 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 comb-shaped magnet which has opposite polarity to each other, and which cylindrically surrounds the plasma chamber. This magnetic configuration suppresses the loss due to E x B drift, and then plasma confinement is enhanced. The profiles of the electron temperature and density are measured around the ECR zones of the fundamentals and the second harmonics for 2.45 GHz and 11-13 GHz microwaves by using Langmuir probe. Their characteristics and effects are clarified under various operating conditions in both of simple multipole and comb-shaped magnetic configurations.

  17. Electron cyclotron emission diagnostics on the large helical device

    NASA Astrophysics Data System (ADS)

    Nagayama, Y.; Kawahata, K.; England, A.; Ito, Y.; Bretz, N.; McCarthy, M.; Taylor, G.; Doane, J.; Ikezi, H.; Edlington, T.; Tomas, J.

    1999-01-01

    The electron cyclotron emission (ECE) diagnostic system is installed on the large helical device (LHD). The system includes the following instruments: a heterodyne radiometer, a Michelson spectrometer, and a grating polychromator. A 63.5 mm corrugated waveguide system is fully utilized. Large collection optics and notch filters at the frequency of the LHD electron cyclotron heating (ECH) were developed for this system. In addition to these filters, the rectangular waveguide notch filters, the ECE measurement with the radiometer has been successfully performed during the ECH.

  18. Fluid equations in the presence of electron cyclotron current drive

    NASA Astrophysics Data System (ADS)

    Jenkins, Thomas G.; Kruger, Scott E.

    2012-12-01

    Two-fluid equations, which include the physics imparted by an externally applied radiofrequency source near electron cyclotron resonance, are derived in their extended magnetohydrodynamic forms using the formalism of Hegna and Callen [Phys. Plasmas 16, 112501 (2009)]. The equations are compatible with the closed fluid/drift-kinetic model developed by Ramos [Phys. Plasmas 17, 082502 (2010); 18, 102506 (2011)] for fusion-relevant regimes with low collisionality and slow dynamics, and they facilitate the development of advanced computational models for electron cyclotron current drive-induced suppression of neoclassical tearing modes.

  19. Fluid equations in the presence of electron cyclotron current drive

    SciTech Connect

    Jenkins, Thomas G.; Kruger, Scott E.

    2012-12-15

    Two-fluid equations, which include the physics imparted by an externally applied radiofrequency source near electron cyclotron resonance, are derived in their extended magnetohydrodynamic forms using the formalism of Hegna and Callen [Phys. Plasmas 16, 112501 (2009)]. The equations are compatible with the closed fluid/drift-kinetic model developed by Ramos [Phys. Plasmas 17, 082502 (2010); 18, 102506 (2011)] for fusion-relevant regimes with low collisionality and slow dynamics, and they facilitate the development of advanced computational models for electron cyclotron current drive-induced suppression of neoclassical tearing modes.

  20. Calculating method for confinement time and charge distribution of ions in electron cyclotron resonance sources

    SciTech Connect

    Dougar-Jabon, V.D.; Umnov, A.M.; Kutner, V.B.

    1996-03-01

    It is common knowledge that the electrostatic pit in a core plasma of electron cyclotron resonance sources exerts strict control over generation of ions in high charge states. This work is aimed at finding a dependence of the lifetime of ions on their charge states in the core region and to elaborate a numerical model of ion charge dispersion not only for the core plasmas but for extracted beams as well. The calculated data are in good agreement with the experimental results on charge distributions and magnitudes for currents of beams extracted from the 14 GHz DECRIS source. {copyright} {ital 1996 American Institute of Physics.}

  1. A 16-channel heterodyne electron cyclotron emission radiometer on J-TEXT.

    PubMed

    Yang, Z J; Phillips, P E; Zhuang, G; Xiao, J S; Huang, H; Rowan, W L; Wang, Z J

    2012-10-01

    To study equilibrium temporal dynamics and the mechanisms of magnetohydrodynamic instabilities, a 16-channel heterodyne electron cyclotron emission (ECE) radiometer has been developed to view the J-TEXT tokamak from the low field side. The ECE radiometer detects second-harmonic extraordinary mode in the frequency band of 94-125 GHz which corresponds to resonances from 1.8 T to 2.2 T. This ECE system consists of an ECE transmission line, a radio frequency unit, and two 8-channel intermediate frequency units. An in situ blackbody calibration source is applied for system calibration by comparison of hot and cold sources in order to provide an absolute temperature measurement.

  2. A 16-channel heterodyne electron cyclotron emission radiometer on J-TEXT

    SciTech Connect

    Yang, Z. J.; Zhuang, G.; Xiao, J. S.; Wang, Z. J.; Phillips, P. E.; Huang, H.; Rowan, W. L.

    2012-10-15

    To study equilibrium temporal dynamics and the mechanisms of magnetohydrodynamic instabilities, a 16-channel heterodyne electron cyclotron emission (ECE) radiometer has been developed to view the J-TEXT tokamak from the low field side. The ECE radiometer detects second-harmonic extraordinary mode in the frequency band of 94-125 GHz which corresponds to resonances from 1.8 T to 2.2 T. This ECE system consists of an ECE transmission line, a radio frequency unit, and two 8-channel intermediate frequency units. An in situ blackbody calibration source is applied for system calibration by comparison of hot and cold sources in order to provide an absolute temperature measurement.

  3. Development of DRAGON electron cyclotron resonance ion source at Institute of Modern Physics

    SciTech Connect

    Lu, W.; Lin, S. H.; Xie, D. Z.; Zhang, X. Z.; Sha, S.; Zhang, W. H.; Cao, Y.; Guo, J. W.; Fang, X.; Guo, X. H.; Li, X. X.; Ma, H. Y.; Wu, Q.; Zhao, H. Y.; Ma, B. H.; Wang, H.; Zhu, Y. H.; Feng, Y. C.; Li, J. Y.; Li, J. Q.; and others

    2012-02-15

    A new room temperature electron cyclotron resonance (ECR) ion source, DRAGON, is under construction at IMP. DRAGON is designed to operate at microwaves of frequencies of 14.5-18 GHz. Its axial solenoid coils are cooled with evaporative medium to provide an axial magnetic mirror field of 2.5 T at the injection and 1.4 T at the extraction, respectively. In comparison to other conventional room temperature ECR ion sources, DRAGON has so far the largest bore plasma chamber of inner diameter of 126 mm with maximum radial fields of 1.4-1.5 T produced by a non-Halbach permanent sextupole magnet.

  4. A preliminary study of the electron cyclotron resonance ion source for the RAON injector

    NASA Astrophysics Data System (ADS)

    Hong, I. S.; Kim, Y.; Choi, S. J.; Heo, J. I.; Jin, H. C.; Park, B. S.

    2016-09-01

    We have built and tested an electron cyclotron resonance (ECR) ion source for the Rare Isotope Accelerator of Newness (RAON) injector. Fully superconducting magnets were developed for the ECR ion source. First, an oxygen plasma was ignited, and a preliminary highly-charged oxygen beam was extracted. Next, a 100 μA beam current of oxygen 5+ was extracted when a 1 kW microwave power was injected using a 28 GHz gyrotron. Finally, an off-site test facility was proposed to test the components of the injector by using heavy-ion beams generated by the ECR ion source.

  5. Development of DRAGON electron cyclotron resonance ion source at Institute of Modern Physics.

    PubMed

    Lu, W; Xie, D Z; Zhang, X Z; Xiong, B; Ruan, L; Sha, S; Zhang, W H; Cao, Y; Lin, S H; Guo, J W; Fang, X; Guo, X H; Li, X X; Ma, H Y; Yang, Y; Wu, Q; Zhao, H Y; Ma, B H; Wang, H; Zhu, Y H; Feng, Y C; Li, J Y; Li, J Q; Sun, L T; Zhao, H W

    2012-02-01

    A new room temperature electron cyclotron resonance (ECR) ion source, DRAGON, is under construction at IMP. DRAGON is designed to operate at microwaves of frequencies of 14.5-18 GHz. Its axial solenoid coils are cooled with evaporative medium to provide an axial magnetic mirror field of 2.5 T at the injection and 1.4 T at the extraction, respectively. In comparison to other conventional room temperature ECR ion sources, DRAGON has so far the largest bore plasma chamber of inner diameter of 126 mm with maximum radial fields of 1.4-1.5 T produced by a non-Halbach permanent sextupole magnet.

  6. Development of a prototype T-shaped fast switching device for electron cyclotron current drive systems

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Kenji; Nagashima, Koji; Honzu, Toshihiko; Saigusa, Mikio; Oda, Yasuhisa; Takahashi, Koji; Sakamoto, Keishi

    2016-09-01

    A T-shaped high-power switching device composed of circular corrugated waveguides with three ports and double dielectric disks made of sapphire was proposed as a fast switching device based on a new principle in electron cyclotron current drive systems. This switching device has the advantages of operating at a fixed frequency and being compact. The design of the prototype switch was obtained by numerical simulations using a finite-difference time-domain (FDTD) method. The size of these components was optimized for the frequency band of 170 GHz. Low-power tests were carried out in a cross-shaped model.

  7. Coherent Cherenkov-Cyclotron Radiation Excited by an Electron Beam in a Metamaterial Waveguide.

    PubMed

    Hummelt, J S; Lu, X; Xu, H; Mastovsky, I; Shapiro, M A; Temkin, R J

    2016-12-02

    An electron beam passing through a metamaterial structure is predicted to generate reversed Cherenkov radiation, an unusual and potentially very useful property. We present an experimental test of this phenomenon using an intense electron beam passing through a metamaterial loaded waveguide. Power levels of up to 5 MW are observed in backward wave modes at a frequency of 2.40 GHz using a one microsecond pulsed electron beam of 490 keV, 84 A in a 400 G magnetic field. Contrary to expectations, the output power is not generated in the Cherenkov mode. Instead, the presence of the magnetic field, which is required to transport the electron beam, induces a Cherenkov-cyclotron (or anomalous Doppler) instability at a frequency equal to the Cherenkov frequency minus the cyclotron frequency. Nonlinear simulations indicate that the Cherenkov-cyclotron mode should dominate over the Cherenkov instability at a lower magnetic field where the highest output power is obtained.

  8. Theoretical determination of electron temperature in electron-cyclotron plasmas

    SciTech Connect

    Uhm, H.S.; Lee, P.H.; Kim, Y.I.; Kim, J.H.; Chang, H.Y.

    1995-12-31

    A basic theory of the plasma electron temperature in ECR plasmas has been reported in recent studies in connection with application to the plasma etching technologies. However, the previous theoretical study of the ECR plasmas is primitive and ad hoc. The authors therefore develop a theory for plasmas generated by the electron-cyclotron-resonance (ECR) mechanism and an experiment is conducted to compare the theoretical prediction and experimental measurements. Due to a large electron mobility along the magnetic field, electrons move quickly out of the system, leaving ions behind and building a space charge potential, which leads to the ambipolar diffusion of ions. In a steady-state condition, the plasma generation by ionization of neutral molecules is in balance with plasma loss due to the diffusion, leading to the electron temperature equation, which is expressed in terms of the plasma size, chamber pressure, and the ionization energy and cross section of neutrals. The electron temperature decreases as the chamber pressure increases. Based on the ambipolar diffusion of ions, a self-consistent theory of the plasma density profile is developed. The power balance condition leads to the plasma density equation, which is also expressed in terms of the electron temperature, the input microwave power and the chamber pressure. It is shown that the plasma density increases, reaches its peak and decreases, as the chamber pressure increases from a small value (0.1 mTorr). After carrying out an experimental observation, it is concluded that the theoretical predictions of the electron temperature and plasma density agree remarkably well with experimental data.

  9. ARTEMIS-B: A room-temperature test electron cyclotron resonance ion source for the National Superconducting Cyclotron Laboratory at Michigan State University

    SciTech Connect

    Machicoane, G.; Cole, D.; Ottarson, J.; Stetson, J.; Zavodszky, P.

    2006-03-15

    The current scheme for ion-beam injection into the coupled cyclotron accelerator at the NSCL involves the use of two electron cyclotron resonance (ECR) ion sources. The first one is a 6.4 GHz fully superconducting that will be replaced within two years by SUSI, a third generation 18 GHz superconducting ECR ion source. The other source, ARTEMIS, is a room-temperature source based on the AECR-U design and built in collaboration with the University of Jyvaeskylae in 1999. Due to cyclotron operation constraint, very little time can be allowed to ion source development and optics studies of the cyclotron injection beam line. In this context, NSCL has decided to build ARTEMIS-B an exact replica of its room-temperature ECR ion source. The goal of this project is threefold. One is to improve the overall reliability of cyclotron operation through tests and studies of various ion source parameters that could benefit beam stability, tuning reproducibility, and of course overall extracted currents performance. Second is to implement and test modifications or upgrade made to the ion source: extraction geometry, new resistive or rf oven design, dual frequency use, liner, etc. Finally, this test source will be used to study various ion optics schemes such as electrostatic quadrupole doublet or triplet at the source extraction or the use of a correction sextupole and assess their effect on the ion beam through the use of an emittance scanner and imaging viewer that will be incorporated into ARTEMIS-B beam line. This article reviews the design and construction of ARTEMIS-B along with some initial commissioning results.

  10. Status report of the 28 GHz superconducting electron cyclotronresonance ion source VENUS

    SciTech Connect

    Leitner, Daniela; Lyneis, Claude M.; Loew, Timothy; Todd, D.S.; Virostek, S.; Tarvainen, O.

    2005-09-01

    The superconducting versatile electron cyclotron resonance ECR ion source for nuclear science (VENUS) is a next generation superconducting ECR ion source designed to produce high-current, high-charge-state ions for the 88-Inch Cyclotron at the Lawrence Berkeley National Laboratory. VENUS also serves as the prototype ion source for the rare isotope accelerator RIA front end, where the goal is to produce intense beams of medium-charge-state ions. Example beams for the RIA accelerator are 15 p mu A of Kr17+ (260 e mu A), 12 p mu A of Xe20+ (240e mu A), and 8 p mu A of U28+ (230 e mu A). To achieve these high currents, VENUS has been optimized for operation at 28 GHz, reaching maximal confinement fields of 4 and 3 T axially and over 2.2 T on the plasma chamber wall radially. After a commissioning phase at 18 GHz, the source started the 28 GHz operation in the summer of 2004. During that ongoing 28 GHz commissioning process, record ion-beam intensities have been extracted. For instance, measured extracted currents for the low to medium charge states were 270 e mu A of Xe27+ and 245 e mu A of Bi29+, while for the higher charge states 15 e mu A of Xe34+, 15 e mu A of Bi41+, and 0.5 e mu A of Bi50+ could be produced. Results from the ongoing 28 GHz commissioning as well as results using double-frequency heating with 18 and 28 GHz for oxygen and xenon are presented. The effect of the minimum B field on the ion source performance has been systematically measured for 18 and 28 GHz. In both cases the performance peaked at a minimum B field of about 80 percent of the resonance field. In addition, a strong dependence of the x-ray flux and energy on the minimum B field value was found.

  11. Design of Electron Cyclotron Heating and Current Drive System of ITER

    SciTech Connect

    Kobayashi, N.; Bigelow, T.; Rasmussen, D.; Bonicelli, T.; Ramponi, G.; Saibene, G.; Cirant, S.; Denisov, G.; Heidinger, R.; Piosczyk, B.; Henderson, M.; Hogge, J.-P.; Thumm, M.; Tran, M. Q.; Rao, S. L.; Sakamoto, K.; Takahashi, K.; Temkin, R. J.; Verhoeven, A. G. A.; Zohm, H.

    2007-09-28

    Since the end of EDA, the design of the Electron Cyclotron Heating and Current Drive (ECH and CD) system has been modified to respond to progress in physics understanding and change of interface conditions. Nominal RF power of 20 MW is shared by four upper launchers or one equatorial launcher RF beams are steered by front steering mirrors providing wide sweeping angle for the RF beam. DC high voltage power supply may be composed of IGBT pulse step modulators because of high frequency modulation and design flexibility to three different types of 170 GHz gyrotrons provided by three parties. The RF power from the 170 GHz gyrotron is transmitted to the launcher by 63.5 mm{phi} corrugated waveguide line and remotely switched by a waveguide switch between the upper launcher and the equatorial launcher. The ECH and CD system has also a start-up sub-system for assist of initial discharge composed of three 127.5 GHz gyrotrons and a dedicated DC high voltage power supply. Three of transmission lines are shared between 170 GHz gyrotron and 127.5 GHz gyrotron so as to inject RF beam for the start-up through the equatorial launcher. R and Ds of components for high power long pulse and mirror steering mechanism have been on-going in the parties to establish a reliable ITER ECH and CD system.

  12. Design of Electron Cyclotron Heating and Current Drive System of ITER

    NASA Astrophysics Data System (ADS)

    Kobayashi, N.; Bigelow, T.; Bonicelli, T.; Cirant, S.; Denisov, G.; Heidinger, R.; Henderson, M.; Hogge, J.-P.; Piosczyk, B.; Ramponi, G.; Rao, S. L.; Rasmussen, D.; Saibene, G.; Sakamoto, K.; Takahashi, K.; Temkin, R. J.; Thumm, M.; Tran, M. Q.; Verhoeven, A. G. A.; Zohm, H.

    2007-09-01

    Since the end of EDA, the design of the Electron Cyclotron Heating and Current Drive (ECH&CD) system has been modified to respond to progress in physics understanding and change of interface conditions. Nominal RF power of 20 MW is shared by four upper launchers or one equatorial launcher RF beams are steered by front steering mirrors providing wide sweeping angle for the RF beam. DC high voltage power supply may be composed of IGBT pulse step modulators because of high frequency modulation and design flexibility to three different types of 170 GHz gyrotrons provided by three parties. The RF power from the 170 GHz gyrotron is transmitted to the launcher by 63.5 mmφ corrugated waveguide line and remotely switched by a waveguide switch between the upper launcher and the equatorial launcher. The ECH&CD system has also a start-up sub-system for assist of initial discharge composed of three 127.5 GHz gyrotrons and a dedicated DC high voltage power supply. Three of transmission lines are shared between 170 GHz gyrotron and 127.5 GHz gyrotron so as to inject RF beam for the start-up through the equatorial launcher. R&Ds of components for high power long pulse and mirror steering mechanism have been on-going in the parties to establish a reliable ITER ECH&CD system.

  13. Electron-cyclotron-heating experiments in tokamaks and stellarators

    SciTech Connect

    England, A.C.

    1983-01-01

    This paper reviews the application of high-frequency microwave radiation to plasma heating near the electron-cyclotron frequency in tokamaks and stellarators. Successful plasma heating by microwave power has been demonstrated in numerous experiments. Predicted future technological developments and current theoretical understanding suggest that a vigorous program in plasma heating will continue to yield promising results.

  14. Numerical studies of electron cyclotron wave current drive on HL-2A tokamak

    SciTech Connect

    Li, J. C.; Gong, X. Y.; Dong, J. Q.; Song, S. D.; Gao, Q. D.; Zheng, P. W.; Du, D.

    2015-06-15

    The electron cyclotron wave (ECW) current drive (CD) for the HL-2A tokamak is investigated numerically with a new ray-tracing and Fokker-Planck code. The code is benchmarked with other well-tested linear and quasilinear codes and is then used to study the electron cyclotron current drive on the HL-2A tokamak. The wave propagation, power deposition, and driven-current profiles are presented. The effect of electron trapping is also assessed. It is found that quasilinear effects are negligible at the present ECW power levels and that when both waves are injected at an angle of 20° on the plasma equatorial plane, the CD efficiency for the HL-2A saturates at ∼0.029 × 10{sup 20 }A/W/m{sup 2} and ∼0.020 × 10{sup 20 }A/W/m{sup 2} for the 0.5 MW/68 GHz first harmonic ordinary (O1) and 1 MW/140 GHz second harmonic extraordinary (X2) modes, respectively. The effects of the plasma density, temperature, and wave-launching position on the driven current are also investigated analytically and numerically.

  15. Electron cyclotron resonance (ECR) ion sources

    SciTech Connect

    Jongen, Y.

    1984-05-01

    Starting with the pioneering work of R. Geller and his group in Grenoble (France), at least 14 ECR sources have been built and tested during the last five years. Most of those sources have been extremely successful, providing intense, stable and reliable beams of highly charged ions for cyclotron injection or atomic physics research. However, some of the operational features of those sources disagreed with commonly accepted theories on ECR source operation. To explain the observed behavior of actual sources, it was found necessary to refine some of the crude ideas we had about ECR sources. Some of those new propositions are explained, and used to make some extrapolations on the possible future developments in ECR sources.

  16. Status report on electron cyclotron resonance ion sources at the Heavy Ion Medical Accelerator in Chiba

    NASA Astrophysics Data System (ADS)

    Kitagawa, A.; Muramatsu, M.; Sekiguchi, M.; Yamada, S.; Jincho, K.; Okada, T.; Yamamoto, M.; Hattori, T.; Biri, S.; Baskaran, R.; Sakata, T.; Sawada, K.; Uno, K.

    2000-02-01

    The Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences (NIRS) is not only dedicated to cancer therapy, it is also utilized with various ion species for basic experiments of biomedical science, physics, chemistry, etc. Two electron cyclotron resonance (ECR) ion sources are installed for production of gaseous ions. One of them, the NIRS-ECR, is a 10 GHz ECR ion source, and is mainly operated to produce C4+ ions for daily clinical treatment. This source realizes good reproducibility and reliability and it is easily operated. The other source, the NIRS-HEC, is an 18 GHz ECR ion source that is expected to produce heavier ion species. The output ion currents of the NIRS-ECR and the NIRS-HEC are 430e μA for C4+ and 1.1e mA for Ar8+, respectively.

  17. Development of Electron Cyclotron Resonance Ion Source for Synthesis of Endohedral Metallofullerenes

    SciTech Connect

    Tanaka, K.; Muramatsu, M.; Uchida, T.; Hanajiri, T.; Yoshida, Y.; Biri, S.; Kitagawa, A.; Kato, Y.

    2008-11-03

    A new electron cyclotron resonance ion source (ECRIS) has been constructed for synthesis of endohedral metallofullerenes. The main purpose of the ion source is to produce new biological and medical materials. The design is based on ECRIS for production of multicharged ion beams with a traditional minimum-B magnetic field. An 8-10 GHz traveling wave tube (TWT) amplifier and a 2.45 GHz magnetron have been applied as microwave sources. Fullerene and metal vapor are introduced with a filament heating micro-oven and an induction heating oven, respectively. In preliminary ion-extraction test, Ar{sup +} is 54 {mu}A. Many broken fullerenes such as C{sub 58} and C{sub 56} are observed in fullerene ion beams.

  18. Electron Cyclotron Maser Emissions from Evolving Fast Electron Beams

    NASA Astrophysics Data System (ADS)

    Tang, J. F.; Wu, D. J.; Chen, L.; Zhao, G. Q.; Tan, C. M.

    2016-05-01

    Fast electron beams (FEBs) are common products of solar active phenomena. Solar radio bursts are an important diagnostic tool for understanding FEBs and the solar plasma environment in which they propagate along solar magnetic fields. In particular, the evolution of the energy spectrum and velocity distribution of FEBs due to the interaction with the ambient plasma and field during propagation can significantly influence the efficiency and properties of their emissions. In this paper, we discuss the possible evolution of the energy spectrum and velocity distribution of FEBs due to energy loss processes and the pitch-angle effect caused by magnetic field inhomogeneity, and we analyze the effects of the evolution on electron-cyclotron maser (ECM) emission, which is one of the most important mechanisms for producing solar radio bursts by FEBs. Our results show that the growth rates all decrease with the energy loss factor Q, but increase with the magnetic mirror ratio σ as well as with the steepness index δ. Moreover, the evolution of FEBs can also significantly influence the fastest growing mode and the fastest growing phase angle. This leads to the change of the polarization sense of the ECM emission. In particular, our results also reveal that an FEB that undergoes different evolution processes will generate different types of ECM emission. We believe the present results to be very helpful for a more comprehensive understanding of the dynamic spectra of solar radio bursts.

  19. Parametric decay of an electromagnetic wave near electron cyclotron harmonics

    SciTech Connect

    Istomin, Y.N.; Leyser, T.B.

    1995-06-01

    A system of equations describing the nonlinear coupling of high frequency electron Bernstein (EB) and upper hybrid (UH) waves near harmonics of the electron cyclotron frequency with low frequency lower hybrid (LH) waves in a homogeneous, weakly magnetized, and weakly collisional plasma is derived. The EB and UH modes are described by a single second order equation, taking into account the interaction with low frequency density fluctuations. The ponderomotive force of the high frequency oscillations increases near the cyclotron harmonics due to the resonance with the electron motion. The obtained equations are used to study the parametric decay of an infinite wavelength electromagnetic pump wave into EB or UH waves and LH waves. The threshold electric fields are sufficiently low to be exceeded in high frequency ionospheric modification experiments. However, the instability cannot be excited for pump frequencies near the cyclotron harmonics. For the decay into EB waves, the resulting forbidden frequency range depends on the harmonic number in a power law manner, consistent with observations of stimulated electromagnetic emissions in ionospheric modification experiments. Further, for sufficiently high pump electric fields the instability is also suppressed, when the frequency mismatch around the eigenfrequencies at which the interaction can occur is of the order of the frequency separation between the EB and UH modes near the cyclotron harmonics. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  20. The development of a room temperature electron cyclotron resonance ion source (Lanzhou electron cyclotron resonance ion source No. 4) with evaporative cooling technology at Institute of Modern Physics

    SciTech Connect

    Lu, W. Sun, L. T.; Qian, C.; Feng, Y. C.; Ma, H. Y.; Zhang, X. Z.; Ma, B. H.; Zhao, H. W.; Guo, J. W.; Fang, X.; Yang, Y.; Xiong, B.; Guo, S. Q.; Ruan, L.

    2015-04-15

    LECR4 (Lanzhou electron cyclotron resonance ion source No. 4) has been successfully constructed at IMP and has also been connected with the Low Energy Beam Transport (LEBT) and Radio Frequency Quadrupole (RFQ) systems. These source magnet coils are cooled through evaporative cooling technology, which is the first attempt with an ECR ion source in the world. The maximum mirror field is 2.5 T (with iron plug) and the effective plasma chamber volume is 1.2 l. It was designed to be operated at 18 GHz and aimed to produce intense multiple charge state heavy ion beams for the linear injector project SSC-Linac at IMP. In February 2014, the first analyzed beam at 18 GHz was extracted. During about three months’ commissioning, some outstanding results have been achieved, such as 1.97 emA of O{sup 6+}, 1.7 emA of Ar{sup 8+}, 1.07 emA of Ar{sup 9+}, and 118 euA of Bi{sup 28+}. The source has also successfully delivered O{sup 5+} and Ar{sup 8+} ion beams for RFQ commissioning in April 2014. This paper will give a brief overview of the design of LECR4. Then, the latest results of this source at 18 GHz will be presented.

  1. The development of a room temperature electron cyclotron resonance ion source (Lanzhou electron cyclotron resonance ion source No. 4) with evaporative cooling technology at Institute of Modern Physics

    NASA Astrophysics Data System (ADS)

    Lu, W.; Sun, L. T.; Qian, C.; Guo, J. W.; Fang, X.; Feng, Y. C.; Yang, Y.; Ma, H. Y.; Zhang, X. Z.; Ma, B. H.; Xiong, B.; Guo, S. Q.; Ruan, L.; Zhao, H. W.

    2015-04-01

    LECR4 (Lanzhou electron cyclotron resonance ion source No. 4) has been successfully constructed at IMP and has also been connected with the Low Energy Beam Transport (LEBT) and Radio Frequency Quadrupole (RFQ) systems. These source magnet coils are cooled through evaporative cooling technology, which is the first attempt with an ECR ion source in the world. The maximum mirror field is 2.5 T (with iron plug) and the effective plasma chamber volume is 1.2 l. It was designed to be operated at 18 GHz and aimed to produce intense multiple charge state heavy ion beams for the linear injector project SSC-Linac at IMP. In February 2014, the first analyzed beam at 18 GHz was extracted. During about three months' commissioning, some outstanding results have been achieved, such as 1.97 emA of O6+, 1.7 emA of Ar8+, 1.07 emA of Ar9+, and 118 euA of Bi28+. The source has also successfully delivered O5+ and Ar8+ ion beams for RFQ commissioning in April 2014. This paper will give a brief overview of the design of LECR4. Then, the latest results of this source at 18 GHz will be presented.

  2. The development of a room temperature electron cyclotron resonance ion source (Lanzhou electron cyclotron resonance ion source No. 4) with evaporative cooling technology at Institute of Modern Physics.

    PubMed

    Lu, W; Sun, L T; Qian, C; Guo, J W; Fang, X; Feng, Y C; Yang, Y; Ma, H Y; Zhang, X Z; Ma, B H; Xiong, B; Guo, S Q; Ruan, L; Zhao, H W

    2015-04-01

    LECR4 (Lanzhou electron cyclotron resonance ion source No. 4) has been successfully constructed at IMP and has also been connected with the Low Energy Beam Transport (LEBT) and Radio Frequency Quadrupole (RFQ) systems. These source magnet coils are cooled through evaporative cooling technology, which is the first attempt with an ECR ion source in the world. The maximum mirror field is 2.5 T (with iron plug) and the effective plasma chamber volume is 1.2 l. It was designed to be operated at 18 GHz and aimed to produce intense multiple charge state heavy ion beams for the linear injector project SSC-Linac at IMP. In February 2014, the first analyzed beam at 18 GHz was extracted. During about three months' commissioning, some outstanding results have been achieved, such as 1.97 emA of O(6+), 1.7 emA of Ar(8+), 1.07 emA of Ar(9+), and 118 euA of Bi(28+). The source has also successfully delivered O(5+) and Ar(8+) ion beams for RFQ commissioning in April 2014. This paper will give a brief overview of the design of LECR4. Then, the latest results of this source at 18 GHz will be presented.

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

    NASA Astrophysics Data System (ADS)

    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. Improved system for perpendicular electron-cyclotron emission measurements on TMX-Upgrade

    SciTech Connect

    Lasnier, C.J.; Ellis, R.F.; James, R.A.

    1986-03-07

    Perpendicular electron-cyclotron emission (PECE) is used on TMX-U to diagnose thermal-barrier hot electrons (T/sub H/ approx. 100 to 400 keV); yielding the time history of the temperature of these relativistic electrons. We describe an improved quasi-optical viewing system for these measurements that uses high sensitivity superheterodyne receivers at fixed frequencies of 60, 98, 130, and 196 GHz. The improved viewing and transport system consists of an off-axis ellipsoidal mirror that images the plasma onto a V-band conical collection horn, an overmoded circular waveguide (7/8'' diam) that transports the radiation outside the vacuum vessel where the polarization is selected, and a high absorptivity Macor beam dump to prevent internal wall reflections from entering the viewing system. A relativistic code is used to calculate optically thin PECE signals from relativistic electrons for various energy and pitch angle distributions. 4 refs., 4 figs.

  5. Improved system for perpendicular electron-cyclotron emission measurements on TMX-U

    SciTech Connect

    Lasnier, C.J.; Ellis, R.F.; James, R.A.

    1986-08-01

    Perpendicular electron-cyclotron emission (PECE) is used on Tandem Mirror Experiment-Upgrade (TMX-U) to diagnose thermal-barrier hot electrons (T-italic/sub H-italic/--100--400 keV, yielding the time history of the temperature of these relativistic electrons. We describe an improved quasioptical viewing system for these measurements that uses high-sensitivity superheterodyne receivers at fixed frequencies of 60, 98, 130, and 196 GHz. The improved viewing and transport system consists of an off-axis ellipsoidal mirror that images the plasma onto a V-band conical collection horn, an overmoded circular waveguide ( 7/8 in. diam) that transports the radiation outside the vacuum vessel where the polarization is selected, and a high-absorptivity Macor beam dump to prevent internal wall reflections from entering the viewing system. A relativistic code is used to calculate optically thin PECE signals from relativistic electrons for various energy and pitch angle distributions.

  6. Permanent magnet electron cyclotron resonance plasma source with remote window

    SciTech Connect

    Berry, L.A.; Gorbatkin, S.M. )

    1995-03-01

    An electron cyclotron resonance (ECR) plasma has been used in conjunction with a solid metal sputter target for Cu deposition over 200 mm diameters. The goal is to develop a deposition system and process suitable for filling submicron, high-aspect ratio ULSI features. The system uses a permanent magnet for creation of the magnetic field necessary for ECR, and is significantly more compact than systems equipped with electromagnets. A custom launcher design allows remote microwave injection with the microwave entrance window shielded from the copper flux. When microwaves are introduced at an angle with respect to the plasma, high electron densities can be produced with a plasma frequency significantly greater than the electron cyclotron frequency. Copper deposition rates of 1000 A/min have been achieved.

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

    SciTech Connect

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

    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.

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

    PubMed

    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.

  9. Analysis of the electron temperature measurement in TCABR tokamak by Electron Cyclotron Emission and Infrared Thomson scattering diagnostics

    NASA Astrophysics Data System (ADS)

    Usuriaga, O. C.; Borges, F. O.; Elfimov, A. G.; da Silva, R. P.; Ono, M. H.; Puglia, P. G. P. P.; Alonso, M. P.; Severo, J. H. F.; Nascimento, I. C.; Sanada, E. K.; de Sá, W. P.; Galvão, R. M. O.; Elizondo, J. I.

    2014-05-01

    This work presents the experimental analysis of the central electron temperature measured by the electron cyclotron emission (ECE) radiometer and the infrared Thomson Scattering (ITS) diagnostic. The detection of the ECE radiation is done by a heterodyne scanning radiometer that works at the second harmonic extraordinary mode, in frequency range from 50 to 85GHz, which allows measurement of the radial profile of electron temperature with good spatial and temporal resolutions. The ITS diagnostic uses a Neodymium Glass laser (wavelength 1.054 μm). This ITS diagnostic measures the electron temperature in the center of plasma column one time during plasma shot. Results also show a discrepancy between the two diagnostics in the electron temperature measurement in the presence of Magnetohydrodynamics activity that gives an explanation for this apparent inconsistency.

  10. Progress in producing megawatt gyrotrons for ECR (electron cyclotron resonance) heating

    SciTech Connect

    Felch, K.; Hess, C.; Huey, H.; Jongewaard, E.; Jory, H.; Neilson, J.; Pendleton, R.; Tsirulnikov, M. )

    1990-10-01

    Varian is carrying out the development of high-power, CW gyrotrons at frequencies ranging from 100--500 GHz for use in electron cyclotron resonance (ECR) heating of magnetically-confined plasma. Initial test vehicles at 140 GHz have utilized TE{sub 15,2,1} interaction cavities, and have been designed to generate short-pulse (up to 20 ms) power levels of 1 MW and up to 400 kW CW. Recently, short-pulse power levels of 940 kW at 35% efficiency have been obtained and average powers of 200 kW have been achieved at peak powers of 400 kW. Long-pulse testing is currently underway. Initial test have resulted in output levels of 400 kW for pulse durations of 380 ms. Design work on 110 GHz, 500 kW CW gyrotron oscillators has recently been completed and a prototype tube has been assembled and is currently being tested. The design of a 110 GHz, 1 MW CW gyrotron, using a novel output coupling approach, is nearly complete. Fabrication of the first 1 MW CW experimental tube is in progress.

  11. Physics Design of a 28 GHz Electron Heating System for the National Spherical Torus Experiment Upgrade

    SciTech Connect

    2013-07-09

    A megawatt-level, 28 GHz electron heating system is being designed to support non-inductive (NI) plasma current (I{sub p}) start-up and local heating and current drive (CD) in H-mode discharges in the National Spherical Torus Experiment Upgrade (NSTX-U). The development of fully NI I{sub p} start-up and ramp-up is an important goal of the NSTX-U research program. 28 GHz electron cyclotron (EC) heating is predicted to rapidly increase the central electron temperature (T{sub e}(0)) of low density NI plasmas generated by Coaxial Helicity Injection (CHI). The increased T{sub e}(0) will significantly reduce the Ip decay rate of CHI plasmas, allowing the coupling of fast wave heating and neutral beam injection. Also 28 GHz electron Bernstein wave (EBW) heating and CD can be used during the I{sub p} flat top in NSTX-U discharges when the plasma is overdense. Ray tracing and Fokker-Planck numerical simulation codes have been used to model EC and EBW heating and CD in NSTX-U. This paper presents a pre-conceptual design for the 28 GHz heating system and some of the results from the numerical simulations.

  12. Status of ECR (Electron Cyclotron Resonance) source technology

    SciTech Connect

    Lyneis, C.M.

    1987-03-01

    ECR (Electron Cyclotron Resonance) ion sources are now in widespread use for the production of high quality multiply charged ion beams for accelerators and atomic physics experiments, and industrial applications are being explored. Several general characteristics of ECR sources explain their widespread acceptance. For use with cyclotrons which require CW multiply charged ion beams, the ECR source has many advantages over heavy-ion PIG sources. Most important is the ability to produce higher charge states at useful intensities for nuclear physics experiments. Since the maximum energy set by the bending limit of a cyclotron scales with the square of the charge state, the installation of ECR sources on cyclotrons has provided an economical path to raise the energy. Another characteristic of ECR sources is that the discharge is produced without cathodes, so that only the source material injected into an ECR source is consumed. As a result, ECR sources can be operated continuously for periods of weeks without interruption. Techniques have been developed in the last few years, which allow these sources to produce beams from solid materials. The beam emittance from ECR sources is in the range of 50 to 200 ..pi.. mm-mrad at 10 kV. The principles of ECR ion sources are discussed, and present and future ECR sources are reviewed.

  13. Development of electron cyclotron emission imaging system on the HL-2A tokamak

    SciTech Connect

    Jiang, M.; Shi, Z. B.; Liu, Z. T.; Ding, X. T.; Li, J.; Zhong, W. L.; Chen, W.; Che, Y. L.; Fu, B. Z.; Cui, Z. Y.; Sun, P.; Liu, Y.; Yang, Q. W.; Duan, X. R.; Che, S.; Domier, C. W.; Luhmann, N. C. Jr.; Hu, X.; Spear, A.

    2013-11-15

    A 2D electron cyclotron emission imaging (ECEI) system has been developed for measurement of electron temperature fluctuations in the HL-2A tokamak. It is comprised of a front-end 24 channel heterodyne imaging array with a tunable RF range spanning 75–110 GHz, and a set of back-end ECEI electronics that together generate 24 × 8 = 192 channel images of the 2nd harmonic X-mode electron cyclotron emission from the HL-2A plasma. The simulated performance of the local oscillator (LO) optics and radio frequency (RF) optics is presented, together with the laboratory characterization results. The Gaussian beams from the LO optics are observed to properly cover the entire detector array. The ECE signals from the plasma are mixed with the LO signal in the array box, then delivered to the electronics system by low-loss microwave cables, and finally to the digitizers. The ECEI system can achieve temporal resolutions of ∼μs, and spatial resolutions of 1 cm (radially) and 2 cm (poloidally)

  14. Electrostatic electron cyclotron instabilities near the upper hybrid layer due to electron ring distributions

    NASA Astrophysics Data System (ADS)

    Eliasson, B.; Speirs, D. C.; Daldorff, L. K. S.

    2016-09-01

    A theoretical study is presented of the electrostatic electron cyclotron instability involving Bernstein modes in a magnetized plasma. The presence of a tenuous thermal ring distribution in a Maxwellian plasma decreases the frequency of the upper hybrid branch of the electron Bernstein mode until it merges with the nearest lower branch with a resulting instability. The instability occurs when the upper hybrid frequency is somewhat above the third, fourth, and higher electron cyclotron harmonics, and gives rise to a narrow spectrum of waves around the electron cyclotron harmonic nearest to the upper hybrid frequency. For a tenuous cold ring distribution together with a Maxwellian distribution an instability can take place also near the second electron cyclotron harmonic. Noise-free Vlasov simulations are used to assess the theoretical linear growth-rates and frequency spectra, and to study the nonlinear evolution of the instability. The relevance of the results to laboratory and ionospheric heating experiments is discussed.

  15. A study of density in electron-cyclotron-resonance plasma

    SciTech Connect

    Uhm, H.S.; Lee, P.H.; Kim, Y.I.; Kim, J.H.; Chang, H.Y.

    1995-08-01

    A theory is developed for the density profile of low-temperature plasmas confined by applied magnetic field and an experiment of the electron-cyclotron-resonance (ECR) plasma is conducted to compare the theoretical prediction and experimental measurements. Due to a large electron mobility along the magnetic field, electrons move quickly out of the system, leaving ions behind and building a space charge potential, which leads to the ambipolar diffusion of ions. In a steady-state condition, the plasma generation by ionization of neutral molecules is in balance with plasma loss due to the diffusion, leading to the electron temperature equation, which is expressed in terms of the plasma size, chamber pressure, and the ionization energy and cross section of neutrals. The power balance condition leads to the plasma density equation, which is also expressed in terms of the electron temperature, the input microwave power and the chamber pressure. It is shown that the plasma density increases, reaches its peak and decreases, as the chamber pressure increases from a small value (0.1 mTorr). These simple expressions of electron temperature and density provide a scaling law of ECR plasma in terms of system parameters. After carrying out an experimental observation, it is concluded that the theoretical predictions of the electron temperature and plasma density agree remarkably well with experimental data. A large-volume plasma generated by the electron-cyclotron-resonance (ECR) mechanism plays a pivotal role in the plasma processing, including thin-film depositions and plasma etching technologies.

  16. Major results of the electron cyclotron heating experiment in the PDX tokamak

    SciTech Connect

    Hsuan, H.; Bol, K.; Bowen, N.; Boyd, D.; Cavallo, A.; Dimits, A.; Doane, J.; Elder, G.; Goldman, M.; Grek, B.

    1984-07-01

    Electron Cyclotron Heating (ECH) experiments on PDX have been carried out with two 60 GHz pulsed gyrotrons each yielding up to approximately 100 kW. The ECH system used two waveguide runs each about 30 meters long. One run included 5 bends and the other, 7 bends. Predetermined waveguide modes were transmitted. The electron cyclotron waves were launched in narrow beams from both the high field and the low field sides of the plasma torus. The major new physics results are: (1) efficient central electron heating for both ohmic and neutral beam heated target plasmas; (2) alteration of MHD behavior using ECH; (3) identification of the trapped electron population with ECH; and (4) signature of velocity-space time evolution during ECH. In the best heating results obtained, Thomson scattering data indicated a central temperature increase from less than or equal to 1.5 keV to greater than or equal to 2.5 keV. This occurred with an average density of about 10/sup 13/ cm/sup -3/ and approximately 80 kW outside-launch ordinary-mode heating.

  17. High spatial resolution upgrade of the electron cyclotron emission radiometer for the DIII-D tokamak

    DOE PAGES

    Truong, D. D.; Austin, M. E.

    2014-11-01

    The 40-channel DIII-D electron cyclotron emission (ECE) radiometer provides measurements of Te(r,t) at the tokamak midplane from optically thick, second harmonic X-mode emission over a frequency range of 83-130 GHz. Heterodyning divides this frequency range into three 2-18 GHz intermediate frequency (IF) bands. The frequency spacing of the radiometer’s channels results in a spatial resolution of ~1-3 cm, depending on local magnetic field and electron temperature. A new high resolution subsystem has been added to the DIII-D ECE radiometer to make sub-centimeter (0.6-0.8 cm) resolution Te measurements. The high resolution subsystem branches off from the regular channels’ IF bands andmore » consists of a microwave switch to toggle between IF bands, a switched filter bank for frequency selectivity, an adjustable local oscillator and mixer for further frequency down-conversion, and a set of eight microwave filters in the 2-4 GHz range. We achieved a higher spatial resolution through the use of a narrower (200 MHz) filter bandwidth and closer spacing between the filters’ center frequencies (250 MHz). This configuration allows for full coverage of the 83-130 GHz frequency range in 2 GHz bands. Depending on the local magnetic field, this translates into a “zoomed-in” analysis of a ~2-4 cm radial region. These high resolution channels will be most useful in the low-field side edge region where modest Te values (1-2 keV) result in a minimum of relativistic broadening. Some expected uses of these channels include mapping the spatial dependence of Alfven eigenmodes, geodesic acoustic modes, and externally applied magnetic perturbations. Initial Te measurements, which demonstrate that the desired resolution is achieved, is presented.« less

  18. High spatial resolution upgrade of the electron cyclotron emission radiometer for the DIII-D tokamak

    SciTech Connect

    Truong, D. D.; Austin, M. E.

