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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. 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. PMID:22380155

  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.

    PubMed

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

    2016-02-01

    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. PMID:26931919

  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. 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. PMID:18315101

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

    PubMed

    Ohnishi, J; Higurashi, Y; Nakagawa, T

    2016-02-01

    We have been developing a high-temperature oven using UO2 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 UO2 was approximately 2.4 mg/h. In these tests, we experienced several problems: the ejection hole of a crucible was blocked with UO2 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.

  9. 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.

  10. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2006-03-01

    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 μA of Kr17+(260 e μA), 12 p μA of Xe20+ (240 e μA of Xe20+), and 8 p μA of U28+(230 e μA). 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 μA of Xe27+ and 245 e μA of Bi29+, while for the higher charge states 15 e μA of Xe34+, 15 e μA of Bi41+, and 0.5 e μA 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% of the resonance field. In addition, a strong dependence of the x-ray flux and energy on the minimum B field value was found.

  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. Design study of a 17.3 GHz electron cyclotron resonance (ECR) ion source at Louvain-la-Neuve

    SciTech Connect

    Standaert, L. Davin, F.; Loiselet, M.

    2014-02-15

    The Cyclotron Resources Center of the Louvain-la-Neuve University is developing a new electron cyclotron resonance ion source to increase the energy of the accelerated beam by injection of higher charge state ions into the cyclotron. The design of the source is based on a 17.3 GHz frequency and classical coils to produce the axial field. The field reaches 2 T at the injection side and 1.2 T at extraction. The total power consumption for the coils is limited to 80 kW. The design features of the source are presented.

  14. 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.

  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.

    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. PMID:26931931

  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.

    PubMed

    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.

  19. Recent development of RIKEN 28 GHz superconducting electron cyclotron resonance ion source

    SciTech Connect

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

    2014-02-15

    Over the past two years, we have tried to improve the performance of the RIKEN superconducting electron cyclotron resonance ion source using several methods. For the production of U vapor, we chose the sputtering method because it is possible to install a large amount of material inside the plasma chamber and thus achieve long-term operation without a break, although it is assumed that the beam intensity is weaker than in the oven technique. We also used an aluminum chamber instead of a stainless steel one. Using these methods, we successfully produced ∼180 eμA of U{sup 35+} and ∼230 eμA of U{sup 33+} at the injected radio frequency (RF) power of ∼4 kW (28 GHz). Very recently, to further increase the beam intensity of U{sup 35+}, we have started to develop a high temperature oven and have successfully produced a highly charged U ion beam. In this contribution, we report on the beam intensity of highly charged U ions as a function of various parameters (RF power and sputtering voltage) and discuss the effects of these parameters on the beam stability in detail.

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

    PubMed

    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. PMID:26931935

  1. Development status of the 18 GHz superconducting electron cyclotron resonance ion source at National Fusion Research Institute

    NASA Astrophysics Data System (ADS)

    You, H. J.; Jang, S. O.; Choo, W. I.; Jung, Y. H.; Lho, T. H.; Yoo, S. J.

    2014-02-01

    A new superconducting 18 GHz electron cyclotron resonance ion source is being developed at the National Fusion Research Institute in South Korea. This source will be dedicated for future application of highly charged ions in the area of matter interaction, diagnostic imaging, and probing. In this paper, we describe the status of the source development consisting of a double electrode biased disk, sputtering systems for metal ion production, diagnostic ports for the extraction region, a variable gap extraction-Einzel lens system, and a low energy beam transport system.

  2. Development status of the 18 GHz superconducting electron cyclotron resonance ion source at National Fusion Research Institute.

    PubMed

    You, H J; Jang, S O; Choo, W I; Jung, Y H; Lho, T H; Yoo, S J

    2014-02-01

    A new superconducting 18 GHz electron cyclotron resonance ion source is being developed at the National Fusion Research Institute in South Korea. This source will be dedicated for future application of highly charged ions in the area of matter interaction, diagnostic imaging, and probing. In this paper, we describe the status of the source development consisting of a double electrode biased disk, sputtering systems for metal ion production, diagnostic ports for the extraction region, a variable gap extraction-Einzel lens system, and a low energy beam transport system.

  3. 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. PMID:26931953

  4. 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.

  5. 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.

  6. 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.

  7. 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. PMID:20192353

  8. Electron Cyclotron Resonance Heating on TEXTOR:. results from the preliminary 110 GHz system

    NASA Astrophysics Data System (ADS)

    Westerhof, E.; Hogeweij, G. M. D.; Hoekzema, J. A.; Schüller, F. C.; Barth, C. J.; Bindslev, H.; Donné, A. J. H.; Dumortier, P.; van Gorkom, J. C.; Jaspers, R. J. E.; Kalupin, D.; Koslowski, H. R.; Krämer-Flecken, A.; Lopes Cardozo, N. J.; van der Meiden, H. J.; Messiaen, A.; Oyevaar, T.; Polman, R. W.; Porte, L.; Udintsev, V. S.; Unterberg, B.; Vervier, M.; van Eester, D.; van Wassenhove, G.; Tec Team

    2003-02-01

    A 110 GHz, 400 kW, 200 ms gyrotron has been employed on TEXTOR for ECRH. The highly localised electron heating allowed the identification of (multiple) electron transport barriers. The RTP q-comb model for the electron heat conductivity gives a good description of TEXTOR results with ECRH in Ohmic discharges. Central ECRH in the current ramp phase speeds up central current penetration due to the highly peaked Te profile. A stable evolution of these discharges with early heating required the combination of counter-NBI with central ECRH. In RI-mode, central ECRH resulted in an increase of the confined energy in proportion to the ECRH power, without signs of power degradation as is usual in RI-mode with NBI and ICRH. Efficient ECRH is observed up to the X-mode cut-off density. The gyrotron has also been successfully used for diagnosis of energetic ions by means of Collective Thomson Scattering.

  9. Recondensation performance of liquid helium cryostat for a 28 GHz electron cyclotron resonance ion source.

    PubMed

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

    2014-02-01

    Cryostat performance is essential for the stable operation of a superconducting magnet. A closed-cycle liquid helium cryostat was adopted for use for a superconducting electron cyclotron resonance (ECR) ion source by recondensing liquid helium vapor. The goal was to maintain the liquid helium filled reservoir at a constant level without transferring any liquid helium during the normal operation of the ECR ion source. To accomplish this, Gifford-McMahon (GM) refrigerators, which have two cold heads, were installed on the top of the cryostat. The cooling power of the GM cryocooler is 1.5 W at the second stage and 50 W at the first stage. Each stage was connected to the liquid helium reservoir, a radiation shield including high-Tc current lead, and related items. Before commissioning the ECR ion source, a preliminary evaluation of the recondensation performance was carried out with the magnet in partial operation. The design of the cryostat, its fabrication, and the experimental results are reported.

  10. Recondensation performance of liquid helium cryostat for a 28 GHz electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    Cryostat performance is essential for the stable operation of a superconducting magnet. A closed-cycle liquid helium cryostat was adopted for use for a superconducting electron cyclotron resonance (ECR) ion source by recondensing liquid helium vapor. The goal was to maintain the liquid helium filled reservoir at a constant level without transferring any liquid helium during the normal operation of the ECR ion source. To accomplish this, Gifford-McMahon (GM) refrigerators, which have two cold heads, were installed on the top of the cryostat. The cooling power of the GM cryocooler is 1.5 W at the second stage and 50 W at the first stage. Each stage was connected to the liquid helium reservoir, a radiation shield including high-Tc current lead, and related items. Before commissioning the ECR ion source, a preliminary evaluation of the recondensation performance was carried out with the magnet in partial operation. The design of the cryostat, its fabrication, and the experimental results are reported.

  11. 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.

  12. Carbon beam extraction with 14.5 GHz electron cyclotron resonance ion source at Korea Atomic Energy Research Institute

    NASA Astrophysics Data System (ADS)

    Lee, Cheol Ho; Oh, Byung-Hoon; Chang, Dae-Sik; Jeong, Sun-Chan

    2014-02-01

    A 14.5 GHz Electron Cyclotron Resonance ion source (ECRIS) has been made to produce C4+ beam for using a carbon therapy facility and recently tested at KAERI. Highly charged carbon ions have been successfully extracted. When using only CO2 gas, the beam current of C4+ was almost 14 μA at 15 kV extraction voltage. To get higher current of the C4+ beam, while optimizing confinement magnetic field configuration (e.g., axial strengths at minimum and extraction side), gas-mixing (CO2/He), and biased disk were introduced. When the gas mixing ratio of the CO2/He gas is 1:8 at an operational pressure of 5 × 10-7 mbar and the disk was biased to -150 V relative to the ion source body, the highest current of the C4+ beam was achieved to be 50 μA, more than three times higher than previously observed only with CO2 gas. Some details on the operating conditions of the ECRIS were discussed.

  13. Carbon beam extraction with 14.5 GHz electron cyclotron resonance ion source at Korea Atomic Energy Research Institute.

    PubMed

    Lee, Cheol Ho; Oh, Byung-Hoon; Chang, Dae-Sik; Jeong, Sun-Chan

    2014-02-01

    A 14.5 GHz Electron Cyclotron Resonance ion source (ECRIS) has been made to produce C(4+) beam for using a carbon therapy facility and recently tested at KAERI. Highly charged carbon ions have been successfully extracted. When using only CO2 gas, the beam current of C(4+) was almost 14 μA at 15 kV extraction voltage. To get higher current of the C(4+) beam, while optimizing confinement magnetic field configuration (e.g., axial strengths at minimum and extraction side), gas-mixing (CO2/He), and biased disk were introduced. When the gas mixing ratio of the CO2/He gas is 1:8 at an operational pressure of 5 × 10(-7) mbar and the disk was biased to -150 V relative to the ion source body, the highest current of the C(4+) beam was achieved to be 50 μA, more than three times higher than previously observed only with CO2 gas. Some details on the operating conditions of the ECRIS were discussed. PMID:24593482

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

    PubMed

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

    2010-02-01

    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.

  15. 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.

  16. Mono 1000: A simple and efficient 2.45 GHz electron cyclotron resonance ion source using a new magnetic structure concept

    NASA Astrophysics Data System (ADS)

    Jardin, P.; Barue, C.; Canet, C.; Dupuis, M.; Flambard, J. L.; Gaubert, G.; Lecesne, N.; Lehérissier, P.; Lemagnen, F.; Leroy, R.; Pacquet, J.-Y.; Pellemoine, F.; Rataud, J.-P.; Laurent, M. G. Saint; Villari, A. C. C.

    2002-02-01

    The production of singly charged atomic and molecular ions with a new 2.45 GHz electron cyclotron resonance ion source has been studied. The ion source Mono 1000 uses a new magnetic confinement structure. The elements Ne, Ar, and Kr are ionized with efficiencies close to 100%, while 45% has been achieved for He. In the case of the molecules SO2 and SF6, more than 90% overall efficiency has been observed with more than 40% of sulfur atoms leaving the source under the form S+. A total extracted yield of 4×1012 singly charged fulleren (C60) ions per second has also been observed.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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. PMID:24593475

  3. High current H{sub 2}{sup +} and H{sub 3}{sup +} beam generation by pulsed 2.45 GHz electron cyclotron resonance ion source

    SciTech Connect

    Xu, Yuan; Peng, Shixiang Ren, Haitao; Zhao, Jie; Chen, Jia; Zhang, Tao; Guo, Zhiyu; Zhang, Ailin; Chen, Jia'er

    2014-02-15

    The permanent magnet 2.45 GHz electron cyclotron resonance ion source at Peking University can produce more than 100 mA hydrogen ion beam working at pulsed mode. For the increasing requirements of cluster ions (H{sub 2}{sup +} and H{sub 3}{sup +}) in linac and cyclotron, experimental study was carried out to further understand the hydrogen plasma processes in the ion source for the generation of cluster ions. The constituents of extracted beam have been analyzed varying with the pulsed duration from 0.3 ms to 2.0 ms (repetition frequency 100 Hz) at different operation pressure. The fraction of cluster ions dramatically increased when the pulsed duration was lower than 0.6 ms, and more than 20 mA pure H{sub 3}{sup +} ions with fraction 43.2% and 40 mA H{sub 2}{sup +} ions with fraction 47.7% were obtained when the operation parameters were adequate. The dependence of extracted ion fraction on microwave power was also measured at different pressure as the energy absorbed by plasma will greatly influence electron temperature and electron density then the plasma processes in the ion source. More details will be presented in this paper.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Electron cyclotron resonance heating on TEXTOR

    NASA Astrophysics Data System (ADS)

    Westerhof, E.; Hoekzema, J. A.; Hogeweij, G. M. D.; Jaspers, R. J. E.; Schüller, F. C.; Barth, C. J.; Bongers, W. A.; Donné, A. J. H.; Dumortier, P.; van der Grift, A. F.; van Gorkom, J. C.; Kalupin, D.; Koslowski, H. R.; Krämer-Flecken, A.; Kruijt, O. G.; Lopes Cardozo, N. J.; Mantica, P.; van der Meiden, H. J.; Merkulov, A.; Messiaen, A.; Oosterbeek, J. W.; Oyevaar, T.; Poelman, A. J.; Polman, R. W.; Prins, P. R.; Scholten, J.; Sterk, A. B.; Tito, C. J.; Udintsev, V. S.; Unterberg, B.; Vervier, M.; van Wassenhove, G.; TEC Team

    2003-11-01

    The 110 GHz and the new 140 GHz gyrotron systems for electron cyclotron resonance heating (ECRH) and ECCD on TEXTOR are described and results of ECRH experiments with the 110 GHz system are reported. Central ECRH on Ohmic plasmas shows the presence of an internal electron transport barrier near q = 1. This is confirmed by modulated ECRH experiments. A central barrier is also indicated by ECRH in radiatively improved (RI) mode discharges and up to two barriers are seen with ECRH during the current ramp phase. ECRH control of sawteeth is reported for both Ohmic and RI mode target plasmas. This paper is an expanded version of the two papers presented on the TEXTOR ECRH system (J.A. Hoekzema et al) and experimental results (E. Westerhof et al) at the 12th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating (Aix-en-Provence, France, 13-16 May 2002).

  9. 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

    SciTech Connect

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

    2014-03-15

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

  10. 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.

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

    PubMed

    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.

  12. 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.

  13. Operation of a quasioptical electron cyclotron maser

    SciTech Connect

    Morse, E.C.; Pyle, R.V.

    1984-12-01

    The electron cyclotron maser or gyrotron concept has been developed to produce sources producing 200 kW at 28 GHz continuously, and higher power outputs and frequencies in pulsed mode. These sources have been useful in electron cyclotron resonance heating (ECRH) in magnetically confined fusion devices. However, higher frequencies and higher power levels will be required in reactor-grade fusion plasmas, with likely requirements of 1.0 MW or more per source at 140 GHz. Conventional gyrotrons follow a trend of decreasing power for increasing frequency. In order to circumvent this problem, the quasioptical electron cyclotron maser was proposed. In this device, the closed resonator of the conventional gyrotron is replaced with an open, Fabry-Perot type resonator. The cavity modes are then the TEM-type modes of an optical laser. The advantage of this configuration is that the cavity size is not a function of frequency, since the length can be any half-integer number of wavelengths. Furthermore, the beam traverses across the cavity transverse to the direction of radiation output, and thus the rf window design is less complicated than in conventional tubes. The rf output, if obtained by diffraction coupling around one of the mirrors, could be in a TEM mode, which would allow for quasioptical transmission of the microwaves into the plasma in fusion devices. 4 references, 1 figure.

  14. 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.

  15. Electron cyclotron emission diagnostics on KSTAR tokamak.

    PubMed

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

    2010-10-01

    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. 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.

  17. 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).

  18. 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.

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

    SciTech Connect

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

    2014-02-15

    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{sup 2} with about 40 W microwave power. To investigate the correlation between the volume of the low electron temperature region and the H{sup −} 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.

  20. 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.

  1. 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%).

  2. Design of an induction linac driven CARM (Cyclotron Auto Resonance Maser) oscillator at 250 GHz

    SciTech Connect

    Caplan, M.; Kulke, B.

    1990-01-24

    We present the design of a 250 GHz, 400 MW Cyclotron Auto Resonance Maser (CARM) oscillator driven by a 1 KA, 2 MeV electron beam produced by the induction linac at the ARC facility of LLNL. The oscillator circuit is designed as a feedback amplifier operating in the TE{sub 11} mode at ten times cutoff terminated at each end with Bragg reflectors. Theory and cold test results are in good agreement for a manufactured Bragg reflector using 50 {mu}m corrugations to ensure mode purity. The CARM is to be operational by February 1990. 3 figs., 2 tabs.

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

    PubMed

    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. PMID:24593510

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Field structure and electron life times in the MEFISTO electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Bodendorfer, M.; Altwegg, K.; Shea, H.; Wurz, P.

    2008-03-01

    The complex magnetic field of the permanent magnet electron cyclotron resonance (ECR) ion source MEFISTO located at the University of Berne has been numerically simulated. For the first time the magnetized volume qualified for electron cyclotron resonance at 2.45 GHz and 87.5 mT has been analyzed in highly detailed 3D simulations with unprecedented resolution. New results were obtained from the numerical simulation of 25,211 electron trajectories. The evident characteristic ion sputtering trident of hexapole confined ECR ion sources has been identified with the field and electron trajectory distribution. Furthermore, unexpected long electron trajectory lifetimes were found.

  11. 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.

  12. 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.

  13. Imaging Cyclotron Orbits of Electrons in Graphene.

    PubMed

    Bhandari, Sagar; Lee, Gil-Ho; Klales, Anna; Watanabe, Kenji; Taniguchi, Takashi; Heller, Eric; Kim, Philip; Westervelt, Robert M

    2016-03-01

    Electrons in graphene can travel for several microns without scattering at low temperatures, and their motion becomes ballistic, following classical trajectories. When a magnetic field B is applied perpendicular to the plane, electrons follow cyclotron orbits. Magnetic focusing occurs when electrons injected from one narrow contact focus onto a second contact located an integer number of cyclotron diameters away. By tuning the magnetic field B and electron density n in the graphene layer, we observe magnetic focusing peaks. We use a cooled scanning gate microscope to image cyclotron trajectories in graphene at 4.2 K. The tip creates a local change in density that casts a shadow by deflecting electrons flowing nearby; an image of flow can be obtained by measuring the transmission between contacts as the tip is raster scanned across the sample. On the first magnetic focusing peak, we image a cyclotron orbit that extends from one contact to the other. In addition, we study the geometry of orbits deflected into the second point contact by the tip.

  14. 23 GHz ferroelectric electron gun based gyrotron

    NASA Astrophysics Data System (ADS)

    Ben-Moshe, R.; Einat, M.

    2011-04-01

    Ferroelectric cathodes have been explored as an alternative electron source for microwave tubes. Past experiments have demonstrated operation at frequencies of 2-10 GHz. Since the ferroelectric cathode is based on surface plasma, the relatively high energy spread limits the tube operation frequency. Hence, the possibility to obtain higher frequencies remained questionable. In this experimental work a gyrotron oscillator was designed with the operation frequency increased toward that of millimeter waves. A cylindrical tube with a cutoff frequency of ˜22 GHz was integrated to a ferroelectric electron gun. Pulses of ˜0.5 μs duration with a frequency of 23 GHz were obtained.

  15. 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.

  16. 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.

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

    NASA Astrophysics Data System (ADS)

    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 C4+ 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 C4+, 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.

  18. 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. PMID:24593538

  19. 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.

  20. Electron-cyclotron-resonant-heated electron distribution functions

    SciTech Connect

    Matsuda, Y.; Nevins, W.M.; Cohen, R.H.

    1981-06-26

    Recent studies at Lawrence Livermore National Laboratory (LLNL) with a bounce-averaged Fokker-Planck code indicate that the energetic electron tail formed by electron-cyclotron resonant heating (ECRH) at the second harmonic is not Maxwellian. We present the results of our bounce-averaged Fokker-Planck code along with some simple analytic models of hot-electron distribution functions.

  1. Electron cyclotron emission imaging in tokamak plasmas

    SciTech Connect

    Munsat, Tobin; Domier, Calvin W.; Kong, Xiangyu; Liang, Tianran; Luhmann, Jr.; Neville C.; Tobias, Benjamin J.; Lee, Woochang; Park, Hyeon K.; Yun, Gunsu; Classen, Ivo. G. J.; Donne, Anthony J. H.

    2010-07-01

    We discuss the recent history and latest developments of the electron cyclotron emission imaging diagnostic technique, wherein electron temperature is measured in magnetically confined plasmas with two-dimensional spatial resolution. The key enabling technologies for this technique are the large-aperture optical systems and the linear detector arrays sensitive to millimeter-wavelength radiation. We present the status and recent progress on existing instruments as well as new systems under development for future experiments. We also discuss data analysis techniques relevant to plasma imaging diagnostics and present recent temperature fluctuation results from the tokamak experiment for technology oriented research (TEXTOR).