    2014-11-01

    The 40-channel DIII-D electron cyclotron emission (ECE) radiometer provides measurements of Te(r,t) at the tokamak midplane from optically thick, second harmonic X-mode emission over a frequency range of 83-130 GHz. Heterodyning divides this frequency range into three 2-18 GHz intermediate frequency (IF) bands. The frequency spacing of the radiometer’s channels results in a spatial resolution of ~1-3 cm, depending on local magnetic field and electron temperature. A new high resolution subsystem has been added to the DIII-D ECE radiometer to make sub-centimeter (0.6-0.8 cm) resolution Te measurements. The high resolution subsystem branches off from the regular channels’ IF bands and consists of a microwave switch to toggle between IF bands, a switched filter bank for frequency selectivity, an adjustable local oscillator and mixer for further frequency down-conversion, and a set of eight microwave filters in the 2-4 GHz range. We achieved a higher spatial resolution through the use of a narrower (200 MHz) filter bandwidth and closer spacing between the filters’ center frequencies (250 MHz). This configuration allows for full coverage of the 83-130 GHz frequency range in 2 GHz bands. Depending on the local magnetic field, this translates into a “zoomed-in” analysis of a ~2-4 cm radial region. These high resolution channels will be most useful in the low-field side edge region where modest Te values (1-2 keV) result in a minimum of relativistic broadening. Some expected uses of these channels include mapping the spatial dependence of Alfven eigenmodes, geodesic acoustic modes, and externally applied magnetic perturbations. Initial Te measurements, which demonstrate that the desired resolution is achieved, is presented.

  19. Cluster Observation Of Ion And Electron Cyclotron Waves Near Magnetopause

    NASA Astrophysics Data System (ADS)

    Silin, I.; Panov, E. V.

    2012-12-01

    We examine observations of electromagnetic ion cyclotron (EMIC) and electron cyclotron waves by Cluster spacecraft during a magnetopause transition near polar cusp region. The waves appear to be generated locally, on the magnetospheric side of the magnetopause current layer, due to large particle temperature anisotropy (T⊥}/T{∥ >3 for all ions and T⊥}/T{∥ ˜ 1.3 for electrons) and large plasma beta (0.5 < β < 10). The compact configuration of Cluster spacecraft and high-resolution electromagnetic field data allowed us to measure the wave vectors k by two independent methods: the wave-telescope and the polarization methods. Such measurements are essential for estimation of minimum energies of particles scattered by EMIC waves via cyclotron resonance. The results show good agreement with linear dispersion theory. The EMIC waves propagate along the magnetic field with frequencies near 1 Hz, wavelength of 260 km at speeds of ˜ 500 km/s. We discuss the implications of these results for the particle diffusion coefficients and minimum resonant scattering energies.

  20. Electron cyclotron emission as a density fluctuation diagnostic

    SciTech Connect

    Lynn, A.G.; Phillips, P.E.; Hubbard, A.

    2004-10-01

    A new technique for measuring density fluctuations using a high-resolution heterodyne electron cyclotron emission (ECE) radiometer has been developed. Although ECE radiometry is typically used for electron temperature measurements, the unique viewing geometry of this system's quasioptical antenna has been found to make the detected emission extremely sensitive to refractive effects under certain conditions. This sensitivity gives the diagnostic the ability to measure very low levels of density fluctuations in the core of Alcator C-Mod tokamak. The refractive effects have been modeled using ray-tracing methods, allowing estimates of the density fluctuation magnitude and spatial localization.

  1. Electron-cyclotron maser instability in relativistic plasmas

    NASA Technical Reports Server (NTRS)

    Pritchett, P. L.

    1986-01-01

    The electron-cyclotron maser instability is studied for the case of an anisotropic electron velocity distribution in the regime where the relativistic corrections to the wave dispersion are significant. Solution of the linear dispersion relation reveals that when the plasma frequency-gyrofrequency ratio is less than v(te)/c, the instability is localized just below k(perpendicular)c/Omega(e) = 1. The growth rate is then strongly peaked for emission at 90 deg to the magnetic field and is considerably larger than would be the case if the cold-plasma dispersion theory were valid. These features are confirmed by EM particle simulations.

  2. Nonlinear heating of ions by electron cyclotron frequency waves

    NASA Astrophysics Data System (ADS)

    Zestanakis, P. A.; Hizanidis, K.; Ram, A. K.; Kominis, Y.

    2010-11-01

    We study the nonlinear interaction of ions with electron cyclotron (EC) wave packets in a magnetized plasma. Previous studies have shown that such interactions with high frequency electrostatic lower hybrid waves can lead to coherent energization of ions. It requires the frequency bandwidth of the wave packet to be broader than the ion cyclotron frequency [1,2]. For the electromagnetic high frequency EC waves we have developed a more general theory, based on the Lie transform canonical perturbation method [3,4]. We apply the theory to the case of two overlapping EC beams. The wave frequency of each beam is assumed to be frequency modulated with a modulation bandwidth comparable to the ion cyclotron frequency. We present results for both X-mode and O-mode and illustrate the conditions for ion energization. [4pt] [1] D. Benisti, A. K. Ram, and A. Bers, Phys. Plasmas 5, 3224 (1998). [0pt] [2] A. K. Ram, A. Bers, and D. Benisti , J. Geophys. Res. 103, 9431 (1998). [0pt] [3] J.R. Cary and A.N. Kaufman, Phys. Fluids 24, 1238 (1981). [0pt] [4] R.L. Dewar, J. Phys A-Math. Gen 9, 2043 (1976).

  3. Design and characterization of a 32-channel heterodyne radiometer for electron cyclotron emission measurements on experimental advanced superconducting tokamak

    SciTech Connect

    Han, X.; Liu, X.; Liu, Y. Li, E. Z.; Hu, L. Q.; Gao, X.; Domier, C. W.; Luhmann, N. C.

    2014-07-15

    A 32-channel heterodyne radiometer has been developed for the measurement of electron cyclotron emission (ECE) on the experimental advanced superconducting tokamak (EAST). This system collects X-mode ECE radiation spanning a frequency range of 104–168 GHz, where the frequency coverage corresponds to a full radial coverage for the case with a toroidal magnetic field of 2.3 T. The frequency range is equally spaced every 2 GHz from 105.1 to 167.1 GHz with an RF bandwidth of ∼500 MHz and the video bandwidth can be switched among 50, 100, 200, and 400 kHz. Design objectives and characterization of the system are presented in this paper. Preliminary results for plasma operation are also presented.

  4. Excitation of Electron Cyclotron Harmonic Waves in Earth's Magnetotail

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaojia

    This dissertation investigates the generation mechanism, spatial distribution and characteristics of electrostatic electron cyclotron harmonic (ECH) waves under different plasma sheet conditions, and quantifies the role of these waves in producing the diffuse aurora. THEMIS observations from five magnetotail seasons, along with ray-tracing, and electron diffusion codes have been utilized towards that goal. By modeling the wave growth and quasi-linear pitch-angle diffusion of electrons with realistic parameters for the magnetic field, loss-cone distribution and wave intensity (obtained from observations as a function of magnetotail location), we estimate the loss-cone fill ratio and the contribution of auroral energy flux from wave-induced electron precipitation. We conclude that ECH waves are the dominant driver of electron precipitation in the middle to outer magnetotail.

  5. A simulation of X-ray shielding for a superconducting electron cyclotron resonance ion source

    SciTech Connect

    Park, Jin Yong; Won, Mi-Sook; Lee, Byoung-Seob; Yoon, Jang-Hee; Choi, Seyong; Ok, Jung-Woo; Choi, Jeong-Sik; Kim, Byoung-Chul

    2014-02-15

    It is generally assumed that large amounts of x-rays are emitted from the ion source of an Electron Cyclotron Resonance (ECR) instrument. The total amount of x-rays should be strictly limited to avoid the extra heat load to the cryostat of the superconducting ECR ion source, since they are partly absorbed by the cold mass into the cryostat. A simulation of x-ray shielding was carried out to determine the effective thickness of the x-ray shield needed via the use of Geant4. X-ray spectra of the 10 GHz Nanogan ECR ion source were measured as a function of the thickness variation in the x-ray shield. The experimental results were compared with Geant4 results to verify the effectiveness of the x-ray shield. Based on the validity in the case of the 10 GHz ECR ion source, the x-ray shielding results are presented by assuming the spectral temperature of the 28 GHz ECR ion source.

  6. First results from the new RIKEN superconducting electron cyclotron resonance ion source (invited).

    PubMed

    Nakagawa, T; Higurashi, Y; Ohnishi, J; Aihara, T; Tamura, M; Uchiyama, A; Okuno, H; Kusaka, K; Kidera, M; Ikezawa, E; Fujimaki, M; Sato, Y; Watanabe, Y; Komiyama, M; Kase, M; Goto, A; Kamigaito, O; Yano, Y

    2010-02-01

    The next generation heavy ion accelerator facility, such as the RIKEN radio isotope (RI) beam factory, requires an intense beam of high charged heavy ions. In the past decade, performance of the electron cyclotron resonance (ECR) ion sources has been dramatically improved with increasing the magnetic field and rf frequency to enhance the density and confinement time of plasma. Furthermore, the effects of the key parameters (magnetic field configuration, gas pressure, etc.) on the ECR plasma have been revealed. Such basic studies give us how to optimize the ion source structure. Based on these studies and modern superconducting (SC) technology, we successfully constructed the new 28 GHz SC-ECRIS, which has a flexible magnetic field configuration to enlarge the ECR zone and to optimize the field gradient at ECR point. Using it, we investigated the effect of ECR zone size, magnetic field configuration, and biased disk on the beam intensity of the highly charged heavy ions with 18 GHz microwaves. In this article, we present the structure of the ion source and first experimental results with 18 GHz microwave in detail.

  7. Combined electron cyclotron ray tracing and transport code studies in the Compact Ignition Tokamak

    SciTech Connect

    Bonoli, P.T.; Englade, R.C.; Porkolab, M. . Plasma Fusion Center); Kritz, A.H. )

    1990-01-01

    The Compact Ignition Tokamak (CIT) operating scenario is envisaged to consist of a start-up phase in which the toroidal magnetic field (B{sub T}), plasma current (I{sub P}) and central electron density (n{sub e}(0)) are simultaneously ramped, followed by a burn cycle and a ramp down cycle. Electron cyclotron radio-frequency (ECRF) power at fixed frequency is ideally suited to heating during the ramp up phase of CIT. The angle of injection of the incident microwave beam can be varied as the toroidal field is ramped, so as to maintain central rf-power deposition. Furthermore, since the EC wave is a propagating mode in vacuum, relatively high power densities can be easily coupled into a compact device. Finally, we note that recent advances in source technology makes ECR heating at (280--310) GHz a viable option. In order to realistically simulate this ramp up scenario, a combined code has been developed in which ECRF ray tracing and absorption, and MHD equilibrium calculation, and thermal and particle transport are treated self-consistently. Previous studies of electron cyclotron resonance heating in CIT were carried out using model profiles of rf absorption based on stand-alone ray tracing and absorption calculations. In addition, these studies held the plasma current, toroidal magnetic field, and density constant in time. In the present work, a time variation in these plasma quantities is imposed and ECRF power deposition is re-calculated during rf injection so as to more realistically and self-consistently simulate ECH-assisted start-up in CIT. The most recent CIT configuration calls for a toroidal field ramp to 11T. Thus, the present studies consider the use of an ECRF source frequency of 308 GHz, with EC waves launched in the ordinary mode of polarization.

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

    SciTech Connect

    Tarvainen, O.; Kurennoy, S.

    2009-03-12

    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.

  9. A proposal for a novel H ion source based on electron cyclotron resonance heating and surface ionization

    SciTech Connect

    Tarvainen, Ollie A; Kurennoy, Sergey

    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.

  10. Improvement of trace element analysis system using RIKEN electron cyclotron resonance ion source and linear accelerator

    SciTech Connect

    Kidera, M.; Nakagawa, T.; Takahashi, K.; Enomoto, S.; Igarashi, K.; Fujimaki, M.; Ikezawa, E.; Kamigaito, O.; Kase, M.; Goto, A.; Yano, Y.

    2006-03-15

    We have developed a new analytical system that consists of an electron cyclotron resonance ion source (RIKEN 18 GHz ECRIS) and a RIKEN heavy ion linear accelerator (RILAC). This system is called trace element analysis using electron cyclotron resonance ion source and RILAC (ECRIS-RILAC-TEA). ECRIS-RILAC-TEA has several advantages as described in the work of Kidera et al. [AIP Conf. Proc. 749, 85 (2005)]. However, many experimental results during the last several years revealed a few problems: (1) large background contamination in the ECRIS, particularly at the surface of the plasma chamber wall, (2) high counting of the ionization chamber and the data taking system that is monitored by the direct beam from the accelerator, and (3) difficulty in the selection of the pilot sample and pilot beam production from the ECRIS for the purpose of normalization. In order to overcome these problems, we conducted several test experiments over the past year. In this article, we report the experimental results in detail and future plans for improving this system.

  11. Characteristics of microinstabilities in electron cyclotron and ohmic heated discharges

    SciTech Connect

    Pusztai, I.; Moradi, S.; Fueloep, T.; Timchenko, N.

    2011-08-15

    Characteristics of microinstabilities in electron cyclotron (EC) and ohmic heated (OH) discharges in the T10 tokamak have been analyzed by linear electrostatic gyrokinetic simulations with gyro[J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] aiming to find insights into the effect of auxiliary heating on the transport. Trapped electron modes are found to be unstable in both OH and the EC heated scenarios. In the OH case the main drive is from the density gradient and in the EC case from the electron temperature gradient. The growth rates and particle fluxes exhibit qualitatively different scaling with the electron-to-ion temperature ratios in the two cases. This is mainly due to the fact that the dominant drives and the collisionalities are different. The inward flow velocity of impurities and the impurity diffusion coefficient decreases when applying EC heating, which leads to lower impurity peaking, consistently with experimental observations.

  12. Characteristics of microinstabilities in electron cyclotron and ohmic heated discharges

    NASA Astrophysics Data System (ADS)

    Pusztai, I.; Moradi, S.; Fülöp, T.; Timchenko, N.

    2011-08-01

    Characteristics of microinstabilities in electron cyclotron (EC) and ohmic heated (OH) discharges in the T10 tokamak have been analyzed by linear electrostatic gyrokinetic simulations with gyro [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] aiming to find insights into the effect of auxiliary heating on the transport. Trapped electron modes are found to be unstable in both OH and the EC heated scenarios. In the OH case the main drive is from the density gradient and in the EC case from the electron temperature gradient. The growth rates and particle fluxes exhibit qualitatively different scaling with the electron-to-ion temperature ratios in the two cases. This is mainly due to the fact that the dominant drives and the collisionalities are different. The inward flow velocity of impurities and the impurity diffusion coefficient decreases when applying EC heating, which leads to lower impurity peaking, consistently with experimental observations.

  13. Nonresonant interactions of electromagnetic ion cyclotron waves with relativistic electrons

    NASA Astrophysics Data System (ADS)

    Chen, Lunjin; Thorne, Richard M.; Bortnik, Jacob; Zhang, Xiao-Jia

    2016-10-01

    The dynamics of relativistic electrons traveling through a parallel-propagating, monochromatic electromagnetic ion cyclotron (EMIC) wave in the Earth's dipole field are investigated via test particle simulations. Both resonant and nonresonant responses in electron pitch angle are considered, and the differences between the two are highlighted. Nonresonant electrons, with energies below the minimum resonant energy down to hundreds of keV, are scattered stochastically in pitch angle and can be scattered into the atmospheric loss cone. The nonresonant effect is attributed to the spatial edge associated with EMIC wave packets. A condition for effective nonresonant response is also provided. This effect is excluded from current quasi-linear theory and can be a potentially important loss mechanism of relativistic and subrelativistic electrons in the radiation belts.

  14. Status of the ITER Electron Cyclotron Heating and Current Drive System

    NASA Astrophysics Data System (ADS)

    Darbos, Caroline; Albajar, Ferran; Bonicelli, Tullio; Carannante, Giuseppe; Cavinato, Mario; Cismondi, Fabio; Denisov, Grigory; Farina, Daniela; Gagliardi, Mario; Gandini, Franco; Gassmann, Thibault; Goodman, Timothy; Hanson, Gregory; Henderson, Mark A.; Kajiwara, Ken; McElhaney, Karen; Nousiainen, Risto; Oda, Yasuhisa; Omori, Toshimichi; Oustinov, Alexander; Parmar, Darshankumar; Popov, Vladimir L.; Purohit, Dharmesh; Rao, Shambhu Laxmikanth; Rasmussen, David; Rathod, Vipal; Ronden, Dennis M. S.; Saibene, Gabriella; Sakamoto, Keishi; Sartori, Filippo; Scherer, Theo; Singh, Narinder Pal; Strauß, Dirk; Takahashi, Koji

    2016-01-01

    The electron cyclotron (EC) heating and current drive (H&CD) system developed for the ITER is made of 12 sets of high-voltage power supplies feeding 24 gyrotrons connected through 24 transmission lines (TL), to five launchers, four located in upper ports and one at the equatorial level. Nearly all procurements are in-kind, following general ITER philosophy, and will come from Europe, India, Japan, Russia and the USA. The full system is designed to couple to the plasma 20 MW among the 24 MW generated power, at the frequency of 170 GHz, for various physics applications such as plasma start-up, central H&CD and magnetohydrodynamic (MHD) activity control. The design takes present day technology and extends toward high-power continuous operation, which represents a large step forward as compared to the present state of the art. The ITER EC system will be a stepping stone to future EC systems for DEMO and beyond.

  15. Production of beam of negative hydrogen and deuterium ions from source with electron cyclotron resonance

    SciTech Connect

    Golovanivskii, K.S.; Dzhayamanna, K.; Dugar-Zhabon, V.D.

    1988-09-01

    The GELIOS-H/sup /minus// ion source is described; it has electron cyclotron resonance and is designed for generation of negative hydrogen and deuterium ions. The source consumes up to 100 W of microwave power at a frequency of 2.4 GHz and provides a stationary beam of H/sup /minus// ions of up to 1.5 mA and D/sup /minus// ions of up to 1.0 mA for an exit-aperture diameter of 6.2 mm and an extraction voltage of 4.5 kV. The life of the source is limited only by the life of the microwave generator.

  16. Electron cyclotron resonance plasma deposition of silicon nitride: Effect of very low rf substrate bias

    NASA Astrophysics Data System (ADS)

    Buckle, K. A.; Rodgers, J.; Pastor, K.; Constantine, C.; Johnson, D.

    1992-05-01

    Plasma deposition of SiN on silicon substrates in a microwave (2.45 GHz) electron cyclotron resonance SiH4/N2/He, in the ratio 4/10/10, discharge has been investigated as a function of rf (40 MHz) self-biasing of the sample. Low levels of rf bias (0-10 W) were investigated and are reported in this letter. The effect of bias was measured for the deposited films with respect to refractive index, etch rate in BHF, Si—H bonding, and the intrinsic film stress. All depositions were conducted at or near room temperature to evaluate the effect of the applied rf bias on film density. All parameters examined indicated that low levels of rf bias help prepare a high quality, dense film at very low substrate temperatures.

  17. Status of the pulsed magnetic field electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Mühle, C.; Ratzinger, U.; Bleuel, W.; Jöst, G.; Leible, K.; Schennach, S.; Wolf, B. H.

    1994-04-01

    Synchrotrons like the heavy-ion synchrotron SIS at GSI need an efficient low duty cycle injector (typical 1-pulse/s and 200-μs pulse length). To improve the peak current, an electron cyclotron resonance (ECR) ion source has been designed using a pulsed magnetic field (PuMa) to force ion extraction. We replaced the hexapole of a 10-GHz Minimafios ECR ion source by a vacuum chamber containing a water-cooled bilayered solenoid coil and a decapole permanent magnetic structure. A pulse line feeds the solenoid with a 250-μs pulse which increases the magnetic field in the minimum B region by 0.3 T. This process opens the magnetic bottle along the beam axis resulting in an extracted ion pulse. First tests of the PuMa ECR configuration in cw and pulsed operation are presented and analyzed.

  18. Electron cyclotron heating at down-shifted frequencies in existing tokamak devices

    SciTech Connect

    Mazzucato, E.; Fidone, I.; Giruzzi, G.; Krivenski, V.

    1985-06-01

    Plasma heating in existing tokamak devices by electron cyclotron waves with frequency (f) significantly smaller than the electron gyrofrequency (f/sub c/) is investigated for the case of Maxwellian plasmas. It is shown that for central electron temperatures larger than 3 keV, strong absorption of extraordinary waves can occur at values of toroidal field for which the condition f = f/sub c/ is not satisfied in the plasma region. The cases of f = 60 GHz and f = 100 GHz are discussed for the PLT and TFTR devices as representative of medium (approx. =30 kG) and high (approx. =50 kG) magnetic field tokamaks, respectively. Numerical calculations with a ray tracing code indicate that most of the rf energy is absorbed in a central plasma region. These results are of practical interest because they significantly simplify the main technical problem of ECH in a tokamak reactor, i.e., the development of high frequency and high power microwave sources.

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

    SciTech Connect

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

    1989-01-01

    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 produced large (about 25-cm-diam), uniform (to within {plus minus}10%), dense (>10{sup 11}-cm{sup -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. 21 refs., 10 figs.

  20. High spatial resolution upgrade of the electron cyclotron emission radiometer for the DIII-D tokamak

    SciTech Connect

    Truong, D. D.; Austin, M. E.

    2014-11-15

    The 40-channel DIII-D electron cyclotron emission (ECE) radiometer provides measurements of T{sub e}(r,t) at the tokamak midplane from optically thick, second harmonic X-mode emission over a frequency range of 83–130 GHz. The frequency spacing of the radiometer's channels results in a spatial resolution of ∼1–3 cm, depending on local magnetic field and electron temperature. A new high resolution subsystem has been added to the DIII-D ECE radiometer to make sub-centimeter (0.6–0.8 cm) resolution T{sub e} measurements. The high resolution subsystem branches off from the regular channels’ IF bands and consists of a microwave switch to toggle between IF bands, a switched filter bank for frequency selectivity, an adjustable local oscillator and mixer for further frequency down-conversion, and a set of eight microwave filters in the 2–4 GHz range. Higher spatial resolution is achieved through the use of a narrower (200 MHz) filter bandwidth and closer spacing between the filters’ center frequencies (250 MHz). This configuration allows for full coverage of the 83–130 GHz frequency range in 2 GHz bands. Depending on the local magnetic field, this translates into a “zoomed-in” analysis of a ∼2–4 cm radial region. Expected uses of these channels include mapping the spatial dependence of Alfven eigenmodes, geodesic acoustic modes, and externally applied magnetic perturbations. Initial T{sub e} measurements, which demonstrate that the desired resolution is achieved, are presented.

  1. Electron cyclotron resonance acceleration of electrons to relativistic energies by a microwave field in a mirror trap

    SciTech Connect

    Sergeichev, K. F.; Karfidov, D. M.; Lukina, N. A.

    2007-06-15

    Results are presented from experiments on the acceleration of electrons by a 2.45-GHz microwave field in an adiabatic mirror trap under electron cyclotron resonance conditions, the electric and wave vectors of the wave being orthogonal to the trap axis. At a microwave electric field of {>=}10 V/cm and air pressures of 10{sup -6}-10{sup -4} Torr (the experiments were also performed with helium and argon), a self-sustained discharge was initiated in which a fraction of plasma electrons were accelerated to energies of 0.3-0.5 MeV. After the onset of instability, the acceleration terminated; the plasma decayed; and the accelerated electrons escaped toward the chamber wall, causing the generation of X-ray emission. Estimates show that electrons can be accelerated to the above energies only in the regime of self-phased interaction with the microwave field, provided that the electrons with a relativistically increased mass penetrate into the region with a higher magnetic field. It is shown that the negative-mass instability also can contribute to electron acceleration. The dynamic friction of the fast electrons by neutral particles in the drift space between the resonance zones does not suppress electron acceleration, so the electrons pass into a runaway regime. Since the air molecules excited by relativistic runaway electrons radiate primarily in the red spectral region, this experiment can be considered as a model of high-altitude atmospheric discharges, known as 'red sprites.'.

  2. Electron gun simulation for 95 GHz gyrotron

    SciTech Connect

    Singh, Udaybir; Kumar, Nitin; Sinha, A.K. E-mail: aksinha@ceeri.ernet.in; Purohit, L.P.

    2011-07-01

    A triode type Magnetron Injection Gun (MIG) for a 2 MW, 95 GHz Gyrotron has been designed by using commercially available code EGUN and another in-house developed code MIGANS. The operating mode of the gyrotron is TE{sub 24.8} and it is operated in the fundamental harmonic. The operating voltages of the modulating anode and the accelerating anode are 61 kV and 85 kV respectively. The parametric dependences of modulating anode voltage and cathode magnetic field on the beam quality have also been studied. (author)

  3. Intense highly charged ion beam production and operation with a superconducting electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Zhao, H. W.; Sun, L. T.; Guo, J. W.; Lu, W.; Xie, D. Z.; Hitz, D.; Zhang, X. Z.; Yang, Y.

    2017-09-01

    The superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is a superconducting-magnet-based electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged heavy ion beams. It is one of the best performing ECRISs worldwide and the first superconducting ECRIS built with an innovative magnet to generate a high strength minimum-B field for operation with heating microwaves up to 24-28 GHz. Since its commissioning in 2005, SECRAL has so far produced a good number of continuous wave intensity records of highly charged ion beams, in which recently the beam intensities of 40Ar+ and 129Xe26+ have, for the first time, exceeded 1 emA produced by an ion source. Routine operations commenced in 2007 with the Heavy Ion accelerator Research Facility in Lanzhou (HIRFL), China. Up to June 2017, SECRAL has been providing more than 28,000 hours of highly charged heavy ion beams to the accelerator demonstrating its great capability and reliability. The great achievement of SECRAL is accumulation of numerous technical advancements, such as an innovative magnetic system and an efficient double-frequency (24 +18 GHz ) heating with improved plasma stability. This article reviews the development of SECRAL and production of intense highly charged ion beams by SECRAL focusing on its unique magnet design, source commissioning, performance studies and enhancements, beam quality and long-term operation. SECRAL development and its performance studies representatively reflect the achievements and status of the present ECR ion source, as well as the ECRIS impacts on HIRFL.

  4. Characteristics of surface sterilization using electron cyclotron resonance plasma

    NASA Astrophysics Data System (ADS)

    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.

  5. Electron cyclotron emission radiometer upgrade on the J-TEXT tokamak

    NASA Astrophysics Data System (ADS)

    Yang, Z. J.; Pan, X. M.; Ma, X. D.; Ruan, B. W.; Zhou, R. B.; Zhang, C.

    2016-11-01

    To meet experimental requirements, the J-TEXT electron cyclotron emission (ECE) diagnostic is being upgraded. The front end antenna and transmission line have been modified and a new 8-channel W-band detecting unit has been developed. The improved ECE system will extend the frequency range from 94.5-124.5 GHz to 80.5-124.5 GHz. This will enable the system to cover the most plasma in the radius direction for BT = 1.8-2.2 T, and it even can cover almost the whole plasma range ρ = - 0.8-0.9 (minus means the high field side) at BT = 1.8 T. A new auxiliary channel bank with 8 narrow band, tunable yttrium iron garnet filters is planned to add to the ECE system. Due to observations along a major radius, perpendicular to BT, and relatively low electron temperature, Doppler and relativistic broadening are minimal and thus high spatial resolution measurements can be made at variable locations with these tunable channels.

  6. Electron cyclotron emission radiometer upgrade on the J-TEXT tokamak.

    PubMed

    Yang, Z J; Pan, X M; Ma, X D; Ruan, B W; Zhou, R B; Zhang, C

    2016-11-01

    To meet experimental requirements, the J-TEXT electron cyclotron emission (ECE) diagnostic is being upgraded. The front end antenna and transmission line have been modified and a new 8-channel W-band detecting unit has been developed. The improved ECE system will extend the frequency range from 94.5-124.5 GHz to 80.5-124.5 GHz. This will enable the system to cover the most plasma in the radius direction for BT = 1.8-2.2 T, and it even can cover almost the whole plasma range ρ = - 0.8-0.9 (minus means the high field side) at BT = 1.8 T. A new auxiliary channel bank with 8 narrow band, tunable yttrium iron garnet filters is planned to add to the ECE system. Due to observations along a major radius, perpendicular to BT, and relatively low electron temperature, Doppler and relativistic broadening are minimal and thus high spatial resolution measurements can be made at variable locations with these tunable channels.

  7. Design of the 2D electron cyclotron emission imaging instrument for the J-TEXT tokamak

    NASA Astrophysics Data System (ADS)

    Pan, X. M.; Yang, Z. J.; Ma, X. D.; Zhu, Y. L.; Luhmann, N. C.; Domier, C. W.; Ruan, B. W.; Zhuang, G.

    2016-11-01

    A new 2D Electron Cyclotron Emission Imaging (ECEI) diagnostic is being developed for the J-TEXT tokamak. It will provide the 2D electron temperature information with high spatial, temporal, and temperature resolution. The new ECEI instrument is being designed to support fundamental physics investigations on J-TEXT including MHD, disruption prediction, and energy transport. The diagnostic contains two dual dipole antenna arrays corresponding to F band (90-140 GHz) and W band (75-110 GHz), respectively, and comprises a total of 256 channels. The system can observe the same magnetic surface at both the high field side and low field side simultaneously. An advanced optical system has been designed which permits the two arrays to focus on a wide continuous region or two radially separate regions with high imaging spatial resolution. It also incorporates excellent field curvature correction with field curvature adjustment lenses. An overview of the diagnostic and the technical progress including the new remote control technique are presented.

  8. Design of the 2D electron cyclotron emission imaging instrument for the J-TEXT tokamak

    SciTech Connect

    Pan, X. M.; Yang, Z. J. Ma, X. D.; Ruan, B. W.; Zhuang, G.; Zhu, Y. L.; Luhmann, N. C.; Domier, C. W.

    2016-11-15

    A new 2D Electron Cyclotron Emission Imaging (ECEI) diagnostic is being developed for the J-TEXT tokamak. It will provide the 2D electron temperature information with high spatial, temporal, and temperature resolution. The new ECEI instrument is being designed to support fundamental physics investigations on J-TEXT including MHD, disruption prediction, and energy transport. The diagnostic contains two dual dipole antenna arrays corresponding to F band (90-140 GHz) and W band (75-110 GHz), respectively, and comprises a total of 256 channels. The system can observe the same magnetic surface at both the high field side and low field side simultaneously. An advanced optical system has been designed which permits the two arrays to focus on a wide continuous region or two radially separate regions with high imaging spatial resolution. It also incorporates excellent field curvature correction with field curvature adjustment lenses. An overview of the diagnostic and the technical progress including the new remote control technique are presented.

  9. Electron cyclotron emission radiometer upgrade on the J-TEXT tokamak

    SciTech Connect

    Yang, Z. J.; Pan, X. M. Ma, X. D.; Ruan, B. W.; Zhou, R. B.; Zhang, C.

    2016-11-15

    To meet experimental requirements, the J-TEXT electron cyclotron emission (ECE) diagnostic is being upgraded. The front end antenna and transmission line have been modified and a new 8-channel W-band detecting unit has been developed. The improved ECE system will extend the frequency range from 94.5-124.5 GHz to 80.5-124.5 GHz. This will enable the system to cover the most plasma in the radius direction for B{sub T} = 1.8–2.2 T, and it even can cover almost the whole plasma range ρ = − 0.8–0.9 (minus means the high field side) at B{sub T} = 1.8 T. A new auxiliary channel bank with 8 narrow band, tunable yttrium iron garnet filters is planned to add to the ECE system. Due to observations along a major radius, perpendicular to B{sub T}, and relatively low electron temperature, Doppler and relativistic broadening are minimal and thus high spatial resolution measurements can be made at variable locations with these tunable channels.

  10. Design of the 2D electron cyclotron emission imaging instrument for the J-TEXT tokamak.

    PubMed

    Pan, X M; Yang, Z J; Ma, X D; Zhu, Y L; Luhmann, N C; Domier, C W; Ruan, B W; Zhuang, G

    2016-11-01

    A new 2D Electron Cyclotron Emission Imaging (ECEI) diagnostic is being developed for the J-TEXT tokamak. It will provide the 2D electron temperature information with high spatial, temporal, and temperature resolution. The new ECEI instrument is being designed to support fundamental physics investigations on J-TEXT including MHD, disruption prediction, and energy transport. The diagnostic contains two dual dipole antenna arrays corresponding to F band (90-140 GHz) and W band (75-110 GHz), respectively, and comprises a total of 256 channels. The system can observe the same magnetic surface at both the high field side and low field side simultaneously. An advanced optical system has been designed which permits the two arrays to focus on a wide continuous region or two radially separate regions with high imaging spatial resolution. It also incorporates excellent field curvature correction with field curvature adjustment lenses. An overview of the diagnostic and the technical progress including the new remote control technique are presented.

  11. Measure of electron cyclotron emission at multiple angles in high T{sub e} plasmas of JET

    SciTech Connect

    Figini, L.; Garavaglia, S.; Farina, D.; Platania, P.; Simonetto, A.; Sozzi, C.; De La Luna, E.; Collaboration: JET-EFDA Contributors

    2010-10-15

    The oblique electron cyclotron emission (ECE) diagnostic installed at JET allows simultaneous analysis of the ECE spectra along three lines of sight (with toroidal angles of 0 deg., {approx}10 deg., and {approx}20 deg.) and two linear polarizations for each oblique line of sight. The diagnostic is capable of measuring EC emission over the band of 75-800 GHz with 5 ms time resolution and 7.5 GHz spectral resolution, and it is designed to investigate the features of ECE spectra related to electron distribution in the thermal velocity range. Instrumental accuracy was assessed using sources at different temperatures (77-900 K) and with plasma emission. ECE from high temperature plasmas and in the presence of fast ions has been compared to simulations performed with the modeling code SPECE, setting an upper limit to possible discrepancies from thermal emission.

  12. Resonance of relativistic electrons with electromagnetic ion cyclotron waves

    DOE PAGES

    Denton, R. E.; Jordanova, V. K.; Bortnik, J.

    2015-06-29

    Relativistic electrons have been thought to more easily resonate with electromagnetic ion cyclotron EMIC waves if the total density is large. We show that, for a particular EMIC mode, this dependence is weak due to the dependence of the wave frequency and wave vector on the density. A significant increase in relativistic electron minimum resonant energy might occur for the H band EMIC mode only for small density, but no changes in parameters significantly decrease the minimum resonant energy from a nominal value. The minimum resonant energy depends most strongly on the thermal velocity associated with the field line motionmore » of the hot ring current protons that drive the instability. High density due to a plasmasphere or plasmaspheric plume could possibly lead to lower minimum resonance energy by causing the He band EMIC mode to be dominant. We demonstrate these points using parameters from a ring current simulation.« less

  13. Resonance of relativistic electrons with electromagnetic ion cyclotron waves

    SciTech Connect

    Denton, R. E.; Jordanova, V. K.; Bortnik, J.

    2015-06-29

    Relativistic electrons have been thought to more easily resonate with electromagnetic ion cyclotron EMIC waves if the total density is large. We show that, for a particular EMIC mode, this dependence is weak due to the dependence of the wave frequency and wave vector on the density. A significant increase in relativistic electron minimum resonant energy might occur for the H band EMIC mode only for small density, but no changes in parameters significantly decrease the minimum resonant energy from a nominal value. The minimum resonant energy depends most strongly on the thermal velocity associated with the field line motion of the hot ring current protons that drive the instability. High density due to a plasmasphere or plasmaspheric plume could possibly lead to lower minimum resonance energy by causing the He band EMIC mode to be dominant. We demonstrate these points using parameters from a ring current simulation.

  14. Electron cyclotron maser based on the combination two-wave resonance

    SciTech Connect

    Savilov, A. V.

    2012-11-01

    A mechanism of a combination two-wave cyclotron interaction between an electron beam and the forward/backward components of a far-from-cutoff standing wave is analyzed. This regime can be promising for the realization of high-power continuous-wave electron cyclotron masers operating in the THz frequency range.

  15. Differential turbulent heating of different ions in electron cyclotron resonance ion source plasma

    SciTech Connect

    Elizarov, L.I.; Ivanov, A.A.; Serebrennikov, K.S.; Vostrikova, E.A.

    2006-03-15

    The article considers the collisionless ion sound turbulent heating of different ions in an electron cyclotron resonance ion source (ECRIS). The ion sound arises due to parametric instability of pumping wave propagating along the magnetic field with the frequency close to that of electron cyclotron. Within the framework of turbulent heating model the different ions temperatures are calculated in gas-mixing ECRIS plasma.

  16. Dynamic regimes of cyclotron instability in the afterglow mode of minimum-B electron cyclotron resonance ion source plasma

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    The paper is concerned with the dynamic regimes of cyclotron instabilities in non-equilibrium plasma of a minimum-B electron cyclotron resonance ion source operated in pulsed mode. The instability appears in decaying ion source plasma shortly (1-10 ms) after switching off the microwave radiation of the klystron, and manifests itself in the form of powerful pulses of electromagnetic emission associated with precipitation of high-energy electrons along the magnetic field lines. Recently it was shown that this plasma instability causes perturbations of the extracted ion current, which limits the performance of the ion source and generates strong bursts of bremsstrahlung emission. In this article we present time-resolved diagnostics of electromagnetic emission bursts related to cyclotron instability in the decaying plasma. The temporal resolution is sufficient to study the fine structure of the dynamic spectra of the electromagnetic emission at different operating regimes of the ion source. It was found that at different values of magnetic field and heating power the dynamic spectra demonstrate common features: Decreasing frequency from burst to burst and an always falling tone during a single burst of instability. The analysis has shown that the instability is driven by the resonant interaction of hot electrons, distributed between the electron cyclotron resonance (ECR) zone and the trap center, with slow extraordinary wave propagation quasi-parallel with respect to the external magnetic field.

  17. ITER Plasma at Electron Cyclotron Frequency Domain: Stimulated Raman Scattering off Gould-Trivelpiece Modes and Generation of Suprathermal Electrons and Energetic Ions

    NASA Astrophysics Data System (ADS)

    Stefan, V. Alexander

    2011-04-01

    Stimulated Raman scattering in the electron cyclotron frequency range of the X-Mode and O-Mode driver with the ITER plasma leads to the ``tail heating'' via the generation of suprathermal electrons and energetic ions. The scattering off Trivelpiece-Gould (T-G) modes is studied for the gyrotron frequency of 170GHz; X-Mode and O-Mode power of 24 MW CW; on-axis B-field of 10T. The synergy between the two-plasmon decay and Raman scattering is analyzed in reference to the bulk plasma heating. Supported in part by Nikola TESLA Labs, La Jolla, CA

  18. Electron cyclotron emission imaging and applications in magnetic fusion energy

    NASA Astrophysics Data System (ADS)

    Tobias, Benjamin John

    Energy production through the burning of fossil fuels is an unsustainable practice. Exponentially increasing energy consumption and dwindling natural resources ensure that coal and gas fueled power plants will someday be a thing of the past. However, even before fuel reserves are depleted, our planet may well succumb to disastrous side effects, namely the build up of carbon emissions in the environment triggering world-wide climate change and the countless industrial spills of pollutants that continue to this day. Many alternatives are currently being developed, but none has so much promise as fusion nuclear energy, the energy of the sun. The confinement of hot plasma at temperatures in excess of 100 million Kelvin by a carefully arranged magnetic field for the realization of a self-sustaining fusion power plant requires new technologies and improved understanding of fundamental physical phenomena. Imaging of electron cyclotron radiation lends insight into the spatial and temporal behavior of electron temperature fluctuations and instabilities, providing a powerful diagnostic for investigations into basic plasma physics and nuclear fusion reactor operation. This dissertation presents the design and implementation of a new generation of Electron Cyclotron Emission Imaging (ECEI) diagnostics on toroidal magnetic fusion confinement devices, or tokamaks, around the world. The underlying physics of cyclotron radiation in fusion plasmas is reviewed, and a thorough discussion of millimeter wave imaging techniques and heterodyne radiometry in ECEI follows. The imaging of turbulence and fluid flows has evolved over half a millennium since Leonardo da Vinci's first sketches of cascading water, and applications for ECEI in fusion research are broad ranging. Two areas of physical investigation are discussed in this dissertation: the identification of poloidal shearing in Alfven eigenmode structures predicted by hybrid gyrofluid-magnetohydrodynamic (gyrofluid-MHD) modeling, and

  19. Amplitudes of electron cyclotron waves transmitted in the ionosphere

    NASA Astrophysics Data System (ADS)

    James, H. G.

    2011-07-01

    During the two-point sounding rocket experiment Observations of Electric-field Distributions in the Ionospheric Plasma-A Unique Strategy-C (OEDIPUS-C, hereinafter OC), Bernstein or electron cyclotron waves (ECWs) were transmitted over magnetic field-aligned emitter-receiver separations of hundreds of meters. Signals were observed at harmonic frequencies mfc of the electron cyclotron frequency fc, where m was 2, 3, and 4, fc ≈ 1.3 MHz, and the electron plasma frequency was less than half of fc. The electric fields at 2fc radiated by the emitting dipoles have been computed from the inhomogeneous Helmholtz wave equation. Using the full hot plasma theory to evaluate the dielectric tensor, a Green's function has been derived, based partly on numerical inversion and facilitated by some simplifications made possible by the given frequency and plasma parameters. Under the assumption of straight-line rays, it is found that the computed absolute voltage levels induced on the receiving dipoles are of the same order of magnitude as the observed levels. The electric field E radiation patterns at 2fc are found to be highly elongated along the direction of the Earth's magnetic induction field B. The component of E perpendicular to B, the radial or ρ component, is much stronger than the other two components in a cylindrical coordinate system. The prediction of strong radial E magnitudes along ray directions very close to B is consistent with the OC observations. These results enlarge our appreciation of distinct characteristics of ECW radiation and propagation that may improve understanding of the role of these electrostatic waves in ionospheric dynamics.

  20. Development of multichannel intermediate frequency system for electron cyclotron emission radiometer on KSTAR Tokamak

    SciTech Connect

    Kogi, Yuichiro; Sakoda, Takuya; Mase, Atsushi; Ito, Naoki; Yokota, Yuya; Yamaguchi, Soichiro; Nagayama, Yoshio; Kawahata, Kazuo; Jeong, Seung H.; Kwon, Myeun

    2008-10-15

    Plasma experiments on KSTAR are scheduled to start up this year (2008). We have developed an electron cyclotron emission (ECE) radiometer to measure the radial electron temperature profiles in KSTAR experiments. The radiometer system consists, briefly, of two downconversion stages, amplifiers, bandpass filter banks, and video detectors. These components are made commercially or developed in house. The system detects ECE power in the frequency range from 110 to 196 GHz, the detected signal being resolved by means of 48 frequency windows. Before installation of this system on KSTAR, we installed a part of this system on large helical device (LHD) to study the system under similar plasma conditions. In this experiment, the signal amplitude, considered to be proportional to the electron temperature, is measured. The time-dependent traces of the electron temperature measured by this radiometer are in good agreement with those provided by the LHD Michelson spectrometer. The system noise level which limits the minimum measurable temperature (converted to the electron temperature) is about 30 eV.

  1. Electron cyclotron heating and current drive: Present experiments to ITER. Revision 1

    SciTech Connect

    Harvey, R.W.; Nevins, W.M.; Smith, G.R.; Lloyd, B.; O`Brien, M.R.; Warrick, C.D.

    1995-08-01

    Electron cyclotron (EC) power has technological and physics advantages for heating and current drive in a tokamak reactor, and advances in source development make it credible for applications in ITER. Strong single pass absorption makes heating to ignition particularly simple. The optimized EC current drive (ECCD) efficiency ({l_angle}n{r_angle}IR/P) shows a linear temperature scaling at temperatures up to {approximately} 15 keV. For temperatures above 30 keV, the efficiency saturates at approximately 0.3{center_dot}10{sup 20} A/(m{sup 2}W) for a frequency of 220 GHz in an ITER target plasma with toroidal field of 6 T, due primarily to harmonic overlap [G.R. Smith et al., Phys. Fluids 30 3633 (1987)] and to a lesser extent due to limitations arising from relativistic effects [N.J. Fisch, Phys. Rev. A 24 3245 (1981)]. The same efficiency can also be obtained at 170 GHz for the same plasma equilibrium except that the magnetic field is reduced to (170/220) {times} 6 T = 4.6 T. The ECCD efficiencies are obtained with the comprehensive 3D, bounce-averaged Fokker-Planck CQL3D codes [R.W. Harvey and M.G. McCoy, Proc. IAEA TCM/Advances in Simulation and Modeling in Thermonuclear Plasmas 1992, Montreal], and BANDIT3D [M.R. O`Brien, M. Cox, C.D. Warrick, and F. S. Zaitsev, ibid.].

  2. High power millimeter wave experiment of ITER relevant electron cyclotron heating and current drive system.

    PubMed

    Takahashi, K; Kajiwara, K; Oda, Y; Kasugai, A; Kobayashi, N; Sakamoto, K; Doane, J; Olstad, R; Henderson, M

    2011-06-01

    High power, long pulse millimeter (mm) wave experiments of the RF test stand (RFTS) of Japan Atomic Energy Agency (JAEA) were performed. The system consists of a 1 MW/170 GHz gyrotron, a long and short distance transmission line (TL), and an equatorial launcher (EL) mock-up. The RFTS has an ITER-relevant configuration, i.e., consisted by a 1 MW-170 GHz gyrotron, a mm wave TL, and an EL mock-up. The TL is composed of a matching optics unit, evacuated circular corrugated waveguides, 6-miter bends, an in-line waveguide switch, and an isolation valve. The EL-mock-up is fabricated according to the current design of the ITER launcher. The Gaussian-like beam radiation with the steering capability of 20°-40° from the EL mock-up was also successfully proved. The high power, long pulse power transmission test was conducted with the metallic load replaced by the EL mock-up, and the transmission of 1 MW/800 s and 0.5 MW/1000 s was successfully demonstrated with no arcing and no damages. The transmission efficiency of the TL was 96%. The results prove the feasibility of the ITER electron cyclotron heating and current drive system. © 2011 American Institute of Physics

  3. Multi-harmonic electron cyclotron instabilities. [diffuse electron aurora

    NASA Technical Reports Server (NTRS)

    Ashour-Abdalla, M.; Kennel, C. F.

    1978-01-01

    The reported investigation constitutes an extension of studies conducted by Ashour-Abdalla and Kennel (1975, 1976, 1978) with respect to a basic plasma model of Young et al. (1973). The model involves a combination of a cold Maxwellian background plasma, a hot plasma, and a 'loss cone' type of free energy source. Previous results on the first cyclotron harmonic bands are extended to multiharmonics. The significance of the obtained relations is discussed and tentative conclusions are presented. Given that the spatial growth rates of the convective modes are comparable, and that simultaneous nonconvective instability (NCI) is possible, it is concluded that multiharmonic emissions ought to be a common feature of the magnetospheric electrostatic wave observations. Since the volume of parameter space for which the first harmonic is NCI, and the volume for which the convective first harmonic mode has significant spatial growth rates, exceed those for the higher harmonics, first harmonic waves should be the most commonly observed and the higher harmonics should usually be accompanied by the first harmonic.

  4. Precipitation of Relativistic Electrons by Electromagnetic Ion Cyclotron (EMIC) Waves

    NASA Astrophysics Data System (ADS)

    Denton, R. E.

    2015-12-01

    We use the electromagnetic ion cyclotron (EMIC) wave fields produced in a two dimensional hybrid code simulation (full dynamics particle ions, but inertialess fluid electrons) in dipole geometry in order to investigate the effect of magnetospheric EMIC waves on relativistic electrons. The plane of the simulation includes variation in the L shell direction and along magnetic field lines. Relativistic test particle electrons are inserted into the simulation when the wave fields are near their maximum amplitude. These electrons can be scattered into the loss cone so that they precipitate into the ionosphere. We find the effective pitch angle diffusion coefficient and probability of precipitation using these test particles. The pitch angle diffusion coefficients are largest for relativistic energies greater than 2 MeV, though they may be substantial for lower energies. The probability of precipitation is highest for low energy particles at small initial equatorial pitch angle. For high initial equatorial pitch angles, the probability of precipitation increases greatly with respect to particle energy. Starting from an isotropic pitch angle distribution of relativistic electrons with a Gaussian spread in the relativistic momentum, we find only a small drop in the probability of precipitation during 13 s time as the particle energy decreases. But that result depends on the initial pitch angle distribution. Starting with a distribution of particles steeply peaked at 90° initial equatorial pitch angle, the probability of precipitation would be greater for high-energy particles. We will discuss the mechanism of pitch angle scattering.

  5. Electron cyclotron beam measurement system in the Large Helical Device

    SciTech Connect

    Kamio, S. Takahashi, H.; Kubo, S.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Ito, S.; Kobayashi, S.; Mizuno, Y.; Okada, K.; Osakabe, M.; Mutoh, T.

    2014-11-15

    In order to evaluate the electron cyclotron (EC) heating power inside the Large Helical Device vacuum vessel and to investigate the physics of the interaction between the EC beam and the plasma, a direct measurement system for the EC beam transmitted through the plasma column was developed. The system consists of an EC beam target plate, which is made of isotropic graphite and faces against the EC beam through the plasma, and an IR camera for measuring the target plate temperature increase by the transmitted EC beam. This system is applicable to the high magnetic field (up to 2.75 T) and plasma density (up to 0.8 × 10{sup 19} m{sup −3}). This system successfully evaluated the transmitted EC beam profile and the refraction.

  6. Determination of the Electron Cyclotron Current Drive Profile

    SciTech Connect

    Luce, T.C.; Petty, C.C.; Schuster, D.I.; Makowski, M.A.

    1999-11-01

    Evaluation of the profile of non-inductive current density driven by absorption of electron cyclotron waves (ECCD) using time evolution of the poloidal flux indicated a broader profile than predicted by theory. To determine the nature of this broadening, a 1-1/2 D transport calculation of current density evolution was used to generate the signals which the DIII-D motional Stark effect (MSE) diagnostic would measure in the event that the current density evolution followed the neoclassical Ohm's law with the theoretical ECCD profile. Comparison with the measured MSE data indicates the experimental data is consistent with the ECCD profile predicted by theory. The simulations yield a lower limit on the magnitude of the ECCD which is at or above the value found in Fokker-Planck calculations of the ECCD including quasilinear and parallel electric field effects.

  7. Pulsed magnetic field-electron cyclotron resonance ion source operation

    SciTech Connect

    Muehle, C.; Ratzinger, U.; Joest, G.; Leible, K.; Schennach, S.; Wolf, B.H.

    1996-03-01

    The pulsed magnetic field (PuMa)-electron cyclotron resonance (ECR) ion source uses a pulsed coil to improve the peak current by opening the magnetic bottle along the beam axis. After demonstration of the principle of the pulsed magnetic extraction, the ion source was tested with different gases. We received promising results from helium to krypton. The influence of the current in the pulsed coil on the analyzed ion current was measured. With increased current levels within the pulsed coil not only the pulse height of the PuMa pulse, but the pulse length can also be controlled. By using the pulsed coil the maximum of the charge state distribution can be shifted to higher charge states. {copyright} {ital 1996 American Institute of Physics.}

  8. Application of compact electron cyclotron resonance ion source

    SciTech Connect

    Muramatsu, M.; Kitagawa, A.; Iwata, Y.; Ogawa, H.; Hojo, S.; Kubo, T.; Kato, Y.; Biri, S.; Fekete, E.; Yoshida, Y.; Drentje, A. G.

    2008-02-15

    The compact electron cyclotron resonance (ECR) ion source with a permanent magnet configuration (Kei2 source) has been developed at National Institute of Radiological Sciences for a new carbon therapy facility. The Kei2 source was designed for production of C{sup 4+} ions; its performance such as beam intensity and stability has already reached the medical requirements. Therefore, the prototype development of the source for medical use is essentially finished. Recently, we have started a few studies on other applications of the source. One is the production of fullerenes in the ECR plasma and modified fullerenes with various atoms for new materials. A second application is the production of multiply charged ions (not only carbon) for ion implantation. In this paper, some basic experiments for these applications are reported.

  9. Electron-cyclotron heating in the Constance 2 mirror experiment

    SciTech Connect

    Mauel, Michael E.

    1982-09-01

    Electron cyclotron heating of a highly-ionized plasma in mirror geometry is investigated. The experimental diagnosis of the electron energy distribution and the comparison of the results of this diagnosis with a two dimensional, time-dependent Fokker-Planck simulation are accomplished in four steps. (1) First, the power balance of the heated and unheated Constance 2 plasma is analyzed experimentally. It is concluded that the heated electrons escape the mirror at a rate dominated by a combination of the influx of cool electrons from outside the mirror and the increased loss rate of the ions. (2) The microwave parameters at the resonance zones are then calculated by cold-plasma ray tracing. High N/sub parallel/ waves are launched and for these waves, strong first-pass absorption is predicted. The absorption strength is qualitatively checked in the experiment by surrounding the plasma with non-reflecting liners. (3) A simplified quasilinear theory including the effect of N/sub parallel/ is developed to model the electrons. An analytic expression is derived for the RF-induced pump-out of the magnetically-confined warm electrons. Results of the Fokker-Planck simulations show the development of the electron energy distribution for several plasma conditions and verify the scaling of the analytic expression for RF-induced diffusion into the loss cone. (4) Sample x-ray and endloss data are presented, and the overall comparison between the simulation and experiment is discussed. The x-ray signals indicate that, for greater RF power, the hot electrondensity increases more rapidly than its temperature. The time history of the endloss data, illustrating RF-enhancement, suggests the predicted scaling for warm-electron pump-out. Finally, a comparison between the measured and predicted energy distribution shows that the bulk, warm and hot components of the heated Constance 2 electrons are indeed reproduced by the simulation.

  10. Cyclotron-absorption measurement of the runaway-electron distribution in a tokamak

    SciTech Connect

    Zvonkov, A.V.; Suvorov, E.V.; Timofeev, A.V.; Fraiman, A.A.

    1983-03-01

    The distribution function of runaway electrons in a tokamak can be determined in the slightly relativistic region from measurements of the absorption coefficient corresponding to electron cyclotron waves. The plasma should be probed in the vertical direction.

  11. H- ion production in electron cyclotron resonance driven multicusp volume source

    NASA Astrophysics Data System (ADS)

    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.

  12. Evidence of local power deposition and electron heating by a standing electromagnetic wave in electron-cyclotron-resonance plasma.

    PubMed

    Durocher-Jean, A; Stafford, L; Dap, S; Makasheva, K; Clergereaux, R

    2014-09-01

    Microwave plasmas excited at electron-cyclotron resonance were studied in the 0.5-15 mTorr pressure range. In contrast with low-limit pressure conditions where the plasma emission highlights a fairly homogeneous spatial structure, a periodic spatial modulation (period ∼6.2 cm) appeared as pressure increased. This feature is ascribed to a local power deposition (related to the electron density) due to the presence of a standing electromagnetic wave created by the feed electromagnetic field (2.45 GHz) in the cavity formed by the reactor walls. Analysis of the electron energy probability function by Langmuir probe and optical emission spectroscopy further revealed the presence of a high-energy tail that showed strong periodic spatial modulation at higher pressure. The spatial evolution of the electron density and of the characteristic temperature of these high-energy electrons coincides with the nodes (maximum) and antinodes (minimum) of the standing wave. These spatially-modulated power deposition and electron heating mechanisms are then discussed.

  13. Plume properties measurement of an Electron Cyclotron Resonance Accelerator

    NASA Astrophysics Data System (ADS)

    Correyero, Sara; Vialis, Theo; Jarrige, Julien; Packan, Denis

    2016-09-01

    Some emergent technologies for Electric Propulsion, such as the Electron Cyclotron Resonance Accelerator (ECRA), include magnetic nozzles to guide and expand the plasma. The advantages of this concept are well known: wall-plasma contact is avoided, it provides a current-free plume, it can allow to control thrust by modifying the magnetic field geometry, etc. However, their industrial application requires the understanding of the physical mechanisms involved, such as the electron thermodynamics at the plasma plume expansion, which is crucial to determine propulsive performances. This work presents a detailed characterization of the plasma plume axial profile in an ECR plasma thruster developed at ONERA. Langmuir, emissive, Faraday and ion energy probes are used to measure the electric potential space evolution, the current and electron energy distribution function in the plume, from the near field to the far field. The experimental results are compared with a quasi-1D (paraxial) steady-state kinetic model of a quasineutral collisionless magnetized plasma which is able to determine consistently the axial evolution of the electric potential and the electron and ion distribution functions with their associated properties.

  14. Electron-cyclotron maser and solar microwave millisecond spike emission

    NASA Technical Reports Server (NTRS)

    Li, Hong-Wei; Li, Chun-Sheng; Fu, Qi-Jun

    1986-01-01

    An intense solar microwave millisecond spike emission (SMMSE) event was observed on May 16, 1981 by Zhao and Jin at Beijing Observatory. The peak flux density of the spikes is high to 5 x 100,000 s.f.u. and the corresponding brightness temperature (BT) reaches approx. 10 to the 15th K. In order to explain the observed properties of SMMSE, it is proposed that a beam of electrons with energy of tens KeV injected from the acceleration region downwards into an emerging magnetic arch forms so-called hollow beam distribution and causes electron-cyclotron maser (ECM) instability. The growth rate of second harmonic X-mode is calculated and its change with time is deduced. It is shown that the saturation time of ECM is t sub s approx. equals 0.42 ms and only at last short stage (delta t less than 0.2 t sub s) the growth rate decreases to zero rather rapidly. So a SMMSE with very high BT will be produced if the ratio of number density of nonthermal electrons to that of background electrons, n sub s/n sub e, is larger than 4 x .00001.

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

    NASA Astrophysics Data System (ADS)

    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

  16. Generation of Electron Cyclotron Harmonic waves around the Moon

    NASA Astrophysics Data System (ADS)

    Katayama, Y.; Kojima, H.; Saito, Y.; Kasahara, Y.; Omura, Y.; Yamamoto, T.; Yokota, S.; Nishino, M. N.; Hashimoto, K.; Ono, T.; Tsunakawa, H.

    2012-12-01

    The study of the electron cyclotron harmonic(ECH) waves has been extensively made in the view point of the magnetospheric physics as well as the microscopic wave-particle interaction. The Japanese lunar satellite Kaguya provides another observation of the ECH waves around the moon. The interaction between the moon and space plasmas results in the generation of the ECH waves. We performed the detailed data analyses using the plasma wave data observed by the Kaguya as well as the linear dispersion analyses. First of all we found the close relation of the ECH wave observation and the magnetic anomaly of the night side of the moon. In order to examine the generation condition of the ECH waves, we consult the Kaguya electron data. The data show that the importance of the coexistence of of electron loss cone velocity distribution and low energy electron beams. The loss cone velocity distribution can be formed by the mirror force at the magnetic anomaly on the surface of the moon. The low energy electron beam can be realized by the acceleration due to the negative potential of the moon surface on the night side. We then assume these two kinds of electron distribution are essential to excite ECH waves. However the loss cone distribution and low energy beam are observed not only in the magnetosphere but also in the wake region, where ECH waves are not observed. This means some parametric dependence of the ECH wave generation even under the coexistence of the electron loss cone distribution and low energy electron beam. In order to make clear the parametric condition of the ECH waves around the moon, we calculate the linear growth rate by solving the kinetic plasma dispersion relation using the realistic plasma parameters of the lobe, plasma sheet and wake regions based on the KAGUYA observation. In the linear dispersion analysis, we assumed hot electrons and cold electrons, and the former have loss cone distribution and the latter has drift velocity which equivalent

  17. Evolution of the axial electron cyclotron maser instability, with applications to solar microwave spikes

    NASA Technical Reports Server (NTRS)

    Vlahos, Loukas; Sprangle, Phillip

    1987-01-01

    The nonlinear evolution of cyclotron radiation from streaming and gyrating electrons in an external magnetic field is analyzed. The nonlinear dynamics of both the fields and the particles are treated fully relativistically and self-consistently. The model includes a background plasma and electrostatic effects. The analytical and numerical results show that a substantial portion of the beam particle energy can be converted to electromagnetic wave energy at frequencies far above the electron cyclotron frequency. In general, the excited radiation can propagate parallel to the magnetic field and, hence, escape gyrothermal absorption at higher cyclotron harmonics. The high-frequency Doppler-shifted cyclotron instability can have saturation efficiencies far higher than those associated with well-known instabilities of the electron cyclotron maser type. Although the analysis is general, the possibility of using this model to explain the intense radio emission observed from the sun is explored in detail.

  18. Plasma injection and capture at electron cyclotron resonance in a mirror system with additional rf fields

    SciTech Connect

    Golovanivskii, K.S.; Dugar-Zhabon, V.D.; Karyaka, V.I.; Milant'ev, V.P.; Turikov, V.A.

    1980-03-01

    Experiments and numerical simulations have been carried out to determine how cyclotron-resonance rf fields in an open magnetic mirror system affect the capture and confinement of a plasma injected along the axis. The results show that at electron cyclotron resonance the fields greatly improve the longitudinal plasma confinement.

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

    PubMed

    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.

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

    SciTech Connect

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

    2012-02-15

    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.

  1. Twenty-channel grating polychromator diagnostic system for electron cyclotron emission measurement in JT-60

    NASA Astrophysics Data System (ADS)

    Ishida, S.; Nagashima, A.; Sato, M.; Isei, N.; Matoba, T.

    1990-10-01

    A twenty-channel grating polychromator diagnostic system has been built to measure the temporal evolution of local electron temperatures in JT-60. A cross Czerny-Turner diffraction grating spectrometer is utilized for the measurement of second-harmonic electron cyclotron emission with extraordinary modes in the range 85-300 GHz, in which a grating plate grooved on both faces with different grating periods is applied effectively to yield a wide coverage for the toroidal fields. The grating angle is automatically set up by control of a stepping motor according to the relation of the grating equation. The diffracted light is detected by 20 indium-antimonide hot-electron bolometers cooled at 4.3 K in a modified Solvay cycle cryogenic refrigerator. A typical resolving power of the instrument was measured to be λ/Δλ˜130, providing a spatial resolution of 2.3 cm at the plasma center. The transmission line over ˜38 m long is composed of oversized S-band waveguides. The total transmissivity of this system is estimated to be ˜0.01.

  2. Design study of electron cyclotron resonance-ion plasma accelerator for heavy ion cancer therapy

    SciTech Connect

    Inoue, T. Sugimoto, S.; Sasai, K.; Hattori, T.

    2014-02-15

    Electron Cyclotron Resonance-Ion Plasma Accelerator (ECR-IPAC) device, which theoretically can accelerate multiple charged ions to several hundred MeV with short acceleration length, has been proposed. The acceleration mechanism is based on the combination of two physical principles, plasma electron ion adiabatic ejection (PLEIADE) and Gyromagnetic Autoresonance (GYRAC). In this study, we have designed the proof of principle machine ECR-IPAC device and simulated the electromagnetic field distribution generating in the resonance cavity. ECR-IPAC device consisted of three parts, ECR ion source section, GYRAC section, and PLEIADE section. ECR ion source section and PLEIADE section were designed using several multi-turn solenoid coils and sextupole magnets, and GYRAC section was designed using 10 turns coil. The structure of ECR-IPAC device was the cylindrical shape, and the total length was 1024 mm and the maximum diameter was 580 mm. The magnetic field distribution, which maintains the stable acceleration of plasma, was generated on the acceleration center axis throughout three sections. In addition, the electric field for efficient acceleration of electrons was generated in the resonance cavity by supplying microwave of 2.45 GHz.

  3. Design study of electron cyclotron resonance-ion plasma accelerator for heavy ion cancer therapy.

    PubMed

    Inoue, T; Hattori, T; Sugimoto, S; Sasai, K

    2014-02-01

    Electron Cyclotron Resonance-Ion Plasma Accelerator (ECR-IPAC) device, which theoretically can accelerate multiple charged ions to several hundred MeV with short acceleration length, has been proposed. The acceleration mechanism is based on the combination of two physical principles, plasma electron ion adiabatic ejection (PLEIADE) and Gyromagnetic Autoresonance (GYRAC). In this study, we have designed the proof of principle machine ECR-IPAC device and simulated the electromagnetic field distribution generating in the resonance cavity. ECR-IPAC device consisted of three parts, ECR ion source section, GYRAC section, and PLEIADE section. ECR ion source section and PLEIADE section were designed using several multi-turn solenoid coils and sextupole magnets, and GYRAC section was designed using 10 turns coil. The structure of ECR-IPAC device was the cylindrical shape, and the total length was 1024 mm and the maximum diameter was 580 mm. The magnetic field distribution, which maintains the stable acceleration of plasma, was generated on the acceleration center axis throughout three sections. In addition, the electric field for efficient acceleration of electrons was generated in the resonance cavity by supplying microwave of 2.45 GHz.

  4. Design study of electron cyclotron resonance-ion plasma accelerator for heavy ion cancer therapy

    NASA Astrophysics Data System (ADS)

    Inoue, T.; Hattori, T.; Sugimoto, S.; Sasai, K.

    2014-02-01

    Electron Cyclotron Resonance-Ion Plasma Accelerator (ECR-IPAC) device, which theoretically can accelerate multiple charged ions to several hundred MeV with short acceleration length, has been proposed. The acceleration mechanism is based on the combination of two physical principles, plasma electron ion adiabatic ejection (PLEIADE) and Gyromagnetic Autoresonance (GYRAC). In this study, we have designed the proof of principle machine ECR-IPAC device and simulated the electromagnetic field distribution generating in the resonance cavity. ECR-IPAC device consisted of three parts, ECR ion source section, GYRAC section, and PLEIADE section. ECR ion source section and PLEIADE section were designed using several multi-turn solenoid coils and sextupole magnets, and GYRAC section was designed using 10 turns coil. The structure of ECR-IPAC device was the cylindrical shape, and the total length was 1024 mm and the maximum diameter was 580 mm. The magnetic field distribution, which maintains the stable acceleration of plasma, was generated on the acceleration center axis throughout three sections. In addition, the electric field for efficient acceleration of electrons was generated in the resonance cavity by supplying microwave of 2.45 GHz.

  5. Acoustic mode driven by fast electrons in TJ-II Electron Cyclotron Resonance plasmas

    NASA Astrophysics Data System (ADS)

    Sun, B. J.; Ochando, M. A.; López-Bruna, D.

    2016-08-01

    Intense harmonic oscillations in radiation signals (δ I/I∼ 5{%}) are commonly observed during Electron Cyclotron Resonance (ECR) heating in TJ-II stellarator plasmas at low line-averaged electron density, 0.15 < \\bar{n}e < 0.6 ×1019 \\text{m}-3 . The frequency agrees with acoustic modes. The poloidal modal structure is compatible with Geodesic Acoustic Modes (GAM) but an n \

  6. Rapid Current Ramp-Up by Cyclotron-Driving Electrons beyond Runaway Velocity

    SciTech Connect

    Uchida, M.; Yoshinaga, T.; Tanaka, H.; Maekawa, T.

    2010-02-12

    The toroidal current has been rapidly ramped-up after the formation of an initial closed flux surface in an electron cyclotron heated discharge in the low aspect ratio torus experiment device. A current carrying fast electron tail is developed well beyond the runaway velocity against the reverse voltage from self-induction, suggesting a forward driving force on the tail by the cyclotron absorption of high N{sub ||} electron Bernstein waves.

  7. Applications of Electron Cyclotron Waves in the DIII-D Tokamak

    SciTech Connect

    Prater, R.; Cengher, M.; Gorelov, I. A.; Lohr, J.; Ponce, D.

    2009-11-26

    Electron cyclotron heating (ECH) and electron cyclotron current drive (ECCD) have progressed from being the subject of experiments to being a prime tool for carrying out experiments on other topics. ECH has different characteristics than neutral beam heating: ECH heats only the electrons, heats very locally and controllably, does not inject momentum or particles, and may be arranged to drive highly localized currents or to just heat. These differences make ECH useful in a very wide range of experiments.

  8. SPECE: a code for Electron Cyclotron Emission in tokamaks

    SciTech Connect

    Farina, D.; Figini, L.; Platania, P.; Sozzi, C.

    2008-03-12

    The code SPECE has been developed for the analysis of electron cyclotron emission (ECE) in a general tokamak equilibrium. The code solves the radiation transport equation along the ray trajectories in a tokamak plasma, in which magnetic equilibrium and plasma profiles are given either analytically or numerically, for a Maxwellian plasma or a non thermal plasma characterized by a distribution function that is the sum of drifting Maxwellian distributions. Ray trajectories are computed making use of the cold dispersion relation, while the absorption and emission coefficients are obtained solving the relevant fully relativistic dispersion relation valid at high electron temperature. The actual antenna pattern is simulated by means of a multi-rays calculation, and the spatial resolution of the ECE measurements is computed by means of an algorithm that takes properly into account the emission along each ray of the beam. Wall effects are introduced in the code by means of a heuristic model. Results of ECE simulations in a standard ITER scenario are presented.

  9. Ultradeep electron cyclotron resonance plasma etching of GaN

    DOE PAGES

    Harrison, Sara E.; Voss, Lars F.; Torres, Andrea M.; ...

    2017-07-25

    Here, ultradeep (≥5 μm) electron cyclotron resonance plasma etching of GaN micropillars was investigated. Parametric studies on the influence of the applied radio-frequency power, chlorine content in a Cl2/Ar etch plasma, and operating pressure on the etch depth, GaN-to-SiO2 selectivity, and surface morphology were performed. Etch depths of >10 μm were achieved over a wide range of parameters. Etch rates and sidewall roughness were found to be most sensitive to variations in RF power and % Cl2 in the etch plasma. Selectivities of >20:1 GaN:SiO2 were achieved under several chemically driven etch conditions where a maximum selectivity of ~39:1 wasmore » obtained using a 100% Cl2 plasma. The etch profile and (0001) surface morphology were significantly influenced by operating pressure and the chlorine content in the plasma. Optimized etch conditions yielded >10 μm tall micropillars with nanometer-scale sidewall roughness, high GaN:SiO2 selectivity, and nearly vertical etch profiles. These results provide a promising route for the fabrication of ultradeep GaN microstructures for use in electronic and optoelectronic device applications. In addition, dry etch induced preferential crystallographic etching in GaN microstructures is also demonstrated, which may be of great interest for applications requiring access to non- or semipolar GaN surfaces.« less

  10. Vertical-viewing electron cyclotron emission diagnostic for the DIII-D tokamak

    SciTech Connect

    James, R.; Janz, S.; Ellis, R.; Boyd, D.; Lohr, J.

    1988-08-01

    The vertical-viewing electron cyclotron emission diagnostic on DIII-D will be used to assess the nonthermal electron distributions resulting from electron cyclotron heating and electron cyclotron current drive experiments. Electron cyclotron emission along a vertical chord is collected using an ellipsoidal focusing mirror and retroreflector (the latter to minimize wall reflections). The emission is then transported approx.20 m using a quasioptical transport system composed of eight lenses and three mirrors, and detected between the 2nd and the 10th harmonics by a fast-scanning (40-Hz) Michelson interferometer. The entire system has been aligned using a Gaussian beam simulator and absolutely calibrated in situ using a cold liquid-nitrogen bath. Details of the design, installation, and calibration will be discussed.

  11. Quasi-steady, marginally unstable electron cyclotron harmonic wave amplitudes

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaojia; Angelopoulos, Vassilis; Ni, Binbin; Thorne, Richard M.; Horne, Richard B.

    2013-06-01

    Electron cyclotron harmonic (ECH) waves have long been considered a potential driver of diffuse aurora in Earth's magnetotail. However, the scarcity of intense ECH emissions in the outer magnetotail suggests that our understanding of the amplification and the relative importance of these waves for electron scattering is lacking. We conduct a comprehensive study of wave growth and quasi-linear diffusion to estimate the amplitude of loss-cone-driven ECH waves once diffusion and growth balance but before convection or losses alter the background hot plasma sheet population. We expect this to be the most common state of the plasma sheet between episodes of fast convection. For any given wave amplitude, we model electron diffusion caused by interaction with ECH waves using a 2-D bounce-averaged Fokker-Planck equation. After fitting the resultant electron distributions as a superposition of multicomponent subtracted bi-Maxwellians, we estimate the maximum path-integrated gain using the HOTRAY ray-tracing code. We argue that the wave amplitude during quasi-steady state is the inflection point on a gain-amplitude curve. During quasi-steady state, ECH wave amplitudes can be significant (~1 mV/m) at L ~ 8 but drop to very low values (<~0.1 mV/m) in the outer magnetotail (L ~ 16) and likely fall below the sensitivity of typical instrumentation relatively close to Earth mainly because of the smallness of the loss cone. Our result reinforces the potentially important role of ECH waves in driving diffuse aurora and suggests that careful comparison of theoretical wave amplitude estimates and observations is required for resolving the equatorial scattering mechanism of diffuse auroral precipitation.

  12. Calibration of the Electron Cyclotron Diagnostic for ITER

    NASA Astrophysics Data System (ADS)

    Phillips, P. E.; Rowan, W. L.; Austin, M. E.; Gentle, K. W.; Huang, H.; Beno, J. H.; Ouroua, A.; Ang, T.; Yang, Z. J.

    2013-10-01

    Electron temperature measurements will be critical to the non-active and deuterium phase of ITER operation and will take on added importance during the alpha heating phase. The ECE diagnostic for these measurements has front end components that must operate reliably during long pulse operation with high neutron and gamma fluxes in spite of limited opportunities for maintenance. Hence, an in-situ emission source is required to calibrate changes in the front end transmission. The calibration unit is a black body emitter (emissivity > 0.75, 100 GHz < f < 1000 GHz) that operates in vacuum at high temperature (700° C) without adversely affecting the vacuum or nearby diagnostics. It was developed at UT-Austin. Long-term field testing at EAST and J-TEXT is underway using variations of the ITER design tailored for the machines. Operation in the field at full temperature verified the basic design and suggested improvements in the heater design. Supported by US-IPO and US DOE grant DE-FG03-97ER54415.

  13. Heating and Current Drive by Electron Cyclotron Waves

    NASA Astrophysics Data System (ADS)

    Prater, R.

    2003-10-01

    The physics model of electron cyclotron heating (ECH) and current drive (ECCD) is becoming well validated through systematic comparisons of theory and experiment. Work has shown that ECCD can be highly localized and robustly controlled, leading to applications including stabilization of MHD instabilities like neoclassical tearing modes, control and sustainment of desired profiles of current density and plasma pressure, and studies of localized transport. These physics applications and the study of the basic physics of ECH and ECCD were enabled by the advent of the gyrotron in the 1980s and of the diamond window for megawatt gyrotrons in the 1990s. The experimental work stimulated a broad base of theory based on first principles which is encapsulated in linear ray tracing codes and fully relativistic quasilinear Fokker-Planck codes. Recent experiments use measurements of the local poloidal magnetic field through the motional Stark effect to determine the magnitude and profile of the locally driven current. The subtle balance between wave-induced diffusion and Coulomb relaxation in velocity space provides an understanding of the effects of trapping of current-carrying electrons in the magnetic well, an effect which can be used to advantage. Strong quasilinear effects and radial transport of electrons which may broaden the driven current profile have also been observed under some conditions and appear to be consistent with theory, but in large devices these are usually insignificant. Additional advantages of ECH compared with other rf heating methods are that the antenna can be far removed from the plasma and the power density can be very high. The agreement of theory and experiment, the broad base of established applications, and the technical advantages of ECH support the application of ECH in next-step tokamaks and stellarators.

  14. A fast multichannel Martin-Puplett interferometer for electron cyclotron emission measurements on JET

    SciTech Connect

    Simonetto, A.; Sozzi, C.; Garavaglia, S.; Nowak, S.; Fessey, J. A.; Collaboration: JET-EFDA Contributors

    2011-11-15

    A Martin Puplett interferometer for electron cyclotron emission (ECE) measurements from JET tokamak plasmas was extended to multichannel operation for simultaneous radial and oblique ECE measurements. This paper describes the new optics and the instrument's performance.

  15. Electron cyclotron resonance deposition of diamond-like films

    NASA Technical Reports Server (NTRS)

    Shing, Y. H.; Pool, F. S.

    1990-01-01

    Electron cyclotron resonance (ECR) microwave plasma CVD has been developed at low pressures (0.0001 - 0.01 torr) and at ambient and high substrate temperatures (up to 750 C), to achieve large-area (greater than 4 in. diameter) depositions of diamondlike amorphous carbon (a - C:H) films. The application of a RF bias to the substrate stage, which induces a negative self-bias voltage, is found to play a critical role in determining carbon bonding configurations and in modifying the film morphology. There are two distinct types of ECR-deposited diamondlike films. One type of diamondlike film exhibits a Raman spectrum consisting of broad and overlapping, graphitic D (1360/cm, line width = 280/cm) and G (1590/cm, line width 140/cm) lines, and the other type has a broad Raman peak centered at appoximately 1500/cm. Examination of plasma species by optical emission spectroscopy shows no correlation between the CH-asterisk emission intensity and the deposition rate of diamondklike films.

  16. Electron cyclotron plasma startup in the GDT experiment

    NASA Astrophysics Data System (ADS)

    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.

  17. Saturation of cyclotron maser instability driven by an electron loss-cone distribution

    NASA Technical Reports Server (NTRS)

    Kuo, S. P.; Lee, M. C.

    1986-01-01

    The resonance diffusion of electrons in velocity space caused by the excited EM wave fields is considered to be the dominant saturation process of cyclotron maser instability that is driven by an electron loss-cone distribution. An upper bound of the saturation level is derived analytically. Since the resulting saturation level is low, the resonance diffusion is indeed responsible for the saturation of the cyclotron maser instability.

  18. Extension of high T{sub e} regime with upgraded electron cyclotron resonance heating system in the Large Helical Device

    SciTech Connect

    Takahashi, H. Shimozuma, T.; Kubo, S.; Yoshimura, Y.; Igami, H.; Ito, S.; Kobayashi, S.; Mizuno, Y.; Okada, K.; Mutoh, T.; Nagaoka, K.; Osakabe, M.; Yamada, I.; Nakano, H.; Yokoyama, M.; Ido, T.; Shimizu, A.; Seki, R.; Ida, K.; Yoshinuma, M.; and others

    2014-06-15

    Enhancement of the output power per gyrotron has been planned in the Large Helical Device (LHD). Three 77-GHz gyrotrons with an output power of more than 1 MW have been operated. In addition, a high power gyrotron with the frequency of 154 GHz (1 MW/5 s, 0.5 MW/CW) was newly installed in 2012, and the total injection power of Electron cyclotron resonance heating (ECRH) reached 4.6 MW. The operational regime of ECRH plasma on the LHD has been extended due to the upgraded ECRH system such as the central electron temperature of 13.5 keV with the line-averaged electron density n{sub e-fir} = 1 × 10{sup 19} m{sup −3}. The electron thermal confinement clearly improved inside the electron internal transport barrier, and the electron thermal diffusivity reached neoclassical level. The global energy confinement time increased with increase of n{sub e-fir}. The plasma stored energy of 530 kJ with n{sub e-fir} = 3.2 × 10{sup 19} m{sup −3}, which is 1.7 times larger than the previous record in the ECRH plasma in the LHD, has been successfully achieved.

  19. Nb{sub 3}Sn superconducting magnets for electron cyclotron resonance ion sources

    SciTech Connect

    Ferracin, P.; Caspi, S.; Felice, H.; Leitner, D.; Lyneis, C. M.; Prestemon, S.; Sabbi, G. L.; Todd, D. S.

    2010-02-15

    Electron cyclotron resonance (ECR) ion sources are an essential component of heavy-ion accelerators. Over the past few decades advances in magnet technology and an improved understanding of the ECR ion source plasma physics have led to remarkable performance improvements of ECR ion sources. Currently third generation high field superconducting ECR ion sources operating at frequencies around 28 GHz are the state of the art ion injectors and several devices are either under commissioning or under design around the world. At the same time, the demand for increased intensities of highly charged heavy ions continues to grow, which makes the development of even higher performance ECR ion sources a necessity. To extend ECR ion sources to frequencies well above 28 GHz, new magnet technology will be needed in order to operate at higher field and force levels. The superconducting magnet program at LBNL has been developing high field superconducting magnets for particle accelerators based on Nb{sub 3}Sn superconducting technology for several years. At the moment, Nb{sub 3}Sn is the only practical conductor capable of operating at the 15 T field level in the relevant configurations. Recent design studies have been focused on the possibility of using Nb{sub 3}Sn in the next generation of ECR ion sources. In the past, LBNL has worked on the VENUS ECR, a 28 GHz source with solenoids and a sextupole made with NbTi operating at fields of 6-7 T. VENUS has now been operating since 2004. We present in this paper the design of a Nb{sub 3}Sn ECR ion source optimized to operate at an rf frequency of 56 GHz with conductor peak fields of 13-15 T. Because of the brittleness and strain sensitivity of Nb{sub 3}Sn, particular care is required in the design of the magnet support structure, which must be capable of providing support to the coils without overstressing the conductor. In this paper, we present the main features of the support structure, featuring an external aluminum shell

  20. Nb3Sn superconducting magnets for electron cyclotron resonance ion sources

    SciTech Connect

    Ferracin, P.; Caspi, S.; Felice, H.; Leitner, D.; Lyneis, C. M.; Prestemon, S.; Sabbi, G. L.; Todd, D. S.

    2009-05-04

    Electron cyclotron resonance (ECR) ion sources are an essential component of heavy-ion accelerators. Over the past few decades advances in magnet technology and an improved understanding of the ECR ion source plasma physics have led to remarkable performance improvements of ECR ion sources. Currently third generation high field superconducting ECR ion sources operating at frequencies around 28 GHz are the state of the art ion injectors and several devices are either under commissioning or under design around the world. At the same time, the demand for increased intensities of highly charged heavy ions continues to grow, which makes the development of even higher performance ECR ion sources a necessity. To extend ECR ion sources to frequencies well above 28 GHz, new magnet technology will be needed in order to operate at higher field and force levels. The superconducting magnet program at LBNL has been developing high field superconducting magnets for particle accelerators based on Nb{sub 3}Sn superconducting technology for several years. At the moment, Nb{sub 3}Sn is the only practical conductor capable of operating at the 15 T field level in the relevant configurations. Recent design studies have been focused on the possibility of using Nb{sub 3}Sn in the next generation of ECR ion sources. In the past, LBNL has worked on the VENUS ECR, a 28 GHz source with solenoids and a sextupole made with NbTi operating at fields of 6-7 T. VENUS has now been operating since 2004. We present in this paper the design of a Nb{sub 3}Sn ECR ion source optimized to operate at an rf frequency of 56 GHz with conductor peak fields of 13-15 T. Because of the brittleness and strain sensitivity of Nb{sub 3}Sn- , particular care is required in the design of the magnet support structure, which must be capable of providing support to the coils without overstressing the conductor. In this paper, we present the main features of the support structure, featuring an external aluminum shell

  1. Nb3Sn superconducting magnets for electron cyclotron resonance ion sources.

    PubMed

    Ferracin, P; Caspi, S; Felice, H; Leitner, D; Lyneis, C M; Prestemon, S; Sabbi, G L; Todd, D S

    2010-02-01

    Electron cyclotron resonance (ECR) ion sources are an essential component of heavy-ion accelerators. Over the past few decades advances in magnet technology and an improved understanding of the ECR ion source plasma physics have led to remarkable performance improvements of ECR ion sources. Currently third generation high field superconducting ECR ion sources operating at frequencies around 28 GHz are the state of the art ion injectors and several devices are either under commissioning or under design around the world. At the same time, the demand for increased intensities of highly charged heavy ions continues to grow, which makes the development of even higher performance ECR ion sources a necessity. To extend ECR ion sources to frequencies well above 28 GHz, new magnet technology will be needed in order to operate at higher field and force levels. The superconducting magnet program at LBNL has been developing high field superconducting magnets for particle accelerators based on Nb(3)Sn superconducting technology for several years. At the moment, Nb(3)Sn is the only practical conductor capable of operating at the 15 T field level in the relevant configurations. Recent design studies have been focused on the possibility of using Nb(3)Sn in the next generation of ECR ion sources. In the past, LBNL has worked on the VENUS ECR, a 28 GHz source with solenoids and a sextupole made with NbTi operating at fields of 6-7 T. VENUS has now been operating since 2004. We present in this paper the design of a Nb(3)Sn ECR ion source optimized to operate at an rf frequency of 56 GHz with conductor peak fields of 13-15 T. Because of the brittleness and strain sensitivity of Nb(3)Sn, particular care is required in the design of the magnet support structure, which must be capable of providing support to the coils without overstressing the conductor. In this paper, we present the main features of the support structure, featuring an external aluminum shell pretensioned with water

  2. The targeted heating and current drive applications for the ITER electron cyclotron system

    SciTech Connect

    Henderson, M.; Darbos, C.; Gandini, F.; Gassmann, T.; Loarte, A.; Omori, T.; Purohit, D.; Saibene, G.; Gagliardi, M.; Farina, D.; Figini, L.; Hanson, G.; Poli, E.; Takahashi, K.

    2015-02-15

    A 24 MW Electron Cyclotron (EC) system operating at 170 GHz and 3600 s pulse length is to be installed on ITER. The EC plant shall deliver 20 MW of this power to the plasma for Heating and Current Drive (H and CD) applications. The EC system is designed for plasma initiation, central heating, current drive, current profile tailoring, and Magneto-hydrodynamic control (in particular, sawteeth and Neo-classical Tearing Mode) in the flat-top phase of the plasma. A preliminary design review was performed in 2012, which identified a need for extended application of the EC system to the plasma ramp-up, flattop, and ramp down phases of ITER plasma pulse. The various functionalities are prioritized based on those applications, which can be uniquely addressed with the EC system in contrast to other H and CD systems. An initial attempt has been developed at prioritizing the allocated H and CD applications for the three scenarios envisioned: ELMy H-mode (15 MA), Hybrid (∼12 MA), and Advanced (∼9 MA) scenarios. This leads to the finalization of the design requirements for the EC sub-systems.