  2. Slow-wave electron cyclotron maser

    SciTech Connect

    Kho, T.H.; Lin, A.T.

    1988-09-15

    The basic physics of a slow-wave electron cyclotron maser (ECM) operating in the Cherenkov regime is considered. This device has the advantage over fast-wave ECM's in that it can be operated with direct axial injection of the electron beam, thus allowing for better control over beam quality and a potentially more compact design. The nonlinear evolution and saturation of the instability are studied using computer simulation. It is shown that high efficiency is attainable and, furthermore, that beam momentum spread is better tolerated in the Doppler-shift-dominated regime than is the case for a fast-wave ECM.

  3. 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.

  4. Electron cyclotron heating and current drive in toroidal geometry

    SciTech Connect

    Kritz, A.H.

    1993-03-01

    The Principal Investigator has continued to work on problems associated both with the deposition and with the emission of electron cyclotron heating power electron cyclotron heating in toroidal plasmas. Inparticular, the work has focused on the use of electron cyclotron heating to stabilize q = 1 and q = 2 instabilities in tokamaks and on the use of electron cyclotron emission as a plasma diagnostic. The research described in this report has been carried out in collaboration with scientists at Princeton, MIT and Livermore. The Principal Investigator is now employed at Lehigh University, and a small group effort on electron cyclotron heating in plasmas has begun to evolve at Lehigh involving undergraduate and graduate students. Work has also been done in support of the electron cyclotron heating and current drive program at the Center for Research in Plasma Physics in Lausanne, Switzerland.

  5. Experimental investigation on electron cyclotron absorption at down-shifted frequency in the PLT tokamak

    SciTech Connect

    Mazzucato, E.; Fidone, I.; Cavallo, A.; von Goeler, S.; Hsuan, H.

    1986-05-01

    The absorption of 60 GHz electron cyclotron waves, with the extraordinary mode and an oblique angle of propagation, has been investigated in the PLT tokamak in the regime of down-shifted frequencies. The production of energetic electrons, with energies of up to 300 to 400 keV, peaks at values of toroidal field (approx. =29 kG) for which the wave frequency is significantly smaller than the electron cyclotron frequency in the whole plasma region. The observations are consistent with the predictions of the relativistic theory of electron cyclotron damping at down-shifted frequency. Existing rf sources make this process a viable method for assisting the current ramp-up, and for heating the plasma of present large tokamaks.

  6. 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.

  7. Electrostatic electron and ion cyclotron harmonic waves in Neptune's magnetosphere

    NASA Technical Reports Server (NTRS)

    Barbosa, D. D.; Kurth, W. S.; Cairns, I. H.; Gurnett, D. A.; Poynter, R. L.

    1990-01-01

    Voyager 2 observations of electrostatic electron and ion cyclotron waves detected in Neptune's magnetosphere are presented. Both types of emission appear in a frequency band above the electron and ion (proton) cyclotron frequencies, respectively, and are tightly confined to the magnetic equator occurring within a few degrees of it. The electron cyclotron modes including an intense upper hybrid resonance emission excited by an unstable loss cone distribution of low-density superthermal electrons. The ion cyclotron waves are interpreted as hydrogen Bernstein modes including an intense lower hybrid resonance emission excited by an unstable ring distribution of low-density pickup N(+) ions deriving from the satellite Triton.

  8. 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.

  9. Analysis of the electron cyclotron maser instability

    NASA Astrophysics Data System (ADS)

    Kuo, S. P.; Cheo, B. R.

    1984-07-01

    The nonlinear evolution of the electron cyclotron maser instability is investigated analytically, with a focus on the saturation due to phase trapping of gyrating particles in the wave. The equations of motion of a single electron moving in the wave are solved; the collective response of electrons to wave fields is obtained by averaging over the initial random phase distribution; and a single nonlinear equation governing the time evolution of the amplitude is derived self-consistently. Numerical results are presented in graphs and shown to be in good agreement with those of a particle simulation, at a significant savings in computational effort. The results are applicable to the improvement of high-power gyrotron-type mm and sub-mm emitters for radar communications or plasma heating in controlled-fusion devices.

  10. First operation of the charge-breeder electron-cyclotron-resonance ion source at the Texas A and M Cyclotron Institute

    SciTech Connect

    May, D. P.; Tabacaru, G.; Abegglen, F. P.; Cornelius, W. D.

    2010-02-15

    The 14.5 GHz electron-cyclotron-resonance ion source (ECRIS) designed and fabricated specifically for charge breeding has been installed at the Texas A and M University Cyclotron Institute for use in the institute's ongoing radioactive-ion-beam upgrade. The initial testing of the source has just begun with magnetic analysis of the ECRIS beam. The source has only been conditioning for a brief time at low microwave power, and it is continuing to improve. After the source has been conditioned and characterized, charge-breeding trials with stable beams from a singly ionizing source will begin.

  11. 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.

  12. 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.

  13. 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. PMID:15903924

  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. Electron cyclotron emission diagnostic for ITER

    SciTech Connect

    Rowan, W.; Austin, M.; Phillips, P.; Beno, J.; Ouroua, A.; Ellis, R.; Feder, R.; Patel, A.

    2010-10-15

    Electron temperature measurements and electron thermal transport inferences will be critical to the nonactive and deuterium phases of ITER operation and will take on added importance during the alpha heating phase. The diagnostic must meet stringent criteria on spatial coverage and spatial resolution during full field operation. During the early phases of operation, it must operate equally well at half field. The key to the diagnostic is the front end design. It consists of a quasioptical antenna and a pair of calibration sources. The radial resolution of the diagnostic is less than 0.06 m. The spatial coverage extends at least from the core to the separatrix with first harmonic O-mode being used for the core and second harmonic X-mode being used for the pedestal. The instrumentation used for the core measurement at full field can be used for detection at half field by changing the detected polarization. Intermediate fields are accessible. The electron cyclotron emission systems require in situ calibration, which is provided by a novel hot calibration source. The critical component for the hot calibration source, the emissive surface, has been successfully tested. A prototype hot calibration source has been designed, making use of extensive thermal and mechanical modeling.

  16. Electron cyclotron emission diagnostic for ITER.

    PubMed

    Rowan, W; Austin, M; Beno, J; Ellis, R; Feder, R; Ouroua, A; Patel, A; Phillips, P

    2010-10-01

    Electron temperature measurements and electron thermal transport inferences will be critical to the nonactive and deuterium phases of ITER operation and will take on added importance during the alpha heating phase. The diagnostic must meet stringent criteria on spatial coverage and spatial resolution during full field operation. During the early phases of operation, it must operate equally well at half field. The key to the diagnostic is the front end design. It consists of a quasioptical antenna and a pair of calibration sources. The radial resolution of the diagnostic is less than 0.06 m. The spatial coverage extends at least from the core to the separatrix with first harmonic O-mode being used for the core and second harmonic X-mode being used for the pedestal. The instrumentation used for the core measurement at full field can be used for detection at half field by changing the detected polarization. Intermediate fields are accessible. The electron cyclotron emission systems require in situ calibration, which is provided by a novel hot calibration source. The critical component for the hot calibration source, the emissive surface, has been successfully tested. A prototype hot calibration source has been designed, making use of extensive thermal and mechanical modeling.

  17. 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.

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

    SciTech Connect

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

    2014-02-15

    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{sup 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{sup 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.

  19. 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.

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

    PubMed

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

    2008-09-01

    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.

  2. 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.

  3. Suppression of cyclotron instability in Electron Cyclotron Resonance ion sources by two-frequency heating

    SciTech Connect

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

    2015-08-15

    Multiple frequency heating is one of the most effective techniques to improve the performance of Electron Cyclotron Resonance (ECR) ion sources. The method increases the beam current and average charge state of the extracted ions and enhances the temporal stability of the ion beams. It is demonstrated in this paper that the stabilizing effect of two-frequency heating is connected with the suppression of electron cyclotron instability. Experimental data show that the interaction between the secondary microwave radiation and the hot electron component of ECR ion source plasmas plays a crucial role in mitigation of the instabilities.

  4. A new way to measure the electron cyclotron frequency

    NASA Astrophysics Data System (ADS)

    Palmer, F. L.

    1993-03-01

    A method is described for using spin flips to measure the 0 to 1 cyclotron transition frequency of a single electron in a Penning trap. Detection can be accomplished with magnetic bottles of 10 T/m2 or less, thereby greatly reducing the thermal broadening of the cyclotron line. This method complements a recently published technique for measuring the anomaly frequency, making a more precise measurement of the electron anomaly ratio possible.

  5. Investigation of the second harmonic electron cyclotron current drive efficiency on the T-10 tokamak

    SciTech Connect

    Razumova, K.A.; Alikaev, V.V.; Dremin, M.M.; Esipchuk, Y.V.; Kislov, A.Y.; Notkin, G.E.; Pavlov, Y.D. ); Forest, C.B.; Lohr, J.; Luce, T.C.; Harvey, R.W. )

    1994-05-01

    Experiments on second harmonic electron cyclotron current drive were done on the T-10 tokamak using four gyrotrons. Total powers up to 1.2 MW at a frequency of 140 GHz were injected. Current generation by electron cyclotron (EC) waves was demonstrated in the experiments. The efficiency [eta] of current generation and its dependence on plasma parameters were measured and it was shown that the efficiency is a nonlinear function of input power, more closely predicted by Fokker--Planck calculations than by linear theory. The interaction of EC waves with the tail of the electron distribution was shown to be important. It was also found that current density profile redistribution played an important role in the plasma behavior.

  6. Nonlinear Optical Phenomena in Cyclotron Resonance of Positive Holes and Electrons in Cu2O

    NASA Astrophysics Data System (ADS)

    Masumi, Taizo; Shimada, Hiroshi

    1991-11-01

    Nonlinear optical phenomena have been observed for the first time in a new cyclotron resonance experiment on the photoexcited positive holes and/or electrons in Cu2O at f{=}35 GHz, T{=}4.2 K and at high density excitation Pex{≥q}100 kW/cm2 of λex{=}460--750 nm. Unexpectedly, we have observed a nonlinear optical growth of the cyclotron resonance absorption of both holes and electrons at the mid-gap high-density excitation of λex{≥q}690 nm. New experimental results reveal so far unknown specific characters of the conduction and valence electrons in detail and of deep levels as well. Here, we tentatively ascribe these phenomena to a possible condensation of polarons and excitons into a new state in Cu2O such as into a bipolaron state via a specific type of double acceptor states.