  3. Modification of argon impurity transport by electron cyclotron heating in KSTAR H-mode plasmas

    NASA Astrophysics Data System (ADS)

    Hong, Joohwan; Henderson, S. S.; Kim, Kimin; Seon, C. R.; Song, Inwoo; Lee, H. Y.; Jang, Juhyeok; Park, Jae Sun; Lee, S. G.; Lee, J. H.; Lee, Seung Hun; Hong, Suk-Ho; Choe, Wonho

    2017-03-01

    Experiments with a small amount of Ar gas injection as a trace impurity were conducted in the Korea Superconducting Tokamak Advanced Research (KSTAR) H-mode plasma ({{B}\\text{T}}   =  2.8 T, {{I}\\text{P}}   =  0.6 MA, and {{P}\\text{NBI}}   =  4.0 MW). 170 GHz electron cyclotron resonance heating (ECH) at 600 and 800 kW was focused along the mid-plane with a fixed major radial position of R   =  1.66 m. The emissivity of the Ar16+ (3.949 {\\mathring{\\text{A}}} ) and Ar15+ (353.860 {\\mathring{\\text{A}}} ) spectral lines were measured by x-ray imaging crystal spectroscopy (XICS) and a vacuum UV (VUV) spectrometer, respectively. ECH reduces the peak Ar15+ emission and increases the Ar16+ emission, an effect largest with 800 kW. The ADAS-SANCO impurity transport code was used to evaluate the Ar transport coefficients. It was found that the inward convective velocity found in the plasma core without ECH was decreased with ECH, while diffusion remained approximately constant resulting in a less-peaked Ar density profile. Theoretical results from the NEO code suggest that neoclassical transport is not responsible for the change in transport, while the microstability analysis using GKW predicts a dominant ITG mode during both ECH and non-ECH plasmas.

  4. Initial high-power testing of the ATF (Advanced Toroidal Facility) ECH (electron cyclotron heating) system

    SciTech Connect

    White, T.L.; Bigelow, T.S.; Kimrey, H.D. Jr.

    1987-01-01

    The Advanced Toroidal Facility (ATF) is a moderate aspect ratio torsatron that will utilize 53.2 GHz 200 kW Electron Cyclotron Heating (ECH) to produce nearly current-free target plasmas suitable for subsequent heating by strong neutral beam injection. The initial configuration of the ECH system from the gyrotron to ATF consists of an optical arc detector, three bellows, a waveguide mode analyzer, two TiO/sub 2/ mode absorbers, two 90/sup 0/ miter bends, two waveguide pumpouts, an insulating break, a gate valve, and miscellaneous straight waveguide sections feeding a launcher radiating in the TE/sub 02/ mode. Later, a focusing Vlasov launcher will be added to beam the ECH power to the saddle point in ATF magnetic geometry for optimum power deposition. The ECH system has several unique features; namely, the entire ECH system is evacuated, the ECH system is broadband, forward power is monitored by a newly developed waveguide mode analyzer, phase correcting miter bends will be employed, and the ECH system will be capable of operating short pulse to cw. Initial high-power tests show that the overall system efficiency is 87%. The waveguide mode analyzer shows that the gyrotron mode output consists of 13% TE/sub 01/, 82.6% TE/sub 02/, 2.5% TE/sub 03/, and 1.9% TE/sub 04/. 4 refs.

  5. An electron cyclotron resonance ion source based low energy ion beam platform

    SciTech Connect

    Sun, L. T.; Shang, Y.; Ma, B. H.; Zhang, X. Z.; Feng, Y. C.; Li, X. X.; Wang, H.; Guo, X. H.; Song, M. T.; Zhao, H. Y.; Zhang, Z. M.; Zhao, H. W.; Xie, D. Z.

    2008-02-15

    To satisfy the requirements of surface and atomic physics study in the field of low energy multiple charge state ion incident experiments, a low energy (10 eV/q-20 keV/q) ion beam platform is under design at IMP. A simple test bench has been set up to test the ion beam deceleration systems. Considering virtues such as structure simplicity, easy handling, compactness, cost saving, etc., an all-permanent magnet ECRIS LAPECR1 [Lanzhou all-permanent magnet electron cyclotron resonance (ECR) ion source No. 1] working at 14.5 GHz has been adopted to produce intense medium and low charge state ion beams. LAPECR1 source has already been ignited. Some intense low charge state ion beams have been produced on it, but the first test also reveals that many problems are existing on the ion beam transmission line. The ion beam transmission mismatches result in the depressed performance of LAPECR1, which will be discussed in this paper. To obtain ultralow energy ion beam, after being analyzed by a double-focusing analyzer magnet, the selected ion beam will be further decelerated by two afocal deceleration lens systems, which is still under design. This design has taken into consideration both ions slowing down and also ion beam focusing. In this paper, the conceptual design of deceleration system will be discussed.

  6. Measurement of electron temperature fluctuations using a tunable correlation electron cyclotron emission system on Alcator C-Mod

    SciTech Connect

    Howard, N. T.; Sung, C.; White, A. E.

    2014-11-15

    A tunable correlation electron cyclotron (CECE) system was recently installed on the Alcator C-Mod tokamak to provide local, quantitative measurement of electron temperature fluctuations in the tokamak core. This system represents a significant upgrade from the original CECE system, expanding the measurement capabilities from 4 to 8 total channels, including 2 remotely tunable YIG filters (6–18 GHz; 200 MHz bandwidth). Additional upgrades were made to the optical system to provide enhanced poloidal resolution and allow for measurement of turbulent fluctuations below k{sub θ}ρ{sub s} < 0.3. These expanded capabilities allow for single shot measurement of partial temperature fluctuation profiles in the region ρ = 0.7 − 0.9 (square root of normalized toroidal flux) in a wide variety of plasma conditions. These measurements are currently being used to provide stringent tests of the gyrokinetic model in ongoing model validation efforts. Details of the hardware upgrades, turbulent fluctuation measurements, and ongoing comparisons with simulations are presented.

  7. Some aspects of electron dynamics in electron cyclotron resonance ion sources

    NASA Astrophysics Data System (ADS)

    Mironov, V.; Bogomolov, S.; Bondarchenko, A.; Efremov, A.; Loginov, V.

    2017-07-01

    Electron dynamics in an electron cyclotron resonance ion source is numerically simulated by using a particle-in-cell code combined with simulations of the ion dynamics. Mean electron energies are found to be around 70 keV, close to values that are derived from spectra of x-ray emission out of the source. The electron lifetime is defined by losses of low-energy electrons created in ionizing collisions; the losses are regulated by electron heating rate, which depends on the magnitude of the microwave electric field. Changes in the ion confinement with variations in the microwave electric field and gas flow are simulated. The influence of electron dynamics on the afterglow and two-frequency heating effects is discussed.

  8. Design of a compact, permanent magnet electron cyclotron resonance ion source for proton and H2(+) beam production.

    PubMed

    Jia, Xianlu; Zhang, Tianjue; Luo, Shan; Wang, Chuan; Zheng, Xia; Yin, Zhiguo; Zhong, Junqing; Wu, Longcheng; Qin, Jiuchang

    2010-02-01

    A 2.45 GHz microwave ion source was developed at China Institute of Atomic Energy (CIAE) for proton beam production of over 60 mA [B.-Q. Cui, Y.-W. Bao, L.-Q. Li, W.-S. Jiang, and R.-W. Wang, Proceedings of the High Current Electron Cyclotron Resonance (ECR) Ion Source for Proton Accelerator, APAC-2001, 2001 (unpublished)]. For various proton beam applications, another 2.45 GHz microwave ion source with a compact structure is designed and will be built at CIAE as well for high current proton beam production. It is also considered to be used for the test of H(2)(+) beam, which could be injected into the central region model cyclotron at CIAE, and accelerated to 5 MeV before extraction by stripping. The required ECR magnetic field is supplied by all the permanent magnets rather than electrical solenoids and six poles. The magnetic field distribution provided by this permanent magnets configuration is a large and uniformly volume of ECR zone, with central magnetic field of a magnitude of approximately 875 Gs [T. Taylor and J. S. C. Wills, Nucl. Instrum. Methods Phys. Res. A 309, 37 (1991)]. The field adjustment at the extraction end can be implemented by moving the position of the magnet blocks. The results of plasma, coupling with 2.45 GHz microwave in the ECR zone inside the ion source are simulated by particle-in-cell code to optimize the density by adjusting the magnetic field distribution. The design configuration of the ion source will be summarized in the paper.

  9. Orbital Angular Momentum (OAM) of Rotating Modes Driven by Electrons in Electron Cyclotron Masers.

    PubMed

    Sawant, Ashwini; Choe, Mun Seok; Thumm, Manfred; Choi, EunMi

    2017-06-13

    The well-defined orbital angular momentum (OAM) of rotating cavity modes operating near the cutoff frequency excited by gyrating electrons in a high-power electron cyclotron maser (ECM)-a gyrotron-has been derived by photonic and electromagnetic wave approaches. A mode generator was built with a high-precision 3D printing technique to mimic the rotating gyrotron modes for precise low-power measurements and shows clear natural production of higher-order OAM modes. Cold-test measurements of higher-order OAM mode generation promise the realization towards wireless long-range communications using high-power ECMs.

  10. Electron cyclotron emission at the fundamental harmonic in GDT magnetic mirror

    NASA Astrophysics Data System (ADS)

    Shalashov, A. G.; Solomakhin, A. L.; Gospodchikov, E. D.; Lubyako, L. V.; Yakovlev, D. V.; Bagryansky, P. A.

    2017-08-01

    New electron cyclotron emission (ECE) diagnostics has been installed to facilitate the successful experiment of electron cyclotron plasma heating (ECRH) in a large open magnetic trap GDT at Budker Institute. The particularities of ECE in the vicinity of the ECRH frequency were studied experimentally for a broad range of discharge scenarios. The measured thermal emission has partly validated the existing physical conceptions about microwave plasma heating in the machine. Besides the expected emission of thermal electrons, a clearly resolved non-thermal ECE was observed which unambiguously confirmed the presence of suprathermal electrons driven by high-power microwave heating.

  11. Annular-beam, 17 GHz free-electron maser experiment

    SciTech Connect

    Earley, L.M.; Carlsten, B.E.; Fazio, M.V.

    1997-06-01

    Experiments have been conducted on a 15-17 GHz free electron maser (FEM) for producing a 500 MW output pulse with a phase stability appropriate for linear collider applications. The electron beam source was a 1 {mu}s, 800 kV, 5 kA, 6-cm-dia annular electron beam machine called BANSHEE. The beam interacted with the TM{sub 02} and TM{sub 03} mode Raman FEM amplifier in a corrugated cylindrical waveguide where the beam runs close to the interaction device walls to reduce the power density in the fields. This greatly reduced the kinetic energy loss caused by the beam potential depression associated with the space charge which was a significant advantage in comparison with conventional solid beam microwave tubes at the same beam current. The experiment was operated in a single shot mode with a large number of diagnostics to measure power, frequency and energy.

  12. Development and studies on a compact electron cyclotron resonance plasma source

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    It is well known that electron cyclotron resonance (ECR) produced plasmas are efficient, high-density plasma sources and have many industrial applications. The concept of a portable compact ECR plasma source (CEPS) would thus become important from an application point of view. This paper gives details of such a CEPS that is both portable and easily mountable on a chamber of any size. It uses a fully integrated microwave line operating at 2.45 GHz, up to 800 W, cw. The required magnetic field is produced by a set of suitably designed NdFeB ring magnets; the device has an overall length of  ≈60 cm and weighs  ≈14 kg including the permanent magnets. The CEPS was attached to a small experimental chamber to judge its efficacy for plasma production. In the pressure range of 0.5-10 mTorr and microwave power of  ≈400-500 W the experiments indicate that the CEPS is capable of producing high-density plasma (≈9  ×  1011-1012 cm-3) with bulk electron temperature in the range  ≈2-3 eV. In addition, a warm electron population with density and temperature in the range ≈7  ×  108-109 cm-3 and  ≈45-80 eV, respectively has been detected. This warm population plays an important role at high pressures in maintaining the high-density plasma, when plasma flow from the CEPS into the test chamber is strongly affected.

  13. Electron Cyclotron Heating system status and upgrades on DIII-D

    DOE PAGES

    Cengher, Mirela; Lohr, John; Gorelov, Yuri; ...

    2016-06-02

    The Electron Cyclotron Heating (ECH) system on the DIII-D tokamak consists of six 110 GHz gyrotrons with corrugated coaxial 31.75 mm waveguide transmission lines and steerable launching mirrors. The system has been gradually updated, leading to increased experimental flexibility and a high system reliability of 91% in the past year. Operationally, the gyrotrons can generate up to a total of 4.8 MW of rf power for pulses up to 5 seconds in length. The maximum ECH energy injected into the DIII-D has been 16.6 MJ. The HE11 mode content is over 85% for all the lines, and the transmission coefficientmore » is better than -1.1 dB for all the transmission lines, close to the theoretical value. A new depressed collector gyrotron was recently installed and was injecting up to 640 kW of power into the plasma during 2014-2015 tokamak operations. Three dual waveguide launchers, which can steer the RF beams ±20 degrees poloidally and toroidally, were used for real-time neoclassical tearing mode control and suppression. The launchers now have increased poloidal scanning speed and beam positioning accuracy of ~±2 mm at the plasma center. A new method of in-situ calibration of the mirror angle was used in conjunction with the upgrading of the encoders and motors for the launchers. Two more gyrotrons are expected to be installed and operational in 2015-2016. The first is a repaired 110 GHz, 1 MW gyrotron that had a gun failure after more than 11 years of operation at DIII-D. The second is a newly designed depressed collector tube in the 1.5 MW class, operating at 117.5 GHz, manufactured by Communications and Power Industries (CPI). It operates in the TE20,9 mode and has achieved 1.8 MW for short pulses during factory testing. Furthermore, this gyrotron is undergoing rework to address a high voltage standoff problem.« less

  14. Electron Cyclotron Heating system status and upgrades on DIII-D

    SciTech Connect

    Cengher, Mirela; Lohr, John; Gorelov, Yuri; Prater, Ron; Torrezan, Antonio; Anderson, James; Ponce, Dan; Chen, Xi; Moeller, Charles; Ellis, Robert

    2016-06-02

    The Electron Cyclotron Heating (ECH) system on the DIII-D tokamak consists of six 110 GHz gyrotrons with corrugated coaxial 31.75 mm waveguide transmission lines and steerable launching mirrors. The system has been gradually updated, leading to increased experimental flexibility and a high system reliability of 91% in the past year. Operationally, the gyrotrons can generate up to a total of 4.8 MW of rf power for pulses up to 5 seconds in length. The maximum ECH energy injected into the DIII-D has been 16.6 MJ. The HE11 mode content is over 85% for all the lines, and the transmission coefficient is better than -1.1 dB for all the transmission lines, close to the theoretical value. A new depressed collector gyrotron was recently installed and was injecting up to 640 kW of power into the plasma during 2014-2015 tokamak operations. Three dual waveguide launchers, which can steer the RF beams ±20 degrees poloidally and toroidally, were used for real-time neoclassical tearing mode control and suppression. The launchers now have increased poloidal scanning speed and beam positioning accuracy of ~±2 mm at the plasma center. A new method of in-situ calibration of the mirror angle was used in conjunction with the upgrading of the encoders and motors for the launchers. Two more gyrotrons are expected to be installed and operational in 2015-2016. The first is a repaired 110 GHz, 1 MW gyrotron that had a gun failure after more than 11 years of operation at DIII-D. The second is a newly designed depressed collector tube in the 1.5 MW class, operating at 117.5 GHz, manufactured by Communications and Power Industries (CPI). It operates in the TE20,9 mode and has achieved 1.8 MW for short pulses during factory testing. Furthermore, this gyrotron is undergoing rework to address a high voltage standoff problem.

  15. Development of a pepper-pot device to determine the emittance of an ion beam generated by electron cyclotron resonance ion sources

    SciTech Connect

    Strohmeier, M.; Benitez, J. Y.; Leitner, D.; Lyneis, C. M.; Todd, D. S.; Bantel, M.

    2010-02-15

    This paper describes the recent development and commissioning of a pepper-pot emittance meter at the Lawrence Berkeley National Laboratory (LBNL). It is based on a potassium bromide (KBr) scintillator screen in combination with a charged coupled device camera. Pepper-pot scanners record the full four-dimensional transverse phase space emittances which are particularly interesting for electron cyclotron resonance ion sources. The strengths and limitations of evaluating emittances using optical pepper-pot scanners are described and systematic errors induced by the optical data acquisition system will be presented. Light yield tests of KBr exposed to different ion species and first emittance measurement data using ion beams extracted from the 6.4 GHz LBNL electron cyclotron resonance ion source are presented and discussed.

  16. Characteristics of heat flux and electromagnetic electron-cyclotron instabilities driven by solar wind electrons

    NASA Astrophysics Data System (ADS)

    Saeed, Sundas; Sarfraz, M.; Yoon, P. H.; Qureshi, M. N. S.

    2017-01-01

    In-situ observations reveal the existence of electron velocity distribution function in the solar wind, where the net distribution can be modeled by a combination of core, halo and strahl. These components often possess a relative drift and with respective temperature anisotropies. The relative drift between the core and halo components leads to heat flux (HF) instability, while temperature anisotropies drive electromagnetic electron-cyclotron (EMEC) instability. These instabilities have been separately studied in the literature, but for the first time, the present study combines both unstable modes in the presence of two free energy sources, namely, excessive parallel pressure and excessive perpendicular temperature. Heat flux instability (which is a left-hand circularly polarized mode) is effectively similar to electron firehose instability, except that the free energy is provided by net relative drift among two component electrons in the background of protons. The heat flux instability is discussed here along with (the right-hand polarized) EMEC instability driven by temperature anisotropy. The unstable heat flux mode is conventionally termed the "whistler" heat flux instability, but it is actually polarized in the opposite sense to the whistler wave. Electromagnetic electron-cyclotron mode, on the other hand, reduces to the proper whistler wave in the absence of free energy source. The present combined analysis clarifies the polarization characteristics of these two modes in an unambiguous manner.

  17. The effects of gas mixing and plasma electrode position on the emittance of an electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Suominen, P.; Tarvainen, O.; Koivisto, H.

    2004-05-01

    Gas mixing is a commonly used method to improve the intensities and the charge state distribution of ion beams extracted from an electron cyclotron resonance ion source (ECRIS). At the same time, the emittance of the ion beam should be as small as possible. In this work we have studied the effect of the gas mixing method on the ion beam quality by measuring the emittance and brightness of different ion beams using helium, oxygen, and argon with several gas feeding ratios. All measurements were performed with the JYFL 6.4 GHz ECRIS. At the second stage of the experiments the emittance and the ion beam brightness were studied as a function of the plasma electrode position. The extraction system constructed for this experiment can be moved online.

  18. Studies of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN

    SciTech Connect

    Toivanen, V. Küchler, D.

    2016-02-15

    The 14.5 GHz GTS-LHC Electron Cyclotron Resonance Ion Source (ECRIS) provides multiply charged heavy ion beams for the CERN experimental program. The GTS-LHC beam formation has been studied extensively with lead, argon, and xenon beams with varied beam extraction conditions using the ion optical code IBSimu. The simulation model predicts self-consistently the formation of triangular and hollow beam structures which are often associated with ECRIS ion beams, as well as beam loss patterns which match the observed beam induced markings in the extraction region. These studies provide a better understanding of the properties of the extracted beams and a way to diagnose the extraction system performance and limitations, which is otherwise challenging due to the lack of direct diagnostics in this region and the limited availability of the ion source for development work.

  19. Studies of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN.

    PubMed

    Toivanen, V; Küchler, D

    2016-02-01

    The 14.5 GHz GTS-LHC Electron Cyclotron Resonance Ion Source (ECRIS) provides multiply charged heavy ion beams for the CERN experimental program. The GTS-LHC beam formation has been studied extensively with lead, argon, and xenon beams with varied beam extraction conditions using the ion optical code IBSimu. The simulation model predicts self-consistently the formation of triangular and hollow beam structures which are often associated with ECRIS ion beams, as well as beam loss patterns which match the observed beam induced markings in the extraction region. These studies provide a better understanding of the properties of the extracted beams and a way to diagnose the extraction system performance and limitations, which is otherwise challenging due to the lack of direct diagnostics in this region and the limited availability of the ion source for development work.

  20. Improved beta (local beta >1) and density in electron cyclotron resonance heating on the RT-1 magnetosphere plasma

    NASA Astrophysics Data System (ADS)

    Nishiura, M.; Yoshida, Z.; Saitoh, H.; Yano, Y.; Kawazura, Y.; Nogami, T.; Yamasaki, M.; Mushiake, T.; Kashyap, A.

    2015-05-01

    This study reports the recent progress in improved plasma parameters of the RT-1 device. Increased input power and the optimized polarization of electron cyclotron resonance heating (ECRH) with an 8.2 GHz klystron produce a significant increase in electron beta, which is evaluated by an equilibrium analysis of the Grad-Shafranov equation. The peak value of the local electron beta βe is found to exceed 1. In the high-beta and high-density regime, the density limit is observed for H, D and He plasmas. The line-averaged density is close to the cutoff density for 8.2 GHz ECRH. When the filling gas pressure is increased, the density limit still exists even in the low-beta region. This result indicates that the density limit is caused by the cutoff density rather than the beta limit. From the analysis of interferometer data, we found that inward diffusion causes a peaked density profile beyond the cutoff density.

  1. Electrostatic ion cyclotron, beam-plasma, and lower hybrid waves excited by an electron beam

    NASA Technical Reports Server (NTRS)

    Singh, N.; Conrad, J. R.; Schunk, R. W.

    1985-01-01

    It is pointed out that electrostatic ion cyclotron (EIC) waves have been extensively investigated in connection with both space and laboratory plasmas. The present investigation has the objective to study the excitation of low-frequency waves in a multiion plasma by electron beams. The frequencies considered range from below the lowest gyrofrequency of the heaviest ion to about the lower hybrid frequency. It is shown that electron-beam instabilities can produce peaks in the growth rate below the cyclotron frequency of each ion species if nonzero perpendicular wave number effects are included in the ion dynamics. The dispersion relations for neutralized ion Bernstein (NIB) and pure ion Bernstein (PIB) waves are considered along with an instability analysis for a cold plasma and warm electron beam, the electron beam-plasma mode, banded ion cyclotron (EIC) waves with small perpendicular wavelengths, and the growth lengths of the waves.

  2. Electrostatic ion cyclotron, beam-plasma, and lower hybrid waves excited by an electron beam

    SciTech Connect

    Singh, N.; Conrad, J.R.; Schunk, R.W.

    1985-06-01

    It is pointed out that electrostatic ion cyclotron (EIC) waves have been extensively investigated in connection with both space and laboratory plasmas. The present investigation has the objective to study the excitation of low-frequency waves in a multiion plasma by electron beams. The frequencies considered range from below the lowest gyrofrequency of the heaviest ion to about the lower hybrid frequency. It is shown that electron-beam instabilities can produce peaks in the growth rate below the cyclotron frequency of each ion species if nonzero perpendicular wave number effects are included in the ion dynamics. The dispersion relations for neutralized ion Bernstein (NIB) and pure ion Bernstein (PIB) waves are considered along with an instability analysis for a cold plasma and warm electron beam, the electron beam-plasma mode, banded ion cyclotron (EIC) waves with small perpendicular wavelengths, and the growth lengths of the waves. 39 references.

  3. Electrostatic ion cyclotron, beam-plasma, and lower hybrid waves excited by an electron beam

    NASA Technical Reports Server (NTRS)

    Singh, N.; Conrad, J. R.; Schunk, R. W.

    1985-01-01

    It is pointed out that electrostatic ion cyclotron (EIC) waves have been extensively investigated in connection with both space and laboratory plasmas. The present investigation has the objective to study the excitation of low-frequency waves in a multiion plasma by electron beams. The frequencies considered range from below the lowest gyrofrequency of the heaviest ion to about the lower hybrid frequency. It is shown that electron-beam instabilities can produce peaks in the growth rate below the cyclotron frequency of each ion species if nonzero perpendicular wave number effects are included in the ion dynamics. The dispersion relations for neutralized ion Bernstein (NIB) and pure ion Bernstein (PIB) waves are considered along with an instability analysis for a cold plasma and warm electron beam, the electron beam-plasma mode, banded ion cyclotron (EIC) waves with small perpendicular wavelengths, and the growth lengths of the waves.

  4. Temperature gradient scale length measurement: A high accuracy application of electron cyclotron emission without calibration

    NASA Astrophysics Data System (ADS)

    Houshmandyar, S.; Yang, Z. J.; Phillips, P. E.; Rowan, W. L.; Hubbard, A. E.; Rice, J. E.; Hughes, J. W.; Wolfe, S. M.

    2016-11-01

    Calibration is a crucial procedure in electron temperature (Te) inference from a typical electron cyclotron emission (ECE) diagnostic on tokamaks. Although the calibration provides an important multiplying factor for an individual ECE channel, the parameter ΔTe/Te is independent of any calibration. Since an ECE channel measures the cyclotron emission for a particular flux surface, a non-perturbing change in toroidal magnetic field changes the view of that channel. Hence the calibration-free parameter is a measure of Te gradient. BT-jog technique is presented here which employs the parameter and the raw ECE signals for direct measurement of electron temperature gradient scale length.

  5. Plasma ion dynamics and beam formation in electron cyclotron resonance ion sources

    SciTech Connect

    Mascali, D.; Neri, L.; Miracoli, R.; Gammino, S.; Celona, L.; Ciavola, G.; Gambino, N.; Chikin, S.

    2010-02-15

    In electron cyclotron resonance ion sources it has been demonstrated that plasma heating may be improved by means of different microwave to plasma coupling mechanisms, including the ''frequency tuning'' and the ''two frequency heating''. These techniques affect evidently the electron dynamics, but the relationship with the ion dynamics has not been investigated in details up to now. Here we will try to outline these relations: through the study of ion dynamics we may try to understand how to optimize the electron cyclotron resonance ion sources brightness. A simple model of the ion confinement and beam formation will be presented, based on particle-in-cell and single particle simulations.

  6. High intensity electron cyclotron resonance proton source for low energy high intensity proton accelerator.

    PubMed

    Roychowdhury, P; Chakravarthy, D P

    2009-12-01

    Electron cyclotron resonance (ECR) proton source at 50 keV, 50 mA has been designed, developed, and commissioned for the low energy high intensity proton accelerator (LEHIPA). Plasma characterization of this source has been performed. ECR plasma was generated with 400-1100 W of microwave power at 2.45 GHz, with hydrogen as working gas. Microwave was fed in the plasma chamber through quartz window. Plasma density and temperature was studied under various operating conditions, such as microwave power and gas pressure. Langmuir probe was used for plasma characterization using current voltage variation. The typical hydrogen plasma density and electron temperature measured were 7x10(11) cm(-3) and 6 eV, respectively. The total ion beam current of 42 mA was extracted, with three-electrode extraction geometry, at 40 keV of beam energy. The extracted ion current was studied as a function of microwave power and gas pressure. Depending on source pressure and discharge power, more than 30% total gas efficiency was achieved. The optimization of the source is under progress to meet the requirement of long time operation. The source will be used as an injector for continuous wave radio frequency quadrupole, a part of 20 MeV LEHIPA. The required rms normalized emittance of this source is less than 0.2 pi mm mrad. The simulated value of normalized emittance is well within this limit and will be measured shortly. This paper presents the study of plasma parameters, first beam results, and the status of ECR proton source.

  7. High intensity electron cyclotron resonance proton source for low energy high intensity proton accelerator

    SciTech Connect

    Roychowdhury, P.; Chakravarthy, D. P.

    2009-12-15

    Electron cyclotron resonance (ECR) proton source at 50 keV, 50 mA has been designed, developed, and commissioned for the low energy high intensity proton accelerator (LEHIPA). Plasma characterization of this source has been performed. ECR plasma was generated with 400-1100 W of microwave power at 2.45 GHz, with hydrogen as working gas. Microwave was fed in the plasma chamber through quartz window. Plasma density and temperature was studied under various operating conditions, such as microwave power and gas pressure. Langmuir probe was used for plasma characterization using current voltage variation. The typical hydrogen plasma density and electron temperature measured were 7x10{sup 11} cm{sup -3} and 6 eV, respectively. The total ion beam current of 42 mA was extracted, with three-electrode extraction geometry, at 40 keV of beam energy. The extracted ion current was studied as a function of microwave power and gas pressure. Depending on source pressure and discharge power, more than 30% total gas efficiency was achieved. The optimization of the source is under progress to meet the requirement of long time operation. The source will be used as an injector for continuous wave radio frequency quadrupole, a part of 20 MeV LEHIPA. The required rms normalized emittance of this source is less than 0.2 {pi} mm mrad. The simulated value of normalized emittance is well within this limit and will be measured shortly. This paper presents the study of plasma parameters, first beam results, and the status of ECR proton source.

  8. Mode converter for electron cyclotron resonance heating of toroidal plasmas

    SciTech Connect

    Motley, R.W.; Hsuan, H.; Glanz, J.

    1980-09-01

    A method is proposed for improving the efficiency of cyclotron resonance heating of a toroidal plasma by ordinary mode radiation from the outside of the torus. Radiation not absorbed in the first pass is reflected from the inside of the torus by a corrugated surface which rotates the polarization by 90/sup 0/, so that a secondary source of extraordinary waves is created in the high field, accessible region of the plasma.

  9. Measurement of turbulent electron temperature fluctuations on the ASDEX Upgrade tokamak using correlated Electron Cyclotron Emission

    NASA Astrophysics Data System (ADS)

    Freethy, S.; Conway, G. D.; Classen, I.; Creely, A. J.; Happel, T.; Vanovac, B.; White, A. E.; ASDEX Upgrade Team

    2016-10-01

    First measurements of core (r/a < 0.95) turbulent electron temperature fluctuations made on the ASDEX Upgrade (AUG) tokamak using a Correlation Electron Cyclotron Emission (CECE) technique are presented. Validation of gyro-kinetic models against measurements of the underlying turbulent micro-structure are essential for developing predictive capabilities for future devices. In tokamak plasmas, turbulent temperature fluctuations are sufficiently broadband ( 0.5 MHz) and low-amplitude ( 1%) that conventional radiometer techniques are fundamentally unable to detect them and a correlation technique is required to further extract the signals. An application of the spectral decorrelation method had been designed and built for AUG. This CECE radiometer shares an optical path with a reflectometer and is sensitive to wavenumbers perpendicular to the magnetic field k⊥ up to 0.76 cm-1 . An upgrade to the focusing mirror will increase this range to k⊥ up to 1.4 cm-1. Measurements in Helium plasmas have been made at three radial locations simultaneously, providing a profile of the temperature fluctuation amplitude in the outer core of Electron Cyclotron Resonance Heated heated L-mode plasmas. New results and future plans will be presented. This work is supported by the US DOE under Grant DE-SC0006419.

  10. Broadband measurement of electron cyclotron emission in TFTR using a quasioptical light collection system and a polarizing Michelson interferometer

    SciTech Connect

    Stauffer, F.J.; Boyd, D.A.; Cutler, R.C.; Diesso, M.; McCarthy, M.P.; Montague, J.; Rocco, R.

    1988-10-01

    For the past four years, a Fourier transform spectrometer diagnostic system, employing a fast-scanning polarizing Michelson interferometer (FMI), has been operating on the TFTR tokamak at the Princeton Plasma Physics Laboratory. It is used to measure the electron cyclotron emission (ECE) spectrum over the range 2.5--18 cm/sup -1/ (75--540 GHz), with a resolution of 0.123 cm/sup -1/ (3.7 GHz), at a rate of 72 spectra per second. The quasioptical system for collecting the light and transporting it through the interferometer to the detector has been designed using the concepts of both Gaussian and geometrical optics. The commercial FMI was custom made for this project and is the state of the art for this type of specialized instrument. The diagnostic system is described and an error propagation analysis of the absolute calibration process is given. Examples of ECE spectra measured in two polarization directions are given and electron temperature profiles derived from each of them are compared.

  11. A mode converter to generate a Gaussian-like mode for injection into the VENUS electron cyclotron resonance ion source

    SciTech Connect

    Lyneis, C. Benitez, J.; Hodgkinson, A.; Strohmeier, M.; Todd, D.; Plaum, B.; Thuillier, T.

    2014-02-15

    A number of superconducting electron cyclotron resonance (ECR) ion sources use gyrotrons at either 24 or 28 GHz for ECR heating. In these systems, the microwave power is launched into the plasma using the TE{sub 01} circular waveguide mode. This is fundamentally different and may be less efficient than the typical rectangular, linearly polarized TE{sub 10} mode used for launching waves at lower frequencies. To improve the 28 GHz microwave coupling in VENUS, a TE{sub 01}-HE{sub 11} mode conversion system has been built to test launching HE{sub 11} microwave power into the plasma chamber. The HE{sub 11} mode is a quasi-Gaussian, linearly polarized mode, which should couple strongly to the plasma electrons. The mode conversion is done in two steps. First, a 0.66 m long “snake” converts the TE{sub 01} mode to the TE{sub 11} mode. Second, a corrugated circular waveguide excites the HE{sub 11} mode, which is launched directly into the plasma chamber. The design concept draws on the development of similar devices used in tokamaks and stellerators. The first tests of the new coupling system are described below.

  12. Electron-cyclotron-heating results on JFT-2, and their implications for the Doublet III ECH design

    SciTech Connect

    Prater, R.; Moeller, C.P.

    1982-03-01

    Electron cyclotron heating experiments are described in which 28 GHz microwave power is injected into the JFT-2 tokamak. Ordinary mode power injected from the low field side increased the central electron temperature from 600 eV to 1000 eV with 110 kW, for densities below the ordinary mode cutoff density of 1.0 x 10/sup 13/ cm/sup -3/. Extraordinary mode power launched obliquely from the high field side increased the temperature from 600 eV to 1200 eV with 85 kW, for densities well below the extraordinary mode cutoff density, and effective heating was maintained close to the cutoff density of 1.6 x 10/sup 13/ cm/sup -3/. The extraordinary mode launched obliquely was also found to heat more efficiently and to a higher density than the extraordinary wave launched perpendicularly. On this basis, the Doublet III ECH experiments which will use up to 2 MW of 60 GHz power are designed to make use of oblique inside launch of a pure extraordinary mode. The waveguide transmission system to accomplish this is discussed.

  13. Intense beam production of highly charged heavy ions by the superconducting electron cyclotron resonance ion source SECRAL.

    PubMed

    Zhao, H W; Sun, L T; Zhang, X Z; Guo, X H; Cao, Y; Lu, W; Zhang, Z M; Yuan, P; Song, M T; Zhao, H Y; Jin, T; Shang, Y; Zhan, W L; Wei, B W; Xie, D Z

    2008-02-01

    There has been increasing demand to provide higher beam intensity and high enough beam energy for heavy ion accelerator and some other applications, which has driven electron cyclotron resonance (ECR) ion source to produce higher charge state ions with higher beam intensity. One of development trends for highly charged ECR ion source is to build new generation ECR sources by utilization of superconducting magnet technology. SECRAL (superconducting ECR ion source with advanced design in Lanzhou) was successfully built to produce intense beams of highly charged ion for Heavy Ion Research Facility in Lanzhou (HIRFL). The ion source has been optimized to be operated at 28 GHz for its maximum performance. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. An innovative design of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28 GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. During the commissioning phase at 18 GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.5 kW by two 18 GHz rf generators. It demonstrates the performance is very promising. Some record ion beam intensities have been produced, for instance, 810 e microA of O(7+), 505 e microA of Xe(20+), 306 e microA of Xe(27+), and so on. The effect of the magnetic field configuration on the ion source performance has been studied experimentally. SECRAL has been put into operation to provide highly charged ion beams for HIRFL facility since May 2007.

  14. Simulation of parameter scaling in electron cyclotron resonance ion source plasmas using the GEM code

    SciTech Connect

    Cluggish, B.; Zhao, L.; Kim, J. S.

    2010-02-15

    Although heating power and gas pressure are two of the two of primary experimental ''knobs'' available to users of electron cyclotron resonance ion sources, there is still no clear understanding of how they interact in order to provide optimal plasma conditions. FAR-TECH, Inc. has performed a series of simulations with its generalized electron cyclotron resonance ion source model in which the power and pressure were varied over a wide range. Analysis of the numerical data produces scaling laws that predict the plasma parameters as a function of the power and pressure. These scaling laws are in general agreement with experimental data.

  15. Electron cyclotron harmonic resonances in high-frequency heating of the ionosphere

    SciTech Connect

    Kuo, Spencer P.

    2013-09-15

    Electron acceleration by upper hybrid waves under cyclotron harmonic resonance interaction is studied. Theory is formulated; the analytical solutions in the second and fourth harmonic cyclotron resonance cases are obtained, and in the third harmonic case, a first order differential equation governing the evolution of the electron energy is derived. The theory is applied for explaining the generation of artificial ionization layers observed in high-frequency (HF) ionospheric heating experiments. The upper hybrid waves are assumed to be excited parametrically by the O-mode HF heating wave. As the decay mode is the lower hybrid wave, the excited upper hybrid waves have wavelengths ranging from 0.25 to 0.5 m, which are short enough to effectively incorporate the finite Larmour radius effect for the harmonic cyclotron resonance interactions as well as have a frequency bandwidth of about 20 kHz, which provides an altitude region of about 10 km for continuous harmonic cyclotron resonance interaction between electrons and descending waves in the slightly inhomogeneous geomagnetic field. The numerical results on electron acceleration show that electron fluxes with energies larger than 14 eV are generated in the three harmonic cases. These energetic electrons cause impact ionizations, which are descending to form artificial ionization layers at the bottom of the ionospheric F region.

  16. Observations of rotation in JET plasmas with electron heating by ion cyclotron resonance heating

    NASA Astrophysics Data System (ADS)

    Hellsten, T.; Johnson, T. J.; Van Eester, D.; Lerche, E.; Lin, Y.; Mayoral, M.-L.; Ongena, J.; Calabro, G.; Crombé, K.; Frigione, D.; Giroud, C.; Lennholm, M.; Mantica, P.; Nave, M. F. F.; Naulin, V.; Sozzi, C.; Studholme, W.; Tala, T.; Versloot, T.; Contributors, JET-EFDA

    2012-07-01

    The rotation of L-mode plasmas in the JET tokamak heated by waves in the ion cyclotron range of frequencies (ICRF) damped on electrons, is reported. The plasma in the core is found to rotate in the counter-current direction with a high shear and in the outer part of the plasma with an almost constant angular rotation. The core rotation is stronger in magnitude than observed for scenarios with dominating ion cyclotron absorption. Two scenarios are considered: the inverted mode conversion scenarios and heating at the second harmonic 3He cyclotron resonance in H plasmas. In the latter case, electron absorption of the fast magnetosonic wave by transit time magnetic pumping and electron Landau damping (TTMP/ELD) is the dominating absorption mechanism. Inverted mode conversion is done in (3He)-H plasmas where the mode converted waves are essentially absorbed by electron Landau damping. Similar rotation profiles are seen when heating at the second harmonic cyclotron frequency of 3He and with mode conversion at high concentrations of 3He. The magnitude of the counter-rotation is found to decrease with an increasing plasma current. The correlation of the rotation with the electron temperature is better than with coupled power, indicating that for these types of discharges the dominating mechanism for the rotation is related to indirect effects of electron heat transport, rather than to direct effects of ICRF heating. There is no conclusive evidence that mode conversion in itself affects rotation for these discharges.

  17. Electron Cyclotron Current Drive by Radial Transport of Particles in the Continuous Current Tokamak

    NASA Astrophysics Data System (ADS)

    Park, Sanghyun

    In the Continuous Current Tokamak at the UCLA, electron cyclotron current drive (ECCD) experiments have been conducted in the absence of ohmic heating or any other power input. With X-band source of 30 kW lasting 1 mS launched from the high field side in X-mode, 240 A of plasma current has been generated at the neutral pressure corresponding to the critical density for the wave frequency. The Spitzer resistivity calculated from the L/R decay time of the current yielded an electron temperature of 100 eV. For the interest of mapping out radial profiles of wave and particle parameters, S-band sources at 2.45 GHz, 1.5 kW lasting 8 mS with duty cycle of 50% have been used for quasi-steady state current drive experiments. There are four launching structures; (1) Inside perpendicular, (2) Outside perpendicular, (3) Outside 60^circ, and (4) Outside -60^circ with respect to the toroidal magnetic field. It has been found that the four ways of microwaves give comparable results in plasma current driven. The plasma current measurements as a function of the radial location of the electron cyclotron resonance layer show a I_{rm p}~ -sin(pi r/a) where R_{res} = R_{0} + r for -a >=q r >=q O. The vertical field dependence has been shown to be I_{rm p}~ -x exp(-x^2) where x is a normalized vertical field for -inftyelectrons as determined by the biased, two-side Langmuir probe show that the current is carried by the bulk of the plasma electrons whose energy is comparable to the plasma electron temperature, and not by the high energy tail of the distribution as predicted by theories based on the Fokker-Planck equation. The vertical and toroidal field

  18. Numerical study of the synergy effects of electron cyclotron wave and two lower-hybrid waves in the current drive process

    NASA Astrophysics Data System (ADS)

    Yang, Youlei; Xiang, Nong; Hu, Ye Min

    2017-08-01

    In recent experiments on the experimental advanced superconducting tokamak, the electron cyclotron wave and the two lower-hybrid waves at different frequencies, i.e., 4.6 GHz and 2.45 GHz, are applied simultaneously to sustain and control the plasma current. To investigate the synergy effects of the three waves, the Fokker-Planck equation with the quasi-linear diffusions induced by the three waves is solved numerically with the CQL3D code [R. W. Harvey and M. G. McCoy, in Proceedings of IAEA Technical Committee Meeting on Advances in Simulation and Modeling of Thermonuclear Plasmas, Montreal, Canada (1992)]. It is found that there might be strong synergy effects between the three waves. The electrons in the low velocity region in the velocity space can be accelerated perpendicularly by the electron cyclotron wave, and their parallel velocities can be increased due to scattering and fall into the resonance regions of the lower-hybrid waves. Therefore, such processes may bring more electrons to resonate with the lower-hybrid waves and enhance the current drive of the lower-hybrid waves. The synergy effects strongly depend on the distance between the resonance regions in the velocity space of the three waves.

  19. Force detected electron spin resonance at 94 GHz.

    PubMed

    Cruickshank, Paul A S; Smith, Graham M

    2007-01-01

    Force detected electron spin resonance (FDESR) detects the presence of unpaired electrons in a sample by measuring the change in force on a mechanical resonator as the magnetization of the sample is modulated under magnetic resonance conditions. The magnetization is coupled to the resonator via a magnetic field gradient. It has been used to both detect and image distributions of electron spins, and it offers both extremely high absolute sensitivity and high spatial imaging resolution. However, compared to conventional induction mode ESR the technique also has a comparatively poor concentration sensitivity and it introduces complications in interpreting and combining both spectroscopy and imaging. One method to improve both sensitivity and spectral resolution is to operate in high magnetic fields in order to increase the sample magnetization and g-factor resolution. In this article we present FDESR measurements on the organic conductor (fluoranthene)(2)PF(6) at 3.2 T, with a corresponding millimeter-wave frequency of 93.5 GHz, which we believe are the highest field results for FDESR reported in the literature to date. A magnet-on-cantilever approach was used, with a high-anisotropy microwave ferrite as the gradient source and employing cyclic saturation to modulate the magnetization at the cantilever fundamental frequency.

  20. The Electron-Optical System of a Gyrotron with an Operating Frequency of 263 GHz for Spectroscopic Research

    NASA Astrophysics Data System (ADS)

    Kuftin, A. N.; Manuilov, V. N.

    2016-07-01

    We describe specific features of modeling numerically the operation of magnetron-injection guns, which form high-quality helical electron beams in gyrotrons operated in the short-wave part of the millimeter-wave band (at a wavelength of 1 mm). As an example, we consider the gun of a gyrotron having an operating frequency of 263 GHz designed for spectroscopic research. It is shown that there are good reasons to perform calculations and optimization of the magnetroninjection un in two steps. At the first step, a simplest two-dimensional model can be used, which allows only for the influence of the field of the electrodes and the intrinsic space charge of the beam on the beam parameters. At the second, final stage one should allow for such factors as roughness of the emitting surface and thermal velocities of electrons. The electron distribution function in oscillatory velocities and the coefficient of electron reflection from the magnetic mirror should be calculated. It is demonstrated that the magnetron-injection gun, which is optimized by the method presented, is sufficiently universal and can be operated both at the first and second cyclotron-frequency harmonics. This opens up the possibility of developing gyrotrons for spectroscopy applications at frequencies of 263 and 526 GHz, respectively, which are required for biological and medical research.

  1. Investigation of relativistic runaway electrons in electron cyclotron resonance heating discharges on Korea Superconducting Tokamak Advanced Research

    SciTech Connect

    Kang, C. S.; Lee, S. G.

    2014-07-15

    The behavior of relativistic runaway electrons during Electron Cyclotron Resonance Heating (ECRH) discharges is investigated in the Korea Superconducting Tokamak Advanced Research device. The effect of the ECRH on the runaway electron population is discussed. Observations on the generation of superthermal electrons during ECRH will be reported, which will be shown to be consistent with existing theory for the development of a superthermal electron avalanche during ECRH [A. Lazaros, Phys. Plasmas 8, 1263 (2001)].

  2. Prospects for advanced electron cyclotron resonance and electron beam ion source charge breeding methods for EURISOL

    SciTech Connect

    Delahaye, P.; Jardin, P.; Maunoury, L.; Traykov, E.; Varenne, F.; Angot, J.; Lamy, T.; Sortais, P.; Thuillier, T.; Ban, G.; Celona, L.; Lunney, D.; Choinski, J.; Gmaj, P.; Jakubowski, A.; Steckiewicz, O.; Kalvas, T.; and others

    2012-02-15

    As the most ambitious concept of isotope separation on line (ISOL) facility, EURISOL aims at producing unprecedented intensities of post-accelerated radioactive isotopes. Charge breeding, which transforms the charge state of radioactive beams from 1+ to an n+ charge state prior to post-acceleration, is a key technology which has to overcome the following challenges: high charge states for high energies, efficiency, rapidity and purity. On the roadmap to EURISOL, a dedicated R and D is being undertaken to push forward the frontiers of the present state-of-the-art techniques which use either electron cyclotron resonance or electron beam ion sources. We describe here the guidelines of this R and D.

  3. Electron cyclotron-electron Bernstein wave emission diagnostics for the COMPASS tokamak.

    PubMed

    Zajac, J; Preinhaelter, J; Urban, J; Zacek, F; Sestak, D; Nanobashvili, S

    2010-10-01

    The COMPASS tokamak recently started operation at the Institute of Plasma Physics AS CR, v.v.i., Prague. A new 16-channel radiometer, operating alternatively in three frequency bands, has been designed and constructed. The system is prepared for detection of normal electron cyclotron emission (O1 or X2) or oblique electron Bernstein wave emission. The end-to-end calibration method includes all components that influence the antenna radiation pattern. A steady recalibration is possible using a noise generator connected to the radiometer input through a fast waveguide PIN-switch. Measurements of the antenna radiation characteristics (2D electric field) were performed in free space as well as in the tokamak chamber, showing the degradation effect of structures on the Gaussian beam shape. First plasma radiation temperature measurements from low-field circular plasmas are available.

  4. Electron cyclotron-electron Bernstein wave emission diagnostics for the COMPASS tokamak

    SciTech Connect

    Zajac, J.; Preinhaelter, J.; Urban, J.; Zacek, F.; Sestak, D.

    2010-10-15

    The COMPASS tokamak recently started operation at the Institute of Plasma Physics AS CR, v.v.i., Prague. A new 16-channel radiometer, operating alternatively in three frequency bands, has been designed and constructed. The system is prepared for detection of normal electron cyclotron emission (O1 or X2) or oblique electron Bernstein wave emission. The end-to-end calibration method includes all components that influence the antenna radiation pattern. A steady recalibration is possible using a noise generator connected to the radiometer input through a fast waveguide PIN-switch. Measurements of the antenna radiation characteristics (2D electric field) were performed in free space as well as in the tokamak chamber, showing the degradation effect of structures on the Gaussian beam shape. First plasma radiation temperature measurements from low-field circular plasmas are available.

  5. Nonlinear electron acceleration by oblique whistler waves: Landau resonance vs. cyclotron resonance

    SciTech Connect

    Artemyev, A. V.; Agapitov, O. V.; Krasnoselskikh, V. V.; Mourenas, D.

    2013-12-15

    This paper is devoted to the study of the nonlinear interaction of relativistic electrons and high amplitude strongly oblique whistler waves in the Earth's radiation belts. We consider electron trapping into Landau and fundamental cyclotron resonances in a simplified model of dipolar magnetic field. Trapping into the Landau resonance corresponds to a decrease of electron equatorial pitch-angles, while trapping into the first cyclotron resonance increases electron equatorial pitch-angles. For 100 keV electrons, the energy gained due to trapping is similar for both resonances. For electrons with smaller energy, acceleration is more effective when considering the Landau resonance. Moreover, trapping into the Landau resonance is accessible for a wider range of initial pitch-angles and initial energies in comparison with the fundamental resonance. Thus, we can conclude that for intense and strongly oblique waves propagating in the quasi-electrostatic mode, the Landau resonance is generally more important than the fundamental one.

  6. Development of a compact electron-cyclotron-resonance ion source for high-energy carbon-ion therapy

    NASA Astrophysics Data System (ADS)

    Muramatsu, M.; Kitagawa, A.; Sakamoto, Y.; Sato, S.; Sato, Y.; Ogawa, Hirotsugu; Yamada, S.; Ogawa, Hiroyuki; Yoshida, Y.; Drentje, A. G.

    2005-11-01

    Ion sources for medical facilities should have characteristics of easy maintenance, low electric power consumption, good stability, and long operation time without problems (one year or longer). For this, a 10GHz compact electron-cyclotron-resonance ion source with all-permanent magnets (Kei2 source) was developed. The maximum mirror magnetic fields on the beam axis are 0.59T at the extraction side and 0.87T at the gas-injection side, while the minimum B strength is 0.25T. These parameters have been optimized for the production of C4+ based on the experience at the 10GHz NIRS-ECR ion source and a previous prototype compact source (Kei source). The Kei2 source has a diameter of 320mm and a length of 295mm. The beam intensity of C4+ was obtained to be 530μA under an extraction voltage of 40kV. The beam stability was better than 6% at C4+ of 280μA during 90h with no adjustment of the operation parameters. The details of the design and beam tests of the source are described in this paper.

  7. Electron Cyclotron Resonance Heating for W7-X

    SciTech Connect

    Michel, G.; Braune, H.; Erckmann, V.; Laqua, H. P.; Marushchenko, N.; Oosterbeek, J. W.; Brand, P.; Kasparek, W.; Gantenbein, G.; Thumm, M.; Weissgerber, M.

    2009-11-26

    The HELIAS-type Stellarator Wendelstein 7-X, which is currently under construction in Greifswald, Germany, will be equipped with a 140 GHz, 10 MW, CW ECRH system. It will be the main plasma heating system for W7-X. The key features and capabilities of the ECRH plant will be discussed together with the envisaged start-up and heating scenarios. We also report on the ECRH stray radiation test facility MISTRAL and on the extension of the gyrotron frequency range.

  8. Simulation on the electronic wave packet cyclotron motion in a Weyl semimetal slab.

    PubMed

    Yao, Haibo; Zhu, Mingfeng; Jiang, Liwei; Zheng, Yisong

    2017-04-20

    We perform a numerical simulation on the time evolution of an electronic wave packet in a Weyl semimetal (WSM) slab driven by a magnetic field. We find that the evolution trajectory of the wave packet depends sensitively on its initial spin state. Only with initial spin state identical to that of the Fermi arc state at the surface it localized, does the wave packet evolution demonstrate the characteristic cyclotron orbit of WSM previously predicted from a semiclassical viewpoint. By analyzing the eigen-expansion of the electronic wave packet, we find the chiral Landau levels (LLs) of the WSM slab, as ingredients of the wave packet, to be responsible for establishing the characteristic WSM cyclotron orbit. In contrast, the nonchiral LLs contribute irregular oscillations to the wave packet evolution, going against the formation of a well-defined cyclotron orbit. In addition, the tilted magnetic field does not affect the motion of the electronic wave packet along the Fermi arcs in the momentum space. It does, however, alter the evolution trajectory of the electronic wave packet in real space and spin space. Finally, the energy disalignment of the Weyl nodes results in a 3D cyclotron orbit in real space.

  9. Status of the PHOENIX electron cyclotron resonance charge breeder at ISOLDE, CERN.

    PubMed

    Barton, Charles; Cederkall, Joakim; Delahaye, Pierre; Kester, Oliver; Lamy, Thierry; Marie-Jeanne, Mélanie

    2008-02-01

    We report here on the last progresses made with the PHOENIX electron cyclotron resonance charge breeder test bench at ISOLDE. Recently, an experiment was performed to test the trapping of (61)Fe daughter nuclides from the decay of (61)Mn nuclides. Preliminary results are given.

  10. Simulation on the electronic wave packet cyclotron motion in a Weyl semimetal slab

    NASA Astrophysics Data System (ADS)

    Yao, Haibo; Zhu, Mingfeng; Jiang, Liwei; Zheng, Yisong

    2017-04-01

    We perform a numerical simulation on the time evolution of an electronic wave packet in a Weyl semimetal (WSM) slab driven by a magnetic field. We find that the evolution trajectory of the wave packet depends sensitively on its initial spin state. Only with initial spin state identical to that of the Fermi arc state at the surface it localized, does the wave packet evolution demonstrate the characteristic cyclotron orbit of WSM previously predicted from a semiclassical viewpoint. By analyzing the eigen-expansion of the electronic wave packet, we find the chiral Landau levels (LLs) of the WSM slab, as ingredients of the wave packet, to be responsible for establishing the characteristic WSM cyclotron orbit. In contrast, the nonchiral LLs contribute irregular oscillations to the wave packet evolution, going against the formation of a well-defined cyclotron orbit. In addition, the tilted magnetic field does not affect the motion of the electronic wave packet along the Fermi arcs in the momentum space. It does, however, alter the evolution trajectory of the electronic wave packet in real space and spin space. Finally, the energy disalignment of the Weyl nodes results in a 3D cyclotron orbit in real space.

  11. Broadband measurements of electron cyclotron emission in TFTR (Tokamak Fusion Test Reactor) using a quasi-optical light collection system and a polarizing Michelson interferometer

    SciTech Connect

    Stauffer, F.J.; Boyd, D.A.; Cutler, R.C.; Diesso, M.; McCarthy, M.P.; Montague, J.; Rocco, R.

    1988-04-01

    For the past three years, a Fourier transform spectrometer diagnostic system, employing a fast-scanning polarizing Michelson interferometer, has been operating on the TFTR tokamak at Princeton Plasma Physics Laboratory. It is used to measure the electron cyclotron emission spectrum over the range 2.5 to 18 cm/sup /minus/1/ (75-540 GHz) with a resolution of 0.123 cm/sup /minus/1/(3.7 GHz), at a rate of 72 spectra per second. The quasi-optical system for collecting the light and transporting it through the interferometer to the detector has been designed using the concepts of both Gaussian and geometrical optics in order to produce a system that is efficient over the entire spectral range. The commerical Michelson interferometer was custom-made for this project and is at the state of the art for this type of specialized instrument. Various pre-installation and post-installation tests of the optical system and the interferometer were performed and are reported here. An error propagation analysis of the absolute calibration process is given. Examples of electron cyclotron emission spectra measured in two polarization directions are given, and electron temperature profiles derived from each of them are compared. 34 refs., 17 figs.

  12. Grating monochromator for electron cyclotron resonance ion source operation

    SciTech Connect

    Muto, Hideshi; Ohshiro, Yukimitsu; Yamaka, Shouichi; Watanabe, Shin-ichi; Yamaguchi, Hidetoshi; Shimoura, Susumu; Oyaizu, Michihiro; Kase, Masayuki; Kubono, Shigeru; Hattori, Toshiyuki

    2013-07-15

    Recently, we started to observe optical line spectra from an ECR plasma using a grating monochromator with a photomultiplier. The light intensity of line spectrum from the ECR plasma had a strong correlation with ion beam intensity measured by a magnetic mass analyzer. This correlation is a significant information for beam tuning because it allows the extraction of the desired ion species from the ECR plasma. Separation of ion species of the same charge to mass ratio with an electromagnetic mass analyzer is known to be an exceptionally complex process, but this research gives new insights into its simplification. In this paper, the grating monochromator method for beam tuning of a Hyper-ECR ion source as an injector for RIKEN azimuthal varying field (AVF) cyclotron is described.

  13. Dependence of ion beam current on position of mobile plate tuner in multi-frequencies microwaves electron cyclotron resonance ion source

    SciTech Connect

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

    2012-02-15

    We are constructing a tandem-type electron cyclotron resonance ion source (ECRIS). The first stage of this can supply 2.45 GHz and 11-13 GHz microwaves to plasma chamber individually and simultaneously. We optimize the beam current I{sub FC} by the mobile plate tuner. The I{sub FC} is affected by the position of the mobile plate tuner in the chamber as like a circular cavity resonator. We aim to clarify the relation between the I{sub FC} and the ion saturation current in the ECRIS against the position of the mobile plate tuner. We obtained the result that the variation of the plasma density contributes largely to the variation of the I{sub FC} when we change the position of the mobile plate tuner.

  14. Dependence of ion beam current on position of mobile plate tuner in multi-frequencies microwaves electron cyclotron resonance ion source.

    PubMed

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

    2012-02-01

    We are constructing a tandem-type electron cyclotron resonance ion source (ECRIS). The first stage of this can supply 2.45 GHz and 11-13 GHz microwaves to plasma chamber individually and simultaneously. We optimize the beam current I(FC) by the mobile plate tuner. The I(FC) is affected by the position of the mobile plate tuner in the chamber as like a circular cavity resonator. We aim to clarify the relation between the I(FC) and the ion saturation current in the ECRIS against the position of the mobile plate tuner. We obtained the result that the variation of the plasma density contributes largely to the variation of the I(FC) when we change the position of the mobile plate tuner.

  15. Measurements of plasma bremsstrahlung and plasma energy density produced by electron cyclotron resonance ion source plasmas

    NASA Astrophysics Data System (ADS)

    Noland, Jonathan David

    2011-12-01

    The goal of this dissertation was to gain an understanding on the relative importance of microwave power, neutral pressure, and magnetic field configuration on the behavior of the hot electrons within an Electron Cyclotron Resonance Ion Source (ECRIS) plasma. This was carried out through measurement of plasma bremsstrahlung with both NaI(Tl) (hv > 30 keV) and CdTe (2 keV < hv < 70 keV) x-ray detectors, and through measurement of the plasma energy density with a diamagnetic loop placed around the plasma chamber. We also examined the anisotropy in x-ray power by simultaneously measuring the x-ray spectra in two orthogonal directions: radially and axially, using NaI(Tl) detectors. We have seen that for a 6.4 GHz ECRIS, both the x-ray power produced by confined electrons and the plasma energy density behave logarithmically with microwave power. The x-ray flux created by electrons lost from the plasma, however, does not saturate. Thus, the small increase in plasma density that occurred at high microwave powers (> 150 W on a 6.4 GHz ECRIS) was accompanied by a large increase in total x-ray power. We suggest that the saturation of x-ray power and plasma energy density was due to rf-induced pitch-angle scattering of the electrons. X-ray power and plasma energy density were also shown to saturate with neutral pressure, and to increase nearly linearly as the gradient of the magnetic field in the resonance zone was decreased. All of these findings were in agreement with the theoretical models describing ECRIS plasmas. We have discussed the use of a diamagnetic loop as a means of exploring various plasma time scales on a relative basis. Specifically, we focused much of our attention on studying how changing ion source parameters, such as microwave power and neutral pressure, would effect the rise and decay of the integrated diamagnetic signal, which can be related to plasma energy density. We showed that increasing microwave power lowers the e-fold times at both the leading

  16. Calibration of a 32 channel electron cyclotron emission radiometer on the HL-2A tokamak

    SciTech Connect

    Shi, Z. B. Jiang, M.; Huang, X. L.; Zhong, W. L.; Chen, W.; Che, Y. L.; Liu, Z. T.; Ding, X. T.; Yang, Q. W.; Duan, X. R.

    2014-02-15

    A novel 32-channel electron cyclotron emission radiometer has been designed and tested for the measurement of electron temperature profiles on the HL-2A tokamak. This system is based on the intermediate frequency filter detection technique, and has the features of wide working frequency range and high spatial resolution. Two relative calibration methods have been investigated: sweeping the toroidal magnetic field and hopping the output frequency of the local oscillator. Preliminary results show that both methods can ensure reasonable profiles.

  17. Critical electron pitch angle anisotropy necessary for chorus generation. [Doppler-shifted cyclotron resonance

    NASA Technical Reports Server (NTRS)

    Burton, R. K.

    1976-01-01

    Simultaneous wave, resonant-particle, and ambient-plasma data from OGO 5 for chorus emissions on August 15, 1968, were found consistent with the theoretical critical pitch-angle-anisotropy condition for whistler-mode instability by Doppler-shifted electron cyclotron resonance. Local generation, as determined by wave normal measurements, occurred only when the pitch-angle anisotropy of resonant electrons required for instability substantially exceeded the critical anisotropy defined by Kennel and Petschek (1966).

  18. Terahertz electron cyclotron maser interactions with an axis-encircling electron beam

    SciTech Connect

    Li, G. D.; Kao, S. H.; Chang, P. C.; Chu, K. R.

    2015-04-15

    To generate terahertz radiation via the electron cyclotron maser instability, harmonic interactions are essential in order to reduce the required magnetic field to a practical value. Also, high-order mode operation is required to avoid excessive Ohmic losses. The weaker harmonic interaction and mode competition associated with an over-moded structure present challenging problems to overcome. The axis-encircling electron beam is a well-known recipe for both problems. It strengthens the harmonic interaction, as well as minimizing the competing modes. Here, we examine these advantages through a broad data base obtained for a low-power, step-tunable, gyrotron oscillator. Linear results indicate far more higher-harmonic modes can be excited with an axis-encircling electron beam than with an off-axis electron beam. However, multi-mode, time-dependent simulations reveal an intrinsic tendency for a higher-harmonic mode to switch over to a lower-harmonic mode at a high beam current or upon a rapid current rise. Methods are presented to identify the narrow windows in the parameter space for stable harmonic interactions.

  19. Characteristics of heat flux and electromagnetic electron-cyclotron instabilities driven by solar wind electrons

    NASA Astrophysics Data System (ADS)

    Saeed, Sundas; Yoon, P. H.; Sarfraz, M.; Qureshi, M. N. S.

    2017-04-01

    In situ observations reveal the existence of electron velocity distribution function in the solar wind, where the net distribution can be modelled by a combination of core, halo and strahl. These components often possess a relative drift and with respective temperature anisotropies. The relative drift between the core and halo components leads to heat flux (HF) instability, while temperature anisotropies drive electromagnetic electron-cyclotron (EMEC) instability. These instabilities have been separately studied in the literature, but for the first time, the present study combines both unstable modes in the presence of two free energy sources, namely, excessive parallel pressure and excessive perpendicular temperature. HF instability (which is a left-hand circularly polarized mode) is effectively similar to electron firehose instability, except that the free energy is provided by net relative drift among two component electrons in the background of protons. The HF instability is discussed here along with (the right-hand polarized) EMEC instability driven by temperature anisotropy. The unstable HF mode is conventionally termed the 'whistler' HF instability, but it is actually polarized in the opposite sense to the whistler wave. EMEC mode, on the other hand, reduces to the proper whistler wave in the absence of free energy source. The present combined analysis clarifies the polarization characteristics of these two modes in an unambiguous manner.

  20. New Electron Cyclotron Emission Diagnostic Based Upon the Electron Bernstein Wave

    SciTech Connect

    P.C. Efthimion; J.C. Hosea; R. Kaita; R. Majeski; G. Taylor

    1999-05-01

    Most magnetically confined plasma devices cannot take advantage of standard Electron Cyclotron Emission (ECE) diagnostics to measure temperature. They either operate at high density relative to their magnetic field or they do not have sufficient density and temperature to reach the blackbody condition. The standard ECE technique measures the electromagnetic waves emanating from the plasma. Here we propose to measure electron Bernstein waves (EBW) to ascertain the local electron temperature in these plasmas. The optical thickness of EBW is extremely high because it is an electrostatic wave with a large k(subscript i). One can reach the blackbody condition with a plasma density approximately equal to 10(superscript 11) cm(superscript -3) and electron temperature approximately equal to 1 eV. This makes it attractive to most plasma devices. One serious issue with using EBW is the wave accessibility. EBW may be accessible by either direct coupling or mode conversion through an extremely narrow layer (approximately 1-2 mm) in low field devices.

  1. Measurements of the fast electron bremsstrahlung emission during electron cyclotron resonance heating in the HL-2A tokamak

    SciTech Connect

    Zhang, Y. P.; Liu, Yi; Song, X. Y.; Yuan, G. L.; Chen, W.; Ji, X. Q.; Ding, X. T.; Yang, J. W.; Zhou, J.; Li, X.; Yang, Q. W.; Duan, X. R.; Pan, C. H.; Liu, Y.

    2010-10-15

    A fast electron bremsstrahlung (FEB) diagnostic technique based on cadmium telluride (CdTe) detector has been developed recently in the HL-2A tokamak for measurements of the temporal evolution of FEB emission in the energy range of 10-200 keV. With a perpendicular viewing into the plasma on the equatorial plane, the hard x-ray spectra with eight different energy channels are measured. The discrimination of the spectra is implemented by an accurate spectrometry. The system also makes use of fast digitization and software signal processing technology. An ambient environment of neutrons, gammas, and magnetic disturbance requires careful shielding. During electron cyclotron resonance heating, the generation of fast electrons and the oscillations of electron fishbone (e-fishbone) have been found. Using the FEB measurement system, it has been experimentally identified that the mode strongly correlates with the electron cyclotron resonance heating produced fast electrons with 30-70 keV.

  2. The effect of electron holes on cyclotron maser emission driven by horseshoe distributions

    NASA Astrophysics Data System (ADS)

    Zhao, G. Q.; Chu, Y. H.; Feng, H. Q.; Wu, D. J.

    2016-11-01

    This Brief Communication presents a quantitative investigation for the effect of electron holes on electron-cyclotron maser (ECM) driven by horseshoe distributions. The investigation is based on an integrated distribution function for the horseshoe distributions with electron holes. Results show that the presence of electron holes can significantly enhance the ECM growth rate by 2-3 times in a very narrow waveband. The present study suggests that these electron holes probably are responsible for some fine structures of radiations, such as narrowband events in auroral kilometric radiation and solar microwave spikes.

  3. Time evolution of endpoint energy of Bremsstrahlung spectra and ion production from an electron cyclotron resonance ion source

    SciTech Connect

    Tarvainen, Ollie; Ropponen, Tommi; Jones, Peter; Kalvas, Taneli

    2008-01-01

    Electron cyclotron resonance ion sources (ECRIS) are used to produce high charge state heavy ion beams for the use of nuclear and materials science, for instance. The most powerful ECR ion sources today are superconducting. One of the problems with superconducting ECR ion sources is the use of high radio frequency (RF) power which results in bremsstrahlung radiation adding an extra heat load to the cryostat. In order to understand the electron heating process and timescales in the ECR plasma, time evolution measurement of ECR bremsstrahlung was carried out. In the measurements JYFL 14 GHz ECRIS was operated in a pulsed mode and bremsstrahlung data from several hundred RF pulses was recorded. Time evolution of ion production was also studied and compared to one of the electron heating theories. To analyze the measurement data at C++ program was developed. Endpoint energies of the bremsstrahlung spectra as a function of axial magnetic field strength, pressure and RF power are presented and ion production timescales obtained from the measurements are compared to bremsstrahlung emission timescales and one of the stochastic heating theories.

  4. Influence of the shear flow on electron cyclotron resonance plasma confinement in an axisymmetric magnetic mirror trap of the electron cyclotron resonance ion source.

    PubMed

    Izotov, I V; Razin, S V; Sidorov, A V; Skalyga, V A; Zorin, V G; Bagryansky, P A; Beklemishev, A D; Prikhodko, V V

    2012-02-01

    Influence of shear flows of the dense plasma created under conditions of the electron cyclotron resonance (ECR) gas breakdown on the plasma confinement in the axisymmetric mirror trap ("vortex" confinement) was studied experimentally and theoretically. A limiter with bias potential was set inside the mirror trap for plasma rotation. The limiter construction and the optimal value of the potential were chosen according to the results of the preliminary theoretical analysis. This method of "vortex" confinement realization in an axisymmetric mirror trap for non-equilibrium heavy-ion plasmas seems to be promising for creation of ECR multicharged ion sources with high magnetic fields, more than 1 T.

  5. Electron-beam buncher to operate over the frequency range 1-4 GHz

    SciTech Connect

    Goldberg, D.A.; Arthur, A.A.; Flood, W.S.; Voelker, F.

    1983-03-01

    We present a description of an electron buncher to be installed in the terminal of a Van de Graaff, which is to produce a modulated beam over the frequency range 1-4 GHz. The modulator geometry has been optimized so that the modulation amplitude should be nearly constant over the frequency ranges 1-2 GHz and 2-4 GHz. Preliminary results indicate the device works as predicted.

  6. Investigation of contamination of correlation ECE signals by electron cyclotron heating at DIII-D

    NASA Astrophysics Data System (ADS)

    Baltzer, M. M.; Rhodes, T. L.; Wang, G.; Sung, C.; Carter, T. A.

    2016-10-01

    Correlation electron cyclotron emission (CECE) is commonly used at DIII-D to extract localized electron temperature fluctuations from passive emission. Very long coherence length signals (10's of cm in length) have been found to contaminate CECE measurements on some plasma discharges using electron cyclotron heating (ECH). Temperature fluctuations levels are observed to increase by as much as 50% due to this effect. Unabsorbed radiation from ECH is under investigation as a possible cause. A simple 1D code modeling the CECE data is used to investigate and test the effects of long coherence length contamination on the temperature fluctuation calculation. Data analysis methods to mitigate this effect have been designed and show significant promise in correcting the final results. Supported by US DOE DE-FG02-08ER54984 and DE-FC02-04ER54698.

  7. The design of a correlation electron cyclotron emission system on J-TEXT

    SciTech Connect

    Yang, Z. J.; Xiao, Y.; Ma, X. D.; Pan, X. M.; Xiao, J. S.

    2015-04-15

    To study the anomalous transport, a correlation electron cyclotron emission (CECE) was planned to be developed on J-TEXT for electron temperature fluctuation measurement. The spectral decorrelation method was employed for the CECE system. It was developed based on the previous 16-channel electron cyclotron emission system. They shared the optical transmission line and mixer. The CECE part consists of 4 channels. Two fixed frequency narrow band filters were used for two channels and two yttrium iron garnet (YIG) filters for the other two channels. To meet the measuring requirement, some tests have been taken for the YIG filters. The results show good performance of the filters. Gaussian optics is used to produce a good poloidal resolution. Wavenumbers resolved by the CECE diagnostic are k{sub θ} ≤ 1.5 rad/cm and k{sub r} ≤ 12 rad/cm. Some preliminary experiment results are also presented in this paper.

  8. Quasi-3D electron cyclotron emission imaging on J-TEXT

    NASA Astrophysics Data System (ADS)

    Zhao, Zhenling; Zhu, Yilun; Tong, Li; Xie, Jinlin; Liu, Wandong; Yu, Changxuan; Yang, Zhoujun; Zhuang, Ge; Luhmann, N. C., Jr.; Domier, C. W.

    2017-09-01

    Electron cyclotron emission imaging (ECEI) can provide measurements of 2D electron temperature fluctuation with high temporal and spatial resolution in magnetic fusion plasma devices. Two ECEI systems located in different toroidal ports with 67.5 degree separation have been implemented on J-TEXT to study the 3D structure of magnetohydrodynamic (MHD) instabilities. Each system consists of 12 (vertical) × 16 (horizontal) = 192 channels and the image of the 2nd harmonic X-mode electron cyclotron emission can be captured continuously in the core plasma region. The field curvature adjustment lens concept is developed to control the imaging plane for receiving optics of the ECEI systems. Field curvature of the image can be controlled to match the emission layer. Consequently, a quasi-3D image of the MHD instability in the core of the plasma has been achieved.

  9. Effects of electron cyclotron current drive on magnetic islands in tokamak plasmas

    NASA Astrophysics Data System (ADS)

    Li, J. C.; Xiao, C. J.; Lin, Z. H.; Wang, K. J.

    2017-08-01

    The effects of the electron cyclotron current drive on magnetic islands in tokamak plasmas are studied using gyrokinetic simulations. By investigating the effects of different characteristics of the driven current, such as current density distribution and deposition location, the factors which can determine the suppression effect on the resistive tearing modes have been explored. It is found that an electron cyclotron wave (ECW) driven current with a larger peak value and more focused deposition region has a better stabilization effect. When the ECW-driven current is closer to the rational surface, it has a better stabilizing effect. These gyrokinetic toroidal code (GTC) linear simulations in the electron fluid limit of the tearing modes in the cylindrical geometry agree well with the magnetohydrodynamic codes. Furthermore, the optimal timing control of the current deposition on resistive tearing modes is demonstrated.

  10. The design of a correlation electron cyclotron emission system on J-TEXT.

    PubMed

    Yang, Z J; Xiao, Y; Ma, X D; Pan, X M; Xiao, J S

    2015-04-01

    To study the anomalous transport, a correlation electron cyclotron emission (CECE) was planned to be developed on J-TEXT for electron temperature fluctuation measurement. The spectral decorrelation method was employed for the CECE system. It was developed based on the previous 16-channel electron cyclotron emission system. They shared the optical transmission line and mixer. The CECE part consists of 4 channels. Two fixed frequency narrow band filters were used for two channels and two yttrium iron garnet (YIG) filters for the other two channels. To meet the measuring requirement, some tests have been taken for the YIG filters. The results show good performance of the filters. Gaussian optics is used to produce a good poloidal resolution. Wavenumbers resolved by the CECE diagnostic are k(θ) ≤ 1.5 rad/cm and k(r) ≤ 12 rad/cm. Some preliminary experiment results are also presented in this paper.

  11. The design of a correlation electron cyclotron emission system on J-TEXT

    NASA Astrophysics Data System (ADS)

    Yang, Z. J.; Xiao, Y.; Ma, X. D.; Pan, X. M.; Xiao, J. S.

    2015-04-01

    To study the anomalous transport, a correlation electron cyclotron emission (CECE) was planned to be developed on J-TEXT for electron temperature fluctuation measurement. The spectral decorrelation method was employed for the CECE system. It was developed based on the previous 16-channel electron cyclotron emission system. They shared the optical transmission line and mixer. The CECE part consists of 4 channels. Two fixed frequency narrow band filters were used for two channels and two yttrium iron garnet (YIG) filters for the other two channels. To meet the measuring requirement, some tests have been taken for the YIG filters. The results show good performance of the filters. Gaussian optics is used to produce a good poloidal resolution. Wavenumbers resolved by the CECE diagnostic are kθ ≤ 1.5 rad/cm and kr ≤ 12 rad/cm. Some preliminary experiment results are also presented in this paper.

  12. Numerical analysis of electrostatic ion cyclotron instability in an electron-positron-ion plasma

    SciTech Connect

    Khorashadizadeh, S. M. Barati Moqadam Niyat, M.; Niknam, A. R.

    2016-06-15

    This paper presents a theoretical study of the effects of positron density on the electrostatic ion cyclotron instability in an electron-positron-ion plasma using the kinetic theory approach. It is supposed that positrons and electrons can drift parallel to the magnetic field either in the same or the opposite directions. The dispersion relation for the electrostatic ion cyclotron waves in an electron-positron-ion plasma is derived, and the numerical results are investigated. It is found that an increase in positron concentration increases the critical drift velocity for excitation of the instability in both configurations. It is also found that as the positron concentration increases the growth rate of instability decreases. In addition, it is shown that at low velocities the maximum instability growth rate for the unidirectional case is higher than the counter-streaming case; however, after a certain velocity, the maximum growth rate in the counter-streaming case dominates that of the unidirectional case.

  13. Temperature gradient scale length measurement: A high accuracy application of electron cyclotron emission without calibration

    SciTech Connect

    Houshmandyar, S. Phillips, P. E.; Rowan, W. L.; Yang, Z. J.; Hubbard, A. E.; Rice, J. E.; Hughes, J. W.; Wolfe, S. M.

    2016-11-15

    Calibration is a crucial procedure in electron temperature (T{sub e}) inference from a typical electron cyclotron emission (ECE) diagnostic on tokamaks. Although the calibration provides an important multiplying factor for an individual ECE channel, the parameter ΔT{sub e}/T{sub e} is independent of any calibration. Since an ECE channel measures the cyclotron emission for a particular flux surface, a non-perturbing change in toroidal magnetic field changes the view of that channel. Hence the calibration-free parameter is a measure of T{sub e} gradient. B{sub T}-jog technique is presented here which employs the parameter and the raw ECE signals for direct measurement of electron temperature gradient scale length.

  14. Electron cyclotron heating and current drive studies during current ramp-up in Tore-Supra

    NASA Astrophysics Data System (ADS)

    Rimini, F. G.; Basiuk, V.; Bourdelle, C.; Bucalossi, J.; Fenzi-Bonizec, C.; Giruzzi, G.; Hoang, G. T.; Lennholm, M.; Sabot, R.; Ségui, J. L.; Thomas, P. R.

    2005-06-01

    In a recent series of experiments, electron cyclotron current drive (ECCD) has been successfully used, at a level of 0.75 MW, for current profile tailoring during the current ramp-up in Tore-Supra. The electron cyclotron resonance heating power deposition was varied from on-axis to off-axis and the direction of the driven current from co to counter. In these conditions, the current profile is significantly modified with respect to those typically obtained in pure ohmic scenarios. Central reversed magnetic shear conditions have been achieved with on-axis counter-ECCD, accompanied by high electron temperature gradients, exhibiting internal transport barrier features. This improved electron transport is maintained for some time on the current flat-top when combining ECCD with ion cyclotron resonance heating in a (H)D minority scheme. Integrated interpretative analysis with the CRONOS code confirms that deeply reversed magnetic shear is indeed attained by on-axis counter-ECCD in low density conditions and in combination with a relatively fast controlled current ramp. The high electron temperature gradient is found to be located inside the negative magnetic shear region.

  15. Nonlinear Fundamental and Harmonic Cyclotron Resonant Scattering of Radiation Belt Ultra-Relativistic Electrons by Oblique Monochromatic EMIC Waves

    NASA Astrophysics Data System (ADS)

    Wang, G.; Su, Z.; Zheng, H.

    2016-12-01

    Cyclotron resonant scattering by electromagnetic ion cyclotron (EMIC) waves has been considered to be responsible for the rapid loss of radiation belt high-energy electrons. Recent studies have revealed the nonlinear character of cyclotron resonance with parallel-propagating EMIC waves. Here we investigate the fundamental and harmonic cyclotron resonance between radiation belt ultra-relativistic electrons and oblique monochromatic EMIC waves. We show that both fundamental and harmonic cyclotron resonance can exhibit significant nonlinearity for oblique EMIC waves. Higher wave obliquity allows stronger nonlinearity of harmonic resonance but weaker nonlinearity of fundamental resonance. The total transport coefficients of nonlinear resonances are found to deviate significantly from the quasi-linear predication. Increase of wave obliquity tends to reduce, to some extent, the difference between nonlinear and quasi-linear transport coefficients. These results suggest that the nonlinear resonant scattering even by oblique EMIC waves should be taken into account in future radiation belt modeling.

  16. Modeling of Trapped Electron Effects on Electron Cyclotron Current Drive for Recent DIII-D Experiments

    SciTech Connect

    Lin-Liu, Y.R.; Sauter, O.; Harvey, R.W.; Chan, V.S.; Luce, T.C.; Prater, R.

    1999-08-01

    Owing to its potential capability of generating localized non-inductive current, especially off-axis, Electron Cyclotron Current Drive (ECCD) is considered a leading candidate for current profile control in achieving Advanced Tokamak (AT) operation. In recent DIII-D proof-of-principle experiments [1], localized off-axis ECCD has been clearly demonstrated for first time. The measured current drive efficiency near the magnetic axis agrees well with predictions of the bounce-averaged Fokker-Planck theory [2,3]. However, the off-axis current drive efficiency was observed to exceed the theoretical results, which predict significant degradation of the current drive efficiency due to trapped electron effects. The theoretical calculations have been based on an assumption that the effective collision frequency is much smaller than the bounce frequency such that the trapped electrons are allowed to complete the banana orbit at all energies. The assumption might be justified in reactor-grade tokamak plasmas, in which the electron temperature is sufficiently high or the velocity of resonant electrons is much larger than the thermal velocity, so that the influence of collisionality on current drive efficiency can be neglected. For off-axis deposition in the present-day experiments, the effect of high density and low temperature is to reduce the current drive efficiency, but the increasing collisionality reduces the trapping of current-carrying electrons, leading to compensating increases in the current drive efficiency. In this work, we use the adjoint function formulation [4] to examine collisionality effects on the current drive efficiency.

  17. Small Signal Analysis of the Induced Resonance Electron Cyclotron Maser.

    DTIC Science & Technology

    1987-05-20

    Gaponov, H. I. Petelin and V. K. Yulpatov, Radiophys. Quantum Electron. 10, 794 (1967). 7. V. L. Bratman, M. A. Moiseev, M. I. Petelin and R. E. Ern...Radiophys. Quantum Electron. 16, 474 (1973). 8. D. V. Kisel’, G. S. Korablev, V. G. Navel’yev, M. I. Petelin and Sh. Ye. Tsimring, Radio Eng. Electron. Phys...19, No. 4, 95 (1974). 9. N. I. Zaytsev, T. B. Pankratova, M. I. Petelin and V. A. Flyagin, Radio Eng. Electron. Phys. 19, No. 5, 103 (1974). 10. V

  18. Ultracompact/ultralow power electron cyclotron resonance ion source for multipurpose applications

    SciTech Connect

    Sortais, P.; Lamy, T.; Medard, J.; Angot, J.; Latrasse, L.; Thuillier, T.

    2010-02-15

    In order to drastically reduce the power consumption of a microwave ion source, we have studied some specific discharge cavity geometries in order to reduce the operating point below 1 W of microwave power (at 2.45 GHz). We show that it is possible to drive an electron cyclotron resonance ion source with a transmitter technology similar to those used for cellular phones. By the reduction in the size and of the required microwave power, we have developed a new type of ultralow cost ion sources. This microwave discharge system (called COMIC, for COmpact MIcrowave and Coaxial) can be used as a source of light, plasma or ions. We will show geometries of conductive cavities where it is possible, in a 20 mm diameter chamber, to reduce the ignition of the plasma below 100 mW and define typical operating points around 5 W. Inside a simple vacuum chamber it is easy to place the source and its extraction system anywhere and fully under vacuum. In that case, current densities from 0.1 to 10 mA/cm{sup 2} (Ar, extraction 4 mm, 1 mAe, 20 kV) have been observed. Preliminary measurements and calculations show the possibility, with a two electrodes system, to extract beams within a low emittance. The first application for these ion sources is the ion injection for charge breeding, surface analyzing system and surface treatment. For this purpose, a very small extraction hole is used (typically 3/10 mm for a 3 {mu}A extracted current with 2 W of HF power). Mass spectrum and emittance measurements will be presented. In these conditions, values down to 1 {pi} mm mrad at 15 kV (1{sigma}) are observed, thus very close to the ones currently observed for a surface ionization source. A major interest of this approach is the possibility to connect together several COMIC devices. We will introduce some new on-going developments such as sources for high voltage implantation platforms, fully quartz radioactive ion source at ISOLDE or large plasma generators for plasma immersion, broad or ribbon

  19. Ultracompact/ultralow power electron cyclotron resonance ion source for multipurpose applicationsa)

    NASA Astrophysics Data System (ADS)

    Sortais, P.; Lamy, T.; Médard, J.; Angot, J.; Latrasse, L.; Thuillier, T.

    2010-02-01

    In order to drastically reduce the power consumption of a microwave ion source, we have studied some specific discharge cavity geometries in order to reduce the operating point below 1 W of microwave power (at 2.45 GHz). We show that it is possible to drive an electron cyclotron resonance ion source with a transmitter technology similar to those used for cellular phones. By the reduction in the size and of the required microwave power, we have developed a new type of ultralow cost ion sources. This microwave discharge system (called COMIC, for COmpact MIcrowave and Coaxial) can be used as a source of light, plasma or ions. We will show geometries of conductive cavities where it is possible, in a 20 mm diameter chamber, to reduce the ignition of the plasma below 100 mW and define typical operating points around 5 W. Inside a simple vacuum chamber it is easy to place the source and its extraction system anywhere and fully under vacuum. In that case, current densities from 0.1 to 10 mA/cm2 (Ar, extraction 4 mm, 1 mAe, 20 kV) have been observed. Preliminary measurements and calculations show the possibility, with a two electrodes system, to extract beams within a low emittance. The first application for these ion sources is the ion injection for charge breeding, surface analyzing system and surface treatment. For this purpose, a very small extraction hole is used (typically 3/10 mm for a 3 μA extracted current with 2 W of HF power). Mass spectrum and emittance measurements will be presented. In these conditions, values down to 1 π mm mrad at 15 kV (1σ) are observed, thus very close to the ones currently observed for a surface ionization source. A major interest of this approach is the possibility to connect together several COMIC devices. We will introduce some new on-going developments such as sources for high voltage implantation platforms, fully quartz radioactive ion source at ISOLDE or large plasma generators for plasma immersion, broad or ribbon beams

  20. Influence of static electron beam`s self-fields on the cyclotron-undulator resonance

    SciTech Connect

    Rozanov, N.E.; Golub, Yu.Ya. |

    1995-12-31

    When undulators with a leading magnetic field B are used, the regime of double resonance is possible in which an undulator period is equal to an electron cyclotron wavelength. In the vicinity of this resonance an amplitude of particle oscillations in the undulator strongly depends on a difference between B and a resonant value of the leading magnetic field. Consequently, it is important to investigate a role of self-fields of the electron beam, in particular, due to its influence on the electron cyclotron wavelength. At the paper analytically and by numerical simulation the influence of the static fields of the annular electron beam on its dynamics in the axisymmetrical magnetic undulator with the leading magnetic field in the vicinity of the cyclotron-undulator resonance is investigated. It is shown that the value of the resonant magnetic field is changed with the rise of beam`s current. A shift of the resonant magnetic field may be both to larger values of B and to smaller ones, when different values of beam and waveguide radii, beam energy and undulator period are considered. A width of the resonance (on B - scale) is increased with the beam current.

  1. Ionospheric Modification at Twice the Electron Cyclotron Frequency

    DTIC Science & Technology

    2007-11-02

    height electron density reflected in ionograms obtained at HAARP and backscatter profiles deduced from ionograms recorded during the ex- monitored from... ionograms were care- Finally, we note the similarity between the current work fully refitted to obtain the true-height electron density and studies of

  2. Free electron laser with small period wiggler and sheet electron beam: A study of the feasibility of operation at 300 GHz with 1 MW CW output power

    SciTech Connect

    Booske, J.H.; Granatstein, V.L.; Antonsen, T.M. Jr.; Destler, W.W.; Finn, J.; Latham, P.E.; Levush, B.; Mayergoyz, I.D.; Radack, D.; Rodgers, J.