  7. 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

  8. Results with the superconducting electron cyclotron resonance ion source VENUS (invited)

    NASA Astrophysics Data System (ADS)

    Lyneis, C. M.; Leitner, D.; Abbott, S. R.; Dwinell, R. D.; Leitner, M.; Silver, C. S.; Taylor, C.

    2004-05-01

    During the last year, the VENUS electron cyclotron resonance (ECR) ion source was commissioned at 18 GHz and preparations for 28 GHz operation, which is set to begin early in 2004, are now underway. The goal of the VENUS ECR ion source project as the RIA research and development injector is the production of 240 eμA of U30+, a high current medium charge state beam. On the other hand, as an injector ion source for the 88-Inch Cyclotron the design objective is the production of 5 eμA of U48+, a low current, very high charge state beam. During the commissioning phase with 18 GHz, tests with various gases and recently metals have been performed with up to 2000 W rf power and the performance is very promising. For example, 1100 eμA of O6+, 180 eμA of Ar12+, 150 eμA of Xe20+, and 100 eμA of Bi24+ were produced in the early commissioning phase, ranking VENUS among the currently highest performance 18 GHz ECR ion sources. The emittance of the beams produced at 18 GHz was measured with a two axis emittance scanner. In FY04 a 10 kW, 28 GHz gyrotron system will be added, which will enable VENUS to reach full performance. The performance of the VENUS ion source, low energy beam transport and its closed loop cryogenic system are described in the article. Recently, a high temperature axial oven has been installed in the source and the first results on metal beams such as bismuth are given. The design of the 28 GHz, 10 kW gyrotron system will also be described.

  9. 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.

  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.

    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.

  11. 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.

  12. 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.

  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. 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.

  15. 2D electron cyclotron emission imaging at ASDEX Upgrade (invited)

    SciTech Connect

    Classen, I. G. J.; Boom, J. E.; Vries, P. C. de; Suttrop, W.; Schmid, E.; Garcia-Munoz, M.; Schneider, P. A.; Tobias, B.; Domier, C. W.; Luhmann, N. C. Jr.; Donne, A. J. H.; Jaspers, R. J. E.; Park, H. K.; Munsat, T.

    2010-10-15

    The newly installed electron cyclotron emission imaging diagnostic on ASDEX Upgrade provides measurements of the 2D electron temperature dynamics with high spatial and temporal resolution. An overview of the technical and experimental properties of the system is presented. These properties are illustrated by the measurements of the edge localized mode and the reversed shear Alfven eigenmode, showing both the advantage of having a two-dimensional (2D) measurement, as well as some of the limitations of electron cyclotron emission measurements. Furthermore, the application of singular value decomposition as a powerful tool for analyzing and filtering 2D data is presented.

  16. Initial Results of Multi-Frequency Electron Cyclotron Heating in the Levitated Dipole Experiment

    SciTech Connect

    Hansen, A.K.; Garnier, D.T.; Mauel, M.; Ortiz, E.E.; Mahar, S.; Boxer, A.C.; Ellsworth, J.L.; Karim, I.; Kesner, J.

    2005-09-26

    The Levitated Dipole Experiment (LDX) has created high-beta, hot-electron plasmas that are confined by a strong dipole electromagnet via multiple-frequency electron cyclotron resonance heating (ECRH). Multiple frequency ECRH is used to investigate how variation of the power deposition profile may be used to adjust the plasma density and pressure profiles. The initial experiments have been performed using up to 3 kW at 2.45 GHz and 3 kW at 6.4 GHz. Variations included switching on and off a single source while injecting constant power with the other source. We have also investigated the role of magnetic shaping, using external coils, on ECRH phenomena and plasma profile control. The preliminary results of these experiments will be presented.

  17. 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)

  18. 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.

  19. Physics design of a 28 GHz electron heating system for the National Spherical Torus experiment upgrade

    SciTech Connect

    Taylor, G.; Bertelli, N.; Ellis, R. A.; Gerhardt, S. P.; Hosea, J. C.; Poli, F.; Harvey, R. W.; Raman, R.; Smirnov, A. P.

    2014-02-12

    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 NSTXU 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 I{sub p} 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.

  20. Physics design of a 28 GHz electron heating system for the National Spherical Torus experiment upgrade

    NASA Astrophysics Data System (ADS)

    Taylor, G.; Bertelli, N.; Ellis, R. A.; Gerhardt, S. P.; Harvey, R. W.; Hosea, J. C.; Poli, F.; Raman, R.; Smirnov, A. P.

    2014-02-01

    A megawatt-level, 28 GHz electron heating system is being designed to support non-inductive (NI) plasma current (Ip) 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 Ip start-up and ramp-up is an important goal of the NSTXU research program. 28 GHz electron cyclotron (EC) heating is predicted to rapidly increase the central electron temperature (Te(0)) of low density NI plasmas generated by Coaxial Helicity Injection (CHI). The increased Te(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 Ip 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.

  1. 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.

  2. 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.

  3. Production of C58 and C56 Ions by Using Electron Cyclotron Resonance Ion Source

    NASA Astrophysics Data System (ADS)

    Tanaka, Kiyokatsu; Uchida, Takashi; Minezaki, Hidekazu; Muramatsu, Masayuki; Biri, Sandor; Asaji, Toyohisa; Shima, Kazushi; Kitagawa, Atsushi; Kato, Yushi; Yoshida, Yoshikazu

    An electron cyclotron resonance ion source (ECRIS) has been developed for a synthesis of endohedral metallofullerenes. The ECRIS has a traditional minimum-B magnetic field and an 8-10 GHz traveling wave tube (TWT) amplifier as a microwave source. C60 plasmas have been generated at the first experiment. Many broken fullerenes C58 and C56 are observed in fullerene ion beams. We investigated the fullerene ion beams against pressures in the ion source. From the results, these fullerene ion currents increase as the decrease of the pressure and the maximum current is 0.81 μA of C602+.

  4. 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.

  5. 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.

  6. 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.}

  7. 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.

  8. Experimental demonstration of a high-power slow wave electron cyclotron maser utilizing corrugated metal structure

    SciTech Connect

    Minami, K.; Ogura, K.; Kurashina, K; Kim, W.; Watanabe, Tsuguhiro; Carmel, Y.; Destler, W.W.; Granatstein, V.L.

    1994-12-31

    High-power microwave (HPM) sources based on electron cyclotron resonance (ECR) such as gyrotrons are fast wave devices and velocity component of electron beam perpendicular to guiding magnetic field is the origin of HPM. HPM sources based on Cherenkove mechanism are slow wave devices and can be driven by a beam without initial perpendicular velocity. The authors present here the experimental result that seems to be the first demonstration of high-power slow wave electron cyclotron maser (ECM) consisting of a large diameter sinusoidally corrugated metal waveguide driven by a beam with predominant parallel velocity. The designed size parameters of slow wave structure (SWS) are as follows: average radius 30 mm, corrugation pitch 3.4 mm, its amplitude h = 1.7 mm and total length 238 mm. They use an annular beam with radius 26.3 mm, energy 55 keV, current 200 A in their experiment. Expected Cherenkov oscillation frequency of TM01 mode is 20 GHz. The observed high-power microwaves can be quantitatively explained by a backward wave oscillation with Cherenkov mechanism enhanced by positive feedback of anomalous Doppler slow cyclotron wave. In conclusion, the slow wave ECM presented here will be a competitive candidate against gyrotrons for generating multi-MW millimeter microwaves available in fusion plasma research.

  9. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-11-01

    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+ is 54 μA. Many broken fullerenes such as C58 and C56 are observed in fullerene ion beams.

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

    PubMed

    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. 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. 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 Te measurements, which demonstrate that the desired resolution is achieved, are presented.

  12. 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.

  13. Comparative electron temperature measurements of Thomson scattering and electron cyclotron emission diagnostics in TCABR plasmas

    SciTech Connect

    Alonso, M. P.; Figueiredo, A. C. A.; Berni, L. A.; Machida, M.

    2010-10-15

    We present the first simultaneous measurements of the Thomson scattering and electron cyclotron emission radiometer diagnostics performed at TCABR tokamak with Alfven wave heating. The Thomson scattering diagnostic is an upgraded version of the one previously installed at the ISTTOK tokamak, while the electron cyclotron emission radiometer employs a heterodyne sweeping radiometer. For purely Ohmic discharges, the electron temperature measurements from both diagnostics are in good agreement. Additional Alfven wave heating does not affect the capability of the Thomson scattering diagnostic to measure the instantaneous electron temperature, whereas measurements from the electron cyclotron emission radiometer become underestimates of the actual temperature values.

  14. 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.

  15. 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.

  16. 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.

  17. 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. PMID:25725830

  18. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Electron Cyclotron Resonance Heating (ECRH) Control System

    SciTech Connect

    Heefner, J.W.; Williams, C.W.; Lauze, R.R.; Karsner, P.G.

    1985-11-11

    The ECRH Control System was installed on the Tandem Mirror Experiment-Upgrade (TMX-U) in 1980. The system provides approximately 1 MW of 28 GHz microwave power to the TMX-U plasma. The subsystems of ECRH that must be controlled include high-voltage charging supplies, series pass tubes, and magnet supplies. In addition to the devices that must be controlled, many interlocks must be continuously monitored. The previous control system used relay logic and analog controls to operate the system. This approach has many drawbacks such as lack of system flexibility and maintainability. In order to address these problems, it was decided to go with a CAMAC and Modicon based system that uses a Hewlett-Packard 9836C personal computer to replace the previous analog controls. 2 figs.

  1. 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.

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

    NASA Astrophysics Data System (ADS)

    Jiang, M.; Shi, Z. B.; Che, S.; Domier, C. W.; Luhmann, N. C.; Hu, X.; Spear, A.; 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.

    2013-11-01

    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).

  3. 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.

  4. 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.

  5. 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.

  6. High-field launch electron cyclotron heating experiments in the ELMO Bumpy Torus

    SciTech Connect

    Rasmussen, D.A.; Batchelor, D.B.; Swain, D.W.; White, T.L.; Kimrey, H.D.; Bigelow, T.S.; Cobble, J.A.; Hillis, D.L.; Richards, R.K.; Uckan, T.