    1988-01-01

    The use of a small period wiggler (/ell//sub ..omega../ < 1 cm) together with a sheet electron beam has been proposed as a low cost source of power for electron cyclotron resonance heating (ECRH) in magnetic fusion plasmas. Other potential applications include space-based radar systems. We have experimentally demonstrated stable propagation of a sheet beam (18 A. 1 mm /times/ 20 mm) through a ten-period wiggler electromagnet with peak field of 1.2 kG. Calculation of microwave wall heating and pressurized water cooling have also been carried out, and indicate the feasibility of operating a near-millimeter, sheet beam FEL with an output power of 1 MW CW (corresponding to power density into the walls of 2 kW/cm/sup 2/). Based on these encouraging results, a proof-of-principle experiment is being assembled, and is aimed at demonstrating FEL operating at 120 GHz with 300 kW output power in 1 ..mu..s pulses: electron energy would be 410 keV. Preliminary design of a 300 GHz 1 MW FEL with an untapered wiggler is also presented. 10 refs., 5 figs., 3 tabs.

  3. Observation of electron temperature turbulence with a correlation electron cyclotron emission radiometer on LHD

    NASA Astrophysics Data System (ADS)

    Kogi, Y.; Higashi, T.; Tamura, N.; Tsuchiya, H.; Kuwahara, D.; Nagayama, Y.; Mase, A.; Takehara, K.; Tokuzawa, T.

    2016-01-01

    Turbulence measurement is important in the study of plasma confinement. We developed a multi-channel correlation electron cyclotron emission (cECE) radiometer system, using an existing conventional ECE radiometer system (RADH) on a large helical device (LHD) . The signal received by the RADH was split and fed to our cECE system, and then electron temperatures at three separate radial positions were measured by resolving frequency component with three narrow (200 MHz) band-pass filters. Data taken by the cECE system were compared with those taken by the RADH system. Turbulence-like signals below 10 kHz were detected by the cECE measurement using coherence analysis, but were not detected by RADH measurement. We considered this to be due to differences in the radial separation length between the two channels and in the radial measurement depth of each channel. The cECE system was able to detect higher frequency turbulence because its separation length and measurement depth in the radial direction was shorter than the correlation length of the turbulence.

  4. Understanding the bursty electron cyclotron emission during a sawtooth crash in the HT-7 tokamak

    SciTech Connect

    Li, Erzhong Hu, Liqun; Chen, Kaiyun

    2014-01-15

    Bursts in electron cyclotron emission (ECE) were observed during sawtooth crashes in HT-7 in discharges with ion cyclotron resonance heating injected near the q = 1 rational surface (q is the safety factor). The local ECE measurement indicated that the bursty radiation is only observed on channels near but a little away outward from the q = 1 magnetic surface. In conjunction with the soft x-ray tomography analysis, it was determined that, for the first time, only a compression process survives in the later stage of fast magnetic reconnection but before prompt heat transport. The compression enhanced the electron radiation temperature, the increased amplitude of which agreed well with the estimation according to a kinetic compression theory model [R. J. Hastie and T. C. Hender, Nucl. Fusion 28, 585 (1988)]. This paper presents the experimental evidence that there indeed exists a transient compression phase which results in the bursty ECE radiation during a sawtooth crash.

  5. Studies on a Q/A selector for the SECRAL electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Sun, L. T.; Feng, Y. C.; Fang, X.; Lu, W.; Zhang, W. H.; Cao, Y.; Zhang, X. Z.; Zhao, H. W.

    2014-08-01

    Electron cyclotron resonance ion sources are widely used in heavy ion accelerators in the world because they are capable of producing high current beams of highly charged ions. However, the design of the Q/A selector system for these devices is challenging, because it must have a sufficient ion resolution while controlling the beam emittance growth. Moreover, this system has to be matched for a wide range of ion beam species with different intensities. In this paper, research on the Q/A selector system at the SECRAL (Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou) platform both in experiment and simulation is presented. Based on this study, a new Q/A selector system has been designed for SECRAL II. The features of the new design including beam simulations are also presented.

  6. Consequences of plasma rotation for neoclassical tearing mode suppression by electron cyclotron current drive

    SciTech Connect

    Ayten, B.; Westerhof, E.

    2012-09-15

    In the generalized Rutherford equation describing the nonlinear evolution of the width of the magnetic island associated with a neoclassical tearing mode, the effect of localized current drive is represented by a term {Delta}{sub CD}{sup Prime }. We investigate oscillations in {Delta}{sub CD}{sup Prime} originating from the rotation of the island through the electron cyclotron power deposition region and their dependence on the collisional time scale on which the driven current is generated, the rotation period, the island size, and the power deposition width. Furthermore, their consequences for the island growth or the stabilization are analyzed. This work shows that the net result of the oscillations in {Delta}{sub CD}{sup Prime} is a slight increase in the stabilizing effect of electron cyclotron current drive and consequently, a reduction in the minimum power requirement to fully suppress an island.

  7. Electron-cyclotron wave scattering by edge density fluctuations in ITER

    SciTech Connect

    Tsironis, Christos; Peeters, Arthur G.; Isliker, Heinz; Chatziantonaki, Ioanna; Vlahos, Loukas; Strintzi, Dafni

    2009-11-15

    The effect of edge turbulence on the electron-cyclotron wave propagation in ITER is investigated with emphasis on wave scattering, beam broadening, and its influence on localized heating and current drive. A wave used for electron-cyclotron current drive (ECCD) must cross the edge of the plasma, where density fluctuations can be large enough to bring on wave scattering. The scattering angle due to the density fluctuations is small, but the beam propagates over a distance of several meters up to the resonance layer and even small angle scattering leads to a deviation of several centimeters at the deposition location. Since the localization of ECCD is crucial for the control of neoclassical tearing modes, this issue is of great importance to the ITER design. The wave scattering process is described on the basis of a Fokker-Planck equation, where the diffusion coefficient is calculated analytically as well as computed numerically using a ray tracing code.

  8. Studies on a Q/A selector for the SECRAL electron cyclotron resonance ion source.

    PubMed

    Yang, Y; Sun, L T; Feng, Y C; Fang, X; Lu, W; Zhang, W H; Cao, Y; Zhang, X Z; Zhao, H W

    2014-08-01

    Electron cyclotron resonance ion sources are widely used in heavy ion accelerators in the world because they are capable of producing high current beams of highly charged ions. However, the design of the Q/A selector system for these devices is challenging, because it must have a sufficient ion resolution while controlling the beam emittance growth. Moreover, this system has to be matched for a wide range of ion beam species with different intensities. In this paper, research on the Q/A selector system at the SECRAL (Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou) platform both in experiment and simulation is presented. Based on this study, a new Q/A selector system has been designed for SECRAL II. The features of the new design including beam simulations are also presented.

  9. Advancements in electron cyclotron emission imaging demonstrated by the TEXTOR ECEI diagnostic upgrade

    SciTech Connect

    Tobias, B.; Kong, X.; Liang, T.; Spear, A.; Domier, C. W.; Luhmann, N. C. Jr.; Classen, I. G. J.; Boom, J. E.; Pol, M. J. van de; Jaspers, R.; Donne, A. J. H.; Park, H. K.; Munsat, T.

    2009-09-15

    A new TEXTOR electron cyclotron emission imaging system has been developed and employed, providing a diagnostic with new features and enhanced capabilities when compared to the legacy system it replaces. Optical coupling to the plasma has been completely redesigned, making use of new minilens arrays for reduced optical aberration and providing the new feature of vertical zoom, whereby the vertical coverage is now remotely adjustable on a shot-by-shot basis from 20-35 cm. Other innovations, such as the implementation of stacked quasioptical planar notch filters, allow for the diagnostic to be operated without interruption or degradation in performance during electron cyclotron resonance heating. Successful commissioning of the new diagnostic and a demonstration of the improved capabilities are presented in this paper, along with a discussion of the new technologies employed.

  10. Higher Harmonic Generation in the Induced Resonance Electron Cyclotron Maser.

    DTIC Science & Technology

    1987-09-01

    Schneider, Phys. Rev. Lett. 2, 504 (1959). 5. J. L. Hirshfield and J. M. Wachtel, Phys. Rev. Lett. 12, 533 (1964). 6. A. V. Gaponov, M. I. Petelin and...V. K. Yulpalov, Radio Phys. Quantum Electron. 10, 794 (1967). 7. V. L. Bratman, M. A. Moiseev, M. I. Petelin and R. E. Erm, Radio Phys. Quantum...Electron. 16, 474 (1973). 8. D. V. Kisel, G. S. Korablev, V. G. Navel’yev, M. I. Petelin and Sh. E. Tsimring, Radio Eng. Electron. Phys. 19, No. 4, 95 (1974

  11. Note: Production of a mercury beam with an electron cyclotron resonance ion source

    SciTech Connect

    Vondrasek, R.; Pardo, R.; Scott, R.

    2013-11-15

    An electron cyclotron resonance ion source has been utilized to produce mercury beams with intensities of 4.5 eμA of {sup 202}Hg{sup 29+} and 3.0 eμA of {sup 202}Hg{sup 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.

  12. Note: Production of a mercury beam with an electron cyclotron resonance ion source.

    PubMed

    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.

  13. Cyclotron auto resonance maser and free electron laser devices: a unified point of view

    NASA Astrophysics Data System (ADS)

    di Palma, E.; Sabia, E.; Dattoli, G.; Licciardi, S.; Spassovsky, I.

    2017-02-01

    We take advantage of previous research in the field of cyclotron auto resonance maser (CARM) and undulator-based free electron laser (U-FEL) sources to establish a common formalism for the relevant description of the underlying physical mechanisms. This strategy is aimed at stressing the deep analogies between the two devices and at providing a practical tool for their study based on the use of well-tested scaling formulae developed independently for the two systems.

  14. Open problems of magnetic island control by electron cyclotron current drive

    NASA Astrophysics Data System (ADS)

    Grasso, D.; Lazzaro, E.; Borgogno, D.; Comisso, L.

    2016-12-01

    This paper reviews key aspects of the problem of magnetic islands control by electron cyclotron current drive in fusion devices. On the basis of the ordering of the basic spatial and time scales of the magnetic reconnection physics, we present the established results, highlighting some of the open issues posed by the small-scale structures that typically accompany the nonlinear evolution of the magnetic islands and constrain the effect of the control action.

  15. Ray-tracing study of electron-cyclotron heating in toroidal geometry

    SciTech Connect

    Kritz, A.H.; Hsuan, H.; Goldfinger, R.C.; Batchelor, D.B.

    1983-03-01

    TORAY, a ray-tracing code has been developed to study electron-cyclotron heating and current drive in toroidal geometry. Ray patterns are initiated similar to those of an actual antenna and a full graphics package has been developed for displaying the behavior of the rays. We study the interplay of the plasma and wave parameters in order to establish which parameters are most important in determining the energy deposition.

  16. Open problems of magnetic island control by electron cyclotron current drive

    DOE PAGES

    Grasso, Daniela; Lazzaro, E.; Borgogno, D.; ...

    2016-11-17

    This study reviews key aspects of the problem of magnetic islands control by electron cyclotron current drive in fusion devices. On the basis of the ordering of the basic spatial and time scales of the magnetic reconnection physics, we present the established results, highlighting some of the open issues posed by the small-scale structures that typically accompany the nonlinear evolution of the magnetic islands and constrain the effect of the control action.

  17. Open problems of magnetic island control by electron cyclotron current drive

    SciTech Connect

    Grasso, Daniela; Lazzaro, E.; Borgogno, D.; Comisso, L.

    2016-11-17

    This study reviews key aspects of the problem of magnetic islands control by electron cyclotron current drive in fusion devices. On the basis of the ordering of the basic spatial and time scales of the magnetic reconnection physics, we present the established results, highlighting some of the open issues posed by the small-scale structures that typically accompany the nonlinear evolution of the magnetic islands and constrain the effect of the control action.

  18. The preliminary tests of the superconducting electron cyclotron resonance ion source DECRIS-SC2.

    PubMed

    Efremov, A; Bekhterev, V; Bogomolov, S; Drobin, V; Loginov, V; Lebedev, A; Yazvitsky, N; Yakovlev, B

    2012-02-01

    A new compact version of the "liquid He-free" superconducting ECR ion source, to be used as an injector of highly charged heavy ions for the MC-400 cyclotron, is designed and built at the Flerov Laboratory of Nuclear Reactions in collaboration with the Laboratory of High Energy Physics of JINR. The axial magnetic field of the source is created by the superconducting magnet and the NdFeB hexapole is used for the radial plasma confinement. The microwave frequency of 14 GHz is used for ECR plasma heating. During the first tests, the source shows a good enough performance for the production of medium charge state ions. In this paper, we will present the design parameters and the preliminary results with gaseous ions.

  19. Electron Cloud Cyclotron Resonances in the Presence of a Short-bunch-length Relativistic Beam

    SciTech Connect

    Celata, C.M.; Furman, Miguel A.; Vay, J.-L.; Yu, Jennifer W.

    2008-09-02

    Computer simulations using the 2D code"POSINST" were used to study the formation of the electron cloud in the wiggler section of the positron damping ring of the International Linear Collider. In order to simulate an x-y slice of the wiggler (i.e., a slice perpendicular to the beam velocity), each simulation assumed a constant vertical magnetic field. At values of the magnetic field where the cyclotron frequency was an integral multiple of the bunch frequency, and where the field strength was less than approximately 0.6 T, equilibrium average electron densities were up to three times the density found at other neighboring field values. Effects of this resonance between the bunch and cyclotron frequency are expected to be non-negligible when the beam bunch length is much less than the product of the electron cyclotron period and the beam velocity, for a beam moving at v~;;c. Details of the dynamics of the resonance are described.

  20. Observation of quasi-periodic frequency sweeping in electron cyclotron emission of nonequilibrium mirror-confined plasma

    NASA Astrophysics Data System (ADS)

    Viktorov, M. E.; Shalashov, A. G.; Mansfeld, D. A.; Golubev, S. V.

    2016-12-01

    Chirping frequency patterns have been observed in the electron cyclotron emission from strongly nonequilibrium plasma confined in a table-top mirror magnetic trap. Such patterns are typical for the formation of nonlinear phase-space structures in a proximity of the wave-particle resonances of a kinetically unstable plasma, also known as the “holes and clumps” mechanism. Our data provides the first experimental evidence for the acting of this mechanism in the electron cyclotron frequency domain.

  1. Electron cyclotron heating of a tokamak reactor at down-shifted frequencies

    SciTech Connect

    Fidone, I.; Giruzzi, G.; Mazzucato, E.

    1985-01-01

    The absorption of electron cyclotron waves in a hot and dense tokamak plasma is investigated for the case of the extraordinary mode for outside launching. It is shown that, for electron temperatures T/sub e/ greater than or equal to 5 keV, strong absorption occurs for oblique propagation at frequencies significantly below the electron gyrofrequency at the plasma center. A new density dependence of the wave absorption is found which is more favorable for plasma heating than the familiar n/sub e//sup -1/ scaling.

  2. Two-dimensional numerical model of electron cyclotron resonance discharge with pointwise mappings

    SciTech Connect

    Eruhimov, V.; Semenov, V.

    2006-03-15

    We suggest a new approach to numerical modeling of electron distribution function in an electron cyclotron resonance (ECR) discharge. The method is based on a pointwise mapping of electron velocity over a single bounce oscillation. We limit our consideration to ECR heating, collisions, ionization, and ambipolar losses from the trap although other processes can be accounted for as well. The method gives a solution close to the brute-force particle-in-cell integration but is incomparably faster. Initial results of experiments are presented.

  3. Linear and Nonlinear Electron Cyclotron Interaction in Open Resonators.

    DTIC Science & Technology

    1981-05-07

    Electron., QE-1, 237(1965). 5. A. V. Gaponov, M~. I. Petelin , and V. K. Yulpatov, Radiophys. Quantum Electron, 10, 794 (1967). 6. Mi. Borenstein and W. E...V. Gaponov, M. I. Petelin , and V. K. Yulpatov, IEEE Trans. MTT-25, 514 (1977). 11. J. L. Hirshfield and V. L. Granatstein, IEEE Trans. MIrT-25, 522...14. A. A. Andronov, V. A. Flyagin, A. V. Gaponov, A. L. Gol’denberg, M. I. Petelin , V. G. Usov, and V. K. Yulpatov, Infrared Physics 18, 385 (1978

  4. Laboratory study of pulsed regimes of electron cyclotron instabilities in a mirror-confined plasma for astrophysical applications

    NASA Astrophysics Data System (ADS)

    Viktorov, Mikhail; Golubev, Sergey; Mansfeld, Dmitry; Izotov, Ivan; Gospodchikov, Egor; Shalashov, Alexander; Demekhov, Andrei

    2014-05-01

    We discuss the use of a mirror-confined plasma of the electron cyclotron resonance discharge for modeling of burst processes in the inner magnetosphere of the Earth associated with the implementation of the plasma cyclotron maser. Heating under the electron cyclotron resonance conditions allows to create two component plasma which is typical for the inner magnetosphere of the Earth. One of the most interesting electron cyclotron resonance manifestations is the generation of bursts of electromagnetic radiation that are related to the explosive growth of cyclotron instabilities of the magnetoactive plasma confined in magnetic traps of various kinds and that are accompanied by particle precipitations from the trap. We investigate several regimes of cyclotron maser which are realized in dense and rarefied plasma, in the presence and absence of a permanent powerful gyrotron microwave radiation as a source of nonequilibrium particles in the plasma. Using the new technique for detection of microwave radiation we studied the dynamical spectrum and the intensity of stimulated electromagnetic radiation from the plasma in a wide frequency band covering all types of cyclotron instabilities. Also possible applications for astrophysical plasma are discussed.

  5. Development of Compact Electron Cyclotron Resonance Ion Source with Permanent Magnets for High-Energy Carbon-Ion Therapy

    NASA Astrophysics Data System (ADS)

    Muramatsu, M.; Kitagawa, A.; Iwata, Y.; Hojo, S.; Sakamoto, Y.; Sato, S.; Ogawa, Hirotsugu; Yamada, S.; Ogawa, Hiroyuki; Yoshida, Y.; Ueda, T.; Miyazaki, H.; Drentje, A. G.

    2008-11-01

    Heavy-ion cancer treatment is being carried out at the Heavy Ion Medical Accelerator in Chiba (HIMAC) with 140 to 400 MeV/n carbon ions at National Institute of Radiological Sciences (NIRS) since 1994. At NIRS, more than 4,000 patients have been treated, and the clinical efficiency of carbon ion radiotherapy has been demonstrated for many diseases. A more compact accelerator facility for cancer therapy is now being constricted at the Gunma University. In order to reduce the size of the injector (consists of ion source, low-energy beam transport and post-accelerator Linac include these power supply and cooling system), an ion source requires production of highly charged carbon ions, lower electric power for easy installation of the source on a high-voltage platform, long lifetime and easy operation. A compact Electron Cyclotron Resonance Ion Source (ECRIS) with all permanent magnets is one of the best types for this purpose. An ECRIS has advantage for production of highly charged ions. A permanent magnet is suitable for reduce the electric power and cooling system. For this, a 10 GHz compact ECRIS with all permanent magnets (Kei2-source) was developed. The maximum mirror magnetic fields on the beam axis are 0.59 T at the extraction side and 0.87 T at the gas-injection side, while the minimum B strength is 0.25 T. These parameters have been optimized for the production of C4+ based on experience at the 10 GHz NIRS-ECR ion source. The Kei2-source has a diameter of 320 mm and a length of 295 mm. The beam intensity of C4+ was obtained to be 618 eμA under an extraction voltage of 30 kV. Outline of the heavy ion therapy and development of the compact ion source for new facility are described in this paper.

  6. A cyclotron resonance model of VLF chorus emissions detected during electron microburst precipitation

    NASA Astrophysics Data System (ADS)

    Skoug, R. M.; Datta, S.; McCarthy, M. P.; Parks, G. K.

    1996-10-01

    VLF chorus, consisting of narrowband rising frequency emissions, has often been observed in association with microburst electron precipitation. We present the first simultaneous rocket observations of these two phenomena, with emphasis on understanding the source of the VLF emissions. The rocket experiment was launched on May 6, 1993, from Poker Flat, Alaska (L=5.6). In this work, the observed 1-4 kHz chorus emissions are interpreted in terms of a cyclotron resonance interaction. The frequency range of the risers and the observed electron energy range agree with those required for this interaction. Using a criterion derived from the conservation of energy during an interaction, it is shown that a cold plasma cyclotron resonance interaction can produce the lower-frequency portions of the observed chorus risers, from ~1000 Hz to ~2500 Hz, while a warm plasma model is required to produce frequencies >2500 Hz. The warm plasma model assumes a two-component plasma, with an isotropic cold component and a bi-Maxwellian warm component. The effect of the warm component is to change the wave dispersion relation, allowing the production of the higher-frequency risers. A portion of the anisotropy required to produce the high-frequency emissions can also be provided by a loss cone distribution. The chorus source is estimated from this cyclotron resonance theory to be located near the equatorial plane.

  7. Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trap.

    PubMed

    Nikolaev, A G; Savkin, K P; Oks, E M; Vizir, A V; Yushkov, G Yu; Vodopyanov, A V; Izotov, I V; Mansfeld, D A

    2012-02-01

    A method for generating high charge state heavy metal ion beams based on high power microwave heating of vacuum arc plasma confined in a magnetic trap under electron cyclotron resonance conditions has been developed. A feature of the work described here is the use of a cusp magnetic field with inherent "minimum-B" structure as the confinement geometry, as opposed to a simple mirror device as we have reported on previously. The cusp configuration has been successfully used for microwave heating of gas discharge plasma and extraction from the plasma of highly charged, high current, gaseous ion beams. Now we use the trap for heavy metal ion beam generation. Two different approaches were used for injecting the vacuum arc metal plasma into the trap--axial injection from a miniature arc source located on-axis near the microwave window, and radial injection from sources mounted radially at the midplane of the trap. Here, we describe preliminary results of heating vacuum arc plasma in a cusp magnetic trap by pulsed (400 μs) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

  8. Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trapa)

    NASA Astrophysics Data System (ADS)

    Nikolaev, A. G.; Savkin, K. P.; Oks, E. M.; Vizir, A. V.; Yushkov, G. Yu.; Vodopyanov, A. V.; Izotov, I. V.; Mansfeld, D. A.

    2012-02-01

    A method for generating high charge state heavy metal ion beams based on high power microwave heating of vacuum arc plasma confined in a magnetic trap under electron cyclotron resonance conditions has been developed. A feature of the work described here is the use of a cusp magnetic field with inherent "minimum-B" structure as the confinement geometry, as opposed to a simple mirror device as we have reported on previously. The cusp configuration has been successfully used for microwave heating of gas discharge plasma and extraction from the plasma of highly charged, high current, gaseous ion beams. Now we use the trap for heavy metal ion beam generation. Two different approaches were used for injecting the vacuum arc metal plasma into the trap - axial injection from a miniature arc source located on-axis near the microwave window, and radial injection from sources mounted radially at the midplane of the trap. Here, we describe preliminary results of heating vacuum arc plasma in a cusp magnetic trap by pulsed (400 μs) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

  9. Upgrade of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN

    NASA Astrophysics Data System (ADS)

    Toivanen, V.; Bellodi, G.; Dimov, V.; Küchler, D.; Lombardi, A. M.; Maintrot, M.

    2016-02-01

    Linac3 is the first accelerator in the heavy ion injector chain of the Large Hadron Collider (LHC), providing multiply charged heavy ion beams for the CERN experimental program. The ion beams are produced with GTS-LHC, a 14.5 GHz electron cyclotron resonance ion source, operated in afterglow mode. Improvement of the GTS-LHC beam formation and beam transport along Linac3 is part of the upgrade program of the injector chain in preparation for the future high luminosity LHC. A mismatch between the ion beam properties in the ion source extraction region and the acceptance of the following Low Energy Beam Transport (LEBT) section has been identified as one of the factors limiting the Linac3 performance. The installation of a new focusing element, an einzel lens, into the GTS-LHC extraction region is foreseen as a part of the Linac3 upgrade, as well as a redesign of the first section of the LEBT. Details of the upgrade and results of a beam dynamics study of the extraction region and LEBT modifications will be presented.

  10. Progress of a room temperature electron cyclotron resonance ion source using evaporative cooling technology at Institute of Modern Physics

    SciTech Connect

    Lu, W.; Xiong, B.; Guo, S. Q.; Cao, R.; Ruan, L.; Zhang, X. Z.; Sun, L. T.; Feng, Y. C.; Ma, B. H.; Zhao, H. W.

    2014-02-15

    A new room temperature ECR ion source, Lanzhou Electron Cyclotron Resonance ion source No. 4 (LECR4, previously named DRAGON), is under intense construction at Institute of Modern Physics. LECR4 is designed to operate with 18 GHz microwave frequency. The maximum axial magnetic fields are 2.3 T at injection and 1.3 T at extraction, and the radial field at the plasma chamber wall of 76 mm inner diameter is 1.0–1.2 T. One of the unique features for LECR4 is that its axial solenoids are winded with solid square copper wires which are immersed in a kind of special evaporative cooling medium for cooling purpose. Till now, a prototype of the cooling system has been successfully constructed and tested, which has demonstrated that the cooling efficiency of the designed system could meet the requirements of LECR4 under the routine operation conditions. All the main components of the ion source have been completed. Assembly and commissioning is ongoing. The latest developments and test results will be presented in this paper.

  11. Design and fabrication of circular and rectangular components for electron-cyclotron-resonant heating of tandem mirror experiment-upgrade

    SciTech Connect

    Felker, B.; Calderon, M.O.; Chargin, A.K.; Coffield, F.E.; Lang, D.D.; Rubert, R.R.; Pedrotti, L.R.; Stallard, B.W.; Gallagher, N.C. Jr.; Sweeney, D.W.

    1983-11-18

    The electron-cyclotron-resonant heating (ECRH) systems of rectangular waveguides on Tandem Mirror Experiment-Upgrade (TMX-U) operated with a overall efficiency of 50%, each system using a 28-GHz, 200-kW pulsed gyrotron. We designed and built four circular-waveguide systems with greater efficiency and greater power-handling capabilities to replace the rectangular waveguides. Two of these circular systems, at the 5-kG second-harmonic heating locations, have a total transmission efficiency of >90%. The two systems at the 10-kG fundamental heating locations have a total transmission efficiency of 80%. The difference in efficiency is due to the additional components required to launch the microwaves in the desired orientation and polarization with respect to magnetic-field lines at the 10-kG points. These systems handle the total power available from each gyrotron but do not have the arcing limitation problem of the rectangular waveguide. Each system requires several complex components. The overall physical layout and the design considerations for the rectangular and circular waveguide components are described here.

  12. Upgrade of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN

    SciTech Connect

    Toivanen, V. Bellodi, G.; Dimov, V.; Küchler, D.; Lombardi, A. M.; Maintrot, M.

    2016-02-15

    Linac3 is the first accelerator in the heavy ion injector chain of the Large Hadron Collider (LHC), providing multiply charged heavy ion beams for the CERN experimental program. The ion beams are produced with GTS-LHC, a 14.5 GHz electron cyclotron resonance ion source, operated in afterglow mode. Improvement of the GTS-LHC beam formation and beam transport along Linac3 is part of the upgrade program of the injector chain in preparation for the future high luminosity LHC. A mismatch between the ion beam properties in the ion source extraction region and the acceptance of the following Low Energy Beam Transport (LEBT) section has been identified as one of the factors limiting the Linac3 performance. The installation of a new focusing element, an einzel lens, into the GTS-LHC extraction region is foreseen as a part of the Linac3 upgrade, as well as a redesign of the first section of the LEBT. Details of the upgrade and results of a beam dynamics study of the extraction region and LEBT modifications will be presented.

  13. Upgrade of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN.

    PubMed

    Toivanen, V; Bellodi, G; Dimov, V; Küchler, D; Lombardi, A M; Maintrot, M

    2016-02-01

    Linac3 is the first accelerator in the heavy ion injector chain of the Large Hadron Collider (LHC), providing multiply charged heavy ion beams for the CERN experimental program. The ion beams are produced with GTS-LHC, a 14.5 GHz electron cyclotron resonance ion source, operated in afterglow mode. Improvement of the GTS-LHC beam formation and beam transport along Linac3 is part of the upgrade program of the injector chain in preparation for the future high luminosity LHC. A mismatch between the ion beam properties in the ion source extraction region and the acceptance of the following Low Energy Beam Transport (LEBT) section has been identified as one of the factors limiting the Linac3 performance. The installation of a new focusing element, an einzel lens, into the GTS-LHC extraction region is foreseen as a part of the Linac3 upgrade, as well as a redesign of the first section of the LEBT. Details of the upgrade and results of a beam dynamics study of the extraction region and LEBT modifications will be presented.

  14. Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trap

    SciTech Connect

    Nikolaev, A. G.; Savkin, K. P.; Oks, E. M.; Vizir, A. V.; Yushkov, G. Yu.; Vodopyanov, A. V.; Izotov, I. V.; Mansfeld, D. A.

    2012-02-15

    A method for generating high charge state heavy metal ion beams based on high power microwave heating of vacuum arc plasma confined in a magnetic trap under electron cyclotron resonance conditions has been developed. A feature of the work described here is the use of a cusp magnetic field with inherent ''minimum-B'' structure as the confinement geometry, as opposed to a simple mirror device as we have reported on previously. The cusp configuration has been successfully used for microwave heating of gas discharge plasma and extraction from the plasma of highly charged, high current, gaseous ion beams. Now we use the trap for heavy metal ion beam generation. Two different approaches were used for injecting the vacuum arc metal plasma into the trap - axial injection from a miniature arc source located on-axis near the microwave window, and radial injection from sources mounted radially at the midplane of the trap. Here, we describe preliminary results of heating vacuum arc plasma in a cusp magnetic trap by pulsed (400 {mu}s) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

  15. A 140 mA cw deuteron electron cyclotron resonance source for the IFMIF-EVEDA project.

    PubMed

    Gobin, R; Beauvais, P-Y; Delferrière, O; De Menezes, D; Tuske, O; Adroit, G; Gauthier, Y; Harrault, F

    2008-02-01

    In the framework of the IFMIF-EVEDA phase (International Fusion Materials Irradiation Facility-Engineering Validation and Engineering Design Activities), the CEA-Saclay is in charged of the design and realization of the 140 mA cw deuteron source. The IFMIF EVEDA demonstrator will be installed in Japan in the next six years and will have to accelerate the deuteron beam up to 9 MeV. CEA will build the source and the low energy beam line (LEBT) and will test the cw high intensity deuteron production at Saclay. The SILHI source is an electron cyclotron resonance (ECR) source, operating at 2.45 GHz. In 2001, it produced more than 130 mA of deuteron beam in pulsed mode to minimize neutron production. Such a result pushes to develop a new ECR source based on the SILHI design and equipped with a specific extraction system. Several options of the accelerator column will be implemented in order to improve the reliability and the efficiency of the source. The IFMIF source and LEBT design will be reported.

  16. Progress of a room temperature electron cyclotron resonance ion source using evaporative cooling technology at Institute of Modern Physics.

    PubMed

    Lu, W; Xiong, B; Zhang, X Z; Sun, L T; Feng, Y C; Ma, B H; Guo, S Q; Cao, R; Ruan, L; Zhao, H W

    2014-02-01

    A new room temperature ECR ion source, Lanzhou Electron Cyclotron Resonance ion source No. 4 (LECR4, previously named DRAGON), is under intense construction at Institute of Modern Physics. LECR4 is designed to operate with 18 GHz microwave frequency. The maximum axial magnetic fields are 2.3 T at injection and 1.3 T at extraction, and the radial field at the plasma chamber wall of 76 mm inner diameter is 1.0-1.2 T. One of the unique features for LECR4 is that its axial solenoids are winded with solid square copper wires which are immersed in a kind of special evaporative cooling medium for cooling purpose. Till now, a prototype of the cooling system has been successfully constructed and tested, which has demonstrated that the cooling efficiency of the designed system could meet the requirements of LECR4 under the routine operation conditions. All the main components of the ion source have been completed. Assembly and commissioning is ongoing. The latest developments and test results will be presented in this paper.

  17. Conditions for electron-cyclotron maser emission in the solar corona

    NASA Astrophysics Data System (ADS)

    Morosan, D. E.; Zucca, P.; Bloomfield, D. S.; Gallagher, P. T.

    2016-05-01

    Context. The Sun is an active source of radio emission ranging from long duration radio bursts associated with solar flares and coronal mass ejections to more complex, short duration radio bursts such as solar S bursts, radio spikes and fibre bursts. While plasma emission is thought to be the dominant emission mechanism for most radio bursts, the electron-cyclotron maser (ECM) mechanism may be responsible for more complex, short-duration bursts as well as fine structures associated with long-duration bursts. Aims: We investigate the conditions for ECM in the solar corona by considering the ratio of the electron plasma frequency ωp to the electron-cyclotron frequency Ωe. The ECM is theoretically possible when ωp/ Ωe< 1. Methods: Two-dimensional electron density, magnetic field, plasma frequency, and electron cyclotron frequency maps of the off-limb corona were created using observations from SDO/AIA and SOHO/LASCO, together with potential field extrapolations of the magnetic field. These maps were then used to calculate ωp/Ωe and Alfvén velocity maps of the off-limb corona. Results: We found that the condition for ECM emission (ωp/ Ωe< 1) is possible at heights <1.07 R⊙ in an active region near the limb; that is, where magnetic field strengths are >40 G and electron densities are >3 × 108 cm-3. In addition, we found comparatively high Alfvén velocities (>0.02c or >6000 km s-1) at heights <1.07 R⊙ within the active region. Conclusions: This demonstrates that the condition for ECM emission is satisfied within areas of the corona containing large magnetic fields, such as the core of a large active region. Therefore, ECM could be a possible emission mechanism for high-frequency radio and microwave bursts.

  18. Observations of correlated broadband electrostatic noise and electron-cyclotron emissions in the plasma sheet. Technical report

    SciTech Connect

    Roeder, J.L.; Angelopoulos, V.; Baumjohann, W.; Anderson, R.R.

    1991-11-15

    Electric field wave observations in the central plasma sheet of the earth's magnetosphere show the correlated occurrence of broadband electrostatic noise and electrostatic electron cyclotron harmonic emissions. A model is proposed in which the broadband emissions are electron acoustic waves generated by an observed low energy electron beam, and the cyclotron emissions are generated by the hot electron loss cone instability. The high degree of correlation between the two emissions is provided in the model by the presence of the cold electron beam population, which allows both of the plasma instabilities to grow.

  19. Electron cyclotron maser emission at oblique angles. [decametric radio bursts from Jupiter

    NASA Technical Reports Server (NTRS)

    Melrose, D. B.; Dulk, G. A.

    1993-01-01

    Possible causes of observations of electron cyclotron maser emissions (ECMEs) at oblique angle (about 60 deg) to the magnetic field are investigated. The paper discusses general concepts of ECME in terms of resonant ellipses and considers electron distributions required to produce ECME at oblique angles, as well as the ways in which the most favorable of these distributions may be produced. A mechanism is proposed that might produce an appropriate 'spiraling beam' distribution, with a peak in velocity space at speed v - v(0) and pitch angle alpha = alpha(0) not equal to 0.

  20. Production of large resonant plasma volumes in microwave electron cyclotron resonance ion sources

    DOEpatents

    Alton, Gerald D.

    1998-01-01

    Microwave injection methods for enhancing the performance of existing electron cyclotron resonance (ECR) ion sources. The methods are based on the use of high-power diverse frequency microwaves, including variable-frequency, multiple-discrete-frequency, and broadband microwaves. The methods effect large resonant "volume" ECR regions in the ion sources. The creation of these large ECR plasma volumes permits coupling of more microwave power into the plasma, resulting in the heating of a much larger electron population to higher energies, the effect of which is to produce higher charge state distributions and much higher intensities within a particular charge state than possible in present ECR ion sources.

  1. X-ray-spectroscopy analysis of electron-cyclotron-resonance ion-source plasmas

    SciTech Connect

    Santos, J. P.; Martins, M. C.; Parente, F.; Costa, A. M.; Marques, J. P.; Indelicato, P.

    2010-12-15

    Analysis of x-ray spectra emitted by highly charged ions in an electron-cyclotron-resonance ion source (ECRIS) may be used as a tool to estimate the charge-state distribution (CSD) in the source plasma. For that purpose, knowledge of the electron energy distribution in the plasma, as well as the most important processes leading to the creation and de-excitation of ionic excited states are needed. In this work we present a method to estimate the ion CSD in an ECRIS through the analysis of the x-ray spectra emitted by the plasma. The method is applied to the analysis of a sulfur ECRIS plasma.

  2. Electron cyclotron maser emission at oblique angles. [decametric radio bursts from Jupiter

    NASA Technical Reports Server (NTRS)

    Melrose, D. B.; Dulk, G. A.

    1993-01-01

    Possible causes of observations of electron cyclotron maser emissions (ECMEs) at oblique angle (about 60 deg) to the magnetic field are investigated. The paper discusses general concepts of ECME in terms of resonant ellipses and considers electron distributions required to produce ECME at oblique angles, as well as the ways in which the most favorable of these distributions may be produced. A mechanism is proposed that might produce an appropriate 'spiraling beam' distribution, with a peak in velocity space at speed v - v(0) and pitch angle alpha = alpha(0) not equal to 0.

  3. Quasilinear theory of the ordinary-mode electron-cyclotron resonance in plasmas

    SciTech Connect

    Arunasalam, V.; Efthimion, P.C.; Hosea, J.C.; Hsuan, H.; Taylor, G.

    1983-11-01

    A coupled set of equations, one describing the time evolution of the ordinary-mode wave energy and the other describing the time evolution of the electron distribution function is presented. The wave damping is mainly determined by T/sub parallel/ while the radiative equilibrium is mainly an equipartition with T/sub perpendicular/. The time rate of change of T/sub perpendicular/, T/sub parallel/, particle (N/sub 0/), and current (J/sub parellel/) densities are examined for finite k/sub parallel/ electron-cyclotron-resonance heating of plasmas.

  4. Dual array 3D electron cyclotron emission imaging at ASDEX Upgrade

    SciTech Connect

    Classen, I. G. J. Bogomolov, A. V.; Domier, C. W.; Luhmann, N. C.; Suttrop, W.; Boom, J. E.; Tobias, B. J.; Donné, A. J. H.

    2014-11-15

    In a major upgrade, the (2D) electron cyclotron emission imaging diagnostic (ECEI) at ASDEX Upgrade has been equipped with a second detector array, observing a different toroidal position in the plasma, to enable quasi-3D measurements of the electron temperature. The new system will measure a total of 288 channels, in two 2D arrays, toroidally separated by 40 cm. The two detector arrays observe the plasma through the same vacuum window, both under a slight toroidal angle. The majority of the field lines are observed by both arrays simultaneously, thereby enabling a direct measurement of the 3D properties of plasma instabilities like edge localized mode filaments.

  5. Efficiency enhancement of anomalous-Doppler electron cyclotron masers with tapered magnetic field

    SciTech Connect

    Xie, Chao-Ran; Hou, Zhi-Ling; Kong, Ling-Bao E-mail: pkliu@pku.edu.cn; Liu, Pu-Kun E-mail: pkliu@pku.edu.cn; Du, Chao-Hai; Jin, Hai-Bo

    2014-02-15

    The efficiency of slow-wave electron cyclotron masers (ECM) is usually low, thus limiting the practical applications. Here, a method of tapered magnetic field is introduced for the efficiency enhancement of the slow-wave ECM. The numerical calculations show that the tapered magnetic-field method can enhance the efficiency of slow-wave ECM significantly. The effect of beam electron velocity spread on the efficiency has also been studied. Although the velocity spread reduces the efficiency, a great enhancement of efficiency can still be obtained by the tapered magnetic field method.

  6. Production of large resonant plasma volumes in microwave electron cyclotron resonance ion sources

    DOEpatents

    Alton, G.D.

    1998-11-24

    Microwave injection methods are disclosed for enhancing the performance of existing electron cyclotron resonance (ECR) ion sources. The methods are based on the use of high-power diverse frequency microwaves, including variable-frequency, multiple-discrete-frequency, and broadband microwaves. The methods effect large resonant ``volume`` ECR regions in the ion sources. The creation of these large ECR plasma volumes permits coupling of more microwave power into the plasma, resulting in the heating of a much larger electron population to higher energies, the effect of which is to produce higher charge state distributions and much higher intensities within a particular charge state than possible in present ECR ion sources. 5 figs.

  7. Particle simulation of intense electron cyclotron heating and beat-wave current drive

    SciTech Connect

    Cohen, B.I.

    1987-10-12

    High-power free-electron lasers make new methods possible for heating plasmas and driving current in toroidal plasmas with electromagnetic waves. We have undertaken particle simulation studies with one and two dimensional, relativistic particle simulation codes of intense pulsed electron cyclotron heating and beat-wave current drive. The particle simulation methods here are conventional: the algorithms are time-centered, second-order-accurate, explicit, leap-frog difference schemes. The use of conventional methods restricts the range of space and time scales to be relatively compact in the problems addressed. Nevertheless, experimentally relevant simulations have been performed. 10 refs., 2 figs.

  8. Commissioning of electron cyclotron emission imaging instrument on the DIII-D tokamak and first data

    SciTech Connect

    Tobias, B.; Domier, C. W.; Liang, T.; Kong, X.; Yu, L.; Luhmann, N. C. Jr.; Yun, G. S.; Park, H. K.; Classen, I. G. J; Boom, J. E.; Donne, A. J. H.; Munsat, T.; Nazikian, R.; Van Zeeland, M.; Boivin, R. L.

    2010-10-15

    A new electron cyclotron emission imaging diagnostic has been commissioned on the DIII-D tokamak. Dual detector arrays provide simultaneous two-dimensional images of T{sub e} fluctuations over radially distinct and reconfigurable regions, each with both vertical and radial zoom capability. A total of 320 (20 verticalx16 radial) channels are available. First data from this diagnostic demonstrate the acquisition of coherent electron temperature fluctuations as low as 0.1% with excellent clarity and spatial resolution. Details of the diagnostic features and capabilities are presented.

  9. Electron acceleration by Z-mode waves associated with cyclotron maser instability

    SciTech Connect

    Lee, K. H.; Lee, L. C.; Omura, Y.

    2012-12-15

    We demonstrate by a particle simulation that Z-mode waves generated by the cyclotron maser instability can lead to a significant acceleration of energetic electrons. In the particle simulation, the initial electron ring distribution leads to the growth of Z-mode waves, which then accelerate and decelerate the energetic ring electrons. The initial ring distribution evolves into an X-like pattern in momentum space, which can be related to the electron diffusion curves. The peak kinetic energy of accelerated electrons can reach 3 to 6 times the initial kinetic energy. We further show that the acceleration process is related to the 'nonlinear resonant trapping' in phase space, and the test-particle calculations indicate that the maximum electron energy gain {Delta}{epsilon}{sub max} is proportional to B{sub w}{sup 0.57}, where B{sub w} is the wave magnetic field.

  10. Turbulence and transport during electron cyclotron heating in the DIII-D tokamak

    SciTech Connect

    Rhodes, T L; Peebles, W A; DeBoo, J C; Prater, R; Kinsey, J E; deGrassie, J S; Bravenec, R V; Burrell, K H; Lohr, J; Petty, C C; Nguyen, X V; Doyle, E J; Greenfield, C M; Zeng, L; Zeeland, M A; Wang, G; Makowski, M A; Staebler, G M; St. John, H E; Solomon, W M

    2007-06-26

    The response of plasma parameters and broad wavenumber turbulence (1--40 cm{sup -1}, k{rho}{sub s} = 0.1--8) to auxiliary electron cyclotron heating (ECH) is reported on. In these plasmas the electron temperature responds most strongly to the ECH while the electron density and ion temperature are kept approximately constant. Thermal fluxes and diffusivities increase appreciably with ECH for both electron and ion channels. Significant changes to the density fluctuations over the full range of measured wavenumbers are observed. This range of wavenumbers encompasses that typically associated with ion temperature gradient, trapped electron mode, and electron temperature gradient modes. Changes in linear growth rates calculated using a gyrokinetic code show consistency with observed fluctuation increases over the whole range of wavenumbers.

  11. Analysis of x-ray spectrum obtained in electron cyclotron resonance x-ray source

    SciTech Connect

    Baskaran, R.; Selvakumaran, T.S.; Sunil Sunny, C.

    2006-03-15

    The analysis of the x-ray spectrum obtained in electron cyclotron resonance (ECR) x-ray source is carried out. Assuming single-particle motion, the electron acceleration and its final energy are calculated for TE{sub 111} cylindrical cavity field and uniform external dc magnetic field. In the calculation, initial coordinates of 40 000 electrons were uniformly selected over the central plane of the cavity using random number generator. The final energy of each electron when it hits the wall is stored and the electron energy distribution is obtained. Using the general purpose Monte Carlo N-particle transport code version 4A, the geometry of the ECR x-ray source is modeled. The x-ray energy spectrum is calculated for the geometry model and the numerically calculated electron energy distribution. The calculated x-ray spectrum is compared with the experimentally measured x-ray spectrum.

  12. Design of a compact, permanent magnet electron cyclotron resonance ion source for proton and H{sub 2}{sup +} beam production

    SciTech Connect

    Jia Xianlu; Zhang Tianjue; Wang Chuan; Zheng Xia; Yin Zhiguo; Zhong Junqing; Wu Longcheng; Qin Jiuchang; Luo Shan

    2010-02-15

    A 2.45 GHz microwave ion source was developed at China Institute of Atomic Energy (CIAE) for proton beam production of over 60 mA [B.-Q. Cui, Y.-W. Bao, L.-Q. Li, W.-S. Jiang, and R.-W. Wang, Proceedings of the High Current Electron Cyclotron Resonance (ECR) Ion Source for Proton Accelerator, APAC-2001, 2001 (unpublished)]. For various proton beam applications, another 2.45 GHz microwave ion source with a compact structure is designed and will be built at CIAE as well for high current proton beam production. It is also considered to be used for the test of H{sub 2}{sup +} beam, which could be injected into the central region model cyclotron at CIAE, and accelerated to 5 MeV before extraction by stripping. The required ECR magnetic field is supplied by all the permanent magnets rather than electrical solenoids and six poles. The magnetic field distribution provided by this permanent magnets configuration is a large and uniformly volume of ECR zone, with central magnetic field of a magnitude of {approx}875 Gs[T. Taylor and J. S. C. Wills, Nucl. Instrum. Methods Phys. Res. A 309, 37 (1991)]. The field adjustment at the extraction end can be implemented by moving the position of the magnet blocks. The results of plasma, coupling with 2.45 GHz microwave in the ECR zone inside the ion source are simulated by particle-in-cell code to optimize the density by adjusting the magnetic field distribution. The design configuration of the ion source will be summarized in the paper.

  13. Post calibration of the two-dimensional electron cyclotron emission imaging instrument with electron temperature characteristics of the magnetohydrodynamic instabilities

    NASA Astrophysics Data System (ADS)

    Choi, M. J.; Park, H. K.; Yun, G. S.; Nam, Y. B.; Choe, G. H.; Lee, W.; Jardin, S.

    2016-01-01

    The electron cyclotron emission imaging (ECEI) instrument is widely used to study the local electron temperature (Te) fluctuations by measuring the ECE intensity IECE ∝ Te in tokamak plasmas. The ECEI measurement is often processed in a normalized fluctuation quantity against the time averaged value due to complication in absolute calibration. In this paper, the ECEI channels are relatively calibrated using the flat Te assumption of the sawtooth crash or the tearing mode island and a proper extrapolation. The 2-D relatively calibrated electron temperature (Te,rel) images are reconstructed and the displacement amplitude of the magnetohydrodynamic modes can be measured for the accurate quantitative growth analysis.

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

    NASA Technical Reports Server (NTRS)

    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.

  15. Mitigation of energetic electrons in the magnetosphere by amplified whistler wave under double cyclotron resonances

    NASA Astrophysics Data System (ADS)

    Kuo, S. P.

    2008-10-01

    An optimal approach reducing the population of MeV electrons in the magnetosphere is presented. Under a double resonance condition, whistler wave is simultaneously in cyclotron resonance with keV and MeV electrons. The injected whistler waves is first amplified by the background keV electrons via loss-cone negative mass instability to become effective in precipitating MeV electrons via cyclotron resonance elevated chaotic scattering. The numerical results show that a small amplitude whistler wave can be amplified by more than 25 dB. The amplification factor reduces only about 10 dB with a 30 dB increase of the initial wave intensity. Use of an amplified whistler wave to scatter 1.5 MeV electrons from an initial pitch angle of 86.5°to a pitch angle <50° is demonstrated. The ratio of the required wave magnetic field to the background magnetic field is calculated to be about 8×10-4.

  16. Simultaneous measurement of core electron temperature and density fluctuations during electron cyclotron heating on DIII-D

    SciTech Connect

    White, A. E.; Schmitz, L.; Peebles, W. A.; Rhodes, T. L.; Carter, T. A.; McKee, G. R.; Shafer, M. W.; Staebler, G. M.; Burrell, K. H.; DeBoo, J. C.; Prater, R.

    2010-02-15

    New measurements show that long-wavelength (k{sub t}hetarho{sub s}<0.5) electron temperature fluctuations can play an important role in determining electron thermal transport in low-confinement mode (L-mode) tokamak plasmas. In neutral beam-heated L-mode tokamak plasmas, electron thermal transport and the amplitude of long-wavelength electron temperature fluctuations both increase in cases where local electron cyclotron heating (ECH) is used to modify the plasma profiles. In contrast, the amplitude of simultaneously measured long-wavelength density fluctuations does not significantly increase. Linear stability analysis indicates that the ratio of the trapped electron mode (TEM) to ion temperature gradient (ITG) mode growth rates increases in the cases with ECH. The increased importance of the TEM drive relative to the ITG mode drive in the cases with ECH may be associated with the increases in electron thermal transport and electron temperature fluctuations.

  17. Influence of Bernstein modes on the efficiency of electron cyclotron resonance x-ray source

    SciTech Connect

    Andreev, V. V.; Nikitin, G.V.; Savanovich, V.Yu.; Umnov, A.M.; Elizarov, L.I.; Serebrennikov, K.S.; Vostrikova, E.A.

    2006-03-15

    The article considers the factors influencing the temperature of hot electron component in an electron cyclotron resonance (ECR) x-ray source. In such sources the electron heating occurs often due to extraordinary electromagnetic wave propagating perpendicularly to the magnetic field. In this case the possibility of the absorption of Bernstein modes is regarded as an additional mechanism of electron heating. The Bernstein modes in an ECR x-ray source can arise due to either linear transformation or parametric instability of external transversal wave. The article briefly reviews also the further experiments which will be carried out to study the influence of Bernstein modes on the increase of hot electron temperature and consequently of x-ray emission.

  18. The nonlinear theory of slow-wave electron cyclotron masers with inclusion of the beam velocity spread

    SciTech Connect

    Kong, Ling-Bao; Wang, Hong-Yu; Hou, Zhi-Ling; Jin, Hai-Bo; Du, Chao-Hai

    2013-12-15

    The nonlinear theory of slow-wave electron cyclotron masers (ECM) with an initially straight electron beam is developed. The evolution equation of the nonlinear beam electron energy is derived. The numerical studies of the slow-wave ECM efficiency with inclusion of Gaussian beam velocity spread are presented. It is shown that the velocity spread reduces the interaction efficiency. -- Highlights: •The theory of slow-wave electron cyclotron masers is considered. •The calculation of efficiency under the resonance condition is presented. •The efficiency under Gaussian velocity spreads has been obtained.

  19. Coherent and Tunable Terahertz Radiation from Graphene Surface Plasmon Polarirons Excited by Cyclotron Electron Beam

    NASA Astrophysics Data System (ADS)

    Zhao, Tao; Gong, Sen; Hu, Min; Zhong, Renbin; Liu, Diwei; Chen, Xiaoxing; Zhang, Ping; Wang, Xinran; Zhang, Chao; Wu, Peiheng; Liu, Shenggang

    2015-11-01

    Terahertz (THz) radiation can revolutionize modern science and technology. To this date, it remains big challenges to develop intense, coherent and tunable THz radiation sources that can cover the whole THz frequency region either by means of only electronics (both vacuum electronics and semiconductor electronics) or of only photonics (lasers, for example, quantum cascade laser). Here we present a mechanism which can overcome these difficulties in THz radiation generation. Due to the natural periodicity of 2π of both the circular cylindrical graphene structure and cyclotron electron beam (CEB), the surface plasmon polaritions (SPPs) dispersion can cross the light line of dielectric, making transformation of SPPs into radiation immediately possible. The dual natural periodicity also brings significant excellences to the excitation and the transformation. The fundamental and hybrid SPPs modes can be excited and transformed into radiation. The excited SPPs propagate along the cyclotron trajectory together with the beam and gain energy from the beam continuously. The radiation density is enhanced over 300 times, up to 105 W/cm2. The radiation frequency can be widely tuned by adjusting the beam energy or chemical potential. This mechanism opens a way for developing desired THz radiation sources to cover the whole THz frequency regime.

  20. Coherent and Tunable Terahertz Radiation from Graphene Surface Plasmon Polarirons Excited by Cyclotron Electron Beam

    PubMed Central

    Zhao, Tao; Gong, Sen; Hu, Min; Zhong, Renbin; Liu, Diwei; Chen, Xiaoxing; Zhang, Ping; Wang, Xinran; Zhang, Chao; Wu, Peiheng; Liu, Shenggang

    2015-01-01

    Terahertz (THz) radiation can revolutionize modern science and technology. To this date, it remains big challenges to develop intense, coherent and tunable THz radiation sources that can cover the whole THz frequency region either by means of only electronics (both vacuum electronics and semiconductor electronics) or of only photonics (lasers, for example, quantum cascade laser). Here we present a mechanism which can overcome these difficulties in THz radiation generation. Due to the natural periodicity of 2π of both the circular cylindrical graphene structure and cyclotron electron beam (CEB), the surface plasmon polaritions (SPPs) dispersion can cross the light line of dielectric, making transformation of SPPs into radiation immediately possible. The dual natural periodicity also brings significant excellences to the excitation and the transformation. The fundamental and hybrid SPPs modes can be excited and transformed into radiation. The excited SPPs propagate along the cyclotron trajectory together with the beam and gain energy from the beam continuously. The radiation density is enhanced over 300 times, up to 105 W/cm2. The radiation frequency can be widely tuned by adjusting the beam energy or chemical potential. This mechanism opens a way for developing desired THz radiation sources to cover the whole THz frequency regime. PMID:26525516

  1. Detection of electron energy distribution function anisotropy in a magnetized electron cyclotron resonance plasma by using a directional Langmuir probe

    SciTech Connect

    Shikama, T. Hasuo, M.; Kitaoka, H.

    2014-07-15

    Anisotropy in the electron energy distribution function (EEDF) in an electron cyclotron resonance plasma with magnetized electrons and weakly magnetized ions is experimentally investigated using a directional Langmuir probe. Under an assumption of independent EEDFs in the directions parallel and perpendicular to the magnetic field, the directional variation of the EEDF is evaluated. In the measured EEDFs, a significantly large population density of electrons with energies larger than 30 eV is found in one of the cross-field directions depending on the magnetic field direction. With the aid of an electron trajectory calculation, it is suggested that the observed anisotropic electrons originate from the EEDF anisotropy and the cross-field electron drift.

  2. Physics design of the in-vessel collection optics for the ITER electron cyclotron emission diagnostic.

    PubMed

    Rowan, W L; Houshmandyar, S; Phillips, P E; Austin, M E; Beno, J H; Hubbard, A E; Khodak, A; Ouroua, A; Taylor, G

    2016-11-01

    Measurement of the electron cyclotron emission (ECE) is one of the primary diagnostics for electron temperature in ITER. In-vessel, in-vacuum, and quasi-optical antennas capture sufficient ECE to achieve large signal to noise with microsecond temporal resolution and high spatial resolution while maintaining polarization fidelity. Two similar systems are required. One views the plasma radially. The other is an oblique view. Both views can be used to measure the electron temperature, while the oblique is also sensitive to non-thermal distortion in the bulk electron distribution. The in-vacuum optics for both systems are subject to degradation as they have a direct view of the ITER plasma and will not be accessible for cleaning or replacement for extended periods. Blackbody radiation sources are provided for in situ calibration.

  3. Physics design of the in-vessel collection optics for the ITER electron cyclotron emission diagnostic

    DOE PAGES

    Rowan, W. L.; Houshmandyar, S.; Phillips, P. E.; ...

    2016-09-07

    Measurement of the electron cyclotron emission (ECE) is one of the primary diagnostics for electron temperature in ITER. In-vessel, in-vacuum, and quasi-optical antennas capture sufficient ECE to achieve large signal to noise with microsecond temporal resolution and high spatial resolution while maintaining polarization fidelity. Two similar systems are required. One views the plasma radially. The other is an oblique view. Both views can be used to measure the electron temperature, while the oblique is also sensitive to non-thermal distortion in the bulk electron distribution. The in-vacuum optics for both systems are subject to degradation as they have a direct viewmore » of the ITER plasma and will not be accessible for cleaning or replacement for extended periods. Here, blackbody radiation sources are provided for in situ calibration.« less

  4. Physics design of the in-vessel collection optics for the ITER electron cyclotron emission diagnostic

    SciTech Connect

    Rowan, W. L.; Houshmandyar, S.; Phillips, P. E.; Austin, M. E.; Beno, J. H.; Hubbard, A. E.; Khodak, A.; Ouroua, A.; Taylor, G.

    2016-09-07

    Measurement of the electron cyclotron emission (ECE) is one of the primary diagnostics for electron temperature in ITER. In-vessel, in-vacuum, and quasi-optical antennas capture sufficient ECE to achieve large signal to noise with microsecond temporal resolution and high spatial resolution while maintaining polarization fidelity. Two similar systems are required. One views the plasma radially. The other is an oblique view. Both views can be used to measure the electron temperature, while the oblique is also sensitive to non-thermal distortion in the bulk electron distribution. The in-vacuum optics for both systems are subject to degradation as they have a direct view of the ITER plasma and will not be accessible for cleaning or replacement for extended periods. Here, blackbody radiation sources are provided for in situ calibration.

  5. Physics design of the in-vessel collection optics for the ITER electron cyclotron emission diagnostic

    SciTech Connect

    Rowan, W. L. Houshmandyar, S.; Phillips, P. E.; Austin, M. E.; Beno, J. H.; Ouroua, A.; Hubbard, A. E.; Khodak, A.; Taylor, G.

    2016-11-15

    Measurement of the electron cyclotron emission (ECE) is one of the primary diagnostics for electron temperature in ITER. In-vessel, in-vacuum, and quasi-optical antennas capture sufficient ECE to achieve large signal to noise with microsecond temporal resolution and high spatial resolution while maintaining polarization fidelity. Two similar systems are required. One views the plasma radially. The other is an oblique view. Both views can be used to measure the electron temperature, while the oblique is also sensitive to non-thermal distortion in the bulk electron distribution. The in-vacuum optics for both systems are subject to degradation as they have a direct view of the ITER plasma and will not be accessible for cleaning or replacement for extended periods. Blackbody radiation sources are provided for in situ calibration.

  6. Physics design of the in-vessel collection optics for the ITER electron cyclotron emission diagnostic

    NASA Astrophysics Data System (ADS)

    Rowan, W. L.; Houshmandyar, S.; Phillips, P. E.; Austin, M. E.; Beno, J. H.; Hubbard, A. E.; Khodak, A.; Ouroua, A.; Taylor, G.

    2016-11-01

    Measurement of the electron cyclotron emission (ECE) is one of the primary diagnostics for electron temperature in ITER. In-vessel, in-vacuum, and quasi-optical antennas capture sufficient ECE to achieve large signal to noise with microsecond temporal resolution and high spatial resolution while maintaining polarization fidelity. Two similar systems are required. One views the plasma radially. The other is an oblique view. Both views can be used to measure the electron temperature, while the oblique is also sensitive to non-thermal distortion in the bulk electron distribution. The in-vacuum optics for both systems are subject to degradation as they have a direct view of the ITER plasma and will not be accessible for cleaning or replacement for extended periods. Blackbody radiation sources are provided for in situ calibration.

  7. Diffusion coefficients from resonant interactions with electrostatic electron cyclotron harmonic waves

    SciTech Connect

    Tripathi, A. K.; Singhal, R. P.

    2009-11-15

    Pitch-angle diffusion coefficients have been calculated for resonant interaction with electrostatic electron cyclotron harmonic (ECH) waves using quasilinear diffusion theory. Unlike previous calculations, the parallel group velocity has been included in this study. Further, ECH wave intensity is expressed as a function of wave frequency and wave normal angle with respect to ambient magnetic field. It is found that observed wave electric field amplitudes in Earth's magnetosphere are sufficient to set electrons on strong diffusion in the energy ranges of a few hundred eV. However, the required amplitudes are larger than the observed values for keV electrons and higher by about a factor of 3 compared to past calculations. Required electric field amplitudes are smaller at larger radial distances. It is concluded that ECH waves are responsible for diffuse auroral precipitation of electrons with energies less than about 500 eV.

  8. Production of U beam from RIKEN 18 GHz electron cyclotron resonance ion source

    SciTech Connect

    Higurashi, Y.; Nakagawa, T.; Kidera, M.; Haba, H.; Aihara, T.; Kase, M.; Goto, A.; Yano, Y.

    2008-02-15

    For the RIKEN radio isotope factory (RIBF) project, we produced the multicharged uranium beam with two methods. To produce lower charge state U ion beams (14+-20+) we used the UF{sub 6} gas as an ionized gas. The typical beam intensity of U{sup 14+-20+} was 2-1 particle {mu}A at the extraction voltage of 14 kV. To produce higher charge state U ion beam (U{sup 35+}), we chose the sputtering method. The beam intensity was 70 particle nA at the extraction voltage of 5.4 kV. Using this method, we successfully produced multicharged U beam continuously for one month without break for RIBF commissioning.

  9. The 8.4 MW Modulator/Regulator Power Systems for the Electron Cyclotron Heating Facility Upgrade at DIII-D

    SciTech Connect

    S.G.E. Pronko; D.S. Baggest

    1999-12-01

    Over the next three years the DIII-D National Fusion Facility at General Atomics will upgrade its electron cyclotron heating (ECH) capability from the present 3 MW at 110 GHz to 10 MW of injected microwave power. There will be ten gyrotron tubes supplied by five 8.4 MW modulator/regulator (M/R) power systems. The project has gained considerable leverage from the acquisition of surplus hardware from the MFTF program that was conducted at LLNL in the early 1980s. One of these systems had been refurbished and converted for use as an ECH power supply earlier. The experience gained and the lessons learned from operating that system have proved valuable in guiding the engineering of the new systems. This paper provides an overview of the power system design and a report on the present status of the project.

  10. Compact injector with alternating phase focusing-interdigital H-mode linac and superconducting electron cyclotron resonance ion source for heavy ion cancer therapy

    NASA Astrophysics Data System (ADS)

    Hayashizaki, Noriyosu; Hattori, Toshiyuki; Matsui, Shinjiro; Tomizawa, Hiromitsu; Yoshida, Toru; Isokawa, Katsushi; Kitagawa, Atsushi; Muramatsu, Masayuki; Yamada, Satoru; Okamura, Masahiro

    2000-02-01

    We have researched a compact medical accelerator with low investment and running cost for the popularization of heavy ion cancer therapy. As the first step, the compact injector system has been investigated for a Heavy Ion Medical Accelerator in Chiba at National Institute of Radiological Sciences. The proposed new injector system consists of a 6 MeV/u interdigital H-mode (IH) linac of 3.1 m long and a 18 GHz superconducting electron cyclotron resonance (ECR) (SC-ECR) ion source. The IH linac with high power efficiency is appropriate to a medical and industrial injector system. Its beam trajectory was simulated and a prototype has been constructed. The SC-ECR ion source has been designed to realize lightweight and low power consumption and the mirror field distribution was estimated.

  11. Fundamental mode rectangular waveguide system for electron-cyclotron resonant heating (ECRH) for tandem mirror experiment-upgrade (TMX-U)

    SciTech Connect

    Rubert, R.R.; Felker, B.; Stallard, B.W.; Williams, C.W.

    1983-12-01

    We present a brief history of TMX-U's electron cyclotron resonant heating (ECRH) progress. We emphasize the 2-year performance of the system, which is composed of four 200-kW pulsed gyrotrons operated at 28 GHz. This system uses WR42 waveguide inside the vacuum vessel, and includes barrier windows, twists, elbows, and antennas, as well as custom-formed waveguides. Outside the TMX-U vessel are directional couplers, detectors, elbows, and waveguide bends in WR42 rectangular waveguide. An arc detector, mode filter, eight-arm mode converter, and water load in the 2.5-in. circular waveguide are attached directly to the gyrotron. Other specific areas discussed include the operational performance of the TMX-U pulsed gyrotrons, windows and component arcing, alignment, mode generation, and extreme temperature variations. Solutions for a number of these problems are described.

  12. Performance of the Argonne National Laboratory electron cyclotron resonance charge breeder

    SciTech Connect

    Vondrasek, R.; Kolomiets, A.; Levand, A.; Pardo, R.; Savard, G.; Scott, R.

    2011-05-15

    An electron cyclotron resonance charge breeder for the Californium rare ion breeder upgrade (CARIBU), a new radioactive beam facility for the Argonne Tandem Linac Accelerator System (ATLAS), has been constructed and commissioned. Charge breeding efficiencies up to 15.6% have been realized for stable beams with a typical breeding time of 10 ms/charge state. The CARIBU system has been undergoing commissioning tests utilizing a 100 mCi {sup 252}Cf fission source. A charge breeding efficiency of 14.8 {+-} 5% has been achieved for the first radioactive beam of {sup 143}Cs{sup 27+}.

  13. Performance of the Argonne National Laboratory electron cyclotron resonance charge breeder

    NASA Astrophysics Data System (ADS)

    Vondrasek, R.; Kolomiets, A.; Levand, A.; Pardo, R.; Savard, G.; Scott, R.

    2011-05-01

    An electron cyclotron resonance charge breeder for the Californium rare ion breeder upgrade (CARIBU), a new radioactive beam facility for the Argonne Tandem Linac Accelerator System (ATLAS), has been constructed and commissioned. Charge breeding efficiencies up to 15.6% have been realized for stable beams with a typical breeding time of 10 ms/charge state. The CARIBU system has been undergoing commissioning tests utilizing a 100 mCi 252Cf fission source. A charge breeding efficiency of 14.8 ± 5% has been achieved for the first radioactive beam of 143Cs27+.

  14. Synchrotron emissivity near the electron cyclotron and upper hybrid frequencies. [from dense, weakly relativistic plasma

    NASA Technical Reports Server (NTRS)

    Freund, H. P.; Wu, C. S.

    1977-01-01

    The spontaneous synchrotron emissivity from a high density, weakly relativistic plasma in thermal equilibrium is discussed. Thermal effects on the dielectric polarization of the plasma are included in the analysis, and the result is compared with computations of the emissivity based upon the cold plasma approximation. A numerical analysis is performed for frequencies in the vicinity of both the electron cyclotron frequency and the upper hybrid resonance. Significant modifications to the synchrotron emissivity in the cold plasma approximation are found in both of these frequency regimes.

  15. Rotation drive and momentum transport with electron cyclotron heating in tokamak plasmas.

    PubMed

    Yoshida, M; Sakamoto, Y; Takenaga, H; Ide, S; Oyama, N; Kobayashi, T; Kamada, Y

    2009-08-07

    The role of electron cyclotron resonance heating (ECRH) on the toroidal rotation velocity profile has been investigated in the JT-60U tokamak device by separating the effects of the change in momentum transport, the intrinsic rotation by pressure gradient, and the intrinsic rotation by ECRH. It is found that ECRH increases the toroidal momentum diffusivity and the convection velocity. It is also found that ECRH drives the codirection (co) intrinsic rotation inside the EC deposition radius and the counterdirection (ctr) intrinsic rotation outside the EC deposition radius. This ctr rotation starts from the EC deposition radius and propagates to the edge region.

  16. Status of the Bio-Nano electron cyclotron resonance ion source at Toyo University.

    PubMed

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

    2014-02-01

    In the paper, the material science experiments, carried out recently using the Bio-Nano electron cyclotron resonance ion source (ECRIS) at Toyo University, are reported. We have investigated several methods to synthesize endohedral C60 using ion-ion and ion-molecule collision reaction in the ECRIS. Because of the simplicity of the configuration, we can install a large choice of additional equipment in the ECRIS. The Bio-Nano ECRIS is suitable not only to test the materials production but also to test technical developments to improve or understand the performance of an ECRIS.

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

    SciTech Connect

    Asaji, T. Ohba, T.; Uchida, T.; Yoshida, Y.; Minezaki, H.; Ishihara, S.; Racz, R.; Biri, S.; Kato, Y.

    2014-02-15

    A synthesis technology of endohedral fullerenes such as Fe@C{sub 60} has developed with an electron cyclotron resonance (ECR) ion source. The production of N@C{sub 60} 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.

  18. Circular waveguide systems for electron-cyclotron-resonant heating of the tandem mirror experiment-upgrade

    SciTech Connect

    Felker, B.; Calderon, M.O.; Chargin, A.K.; Coffield, F.E.; Gallagher, N.C. Jr.; Lang, D.D.; Pedrotti, L.R.; Rubert, R.R.; Stallard, B.W.; Sweeney, D.W.

    1983-11-18

    Extensive use of electron cyclotron resonant heating (ECRH) in the Tandem Mirror Experiment-Upgrade (TMX-U) requires continuous development of components to improve efficiency, increase reliability, and deliver power to new locations with respect to the plasma. We have used rectangular waveguide components on the experiment and have developed, tested, and installed circular waveguide components. We replaced the rectangular with the circular components because of the greater transmission efficiency and power-handling capability of the circular ones. Design, fabrication, and testing of all components are complete for all systems. In this paper we describe the design criteria for the system.

  19. Bio-Nano ECRIS: An electron cyclotron resonance ion source for new materials production

    SciTech Connect

    Uchida, T.; Minezaki, H.; Tanaka, K.; Asaji, T.; Muramatsu, M.; Kitagawa, A.; Kato, Y.; Biri, S.

    2010-02-15

    We developed an electron cyclotron resonance ion source (ECRIS) for new materials production on nanoscale. Our main target is the endohedral fullerenes, which have potential in medical care, biotechnology, and nanotechnology. In particular, iron-encapsulated fullerene can be applied as a contrast material for magnetic resonance imaging or microwave heat therapy. Thus, our new ECRIS is named the Bio-Nano ECRIS. In this article, the recent progress of the development of the Bio-Nano ECRIS is reported: (i) iron ion beam production using induction heating oven and (ii) optimization of singly charged C{sub 60} ion beam production.

  20. Multicusp type machine for electron cyclotron resonance plasma with reduced dimensions

    NASA Astrophysics Data System (ADS)

    Amemiya, H.; Maeda, M.

    1996-03-01

    Plasmas are created in a cusp type magnetic trap using electron cyclotron resonance heating. The magnetic field is generated with permanent magnets forming a 12-pole, whereby the polarity at the ends of the rods has been reversed in order to obtain end plugs and to improve the plasma confinement. In this way, the plasma volume could be reduced such that the cross section was close to or smaller than the cutoff width of a circular waveguide. This increases the microwave power absorbed and gives a high plasma density even above the cutoff value.

  1. Note: Upgrade of electron cyclotron emission imaging system and preliminary results on HL-2A tokamak

    SciTech Connect

    Jiang, M. Shi, Z. B.; Zhong, W. L.; Chen, W.; Liu, Z. T.; Ding, X. T.; Yang, Q. W.; Zhang, B. Y.; Shi, P. W.; Liu, Y.; Fu, B. Z.; Xu, Y.; Domier, C. W.; Luhmann, N. C.; Yang, Z. C.

    2015-07-15

    The electron cyclotron emission imaging system on the HL-2A tokamak has been upgraded to 24 (poloidally) × 16 (radially) channels based on the previous 24 × 8 array. The measurement region can be flexibly shifted due to the independence of the two local oscillator sources, and the field of view can be adjusted easily by changing the position of the zoom lenses. The temporal resolution is about 2.5 μs and the achievable spatial resolution is 1 cm. After laboratory calibration, it was installed on HL-2A tokamak in 2014, and the local 2D mode structures of MHD activities were obtained for the first time.

  2. Polarization Studies in Electron Cyclotron Heating Experiments on the Versator II Tokamak.

    DTIC Science & Technology

    1982-07-30

    ae. Distribution/ POLARIZATION STUDIES IN ELECTRON Availability Codes CYCLOTRON HEATING EXPERIMENTS ON Avail and/or THE VERSATOR II TOKAMAK Dist...ON THE VERSATOR II TOKAMAK 08/25/80 - 08/25/81 S. PERFORMING ORG. REPORT NUMMER _J206-82-011/6202 7. AUTHOR(e) S. CONTRACT OR GRANT NUMER(e) NRL...toroidally confined plasmas, only recently has it become possible to perform such an experiment on the hot, well confined plasmas in a tokamak . This advance

  3. Enhancing the efficiency of slow-wave electron cyclotron masers with the tapered refractive index

    SciTech Connect

    Kong Lingbao; Hou Zhiling; Jing Jian; Jin Haibo; Du Chaohai

    2013-04-15

    The nonlinear analysis of slow-wave electron cyclotron masers (ECM) based on anomalous Doppler effect in a slab waveguide is presented. A method of tapered refractive index (TRI) is proposed to enhance the efficiency of slow-wave ECM. The numerical calculations show that the TRI method can significantly enhance the efficiency of slow-wave ECM with the frequency ranging from the microwave to terahertz band. The effect of beam velocity spread on the efficiency has also been studied. Although the velocity spread suppresses the efficiency significantly, a great enhancement of efficiency can still be introduced by the TRI method.

  4. Simulation and beamline experiments for the superconducting electron cyclotron resonance ion source VENUS

    SciTech Connect

    Todd, Damon S.; Leitner, Daniela; Lyneis, Claude M.; Grote, David P.

    2008-02-15

    The particle-in-cell code WARP has been enhanced to incorporate both two- and three-dimensional sheath extraction models giving WARP the capability of simulating entire ion beam transport systems including the extraction of beams from plasma sources. In this article, we describe a method of producing initial ion distributions for plasma extraction simulations in electron cyclotron resonance (ECR) ion sources based on experimentally measured sputtering on the source biased disk. Using this initialization method, we present preliminary results for extraction and transport simulations of an oxygen beam and compare them with experimental beam imaging on a quartz viewing plate for the superconducting ECR ion source VENUS.

  5. Bio-Nano ECRIS: An electron cyclotron resonance ion source for new materials productiona)

    NASA Astrophysics Data System (ADS)

    Uchida, T.; Minezaki, H.; Tanaka, K.; Muramatsu, M.; Asaji, T.; Kato, Y.; Kitagawa, A.; Biri, S.; Yoshida, Y.

    2010-02-01

    We developed an electron cyclotron resonance ion source (ECRIS) for new materials production on nanoscale. Our main target is the endohedral fullerenes, which have potential in medical care, biotechnology, and nanotechnology. In particular, iron-encapsulated fullerene can be applied as a contrast material for magnetic resonance imaging or microwave heat therapy. Thus, our new ECRIS is named the Bio-Nano ECRIS. In this article, the recent progress of the development of the Bio-Nano ECRIS is reported: (i) iron ion beam production using induction heating oven and (ii) optimization of singly charged C60 ion beam production.

  6. Effect of pulse-modulated microwaves on fullerene ion production with electron cyclotron resonance ion source.

    PubMed

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

    2012-02-01

    Fullerene plasmas generated by pulse-modulated microwaves have been investigated under typical conditions at the Bio-Nano electron cyclotron resonance ion source. The effect of the pulse modulation is distinct from that of simply structured gases, and then the density of the fullerene plasmas increased as decreasing the duty ratio. The density for a pulse width of 10 μs at the period of 100 μs is 1.34 times higher than that for CW mode. We have studied the responses of fullerene and argon plasmas to pulsed microwaves. After the turnoff of microwave power, fullerene plasmas lasted ∼30 times longer than argon plasmas.

  7. Demonstration of effective control of fast-ion-stabilized sawteeth by electron-cyclotron current drive.

    PubMed

    Lennholm, M; Eriksson, L-G; Turco, F; Bouquey, F; Darbos, C; Dumont, R; Giruzzi, G; Jung, M; Lambert, R; Magne, R; Molina, D; Moreau, P; Rimini, F; Segui, J-L; Song, S; Traisnel, E

    2009-03-20

    In a tokamak plasma, sawtooth oscillations in the central temperature, caused by a magnetohydrodynamic instability, can be partially stabilized by fast ions. The resulting less frequent sawtooth crashes can trigger unwanted magnetohydrodynamic activity. This Letter reports on experiments showing that modest electron-cyclotron current drive power, with the deposition positioned by feedback control of the injection angle, can reliably shorten the sawtooth period in the presence of ions with energies >or=0.5 MeV. Certain surprising elements of the results are evaluated qualitatively in terms of existing theory.

  8. Demonstration of Effective Control of Fast-Ion-Stabilized Sawteeth by Electron-Cyclotron Current Drive

    SciTech Connect

    Lennholm, M.; Eriksson, L.-G.; Turco, F; Bouquey, F.; Darbos, C.; Dumont, R.; Giruzzi, G.; Jung, M.; Lambert, R.; Magne, R.; Molina, D.; Moreau, P.; Rimini, F.; Segui, J-L.; Song, S.; Traisnel, E.

    2009-03-20

    In a tokamak plasma, sawtooth oscillations in the central temperature, caused by a magnetohydrodynamic instability, can be partially stabilized by fast ions. The resulting less frequent sawtooth crashes can trigger unwanted magnetohydrodynamic activity. This Letter reports on experiments showing that modest electron-cyclotron current drive power, with the deposition positioned by feedback control of the injection angle, can reliably shorten the sawtooth period in the presence of ions with energies {>=}0.5 MeV. Certain surprising elements of the results are evaluated qualitatively in terms of existing theory.

  9. Note: Upgrade of electron cyclotron emission imaging system and preliminary results on HL-2A tokamak.

    PubMed

    Jiang, M; Shi, Z B; Domier, C W; Luhmann, N C; Zhong, W L; Chen, W; Liu, Z T; Ding, X T; Yang, Q W; Zhang, B Y; Yang, Z C; Shi, P W; Liu, Y; Fu, B Z; Xu, Y

    2015-07-01

    The electron cyclotron emission imaging system on the HL-2A tokamak has been upgraded to 24 (poloidally) × 16 (radially) channels based on the previous 24 × 8 array. The measurement region can be flexibly shifted due to the independence of the two local oscillator sources, and the field of view can be adjusted easily by changing the position of the zoom lenses. The temporal resolution is about 2.5 μs and the achievable spatial resolution is 1 cm. After laboratory calibration, it was installed on HL-2A tokamak in 2014, and the local 2D mode structures of MHD activities were obtained for the first time.

  10. Wall-loss distribution of charge breeding ions in an electron cyclotron resonance ion source

    SciTech Connect

    Jeong, S. C.; Oyaizu, M.; Imai, N.; Hirayama, Y.; Ishiyama, H.; Miyatake, H.; Niki, K.; Okada, M.; Watanabe, Y. X.; Otokawa, Y.; Osa, A.; Ichikawa, S.

    2011-03-15

    The ion loss distribution in an electron cyclotron resonance ion source (ECRIS) was investigated to understand the element dependence of the charge breeding efficiency in an electron cyclotron resonance (ECR) charge breeder. The radioactive {sup 111}In{sup 1+} and {sup 140}Xe{sup 1+} ions (typical nonvolatile and volatile elements, respectively) were injected into the ECR charge breeder at the Tokai Radioactive Ion Accelerator Complex to breed their charge states. Their respective residual activities on the sidewall of the cylindrical plasma chamber of the source were measured after charge breeding as functions of the azimuthal angle and longitudinal position and two-dimensional distributions of ions lost during charge breeding in the ECRIS were obtained. These distributions had different azimuthal symmetries. The origins of these different azimuthal symmetries are qualitatively discussed by analyzing the differences and similarities in the observed wall-loss patterns. The implications for improving the charge breeding efficiencies of nonvolatile elements in ECR charge breeders are described. The similarities represent universal ion loss characteristics in an ECR charge breeder, which are different from the loss patterns of electrons on the ECRIS wall.

  11. Interpretation of the electron cyclotron emission signal from optically marginal plasmas

    NASA Astrophysics Data System (ADS)

    Ayub, Muhammad Khawar; Yun, Gunsu S.; Lee, Woochang; Park, Hyeon K.

    2017-02-01

    The interpretation of electron cyclotron emission (ECE) signal from the optically marginal region of magnetized plasma is presented. The density and the temperature fluctuations associated with the edge localized modes (ELMs) observed in the KSTAR tokamak are estimated by assuming an ELM filamentary structure as a flux tube bulges out like a ballooning mode instability. Synthetic ECE signals from the rotating ELM are calculated based on the measured electron temperature profile and an assumed electron density profile constrained by the measured line-averaged density, yielding an 0.02 relative fluctuation level in agreement with the experimental observations. The measured ECE signal is nearly in phase with the density modulation associated with the rotating ELM. This implies that the ECE signal corresponding to the ELM filaments has a significant contribution from the density fluctuations.

  12. Feasibility study for a correlation electron cyclotron emission turbulence diagnostic based on nonlinear gyrokinetic simulations

    NASA Astrophysics Data System (ADS)

    White, A. E.; Howard, N. T.; Mikkelsen, D. R.; Greenwald, M.; Candy, J.; Waltz, R. E.

    2011-11-01

    This paper describes the use of nonlinear gyrokinetic simulations to assess the feasibility of a new correlation electron cyclotron emission (CECE) diagnostic that has been proposed for the Alcator C-Mod tokamak (Marmar et al 2009 Nucl. Fusion 49 104014). This work is based on a series of simulations performed with the GYRO code (Candy and Waltz 2003 J. Comput. Phys. 186 545). The simulations are used to predict ranges of fluctuation level, peak poloidal wavenumber and radial correlation length of electron temperature fluctuations in the core of the plasma. The impact of antenna pattern and poloidal viewing location on measurable turbulence characteristics is addressed using synthetic diagnostics. An upper limit on the CECE sample volume size is determined. The modeling results show that a CECE diagnostic capable of measuring transport-relevant, long-wavelength (kθρs < 0.5) electron temperature fluctuations is feasible at Alcator C-Mod.

  13. DETAILED MEASUREMENTS OF THE ELECTRON CYCLOTRON CURRENT DRIVE EFFICIENCY ON DIIID

    SciTech Connect

    PETTY, C.C.; PRATER, R.; LOHR, J.; LUCE, T.C.; FOX,W.R.; HARVEY, R.W.; KINSEY, J.E.; LAO, L.L.; MAKOWSKI, M.A.

    2002-05-01

    Electron cyclotron current drive (ECCD) experiments on the DIII-D tokamak are solidifying the physics basis for localized, off-axis current drive, the goal being to validate a predictive model for ECCD. The ECCD profiles are determined from the magnetic field pitch angles measured by motional Stark effect (MSE) polarimetry. The measured ECCD switches from the co to the counter direction as the toroidal injection angle is varied with a profile width that is in accordance with ray tracing calculations. Tests of electron trapping in low beta plasmas show that the ECCD efficiency decreases rapidly as the deposition is moved off-axis and towards the outboard side of the plasma, but the detrimental effects of electron trapping on the current drive are greatly reduced in high beta plasmas. Overall, the measured ECCD is in good agreement with theoretical calculations using a quasilinear Fokker-Planck code over a wide range of injection angles and plasma parameters.

  14. A theory of electron cyclotron waves generated along auroral field lines observed by ground facilities

    NASA Technical Reports Server (NTRS)

    Wu, C. S.; Yoon, Peter H.; Freund, H. P.

    1989-01-01

    A generation mechanism for radio waves in the frequency range 150 - 700 kHz observed by ground facilities is suggested in terms of an electromagnetic electron cyclotron instability driven by auroral electrons. The excited waves can propagate downward along the ambient magnetic field lines and are thus observable with ground facilities. The trapped auroral electrons are supposed to play an important role in the generation process, because they give rise to a thermal anisotropy which consequently leads to the instability. The present work is a natural extension of the theory proposed earlier by Wu et al. (1983) which was discussed in a different context but may be used to explain the observed waves originated at low altitudes. This paper presents a possible wave generation mechanism valid in the entire auroral field-line region of interest.

  15. Electron cyclotron resonance ion source plasma characterization by energy dispersive x-ray imaging

    NASA Astrophysics Data System (ADS)

    Rácz, R.; Mascali, D.; Biri, S.; Caliri, C.; Castro, G.; Galatà, A.; Gammino, S.; Neri, L.; Pálinkás, J.; Romano, F. P.; Torrisi, G.

    2017-07-01

    Pinhole and CCD based quasi-optical x-ray imaging technique was applied to investigate the plasma of an electron cyclotron resonance ion source (ECRIS). Spectrally integrated and energy resolved images were taken from an axial perspective. The comparison of integrated images taken of argon plasma highlights the structural changes affected by some ECRIS setting parameters, like strength of the axial magnetic confinement, RF frequency and microwave power. Photon counting analysis gives precise intensity distribution of the x-ray emitted by the argon plasma and by the plasma chamber walls. This advanced technique points out that the spatial positions of the electron losses are strongly determined by the kinetic energy of the electrons themselves to be lost and also shows evidences how strongly the plasma distribution is affected by slight changes in the RF frequency.

  16. Amplification of radiation near cyclotron frequency due to electron population inversion

    NASA Technical Reports Server (NTRS)

    Lee, L. C.; Wu, C. S.

    1980-01-01

    Amplification of electromagnetic waves via the cyclotron maser mechanism by a population of weakly relativistic electrons is studied. The effect of a tenuous population of low energy background plasma is included. It is found that both the ordinary and extraordinary modes can be excited by the weakly relativistic electrons with a loss-cone distribution. The growth rate for the extraordinary mode is much higher than that for the ordinary mode. Velocity spread in the energetic electron distribution function may reduce the growth rate by a factor of approximately 10 from that in the monoenergetic case. The maximum growth rate for the fast extraordinary mode (X mode) occurs near the upper hybrid cutoff frequency. Numerical results are obtained and discussed.

  17. Simultaneous propagation of heat waves induced by sawteeth and electron cyclotron heating power modulation in the RTP tokamak

    SciTech Connect

    Gorini, G.; Mantica, P.; Hogeweij, G.M.D.; De Luca, F.; Jacchia, A.; Konings, J.A.; Lopes Cardozo, N.J.; Peters, M. Dipartimento di Fisica, universita degli Studi di Milano, via Celoria 16, I-20133 Milano Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNP, via Bassini 15, I-20133 Milano )

    1993-09-27

    The incremental electron heat diffusivity [chi][sup inc] is determined in Rijnhuizen Tokamak Project plasmas by measurements of simultaneous heat pulses due to (1) the sawtooth instability and (2) modulated electron cyclotron heating. No systematic difference is observed between the two measured [chi][sup inc] values, which are both significantly larger ([chi][sup inc]/[chi][sub [ital e

  18. Theoretical study of electromagnetic electron cyclotron waves in the presence of AC field in Uranian magnetosphere

    NASA Astrophysics Data System (ADS)

    Pandey, R. S.; Kaur, Rajbir

    2015-10-01

    Electromagnetic electron cyclotron (EMEC) waves with temperature anisotropy in the magnetosphere of Uranus have been studied in present work. EMEC waves are investigated using method of characteristic solution by kinetic approach, in presence of AC field. In 1986, Voyager 2 encounter with Uranus revealed that magnetosphere of Uranus exhibit non-Maxwellian high-energy tail distribution. So, the dispersion relation, real frequency and growth rate are evaluated using Lorentzian Kappa distribution function. Effect of temperature anisotropy, AC frequency and number density of particles is found. The study is also extended to oblique propagation of EMEC waves in presence and absence of AC field. Through comprehensive mathematical analysis it is found that when EMEC wave propagates parallel to intrinsic magnetic field of Uranus, its growth is more enhanced than in case of oblique propagation. Results are also discussed in context to magnetosphere of Earth and also gives theoretical explanation to existence of high energetic particles observed by Voyager 2 in the magnetosphere of Uranus. The results can present a further insight into the nature of electron-cyclotron instability condition for the whistler mode waves in the outer radiation belts of Uranus or other space plasmas.