    1985-05-01

    The midplane microwave heating system in the ELMO Bumpy Torus (EBT) was supplemented with power launched from the high-field side of the fundamental resonance by an antenna in the magnet coil throat. Up to 43 kW of polarized (extraordinary mode), 28-GHz power was successfully launched with one antenna. Measurements were made of changes in the core and hot electron ring plasma parameters when throat-launch power was added. In sharp contrast to initial expectations, the bulk core plasma parameters were degraded while the ring parameters, in the launch cavity, were improved. These results are explained in light of a modified picture of electron cyclotron heating (ECH) in EBT. A picture of localized microwave absorption and particle losses is supported by additional measurements.

  7. Laboratory modeling of pulsed regimes of electron cyclotron instabilities

    NASA Astrophysics Data System (ADS)

    Golubev, S. V.; Mansfeld, D. A.; Viktorov, M. E.; Izotov, I. V.; Vodopyanov, A. V.; Demekhov, A. G.; Shalashov, A. G.

    2012-04-01

    One of the most interesting electron cyclotron resonance (ECR) 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. Such phenomena are observed in a wide range of plasma parameters under various conditions: in the magnetospheres of the Earth and planets, in solar coronal loops, and in laboratory magnetic traps. We demonstrate the use of a laboratory setup based on a magnetic mirror trap with plasma sustained by a gyrotron radiation under ECR conditions for investigation of the cyclotron instabilities similar to the ones which take place in space plasmas. Two regimes of the cyclotron instability are studied. In the first place, quasi-periodic pulsed precipitation of energetic electrons from the trap, accompanied by microwave bursts at frequencies below the electron gyrofrequency in the center of the trap, is detected. The study of the microwave plasma emission and the energetic electrons precipitated from the trap shows that the precipitation is related to the excitation of whistlers propagating nearly parallel to the trap axis. The observed instability has much in common with phenomena in space magnetic traps, such as radiation belts of magnetized planets and solar coronal loops. Such regimes have much in common with the quasi-periodic VLF radiation in the Earth's inner magnetosphere (with periods of T ~ 100 s) and can also be met in solar flaring loops and at other space objects. In the second place, we have detected and investigated quasi-periodic series of pulsed energetic electron precipitations in the decaying plasma of a pulsed ECR discharge in a mirror axisymmetric magnetic trap. The observed particle ejections from the trap are interpreted as the result of resonant interaction between energetic electrons and a slow extraordinary wave

  8. Measurement of cyclotron resonance relaxation time in the two-dimensional electron system

    SciTech Connect

    Andreev, I. V. Muravev, V. M.; Kukushkin, I. V.; Belyanin, V. N.

    2014-11-17

    Dependence of cyclotron magneto-plasma mode relaxation time on electron concentration and temperature in the two-dimensional electron system in GaAs/AlGaAs quantum wells has been studied. Comparative analysis of cyclotron and transport relaxation time has been carried out. It was demonstrated that with the temperature increase transport relaxation time tends to cyclotron relaxation time. It was also shown that cyclotron relaxation time, as opposed to transport relaxation time, has a weak electron density dependence. The cyclotron time can exceed transport relaxation time by an order of magnitude in a low-density range.

  9. Electron Bernstein wave heating by electron cyclotron wave injection from the high-field side in LHD

    NASA Astrophysics Data System (ADS)

    Yoshimura, Y.; Igami, H.; Kubo, S.; Shimozuma, T.; Takahashi, H.; Nishiura, M.; Ohdachi, S.; Tanaka, K.; Ida, K.; Yoshinuma, M.; Suzuki, C.; Ogasawara, S.; Makino, R.; Idei, H.; Kumazawa, R.; Mutoh, T.; Yamada, H.; the LHD Experiment Group

    2013-06-01

    In the Large Helical Device (LHD), evident electron Bernstein wave (EBW) heating was successfully performed. The experiment was carried out using the electron cyclotron heating (ECH) system that was upgraded by installation of high-power, long-pulse 77 GHz gyrotrons. The EBW heating was achieved by a mode conversion from injected EC wave to EBW, by the so-called slow-XB technique where an X-mode wave is injected to the plasma from the high magnetic field side. The specific magnetic configuration of LHD provides a good opportunity to realize the slow-XB technique, which is generally difficult for tokamaks. With the slow-XB technique, increases in kinetically evaluated electron energy Wpe and electron temperature Te were observed in overdense plasmas. An electron heating in the so-called super dense core plasma in LHD, which is characterized with an internal diffusion barrier and a steep density gradient at the plasma core, was successfully demonstrated in the plasma core region where the central electron density ne0 of 17 × 1019 m-3 was about 1.2 times higher, at the beginning of the EC-wave injection, than the left-hand cut-off density of applied 77 GHz EC waves.

  10. 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.

  11. Calibration of electron cyclotron emission radiometer for KSTAR.

    PubMed

    Kogi, Y; Jeong, S H; Lee, K D; Akaki, K; Mase, A; Kuwahara, D; Yoshinaga, T; Nagayama, Y; Kwon, M; Kawahata, K

    2010-10-01

    We developed and installed an electron cyclotron emission radiometer for taking measurements of Korea Superconducting Tokamak Advanced Research (KSTAR) plasma. In order to precisely measure the absolute value of electron temperatures, a calibration measurement of the whole radiometer system was performed, which confirmed that the radiometer has an acceptably linear output signal for changes in input temperature. It was also found that the output power level predicted by a theoretical calculation agrees with that obtained by the calibration measurement. We also showed that the system displays acceptable noise-temperature performance around 0.23 eV.

  12. Generating electron cyclotron resonance plasma using distributed scheme

    SciTech Connect

    Huang, C. C.; Chang, T. H.; Chen, N. C.; Chao, H. W.; Chen, C. C.; Chou, S. F.

    2012-08-06

    This study employs a distributed microwave input system and permanent magnets to generate large-area electron cyclotron resonance (ECR) plasma. ECR plasmas were generated with nitrogen gas, and the plasma density was measured by Langmuir probe. A uniform ECR plasma with the electron density fluctuation of {+-}9.8% over 500 mm Multiplication-Sign 500 mm was reported. The proposed idea of generating uniform ECR plasma can be scaled to a much larger area by using n Multiplication-Sign n microwave input array system together with well-designed permanent magnets.

  13. 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.

  14. 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.

  15. 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. PMID:20192341

  16. 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.

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

    NASA Astrophysics Data System (ADS)

    Tarvainen, O.; Kurennoy, S.

    2009-03-01

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

  18. Electron cyclotron heating and current drive in toroidal geometry. Technical progress report

    SciTech Connect

    Kritz, A.H.

    1993-03-01

    The Principal Investigator has continued to work on problems associated both with the deposition and with the emission of electron cyclotron heating power electron cyclotron heating in toroidal plasmas. Inparticular, the work has focused on the use of electron cyclotron heating to stabilize q = 1 and q = 2 instabilities in tokamaks and on the use of electron cyclotron emission as a plasma diagnostic. The research described in this report has been carried out in collaboration with scientists at Princeton, MIT and Livermore. The Principal Investigator is now employed at Lehigh University, and a small group effort on electron cyclotron heating in plasmas has begun to evolve at Lehigh involving undergraduate and graduate students. Work has also been done in support of the electron cyclotron heating and current drive program at the Center for Research in Plasma Physics in Lausanne, Switzerland.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Characterization of proton beam emission from an electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Jain, S. K.; Tayyab, M.; Bagchi, S.; Chakera, J. A.; Naik, P. A.

    2013-04-01

    We report here characterization of the ions produced in the Electron Cyclotron Resonance Ion Source (ECRIS) at RRCAT, which operates at 2.45 GHz and is aimed to produce a 50 keV, 30 mA proton beam. The plasma in the source was created using microwave power in the range of 150-1200 W. An efficient, single hole, three-electrode ion extraction system was employed to extract the ion beam from the ECRIS, and the extracted ion beam was characterized using a Thomson Parabola Ion Spectrograph, which provides complete information of all the differently charged species present in the plasma. The extracted ion beam current measured up to 8 mA beam current for 25 keV accelerating field and followed the Child-Langmuir law.

  4. 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.

  5. 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.

  6. Parametric instabilities during electron cyclotron heating of tandem mirrors

    NASA Technical Reports Server (NTRS)

    Nicholson, D. R.

    1984-01-01

    Electron cyclotron resonance heating is one of the most commonly used methods of heating electrons in the plugs and in the thermal barriers of tandem mirrors. The intense coherent electromagnetic waves used for such heating are susceptible to parametric decay into other modes. Significant growth rates are found for the decay of either ordinary or extraordinary waves into two magnetized electron plasma waves. This and related effects may result in electron heating mechanisms rather different than those assumed in linear ray-tracing calculations. These results may help explain the unusual effects observed during heating of the Phaedrus tandem mirror device. In the general case, these instabilities may be strongly inhibited by density gradients.

  7. 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.

  8. 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.

  9. Numerical model of electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  10. Beam injection improvement for electron cyclotron resonance charge breeders

    SciTech Connect

    Lamy, T.; Angot, J.; Sortais, P.; Thuillier, T.

    2012-02-15

    The injection of a 1+ beam into an electron cyclotron resonance (ECR) charge breeder is classically performed through a grounded tube placed on its axis at the injection side. This tube presents various disadvantages for the operation of an ECR charge breeder. First experiments without a grounded tube show a better use of the microwave power and a better charge breeding efficiency. The optical acceptance of the charge breeder without decelerating tube allows the injection of high intensity 1+ ion beams at high energy, allowing metals sputtering inside the ion source. The use of this method for refractory metallic ion beams production is evaluated.

  11. Electron-cyclotron maser instability driven by a loss-cone distribution

    SciTech Connect

    Lau, Y.Y.; Chu, K.

    1983-01-24

    It is shown that the electron-cyclotron maser instabilities may readily be excited in a plasma with a loss-cone distribution when the electron temperature exceeds a few tens of kiloelectronvolts. The growth rate is typically a few percent of the electron-cyclotron frequency. The appearance of the instability can be avoided by proper control of the plasma density.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Upgrades to the TEXTOR electron cyclotron emission imaging diagnostic

    NASA Astrophysics Data System (ADS)

    Domier, C. W.; Xia, Z. G.; Zhang, P.; Luhmann, N. C.; Park, H. K.; Mazzucato, E.; van de Pol, M. J.; Classen, I. G. J.; Donné, A. J. H.; Jaspers, R.