  19. Instability of surface electron cyclotron TM-modes influenced by non-monochromatic alternating electric field

    SciTech Connect

    Girka, I. O. Girka, V. O.; Sydora, R. D.; Thumm, M.

    2016-06-15

    The influence of non-monochromaticity of an external alternating electric field on excitation of TM eigenmodes at harmonics of the electron cyclotron frequency is considered here. These TM-modes propagate along the plasma interface in a metal waveguide. An external static constant magnetic field is oriented perpendicularly to the plasma interface. The problem is solved theoretically using the kinetic Vlasov-Boltzmann equation for description of plasma particles motion and the Maxwell equations for description of the electromagnetic mode fields. The external alternating electric field is supposed to be a superposition of two waves, whose amplitudes are different and their frequencies correlate as 2:1. An infinite set of equations for electric field harmonics of these modes is derived with the aid of nonlinear boundary conditions. This set is solved using the wave packet approach consisting of the main harmonic frequency and two nearest satellite temporal harmonics. Analytical studies of the obtained set of equations allow one to find two different regimes of parametric instability, namely, enhancement and suppression of the instability. Numerical analysis of the instability is carried out for the three first electron cyclotron harmonics.

  20. Experiment study of an electron cyclotron resonant ion source based on a tapered resonance cavity

    SciTech Connect

    Yang, Juan; Shi, Feng; Jin, Yizhou; Wang, Yunmin; Komurasaki, Kimiya

    2013-12-15

    Electron cyclotron resonant plasma is one type of magnetised plasma generated by continuous microwave energy. It has the property of high degree of ionization and large volume at low gas pressure, which makes it useful for space propulsion and material processing. This article presents the experiment study of the plasma properties and ion beam extraction from an electron cyclotron resonant ion source based on a tapered resonance cavity. Optical emission spectroscopy based on a simple collisional radiation model was used for plasma diagnosis. Experiment results show that, at microwave power setting ranging from 7.06 to 17.40 W and mass flow rate ranging from 1 to 10 sccm, argon gas can be ionized. Ion beam of 109.1 mA from the ion source can be extracted at microwave power of 30 W, mass flow rate of 10 sccm, and accel voltage of 800 V. The diagnosed plasma temperature and density are 2.4–5.2 eV and 2 × 10{sup 16}–4.8 × 10{sup 17} m{sup −3}, respectively.

  1. Integrated modeling of electron cyclotron resonance ion sources and charge breeders with GEM, MCBC, and IonEx

    SciTech Connect

    Kim, J. S.; Zhao, L.; Cluggish, B. P.; Galkin, S. A.; Grubert, J. E.; Pardo, R. C.; Vondrasek, R. C.

    2010-02-15

    A numerical toolset to help in understanding physical processes in the electron cyclotron resonance charge breeder (ECRCB) and further to help optimization and design of current and future machines is presented. The toolset consists of three modules (Monte Carlo charge breeding code, generalized electron cyclotron resonance ion source modeling, and ion extraction), each modeling different processes occurring in the ECRCB from beam injection to extraction. The toolset provides qualitative study, such as parameter studies, and scaling of the operation, and physical understanding in the ECRCB. The methodology and a sample integrated modeling are presented.

  2. Study of ion beam transport from the SECRAL electron cyclotron resonance ion source at the Institute of Modern Physics.

    PubMed

    Cao, Y; Lu, W; Zhang, W H; Sha, S; Yang, Y; Ma, B H; Wang, H; Zhu, Y H; Guo, J W; Fang, X; Lin, S H; Li, X X; Feng, Y C; Li, J Y; Zhao, H Y; Ma, H Y; Zhang, X Z; Guo, X H; Wu, Q; Sun, L T; Zhao, H W; Xie, D Z

    2012-02-01

    Ion beam transport from the Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou (SECRAL) electron cyclotron resonance ion source was studied at the Institute of Modern Physics during 2010. Particle-in-cell simulations and experimental results have shown that both space charge and magnetic aberrations lead to a larger beam envelope and emittance growth. In the existing SECRAL extraction beam line, it has been shown that raising the solenoid lens magnetic field reduces aberrations in the subsequent dipole and results in lower emittance. Detailed beam emittance measurements are presented in this paper.

  3. Electron cyclotron emission radiometer upgrade on the Joint European Torus (JET) tokamak

    SciTech Connect

    Luna, E. de la; Sanchez, J.; Tribaldos, V.; Conway, G.; Suttrop, W.; Fessey, J.; Prentice, R.; Gowers, C.; Chareau, J. M.

    2004-10-01

    The capabilities of the Joint European Torus (JET) electron cyclotron emission (ECE) diagnostics have recently been extended with an upgrading of the heterodyne radiometer. The number of channels has been doubled to 96 channels, with a frequency separation corresponding to <1 cm for JET magnetic field gradient, and with a frequency response of 1 MHz. This enhancement has increased the radial coverage of the ECE electron temperature measurements in JET to approximately the full plasma column (limited at R>2.6 m for the X-mode due to harmonic overlap) at almost all magnetic field values used at JET (1.7 T

  4. Design of a correlation electron cyclotron emission diagnostic for Alcator C-Moda)

    NASA Astrophysics Data System (ADS)

    Sung, C.; White, A. E.; Irby, J. H.; Leccacorvi, R.; Vieira, R.; Oi, C. Y.; Peebles, W. A.; Nguyen, X.

    2012-10-01

    A correlation electron cyclotron emission (CECE) diagnostic has been installed in Alcator C-Mod. In order to measure electron temperature fluctuations, this diagnostic uses a spectral decorrelation technique. Constraints obtained with nonlinear gyrokinetic simulations guided the design of the optical system and receiver. The CECE diagnostic is designed to measure temperature fluctuations which have kθ ≤ 4.8 cm-1 (kθρs < 0.5) using a well-focused beam pattern. Because the CECE diagnostic is a dedicated turbulence diagnostic, the optical system is also flexible, which allows for various collimating lenses and antenna to be used. The system overview and the demonstration of its operability as designed are presented in this paper.

  5. Sawtooth stabilization by localized electron cyclotron heating in a tokamak plasma

    SciTech Connect

    Hanada, K.; Tanaka, H.; Iida, M.; Minami, T.; Maekawa, T.; Terumichi, Y.; Tanaka, S. . Dept. of Physics); Ide, S. . Naka Fusion Research Establishment); Nakamura, M. ); Yamada, M.; Manickam, J.; White, R.B. . Plasma Physics Lab.)

    1990-11-01

    Sawtooth oscillations (STO) in the ohmically heated WT-3 tokamak are strongly modified or suppressed by localized electron cyclotron resonance heating (ECH) near the q = 1 surface, where q refers to the safety factor. The effect of ECH is much stronger when it is applied on the high field side (the inner side of the tokamak) as compared to the low field side (outer side). Complete suppression of the STO is achieved for the duration of the ECH when it is applied on the high field side, in a low density plasma, provided the ECH power exceeds a thresholds value. The STO stabilization is attributed to a modification of the current density profile by hot electrons generated by ECH, which reduces the shear in the q = region. 14 refs., 5 figs.

  6. Current drive with combined electron cyclotron wave and high harmonic fast wave in tokamak plasmas

    NASA Astrophysics Data System (ADS)

    Li, J. C.; Gong, X. Y.; Dong, J. Q.; Wang, J.; Zhang, N.; Zheng, P. W.; Yin, C. Y.

    2016-12-01

    The current driven by combined electron cyclotron wave (ECW) and high harmonic fast wave is investigated using the GENRAY/CQL3D package. It is shown that no significant synergetic current is found in a range of cases with a combined ECW and fast wave (FW). This result is consistent with a previous study [Harvey et al., in Proceedings of IAEA TCM on Fast Wave Current Drive in Reactor Scale Tokamaks (Synergy and Complimentarily with LHCD and ECRH), Arles, France, IAEA, Vienna, 1991]. However, a positive synergy effect does appear with the FW in the lower hybrid range of frequencies. This positive synergy effect can be explained using a picture of the electron distribution function induced by the ECW and a very high harmonic fast wave (helicon). The dependence of the synergy effect on the radial position of the power deposition, the wave power, the wave frequency, and the parallel refractive index is also analyzed, both numerically and physically.

  7. Adaptive-array Electron Cyclotron Emission diagnostics using data streaming in a Software Defined Radio system

    NASA Astrophysics Data System (ADS)

    Idei, H.; Mishra, K.; Yamamoto, M. K.; Hamasaki, M.; Fujisawa, A.; Nagashima, Y.; Hayashi, Y.; Onchi, T.; Hanada, K.; Zushi, H.; the QUEST Team

    2016-04-01

    Measurement of the Electron Cyclotron Emission (ECE) spectrum is one of the most popular electron temperature diagnostics in nuclear fusion plasma research. A 2-dimensional ECE imaging system was developed with an adaptive-array approach. A radio-frequency (RF) heterodyne detection system with Software Defined Radio (SDR) devices and a phased-array receiver antenna was used to measure the phase and amplitude of the ECE wave. The SDR heterodyne system could continuously measure the phase and amplitude with sufficient accuracy and time resolution while the previous digitizer system could only acquire data at specific times. Robust streaming phase measurements for adaptive-arrayed continuous ECE diagnostics were demonstrated using Fast Fourier Transform (FFT) analysis with the SDR system. The emission field pattern was reconstructed using adaptive-array analysis. The reconstructed profiles were discussed using profiles calculated from coherent single-frequency radiation from the phase array antenna.

  8. Design of a correlation electron cyclotron emission diagnostic for Alcator C-Mod

    SciTech Connect

    Sung, C.; White, A. E.; Irby, J. H.; Leccacorvi, R.; Vieira, R.; Oi, C. Y.; Peebles, W. A.; Nguyen, X.

    2012-10-15

    A correlation electron cyclotron emission (CECE) diagnostic has been installed in Alcator C-Mod. In order to measure electron temperature fluctuations, this diagnostic uses a spectral decorrelation technique. Constraints obtained with nonlinear gyrokinetic simulations guided the design of the optical system and receiver. The CECE diagnostic is designed to measure temperature fluctuations which have k{sub {theta}}{<=} 4.8 cm{sup -1} (k{sub {theta}}{rho}{sub s} < 0.5) using a well-focused beam pattern. Because the CECE diagnostic is a dedicated turbulence diagnostic, the optical system is also flexible, which allows for various collimating lenses and antenna to be used. The system overview and the demonstration of its operability as designed are presented in this paper.

  9. Experiment and analysis of the neutralization of the electron cyclotron resonance ion thruster

    NASA Astrophysics Data System (ADS)

    Jin, Yizhou; Yang, Juan; Sun, Jun; Liu, Xianchuang; Huang, Yizhi

    2017-10-01

    An electron cyclotron resonance ion thruster must emit an electron current equivalent to its ion beam current to prevent the thruster system from being electrically charged. This operation is defined as neutralization. The factors which influence neutralization are categorized into the ion beam current parameters, the neutralizer input parameters, and the neutralizer position. To understand the mechanism of neutralization, an experiment and a calculation study on how these factors influence thruster neutralization are presented. The experiment results show that the minimum bias voltage of the neutralizer was -60 V at the ion beam current of 80 mA for the argon propellant, and a critical gas flow rate existed, below which the coupling voltage increased sharply. Based on the experiment, the neutralization was analyzed by means of a one-dimensional calculation model. The computation results show that the coupling voltage was influenced by the beam divergence and the negative potential zone near the grids.

  10. Electron effective mass enhancement in Ga(AsBi) alloys probed by cyclotron resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Pettinari, G.; Drachenko, O.; Lewis, R. B.; Tiedje, T.

    2016-12-01

    The effect of Bi incorporation on the conduction band structure of Ga(AsBi) alloys is revealed by a direct estimation of the electron effective mass via cyclotron resonance absorption spectroscopy at THz frequencies in pulsed magnetic fields up to 65 T. A strong enhancement in the electron effective mass with increasing Bi content is reported, with a value of mass ˜40 % higher than that in GaAs for ˜1.7 % of Bi. This experimental evidence unambiguously indicates a Bi-induced perturbation of the host conduction band states and calls for a deep revision of the theoretical models describing dilute bismides currently proposed in the literature, the majority of which neglect or exclude that the incorporation of a small percentage of Bi may affect the conduction band states of the host material.

  11. Microwave electron cyclotron electron resonance (ECR) ion source with a large, uniformly distributed, axially symmetric, ECR plasma volume

    DOEpatents

    Alton, Gerald D.

    1996-01-01

    An electron cyclotron resonance (ECR) ion source includes a primary mirror coil disposed coaxially around a vacuum vessel in which a plasma is induced and introducing a solenoidal ECR-producing field throughout the length of the vacuum vessel. Radial plasma confinement is provided by a multi-cusp, multi-polar permanent magnet array disposed azimuthally around the vessel and within the primary mirror coil. Axial confinement is provided either by multi-cusp permanent magnets at the opposite axial ends of the vessel, or by secondary mirror coils disposed on opposite sides of the primary coil.

  12. Compositional study of silicon oxynitride thin films deposited using electron cyclotron resonance plasma-enhanced chemical vapor deposition technique

    SciTech Connect

    Baumann, H.; Sah, R.E.

    2005-05-01

    We have used backscattering spectrometry and {sup 15}N({sup 1}H,{alpha},{gamma}){sup 12}C nuclear reaction analysis techniques to study in detail the variation in the composition of silicon oxynitride films with deposition parameters. The films were deposited using 2.45 GHz electron cyclotron resonance plasma-enhanced chemical vapor deposition (PECVD) technique from mixtures of precursors argon, nitrous oxide, and silane at deposition temperature 90 deg. C. The deposition pressure and nitrous oxide-to-silane gas flow rates ratio have been found to have a pronounced influence on the composition of the films. When the deposition pressure was varied for a given nitrous oxide-to-silane gas flow ratio, the amount of silicon and nitrogen increased with the deposition pressure, while the amount of oxygen decreased. For a given deposition pressure, the amount of incorporated nitrogen and hydrogen decreased while that of oxygen increased with increasing nitrous oxide-to-silane gas flow rates ratio. For nitrous oxide-to-silane gas flow ratio of 5, we obtained films which contained neither chemically bonded nor nonbonded nitrogen atoms as revealed by the results of infrared spectroscopy, backscattering spectrometry, and nuclear reaction analysis. Our results demonstrate the nitrogen-free nearly stoichiometric silicon dioxide films can be prepared from a mixture of precursors argon, nitrous oxide, and silane at low substrate temperature using high-density PECVD technique. This avoids the use of a hazardous and an often forbidden pair of silane and oxygen gases in a plasma reactor.

  13. ASTRA Modeling of Electron Cyclotron Heating in the Helically Symmetric Experiment

    SciTech Connect

    Talmadge, Joseph N.; Likin, Konstantin M.; Abdou, Ali El-Sayed Ali; Almagri, Abdulgader F.; Anderson, David T.; Anderson, F. Simon B.; Canik, John M.; Deng, Chuanbao; Gerhardt, Stefan P.; Zhai, Kan

    2004-09-15

    Thomson scattering and diamagnetic loop measurements in a hot electron plasma in the Helically Symmetric Experiment (HSX) indicate that the central electron temperature and stored energy increase linearly with power. Experimentally it is found that the central electron temperature is roughly independent of plasma density. The ASTRA code is used to model electron cyclotron heating for a magnetic configuration that is quasi-symmetric as well as for a configuration in which the symmetry is broken. The experimental results are consistent with an anomalous thermal conductivity that scales inversely with the density. However, the experimental scaling of the stored energy against density is not usually in agreement with the model. From the measured X-ray flux and the high absorbed power, as well as from the calculated low single-pass absorption efficiency, it is concluded that at low densities, a nonthermal electron population accounts for a significant fraction of the stored energy. With the ASTRA code, it is also possible to model under what conditions the central electron temperature in the quasi-symmetric configuration will be measurably greater than the temperature in the nonsymmetric configuration. These calculations depend greatly on the radial electric field of the nonsymmetric plasma but suggest that at somewhat higher density and higher power than achieved to date, differences in the central electron temperature may be observed.

  14. Electron cyclotron resonance heating by magnetic filter field in a negative hydrogen ion source

    SciTech Connect

    Kim, June Young Cho, Won-Hwi; Dang, Jeong-Jeung; Chung, Kyoung-Jae Hwang, Y. S.

    2016-02-15

    The influence of magnetic filter field on plasma properties in the heating region has been investigated in a planar-type inductively coupled radio-frequency (RF) H{sup −} ion source. Besides filtering high energy electrons near the extraction region, the magnetic filter field is clearly observed to increase the electron temperature in the heating region at low pressure discharge. With increasing the operating pressure, enhancement of electron temperature in the heating region is reduced. The possibility of electron cyclotron resonance (ECR) heating in the heating region due to stray magnetic field generated by a filter magnet located at the extraction region is examined. It is found that ECR heating by RF wave field in the discharge region, where the strength of an axial magnetic field is approximately ∼4.8 G, can effectively heat low energy electrons. Depletion of low energy electrons in the electron energy distribution function measured at the heating region supports the occurrence of ECR heating. The present study suggests that addition of axial magnetic field as small as several G by an external electromagnet or permanent magnets can greatly increase the generation of highly ro-vibrationally excited hydrogen molecules in the heating region, thus improving the performance of H{sup −} ion generation in volume-produced negative hydrogen ion sources.

  15. Nonlinear fundamental and harmonic cyclotron resonant scattering of radiation belt ultrarelativistic electrons by oblique monochromatic EMIC waves

    NASA Astrophysics Data System (ADS)

    Wang, Geng; Su, Zhenpeng; Zheng, Huinan; Wang, Yuming; Zhang, Min; Wang, Shui

    2017-02-01

    Cyclotron resonant scattering by electromagnetic ion cyclotron (EMIC) waves has been considered to be responsible for the rapid loss of radiation belt high-energy electrons. For parallel-propagating EMIC waves, the nonlinear character of cyclotron resonance has been revealed in recent studies. Here we present the first study on the nonlinear fundamental and harmonic cyclotron resonant scattering of radiation belt ultrarelativistic electrons by oblique EMIC waves on the basis of test particle simulations. Higher wave obliquity produces stronger nonlinearity of harmonic resonances but weaker nonlinearity of fundamental resonance. Compared to the quasi-linear prediction, these nonlinear resonances yield a more rapid loss of electrons over a wider pitch angle range. In the quasi-linear regime, the ultrarelativistic electrons are lost in the equatorial pitch angle range αeq<75°, nearly independent of wave normal angle ψ. In contrast, the upper pitch angle cutoff of nonlinear losses tends to increase with the wave normal angle increasing, which is about αeq=82° at ψ = 0° and αeq>87.5° at ψ = 20° and 40°. At the resonant pitch angles αeq<75°, the difference between quasi-linear and nonlinear loss timescales tends to decrease with the wave normal angle increasing. At ψ = 0° and 20°, the nonlinear electron loss timescale is 10% shorter than the quasi-linear prediction; at ψ = 40°, the difference in loss timescales is reduced to <5%.

  16. Electromagnetic cyclotron-loss-cone instability associated with weakly relativistic electrons

    NASA Technical Reports Server (NTRS)

    Wong, H. K.; Wu, C. S.; Ke, F. J.; Schneider, R. S.; Ziebell, L. F.

    1982-01-01

    The amplification of fast extraordinary mode waves at frequencies very close to the electron cyclotron frequency, due to the presence of a population of energetic electrons with a loss-cone type distribution, is studied. Low-energy background electrons are included in the analysis. Two types of loss-cone distribution functions are considered, and it is found that the maximum growth rates for both distribution functions are of the same order of magnitude. When the thermal effects of the energetic electrons are included in the dispersion equation, the real frequencies of the waves are lower than those obtained by using the cold plasma approximation. This effect tends to enhance the growth rate. An idealized case including a parallel electric field such that the distribution function of the trapped energetic electrons is modified is also considered. It is assumed that the parallel electric field can remove the low-energy background electrons away from the source region of radiation. Both these effects increase the growth rate.

  17. Post calibration of the two-dimensional electron cyclotron emission imaging instrument with electron temperature characteristics of the magnetohydrodynamic instabilities

    SciTech Connect

    Choi, M. J.; Park, H. K.; Yun, G. S.; Nam, Y. B.; Choe, G. H.; Lee, W.; Jardin, S.

    2016-01-15

    The electron cyclotron emission imaging (ECEI) instrument is widely used to study the local electron temperature (T{sub e}) fluctuations by measuring the ECE intensity I{sub ECE} ∝ T{sub e} in tokamak plasmas. The ECEI measurement is often processed in a normalized fluctuation quantity against the time averaged value due to complication in absolute calibration. In this paper, the ECEI channels are relatively calibrated using the flat T{sub e} assumption of the sawtooth crash or the tearing mode island and a proper extrapolation. The 2-D relatively calibrated electron temperature (T{sub e,rel}) images are reconstructed and the displacement amplitude of the magnetohydrodynamic modes can be measured for the accurate quantitative growth analysis.

  18. A Scaling Law of Plasma Confining Potential Formation with Electron Cyclotron Heating Powers in GAMMA 10

    SciTech Connect

    Numakura, T.; Cho, T.; Kohagura, J.; Hirata, M.; Fukai, T.; Yoshida, M.; Minami, R.; Kiminami, S.; Sakamoto, K.; Imai, T.; Miyoshi, S.

    2005-01-15

    Scaling laws of potential formation and associated effects are theoretically and experimentally investigated in the GAMMA 10 tandem mirror. In GAMMA 10, the main tandem-mirror operations from 1979 to 2003 are characterized in terms of (i) a high-potential mode having kV-order plasma-confining potentials, and (ii) a hot-ion mode yielding fusion neutrons with 10-20 keV bulk-ion temperatures. In this paper, the externally controllable parameter scaling including electron cyclotron heating (ECH) powers for potential formation covering over these two representative operational modes is investigated; that is, the construction of 'the central-cell plasma-confining potentials' {phi}{sub c} formation scaling with plug ECH is studied on the basis of the electron energy-balance equation and Cohen's strong electron cyclotron heating (ECH) theory for investigating the formation physics of plasma confining potentials.It is found that our proposed scaling formulae are in good agreement with the experimental data in the two representative operational modes of the high-potential and hot-ion modes in the GAMMA 10 tandem mirror.This scaling shows a favorable increase in confining potentials with installing more powerful ECH sources by the use of ECH powers over the present 250 kW. On the basis of the scaling prediction, we also report the design of a newly developed 500 kW gyrotron for an application to investigate the validity of the above described {phi}{sub c} formation scaling with plug ECH aiming at achieving higher plasma parameters.

  19. Cyclotron resonant scattering feature simulations. I. Thermally averaged cyclotron scattering cross sections, mean free photon-path tables, and electron momentum sampling

    NASA Astrophysics Data System (ADS)

    Schwarm, F.-W.; Schönherr, G.; Falkner, S.; Pottschmidt, K.; Wolff, M. T.; Becker, P. A.; Sokolova-Lapa, E.; Klochkov, D.; Ferrigno, C.; Fürst, F.; Hemphill, P. B.; Marcu-Cheatham, D. M.; Dauser, T.; Wilms, J.

    2017-01-01

    Context. Electron cyclotron resonant scattering features (CRSFs) are observed as absorption-like lines in the spectra of X-ray pulsars. A significant fraction of the computing time for Monte Carlo simulations of these quantum mechanical features is spent on the calculation of the mean free path for each individual photon before scattering, since it involves a complex numerical integration over the scattering cross section and the (thermal) velocity distribution of the scattering electrons. Aims: We aim to numerically calculate interpolation tables which can be used in CRSF simulations to sample the mean free path of the scattering photon and the momentum of the scattering electron. The tables also contain all the information required for sampling the scattering electron's final spin. Methods: The tables were calculated using an adaptive Simpson integration scheme. The energy and angle grids were refined until a prescribed accuracy is reached. The tables are used by our simulation code to produce artificial CRSF spectra. The electron momenta sampled during these simulations were analyzed and justified using theoretically determined boundaries. Results: We present a complete set of tables suited for mean free path calculations of Monte Carlo simulations of the cyclotron scattering process for conditions expected in typical X-ray pulsar accretion columns (0.01 ≤ B/Bcrit ≤ 0.12, where Bcrit = 4.413 × 1013 G, and 3 keV ≤ kBT ≤ 15 keV). The sampling of the tables is chosen such that the results have an estimated relative error of at most 1/15 for all points in the grid. The tables are available online (see link in footnote, page 1). The electronic tables described here are available at http://www.sternwarte.uni-erlangen.de/research/cyclo

  20. Excitation of electrostatic waves in the electron cyclotron frequency range during magnetic reconnection in laboratory overdense plasmas

    SciTech Connect

    Kuwahata, A.; Igami, H.; Kawamori, E.; Kogi, Y.; Inomoto, M.; Ono, Y.

    2014-10-15

    We report the observation of electromagnetic radiation at high harmonics of the electron cyclotron frequency that was considered to be converted from electrostatic waves called electron Bernstein waves (EBWs) during magnetic reconnection in laboratory overdense plasmas. The excitation of EBWs was attributed to the thermalization of electrons accelerated by the reconnection electric field around the X-point. The radiative process discussed here is an acceptable explanation for observed radio waves pulsation associated with major flares.

  1. Simultaneous observations of subauroral electron temperature enhancements and electromagnetic ion cyclotron waves

    NASA Technical Reports Server (NTRS)

    Erlandson, R. E.; Aggson, T. L.; Hogey, W. R.; Slavin, J. A.

    1993-01-01

    Observational results from an investigation of LF (0.5-4.0 Hz) electromagnetic ion cyclotron waves and subauroral electron temperature enhancements recorded from the DE-2 satellite are presented. Four different wave events were analyzed, all recorded at magnetic latitudes from 57-60 deg, magnetic local times from 8-14 hr, and altitudes from 600-900 km. The peak wave amplitudes during the events ranged from 8-70 nT and 5-30 mV/m in the magnetic and electric field, respectively. Te enhancements at the time of the waves were observed in three of four events. A linear relationship between the wave magnetic field spectral density and Te enhancements was found for these events. The Te enhancements were also correlated with an enhanced flux of low energy electrons. During one event (82104) an enhanced flux of electrons were observed at energies up to 50 eV and at nearly all pitch angles, although the flux was largest in the precipitating and upflowing directions. It is suggested that the waves are responsible for heating the low energy electrons which precipitate to the ionosphere and produce the observed Te enhancements. The upflowing electron population appears to be heated at ionospheric altitudes, below the DE-2 satellite.

  2. Linear analysis of a rectangular waveguide cyclotron maser with a sheet electron beam

    SciTech Connect

    Zhao Ding; Ding Yaogen; Wang Yong; Ruan Cunjun

    2010-11-15

    A linear theory for a rectangular waveguide cyclotron maser with a sheet electron beam is developed by using the Laplace transformation approach. This theory can be applied to any TE{sub mn} rectangular waveguide mode. The corresponding equations for the TM{sub mn} mode in the rectangular waveguide are also derived as a useful reference. Especially, the effect from the coupling between degenerate modes, which is induced by the nonideal rectangular waveguide walls, on the dispersion relation is considered in order to provide a more accurate model for the real devices. Through numerical calculations, the linear growth rate, launching loss, and spontaneous oscillations (caused by the absolute instability and backward wave oscillation) of this new structure can be analyzed in detail. It is worthwhile to point out that the operation at higher power levels of the rectangular waveguide sheet beam system is possible.

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

    PubMed

    Kato, Yushi; Yano, Keisuke; Nishiokada, Takuya; Nagaya, Tomoki; Kimura, Daiju; Kumakura, Sho; Imai, Youta; Hagino, Shogo; Otsuka, Takuro; Sato, Fuminobu

    2016-02-01

    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.

  4. Two-chamber configuration of Bio-Nano electron cyclotron resonance ion source for fullerene modification.

    PubMed

    Uchida, T; Rácz, R; Muramatsu, M; Kato, Y; Kitagawa, A; Biri, S; Yoshida, Y

    2016-02-01

    We report on the modification of fullerenes with iron and chlorine using two individually controllable plasmas in the Bio-Nano electron cyclotron resonance ion source (ECRIS). One of the plasmas is composed of fullerene and the other one is composed of iron and chlorine. The online ion beam analysis allows one to investigate the rate of the vapor-phase collisional modification process in the ECRIS, while the offline analyses (e.g., liquid chromatography-mass spectrometry) of the materials deposited on the plasma chamber can give information on the surface-type process. Both analytical methods show the presence of modified fullerenes such as fullerene-chlorine, fullerene-iron, and fullerene-chlorine-iron.

  5. Review of highly charged heavy ion production with electron cyclotron resonance ion source (invited)

    NASA Astrophysics Data System (ADS)

    Nakagawa, T.

    2014-02-01

    The electron cyclotron resonance ion source (ECRIS) plays an important role in the advancement of heavy ion accelerators and other ion beam applications worldwide, thanks to its remarkable ability to produce a great variety of intense highly charged heavy ion beams. Great efforts over the past decade have led to significant ECRIS performance improvements in both the beam intensity and quality. A number of high-performance ECRISs have been built and are in daily operation or are under construction to meet the continuously increasing demand. In addition, comprehension of the detailed and complex physical processes in high-charge-state ECR plasmas has been enhanced experimentally and theoretically. This review covers and discusses the key components, leading-edge developments, and enhanced ECRIS performance in the production of highly charged heavy ion beams.

  6. Two-chamber configuration of Bio-Nano electron cyclotron resonance ion source for fullerene modification

    NASA Astrophysics Data System (ADS)

    Uchida, T.; Rácz, R.; Muramatsu, M.; Kato, Y.; Kitagawa, A.; Biri, S.; Yoshida, Y.

    2016-02-01

    We report on the modification of fullerenes with iron and chlorine using two individually controllable plasmas in the Bio-Nano electron cyclotron resonance ion source (ECRIS). One of the plasmas is composed of fullerene and the other one is composed of iron and chlorine. The online ion beam analysis allows one to investigate the rate of the vapor-phase collisional modification process in the ECRIS, while the offline analyses (e.g., liquid chromatography-mass spectrometry) of the materials deposited on the plasma chamber can give information on the surface-type process. Both analytical methods show the presence of modified fullerenes such as fullerene-chlorine, fullerene-iron, and fullerene-chlorine-iron.

  7. Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS

    SciTech Connect

    Thomae, R. Conradie, J.; Fourie, D.; Mira, J.; Nemulodi, F.; Kuechler, D.; Toivanen, V.

    2016-02-15

    At iThemba Laboratory for Accelerator Based Sciences (iThemba LABS) an electron cyclotron ion source was installed and commissioned. This source is a copy of the Grenoble Test Source (GTS) for the production of highly charged ions. The source is similar to the GTS-LHC at CERN and named GTS2. A collaboration between the Accelerators and Beam Physics Group of CERN and the Accelerator and Engineering Department of iThemba LABS was proposed in which the development of high intensity argon and xenon beams is envisaged. In this paper, we present beam experiments with the GTS2 at iThemba LABS, in which the results of continuous wave and afterglow operation of xenon ion beams with oxygen as supporting gases are presented.

  8. Investigation of fast particle driven instabilities by 2D electron cyclotron emission imaging on ASDEX Upgrade

    NASA Astrophysics Data System (ADS)

    Classen, I. G. J.; Lauber, Ph; Curran, D.; Boom, J. E.; Tobias, B. J.; Domier, C. W.; Luhmann, N. C., Jr.; Park, H. K.; Garcia Munoz, M.; Geiger, B.; Maraschek, M.; Van Zeeland, M. A.; da Graça, S.; ASDEX Upgrade Team

    2011-12-01

    Detailed measurements of the 2D mode structure of Alfvén instabilities in the current ramp-up phase of neutral beam heated discharges were performed on ASDEX Upgrade, using the electron cyclotron emission imaging (ECEI) diagnostic. This paper focuses on the observation of reversed shear Alfvén eigenmodes (RSAEs) and bursting modes that, with the use of the information from ECEI, have been identified as beta-induced Alfvén eigenmodes (BAEs). Both RSAEs with first and second radial harmonic mode structures were observed. Calculations with the linear gyro-kinetic code LIGKA revealed that the ratio of the damping rates and the frequency difference between the first and second harmonic modes strongly depended on the shape of the q-profile. The bursting character of the BAE type modes, which were radially localized to rational q surfaces, was observed to sensitively depend on the plasma parameters, ranging from strongly bursting to almost steady state.

  9. Closure of the single fluid magnetohydrodynamic equations in presence of electron cyclotron current drive

    SciTech Connect

    Westerhof, E. Pratt, J.

    2014-10-15

    In the presence of electron cyclotron current drive (ECCD), the Ohm's law of single fluid magnetohydrodynamics is modified as E + v × B = η(J – J{sub EC}). This paper presents a new closure relation for the EC driven current density appearing in this modified Ohm's law. The new relation faithfully represents the nonlocal character of the EC driven current and its main origin in the Fisch-Boozer effect. The closure relation is validated on both an analytical solution of an approximated Fokker-Planck equation as well as on full bounce-averaged, quasi-linear Fokker-Planck code simulations of ECCD inside rotating magnetic islands. The new model contains the model put forward by Giruzzi et al. [Nucl. Fusion 39, 107 (1999)] in one of its limits.

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

    SciTech Connect

    Kato, Yushi Yano, Keisuke; Nishiokada, Takuya; Nagaya, Tomoki; Kimura, Daiju; Kumakura, Sho; Imai, Youta; Hagino, Shogo; Otsuka, Takuro; Sato, Fuminobu

    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. Nonlinear response of magnetic islands to localized electron cyclotron current injection

    SciTech Connect

    Borgogno, D.; Comisso, L.; Grasso, D.; Lazzaro, E.

    2014-06-15

    The magnetic island evolution under the action of a current generated externally by electron cyclotron wave beams is studied using a reduced resistive magnetohydrodynamics plasma model. The use of a two-dimensional reconnection model shows novel features of the actual nonlinear evolution as compared to the zero-dimensional model of the generalized Rutherford equation. When the radio frequency control is applied to a small magnetic island, the complete annihilation of the island width is followed by a spatial phase shift of the island, referred as “flip” instability. On the other hand, a current-drive injection in a large nonlinear island can be accompanied by the occurrence of a Kelvin-Helmholtz instability. These effects need to be taken into account in designing tearing mode control systems based on radio frequency current-drive.

  12. Progress towards the development of a realistic electron cyclotron resonance ion source extraction model

    SciTech Connect

    Winklehner, D.; Leitner, D.; Benitez, J. Y.; Lyneis, C. M.; Strohmeier, M. M.

    2012-02-15

    In this paper, an ongoing effort to provide a simulation and design tool for electron cyclotron resonance ion source extraction and low energy beam transport is described and benchmarked against experimental results. Utilizing the particle-in-cell code WARP, a set of scripts has been developed: A semiempirical method of generating initial conditions, a 2D-3D hybrid method of plasma extraction and a simple beam transport deck. Measured emittances and beam profiles of uranium and helium beams are shown and the influence of the sextupole part of the plasma confinement field is investigated. The results are compared to simulations carried out using the methods described above. The results show that the simulation model (with some additional refinements) represents highly charged, well-confined ions well, but that the model is less applicable for less confined, singly charged ions.

  13. Optimization of a coaxial electron cyclotron resonance plasma thruster with an analytical model

    SciTech Connect

    Cannat, F. E-mail: felix.cannat@gmail.com; Lafleur, T.; Jarrige, J.; Elias, P.-Q.; Packan, D.; Chabert, P.

    2015-05-15

    A new cathodeless plasma thruster currently under development at Onera is presented and characterized experimentally and analytically. The coaxial thruster consists of a microwave antenna immersed in a magnetic field, which allows electron heating via cyclotron resonance. The magnetic field diverges at the thruster exit and forms a nozzle that accelerates the quasi-neutral plasma to generate a thrust. Different thruster configurations are tested, and in particular, the influence of the source diameter on the thruster performance is investigated. At microwave powers of about 30 W and a xenon flow rate of 0.1 mg/s (1 SCCM), a mass utilization of 60% and a thrust of 1 mN are estimated based on angular electrostatic probe measurements performed downstream of the thruster in the exhaust plume. Results are found to be in fair agreement with a recent analytical helicon thruster model that has been adapted for the coaxial geometry used here.

  14. Fabrication of ultrathin Ni-Zn ferrite films using electron cyclotron resonance sputtering method

    SciTech Connect

    Tanaka, Terumitsu; Kurisu, Hiroki; Matsuura, Mitsuru; Shimosato, Yoshihiro; Okada, Shigenobu; Oshiro, Kazunori; Fujimori, Hirotaka; Yamamoto, Setsuo

    2006-04-15

    Well-crystallized Ni-Zn ferrite (Ni{sub 0.4}Zn{sub 0.6}Fe{sub 2}O{sub 4}) highly oriented ultrathin films were obtained at a substrate temperature of 200 deg. C by a reactive sputtering method utilizing electron cyclotron resonance microwave plasma, which is very effective to crystallize oxide or nitride materials without heat treatment. Thin films of Ni-Zn ferrite deposited on a MgO (100) underlayer showed an intense X-ray-diffraction peak of (400) from the Ni-Zn ferrite as compared to similar films deposited directly onto thermally oxidized Si substrates. A 1.5-nm-thick Ni-Zn ferrite film, which corresponds to twice the lattice constant for bulk Ni-Zn ferrite, crystallized on a MgO (100) underlayer.

  15. Optics design for Electron Cyclotron Emission Imaging system on J-TEXT

    NASA Astrophysics Data System (ADS)

    Ma, X. D.; Yang, Z. J.; Zhu, Y. L.; Pan, X. M.; Xiao, Y.; Ruan, B. W.; Zhuang, G.; Xie, J. L.

    2016-05-01

    An electron cyclotron emission imaging (ECEI) system is being developed for J-TEXT. It is comprised of two 16-channel antenna arrays that share the same toroidal window for the purpose of observing separate radial regions of the tokamak plasma simultaneously. Two imaging optic units have been designed, which share the same zoom lenses, but have different focus lenses. The setup is flexible and achieves good spatial resolution. In particular, the poloidal zoom factor can achieve 1.17 to 2.20. The desired focal plane can range anywhere from high field side (HFS) edge to low field side (LFS) edge. The effective field curvature adjustment (FCA) lenses have been adopted for the ECEI imaging optic system, which make the image plane flat enough to match the emission layer in order to increase the image quality.

  16. Numerical study on the stabilization of neoclassical tearing modes by electron cyclotron current drive

    SciTech Connect

    Wang, Xiaoguang; Zhang, Xiaodong; Wu, Bin; Zhu, Sizheng; Hu, Yemin

    2015-02-15

    It is well known that electron cyclotron current drive (ECCD) around the o-point of magnetic island along the plasma current direction can stabilize neoclassical tearing modes (NTMs) in tokamak devices. The effects of the radial misalignment between the island and the driven current, the phase misalignment, and the on-duty ratio for modulated current drive on NTM stabilization are studied numerically in this paper. A small radial misalignment is found to significantly decrease the stabilizing effect. When a sufficiently large phase misalignment occurs for the modulated ECCD, the stabilization effect is also reduced a lot. The optimal on-duty ratio of modulated ECCD to stabilize NTMs is found to be in the range of 60%–70%. A larger on-duty ratio than 50% could also mitigate the effect of phase misalignment if it is not too large. There is no benefit from modulation if the phase misalignment is larger than a threshold.

  17. Spectroscopic ellipsometry analysis of silicon nanotips obtained by electron cyclotron resonance plasma etching.

    PubMed

    Mendoza-Galván, Arturo; Järrendahl, Kenneth; Arwin, Hans; Huang, Yi-Fan; Chen, Li-Chyong; Chen, Kuei-Hsien

    2009-09-10

    Silicon nanotips fabricated by electron cyclotron resonance plasma etching of silicon wafers are studied by spectroscopic ellipsometry. The structure of the nanotips is composed of columns 100-140 nm wide and spaced by about 200 nm. Ellipsometry data covering a wide spectral range from the midinfrared to the visible are described by modeling the nanotip layer as a graded uniaxial film using the Bruggeman effective medium approximation. The ellipsometry data in the infrared range reveal two absorption bands at 754 and 955 cm(-1), which cannot be resolved with transmittance measurements. These bands indicate that the etching process is accompanied with formation of carbonaceous SiC and CH(n) species that largely modify the composition of the original crystalline silicon material affecting the optical response of the nanotips.

  18. Two-chamber configuration of Bio-Nano electron cyclotron resonance ion source for fullerene modification

    SciTech Connect

    Uchida, T.; Rácz, R.; Biri, S.; Kato, Y.; Yoshida, Y.

    2016-02-15

    We report on the modification of fullerenes with iron and chlorine using two individually controllable plasmas in the Bio-Nano electron cyclotron resonance ion source (ECRIS). One of the plasmas is composed of fullerene and the other one is composed of iron and chlorine. The online ion beam analysis allows one to investigate the rate of the vapor-phase collisional modification process in the ECRIS, while the offline analyses (e.g., liquid chromatography-mass spectrometry) of the materials deposited on the plasma chamber can give information on the surface-type process. Both analytical methods show the presence of modified fullerenes such as fullerene-chlorine, fullerene-iron, and fullerene-chlorine-iron.

  19. Refractory rf ovens and sputter probes for electron cyclotron resonance ion source

    SciTech Connect

    Cavenago, M.; Galata, A.; Kulevoy, T.; Petrenko, S.; Sattin, M.; Facco, A.

    2008-02-15

    Beams from electron cyclotron resonance ion source (ECRIS) with radio frequency ovens for refractory material (using a Mo coil) were recently demonstrated; results for Ti and V are here discussed, with temperature T{sub s}{>=}2300 K stably maintained and extracted current of about 1000 nA for V{sup 8+} and V{sup 9+}. The status of sputter probes is also reported, and the reason why trapping efficiency may be lower than in the oven case are investigated. The simple tubular probe concept show typical currents of Sn{sup 18+} about 250 nA, for the most abundant isotopes, but an operating pressure of about 300 {mu}Pa may be required. Some preliminary experiments were performed with Penning probes, showing that transmission of Sn or Pr from Penning cathode to ECRIS plasma is limited. Placement of tin onto anticathode and use of collimator between Penning and ECRIS are also discussed.

  20. New compact and efficient local oscillator optic system for the KSTAR electron cyclotron emission imaging system

    SciTech Connect

    Nam, Y. B. Yun, G. S.; Lee, D. J.; Lee, J.; Lee, W.; Kim, C.; Park, H. K.

    2016-11-15

    Electron cyclotron emission imaging (ECEI) diagnostic on Korean Superconducting Tokamak Advanced Research utilizes quasi-optical heterodyne-detection method to measure 2D (vertical and radial) T{sub e} fluctuations from two toroidally separated poloidal cross section of the plasma. A cylindrical lens local oscillator (LO) optics with optical path length (OPL) 2–2.5 m has been used in the current ECEI system to couple the LO source to the 24 vertically aligned array of ECE detectors. For efficient and compact LO optics employing the Powell lens is proposed so that the OPL of the LO source is significantly reduced from ∼2.0 m to 0.4 m with new optics. The coupling efficiency of the LO source is expected to be improved especially at the edge channels. Results from the optical simulation together with the laboratory test of the prototype optics will be discussed in this paper.