    2006-10-01

    A 128 channel electron cyclotron emission imaging instrument has been routinely used to study magnetohydrodynamics physics such as m =1 and m =2 modes on the TEXTOR tokamak. As currently configured, each of the 16 mixer array elements measures plasma emission at 8 simultaneous frequencies to form a 16×8 image of electron temperature profiles and fluctuations over an area of 16cm (vertical) by 6cm (horizontal). A redesigned mixer array, coupled with new wideband electronics to be installed later this year, will increase the plasma coverage to 17cm(v)×9cm(h). The new arrangement offers increased temperature resolution together with new gain and video bandwidth controls in a highly modular configuration for ease of maintenance and facilitation of future upgrades both in frequency coverage as well as number of channels.

  17. Modeling multiple-frequency electron cyclotron resonance heating

    NASA Astrophysics Data System (ADS)

    Spencer, J. Andrew; Kim, Charlson; Kim, Jin-Soo; Evstatiev, Evstati G.; Svidzinski, Vladimir; Cluggish, Brian

    2014-02-01

    Electron cyclotron resonance (ECR) heating influences two of the main parameters (electron temperature and, indirectly, density) that determine the charge state of the ions produced in an ECR ion source (ECRIS). Therefore, various schemes to optimize ECR heating in the ECRIS have been pursued such as multiple-frequency heating, the radio-frequency tuning effect, volume heating, or wide-band heating. We investigate two-frequency ECR heating of electrons in a simple magnetic mirror field by right handed circularly polarized waves with infinite phase velocity. The study shows a heating barrier different from the well-know adiabatic barrier. Study also revealed a mechanism whereby multiple frequencies give improved heating. A preliminary interpretation of the study is presented.

  18. Stimulated Electromagnetic Emissions near the Second Electron Cyclotron Harmonic

    NASA Astrophysics Data System (ADS)

    Pau, J.; Cheung, P. Y.; Zwi, H.; Wong, A. Y.

    1996-11-01

    First results of broadband stimulated electromagnetic emissions (SEE) near the second electron cyclotron harmonic (2Ω_e) are presented. The results were obtained at a recent HF heating campaign at the HIPAS Observatory with the heater frequency ωo near 2Ωe at 2.85 MHz. Experiments were performed for both O and X-mode polarizations, and under both continuous (CW) and low duty-cycle short pulse heating conditions. Typical SEE spectral features, such as the Downshifted Maximum (DM), the Broad Upshifted Maximum (BUM), and the Broad Symmetric Sidebands (BSS) were observed. While such spectral features were observed routinely at heater frequencies near the third electron cyclotron harmonic and higher at other heating facilities, this is the first observation that demonstrates that such features can also be excited near 2Ω_e. Comparison will be made between our results and past observations at higher frequencies. Physics issues involving the generation of these features such as the formation of field aligned striations and the conversion of HF pump wave to upper hybrid wave will also be discussed.

  19. Multicharged ion source based on Penning-type discharge with electron cyclotron resonance heating by millimeter waves.

    PubMed

    Vodopyanov, A V; Izotov, I V; Mansfeld, D A; Yushkov, G Yu

    2012-02-01

    We suggest a Penning-type discharge as a trigger discharge for fast development of pulsed electron cyclotron resonance plasma. The Penning-type discharge glows at a low pressure as needed. Gyrotron radiation (75 GHz, 200 kW, 1 ms) was used for plasma heating. Fully striped helium ions were demonstrated, average charge of ions in the plasma was ≈ 2. Experiment and calculations show that high charge states of heavier gases require lower initial pressure and longer development time. Only moderate charge states are achievable in this pulsed scheme.

  20. 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

  1. 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

  2. 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.

  3. Theory of electron-cyclotron-resonance laser accelerators

    SciTech Connect

    Chen, C. )

    1992-11-15

    The cyclotron-resonance laser (CRL) accelerator is a novel concept of accelerating continuous charged-particle beams to moderately or highly relativistic energies. This paper discusses prospects and limitations of this concept. In particular, the nonlinear coupling of an intense traveling electromagnetic wave with an electron beam in a guide magnetic field is studied, and the effects of wave dispersion on particle acceleration are analyzed. For a tenuous beam, it is shown in a single-particle theory that the maximum energy gain and the maximum acceleration distance for the beam electrons in CRL accelerators with optimal magnetic taper exhibit power-law scaling on the degree of wave dispersion (measured by the parameter [omega]/[ital ck][sub [parallel

  4. Currents induced in tokamaks by electron cyclotron heating

    SciTech Connect

    Eldridge, O. C.

    1980-10-01

    Generation of a plasma current is predicted in association with strong electron cyclotron heating in tokamaks or in any plasma with transverse magnetic field gradients. The current predicted in present-day tokamaks is of the order of one-quarter ampere per watt, which is large enough to be detected in heating experiments in progress. The current scales linearly with electron temperature and heating power and inversely with density and major radius. The mechanism depends on the Doppler shift for electrons streaming along magnetic field lines. Electrons streaming toward the source of radiation are resonant at a larger magnetic field. When the interaction is strong, radiation incident from the high field side is absorbed before reaching the cold electron resonant surface, and, so, a unidirectional population of electrons is heated. The anisotropic electron distribution gains momentum by collisions with ions. For small tokamaks the extraordinary wave should be launched for current drive, but for reactors the ordinary wave produces a sufficiently strong interaction.

  5. 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.

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

    PubMed

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

    2008-10-01

    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.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. The electron cyclotron resonance ion source with arc-shaped coils concept (invited).

    PubMed

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

    2012-02-01

    The main limitation to further improve the performance of ECR ion sources is set by the magnet technology related to the multipole magnet field used for the closed minimum-B structure. The JYFL ion source group has sought different approaches to improve the strength of the minimum-B structure required for the production of highly charged ion beams. It was found out that such a configuration can be realized with arc shaped coils. The first prototype, electron cyclotron resonance ion source with arc-shaped coils (ARC-ECRIS), was constructed and tested at JYFL in 2006. It was confirmed that such an ion source can be used for the production of highly charged ion beams. Regardless of several cost-driven compromises such as extraction mirror ratio of 1.05-1.2, microwave frequency of 6.4 GHz, and beam line with limited capacity, Ar(4+) beam intensity of up to 2 μA was measured. Subsequent design study has shown that the ARC-ECRIS operating at the microwave frequency above 40 GHz could be constructed. This specific design would be based on NbTi-wires and it fulfills the experimental magnetic field scaling laws. In this article, the ARC-ECRIS concept and its potential applications will be described. PMID:22380159

  10. 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.].

  11. 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.

  12. The electron cyclotron resonance ion source with arc-shaped coils concept (invited).

    PubMed

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

    2012-02-01

    The main limitation to further improve the performance of ECR ion sources is set by the magnet technology related to the multipole magnet field used for the closed minimum-B structure. The JYFL ion source group has sought different approaches to improve the strength of the minimum-B structure required for the production of highly charged ion beams. It was found out that such a configuration can be realized with arc shaped coils. The first prototype, electron cyclotron resonance ion source with arc-shaped coils (ARC-ECRIS), was constructed and tested at JYFL in 2006. It was confirmed that such an ion source can be used for the production of highly charged ion beams. Regardless of several cost-driven compromises such as extraction mirror ratio of 1.05-1.2, microwave frequency of 6.4 GHz, and beam line with limited capacity, Ar(4+) beam intensity of up to 2 μA was measured. Subsequent design study has shown that the ARC-ECRIS operating at the microwave frequency above 40 GHz could be constructed. This specific design would be based on NbTi-wires and it fulfills the experimental magnetic field scaling laws. In this article, the ARC-ECRIS concept and its potential applications will be described.

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

    SciTech Connect

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

    2011-06-15

    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 deg. - 40 deg. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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. PMID:25314546

  18. Electron Cyclotron Emission Imaging on ITER with Rowland Circle Optics

    NASA Astrophysics Data System (ADS)

    Liu, Jason; Lee, Woochang; Leem, June-Eok; Bitter, Manfred; Park, Hyeon; Yun, Gunsu

    2015-11-01

    The implementation of advanced electron cyclotron emission imaging (ECEI) systems on the major tokamaks TEXTOR1, DIII-D2,3, KSTAR4, EAST5, and ASDEX Upgrade6 has revolutionized the diagnosis of MHD activities and improved our understanding of various instabilities. However, the conventional ECEI systems cannot be applied to ITER because of the space constraints and excessive radiation that would be encountered in the diagnostic port plugs. This paper describes an alternative optical concept that employs the Rowland circle imaging geometry to implement an advanced ECEI system on ITER that is suitable for the tight space and harsh environments of the diagnostic port plugs. Such a system would match the capabilities of conventional ECEI diagnostics and would be capable of simultaneous core and edge measurements.

  19. 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.

  20. 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.

  1. 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.}

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

    NASA Astrophysics Data System (ADS)

    Mühle, C.; Ratzinger, U.; Jöst, 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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. PMID:24593537

  8. 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.

  9. 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.

  10. 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.

  11. Electron Cyclotron Current Drive at High Electron Temperature on DIII-D

    NASA Astrophysics Data System (ADS)

    Petty, C. C.; Austin, M. E.; Harvey, R. W.; Lohr, J.; Luce, T. C.; Makowski, M. A.; Prater, R.

    2007-09-01

    Experiments on DIII-D have measured the electron cyclotron current drive (ECCD) efficiency for co- and counter-injection in low density plasmas with radiation temperatures from electron cyclotron emission (ECE) above 20 keV. The radiation temperature is generally higher than the Thomson scattering temperature, indicating that there is a significant population of non-thermal electrons. The experimental ECCD profile measured with motional Stark effect (MSE) polarimetry is found to agree with quasi-linear theory except for the highest power density cases (QEC/ne2≫1). Radial transport of the energetic electrons with diffusion coefficients of ˜0.4 m2/s is needed to model the broadened ECCD profile at high power density.

  12. 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 \

  13. Pulse-Heated Vertical Electron Cyclotron Emission Diagnostic

    NASA Astrophysics Data System (ADS)

    Voss, Keith Edward

    1995-01-01

    Determination of plasma parameters in tokamak experiments is of primary importance for learning to control and optimize fusion plasmas. Electron cyclotron emission (ECE) diagnostics play an important role in these experiments and are planned for future test reactors, since they require only simple collecting optics in the harsh reactor environment. A novel diagnostic system, which extracts information about plasma parameters by examining the ECE resulting from a perturbation of the plasma, was examined and applied on the PBX-M tokamak. This diagnostic uses a brief pulse of power from the lower hybrid current drive system to create a population of superthermal electrons. These electrons evolve according to the Fokker-Planck equation, which involves dependences on the magnetic field pitch, ion charge state, background density, and electric field. Coincident with the evolution of the electrons is the evolution of their ECE radiation. The diagnostic exploits the fact that the temporal changes in the radiation are dependent upon those parameters which affect the electrons. The analysis method, which compares measured experimental signal with simulated radiation (as functions of frequency and time) and determines most probable plasma parameter values, was computationally tested for effectiveness and robustness. The method was extended to include determination of parameters of the lower hybrid current drive power deposition. A measurement system, based on a grating polychromator, was assembled, tested, and calibrated, and pulse-heated vertical ECE data were collected from the PBX-M tokamak. A proof-of-principle test of the diagnostic yielded positive results, resulting in information about the lower hybrid current drive deposition location.

  14. Survey of electron cyclotron waves in the magnetosphere and the diffuse auroral electron precipitation

    SciTech Connect

    Roeder, J.L.; Koons, H.C.

    1990-03-09

    Narrowband electrostatic wave emissions at frequencies above the local electron cyclotron frequency are known variously as electron cyclotron harmonic (ECH) waves or n+1/2 waves since they tend to occur at odd half-multiples of the electron cyclotron frequency. Natural ECH emissions in the outer magnetosphere are often cited as the electron scattering mechanism which results in the diffuse auroral precipitation. A survey is presented of the characteristics of these waves using data from both the SCATHA and AMPTE-IRM plasma wave instruments. The emissions were observed most often in the 0300-0600 LT sector at L = approx. 4-8 and magnetic latitudes in the range + or - 10 deg. In this region, emissions exceeding 35 microVolt/m were detected only 25% of the time and those exceeding 12 microVolt/m were detected 60% of the time. In agreement with Belmont et al., we consider these amounts grossly insufficient to account for the diffuse auroral electron precipitation by quasilinear pitch angle diffusion.

  15. 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.

  16. Extension of high Te regime with upgraded electron cyclotron resonance heating system in the Large Helical Device

    NASA Astrophysics Data System (ADS)

    Takahashi, H.; Shimozuma, T.; Kubo, S.; Yoshimura, Y.; Igami, H.; Ito, S.; Kobayashi, S.; Mizuno, Y.; Okada, K.; Mutoh, T.; Nagaoka, K.; Murakami, S.; Osakabe, M.; Yamada, I.; Nakano, H.; Yokoyama, M.; Ido, T.; Shimizu, A.; Seki, R.; Ida, K.; Yoshinuma, M.; Kariya, T.; Minami, R.; Imai, T.; Marushchenko, N. B.; Turkin, Y.

    2014-06-01

    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 ne_fir = 1 × 1019 m-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 ne_fir. The plasma stored energy of 530 kJ with ne_fir = 3.2 × 1019 m-3, which is 1.7 times larger than the previous record in the ECRH plasma in the LHD, has been successfully achieved.

  17. 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.

  18. 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

  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. 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.

  3. Control of electron temperature and space potential gradients by superposition of thermionic electrons on electron cyclotron resonance plasmas.

    PubMed

    Moon, Chanho; Kaneko, Toshiro; Tamura, Shuichi; Hatakeyama, Rikizo

    2010-05-01

    An electron temperature gradient (ETG) is formed perpendicular to the magnetic field lines by superimposing low-temperature thermionic electrons emitted from a tungsten hot plate upon high-temperature electrons of an electron cyclotron resonance plasma, which pass through two different-shaped mesh grids. The radial profile of the plasma space potential can be controlled independent of the ETG by changing the bias voltages of the hot plate.

  4. 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.

  5. Excitation of the half-cyclotron waves by the counterstreaming electron-positron beams

    SciTech Connect

    Shokri, B.; Khorashadizadeh, S.M.

    2005-08-15

    The dispersion relation of the half-cyclotron waves excited by the interaction of the two counterstreaming electron-positron-plasma beams is obtained. Furthermore, obtaining the growth rate and the threshold for the instability development, the excitation of the half-cyclotron waves in a system of two rotating monoenergetic electron-positron counterstreaming beams flowing parallel to the external magnetic field is investigated.

  6. Multichannel heterodyne radiometer with computer control for electron cyclotron emission measurements of a tokomak plasma

    SciTech Connect

    Cima, G.; Ramponi, G.; Simonetto, A.

    1985-10-01

    A multichannel heterodyne radiometer in the frequency range 50--75 GHz which has been used to measure the second-harmonic cyclotron emission of the Thor Tokomak plasma is described. Real-time frequency switching, analog output averaging, autocalibration, data-acquisition, and graphical display are all functions performed under control of an Apple II personal computer. Typical experimental results are presented to illustrate the measuring capabilities of the instrument.

  7. Multichannel heterodyne radiometer with computer control for electron cyclotron emission measurements of a tokamak plasma

    NASA Astrophysics Data System (ADS)

    Cima, G.; Ramponi, G.; Simonetto, A.

    1985-10-01

    A multichannel heterodyne radiometer in the frequency range 50-75 GHz which has been used to measure the second-harmonic cyclotron emission of the Thor Tokomak plasma is described. Real-time frequency switching, analog output averaging, autocalibration, data-acquisition, and graphical display are all functions performed under control of an Apple II personal computer. Typical experimental results are presented to illustrate the measuring capabilities of the instrument.

  8. Efficiency of combined cyclotron--[hacek C]erenkov interaction between electrons and electromagnetic fields

    SciTech Connect

    Nusinovich, G.S.; Vlasov, A.N. )

    1993-02-01

    A theory is presented describing the electron cyclotron interaction at frequencies near cutoff, followed by a [hacek C]erenkov interaction region. In such a case, the cyclotron interaction withdraws only the orbital component of electron momentum, while in the [hacek C]erenkov interaction the electrons lose their axial momentum. It is shown that the addition of the [hacek C]erenkov interaction significantly enhances the total electronic efficiency. Since both kinds of operation are relatively insensitive to electron velocity spread, the efficiency of the combined interaction is also rather tolerant to velocity spread. Thus, rather efficient sources of electromagnetic radiation based on poor quality electron beams may be developed.

  9. 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.

  10. Dynamic Confinement of ITER Plasma by O-Mode Driver at Electron Cyclotron Frequency Range

    NASA Astrophysics Data System (ADS)

    Stefan, V. Alexander

    2009-05-01

    A low B-field side launched electron cyclotron O-Mode driver leads to the dynamic rf confinement, in addition to rf turbulent heating, of ITER plasma. The scaling law for the local energy confinement time τE is evaluated (τE ˜ 3neTe/2Q, where (3/2) neTe is the local plasma thermal energy density and Q is the local rf turbulent heating rate). The dynamics of unstable dissipative trapped particle modes (DTPM) strongly coupled to Trivelpiece-Gould (T-G) modes is studied for gyrotron frequency 170GHz; power˜24 MW CW; and on-axis B-field ˜ 10T. In the case of dynamic stabilization of DTPM turbulence and for the heavily damped T-G modes, the energy confinement time scales as τE˜(I0)-2, whereby I0(W/m^2) is the O-Mode driver irradiance. R. Prater et. al., Nucl. Fusion 48, No 3 (March 2008). E. P. Velikhov, History of the Russian Tokamak and the Tokamak Thermonuclear Fusion Research Worldwide That Led to ITER (Documentary movie; Stefan Studios Int'l, La Jolla, CA, 2008; E. P. Velikhov, V. Stefan.) M N Rosenbluth, Phys. Scr. T2A 104-109 1982 B. B. Kadomtsev and O. P. Pogutse, Nucl. Fusion 11, 67 (1971).

  11. Plasma studies of the permanent magnet electron cyclotron resonance ion source at Peking University

    SciTech Connect

    Ren, H. T.; Peng, S. X. Xu, Y.; Zhao, J.; Lu, P. N.; Chen, J.; Zhang, A. L.; Zhang, T.; Guo, Z. Y.; Chen, J. E.

    2014-02-15

    At Peking University (PKU) we have developed several 2.45 GHz Permanent Magnet Electron Cyclotron Resonance ion sources for PKUNIFTY, SFRFQ, Coupled RFQ and SFRFQ, and Dielectric-Wall Accelerator (DWA) projects (respectively, 50 mA of D{sup +}, 10 mA of O{sup +}, 10 mA of He{sup +}, and 50 mA of H{sup +}). In order to improve performance of these ion sources, it is necessary to better understand the principal factors that influence the plasma density and the atomic ion fraction. Theoretical analysis about microwave transmission and cut-off inside the discharge chamber were carried out to study the influence of the discharge chamber diameters. As a consequence, experimental studies on plasma density and ion fraction with different discharge chamber sizes have been carried out. Due to the difficulties in measuring plasma density inside the discharge chamber, the output beam current was measured to reflect the plasma density. Experimental results show that the plasma density increases to the maximum and then decreases significantly as the diameter changed from 64 mm to 30 mm, and the atomic ion fraction has the same tendency. The maximum beam intensity was obtained with the diameter of 35 mm, but the maximum atomic ion fraction with a diameter of 40 mm. The experimental results are basically accordant with the theoretical calculation. Details are presented in this paper.

  12. Plasma studies of the permanent magnet electron cyclotron resonance ion source at Peking University

    NASA Astrophysics Data System (ADS)

    Ren, H. T.; Peng, S. X.; Xu, Y.; Zhao, J.; Lu, P. N.; Chen, J.; Zhang, A. L.; Zhang, T.; Guo, Z. Y.; Chen, J. E.

    2014-02-01

    At Peking University (PKU) we have developed several 2.45 GHz Permanent Magnet Electron Cyclotron Resonance ion sources for PKUNIFTY, SFRFQ, Coupled RFQ&SFRFQ, and Dielectric-Wall Accelerator (DWA) projects (respectively, 50 mA of D+, 10 mA of O+, 10 mA of He+, and 50 mA of H+). In order to improve performance of these ion sources, it is necessary to better understand the principal factors that influence the plasma density and the atomic ion fraction. Theoretical analysis about microwave transmission and cut-off inside the discharge chamber were carried out to study the influence of the discharge chamber diameters. As a consequence, experimental studies on plasma density and ion fraction with different discharge chamber sizes have been carried out. Due to the difficulties in measuring plasma density inside the discharge chamber, the output beam current was measured to reflect the plasma density. Experimental results show that the plasma density increases to the maximum and then decreases significantly as the diameter changed from 64 mm to 30 mm, and the atomic ion fraction has the same tendency. The maximum beam intensity was obtained with the diameter of 35 mm, but the maximum atomic ion fraction with a diameter of 40 mm. The experimental results are basically accordant with the theoretical calculation. Details are presented in this paper.

  13. 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.

  14. 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.

  15. Electron energy distribution function by using probe method in electron cyclotron resonance multicharged ion source

    SciTech Connect

    Kumakura, Sho Kurisu, Yosuke; Kimura, Daiju; Yano, Keisuke; Imai, Youta; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

    2014-02-15

    We are constructing a tandem type electron cyclotron resonance (ECR) ion source (ECRIS). High-energy electrons in ECRIS plasma affect electron energy distribution and generate multicharged ion. In this study, we measure electron energy distribution function (EEDF) of low energy region (≦100 eV) in ECRIS plasma at extremely low pressures (10{sup −3}–10{sup −5} Pa) by using cylindrical Langmuir probe. From the result, it is found that the EEDF correlates with the electron density and the temperature from the conventional probe analysis. In addition, we confirm that the tail of EEDF spreads to high energy region as the pressure rises and that there are electrons with high energy in ECR multicharged ion source plasma. The effective temperature estimated from the experimentally obtained EEDF is larger than the electron temperature obtained from the conventional method.

  16. Electron energy distribution function by using probe method in electron cyclotron resonance multicharged ion source.

    PubMed

    Kumakura, Sho; Kurisu, Yosuke; Kimura, Daiju; Yano, Keisuke; Imai, Youta; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

    2014-02-01

    We are constructing a tandem type electron cyclotron resonance (ECR) ion source (ECRIS). High-energy electrons in ECRIS plasma affect electron energy distribution and generate multicharged ion. In this study, we measure electron energy distribution function (EEDF) of low energy region (≦100 eV) in ECRIS plasma at extremely low pressures (10(-3)-10(-5) Pa) by using cylindrical Langmuir probe. From the result, it is found that the EEDF correlates with the electron density and the temperature from the conventional probe analysis. In addition, we confirm that the tail of EEDF spreads to high energy region as the pressure rises and that there are electrons with high energy in ECR multicharged ion source plasma. The effective temperature estimated from the experimentally obtained EEDF is larger than the electron temperature obtained from the conventional method.

  17. 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.

  18. 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.

  19. Experimental Comparison of Microwave, Oxygen Plasmas in a Conventional Electron-Cyclotron Resonance, Diverging Magnetic Field and in a Multi-pole Magnetic Field Geometry

    NASA Astrophysics Data System (ADS)

    Akitsu, Tetsuya

    1998-10-01

    A plasma-enhanced reactive sputtering was developed for the deposition of oriented thin crustals of metallic-oxide compound. An oxygen plasma was excited with microwave, electron cyclotron resonance discharge at 2.45 GHz and a compact DC magnetron sputtering was combined. The discharge characteristics was compared in two types of magnetic field configurations.using the optical emission spectroscopy and the appearance potential mass-spectrometry. In a divergent magnetic field, the microwave was absorbed in a single electron-cyclotron resonance Layer, 30-45 mm apart from a crystallized ceramic vesse, and the deposition region was exposed to a freely expanding plasma. Next, the end of the magnetic field line was closed with a magnetic circuit and the source plasma was magnetically confined in the local mirror, thus only neutral oxygen was allowed to expand into the deposition region.

  20. 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.

  1. First beams from the new electron cyclotron resonance source LEGIS (LEGnaro ecrIS) at INFN-LNL

    SciTech Connect

    Galata, A.; Sattin, M.; Scarpa, F.; Facco, A.; Kulevoy, T.

    2010-02-15

    From April 2008 the PIAVE injector for the ALPI booster was involved in the upgrade of the high voltage platform housing an electron cyclotron resonance (ECR) source. A 14.5 GHz SUPERNANOGAN type ECR replaced the existing source ALICE; at the same time, the whole platform beam line was redesigned and beam shaping and diagnostic system were installed. The source and the platform were ready to be put into operation in January 2009. PIAVE's commissioning was started from late March and completed in May 2009 using an argon beam. A description of the upgrade will be given in the following; beam quality leading to an improved transmission through the injector will be shown. Results on first gaseous and metallic beams produced will also be given.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. First beams from the new electron cyclotron resonance source LEGIS (LEGnaro ecrIS) at INFN-LNL.

    PubMed

    Galatà, A; Kulevoy, T; Sattin, M; Scarpa, F; Facco, A

    2010-02-01

    From April 2008 the PIAVE injector for the ALPI booster was involved in the upgrade of the high voltage platform housing an electron cyclotron resonance (ECR) source. A 14.5 GHz SUPERNANOGAN type ECR replaced the existing source ALICE; at the same time, the whole platform beam line was redesigned and beam shaping and diagnostic system were installed. The source and the platform were ready to be put into operation in January 2009. PIAVE's commissioning was started from late March and completed in May 2009 using an argon beam. A description of the upgrade will be given in the following; beam quality leading to an improved transmission through the injector will be shown. Results on first gaseous and metallic beams produced will also be given.

  4. 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.

  5. 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. PMID:26932095

  6. Electron temperature measurements during electron cyclotron heating on PDX using a ten channel grating polychromator

    SciTech Connect

    Cavallo, A.; Hsuan, H.; Boyd, D.; Grek, B.; Johnson, D.; Kritz, A.; Mikkelsen, D.; LeBlanc, B.; Takahashi, H.

    1984-10-01

    During first harmonic electron cyclotron heating (ECH) on the Princeton Divertor Experiment (PDX) (R/sub 0/ = 137 cm, a = 40 cm), electron temperature was monitored using a grating polychromator which measured second harmonic electron cyclotron emission from the low field side of the tokamak. Interference from the high power heating pulse on the broadband detectors in the grating instrument was eliminated by using a waveguide filter in the transmission line which brought the emission signal to the grating instrument. Off-axis (approx. 4 cm) location of the resonance zone resulted in heating without sawtooth or m = 1 activity. However, heating with the resonance zone at the plasma center caused very large amplitude sawteeth accompanied by strong m = 1 activity: ..delta..T/T/sub MAX/ approx. = 0.41, sawtooth period approx. = 4 msec, m = 1 period approx. = 90 ..mu.. sec, (11 kHz). This is the first time such intense MHD activity driven by ECH has been observed. (For both cases there was no sawtooth activity in the ohmic phase of the discharge before ECH.) At very low densities there is a clear indication that a superthermal electron population is created during ECH.

  7. A status report of the multipurpose superconducting electron cyclotron resonance ion source.

    PubMed

    Ciavola, G; Gammino, S; Barbarino, S; Celona, L; Consoli, F; Gallo, G; Maimone, F; Mascali, D; Passarello, S; Galatà, A; Tinschert, K; Spaedtke, P; Lang, R; Maeder, J; Rossbach, J; Koivisto, H; Savonen, M; Koponen, T; Suominen, P; Ropponen, T; Baruè, C; Lechartier, M; Beijers, J P M; Brandenburg, S; Kremers, H R; Vanrooyen, D; Kuchler, D; Scrivens, R; Schachter, L; Dobrescu, S; Stiebing, K

    2008-02-01

    Intense heavy ion beam production with electron cyclotron resonance (ECR) ion sources is a common requirement for many of the accelerators under construction in Europe and elsewhere. An average increase of about one order of magnitude per decade in the performance of ECR ion sources was obtained up to now since the time of pioneering experiment of R. Geller at CEA, Grenoble, and this trend is not deemed to get the saturation at least in the next decade, according to the increased availability of powerful magnets and microwave generators. Electron density above 10(13) cm(-3) and very high current of multiply charged ions are expected with the use of 28 GHz microwave heating and of an adequate plasma trap, with a B-minimum shape, according to the high B mode concept [S. Gammino and G. Ciavola, Plasma Sources Sci. Technol. 5, 19 (1996)]. The MS-ECRIS ion source has been designed following this concept and its construction is underway at GSI, Darmstadt. The project is the result of the cooperation of nine European institutions with the partial funding of EU through the sixth Framework Programme. The contribution of different institutions has permitted to build in 2006-2007 each component at high level of expertise. The description of the major components will be given in the following with a view on the planning of the assembly and commissioning phase to be carried out in fall 2007. An outline of the experiments to be done with the MS-ECRIS source in the next two years will be presented.

  8. 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.

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

    NASA Astrophysics Data System (ADS)

    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 16×8 images of Te 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. 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.

  11. 2D electron cyclotron emission imaging at ASDEX Upgrade (invited)a)

    NASA Astrophysics Data System (ADS)

    Classen, I. G. J.; Boom, J. E.; Suttrop, W.; Schmid, E.; Tobias, B.; Domier, C. W.; Luhmann, N. C.; Donné, A. J. H.; Jaspers, R. J. E.; de Vries, P. C.; Park, H. K.; Munsat, T.; García-Muñoz, M.; Schneider, P. A.

    2010-10-01

    The newly installed electron cyclotron emission imaging diagnostic on ASDEX Upgrade provides measurements of the 2D electron temperature dynamics with high spatial and temporal resolution. An overview of the technical and experimental properties of the system is presented. These properties are illustrated by the measurements of the edge localized mode and the reversed shear Alfvén eigenmode, showing both the advantage of having a two-dimensional (2D) measurement, as well as some of the limitations of electron cyclotron emission measurements. Furthermore, the application of singular value decomposition as a powerful tool for analyzing and filtering 2D data is presented.

  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. 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.

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

    PubMed

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

    2014-02-01

    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 TE01 circular waveguide mode. This is fundamentally different and may be less efficient than the typical rectangular, linearly polarized TE10 mode used for launching waves at lower frequencies. To improve the 28 GHz microwave coupling in VENUS, a TE01-HE11 mode conversion system has been built to test launching HE11 microwave power into the plasma chamber. The HE11 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 TE01 mode to the TE11 mode. Second, a corrugated circular waveguide excites the HE11 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.

  15. 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.

  16. 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. PMID:18315105

  17. Intense beam production of highly charged heavy ions by the superconducting electron cyclotron resonance ion source SECRAL (invited)a)

    NASA Astrophysics Data System (ADS)

    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 28GHz 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 28GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6T at injection, 2.2T at extraction, and a radial sextupole field of 2.0T at plasma chamber wall. During the commissioning phase at 18GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.5kW by two 18GHz rf generators. It demonstrates the performance is very promising. Some record ion beam intensities have been produced, for instance, 810eμA of O7+, 505eμA of Xe20+, 306eμA of Xe27+, 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.

  18. Simulation of electron behavior in PIG ion source for 9 MeV cyclotron

    NASA Astrophysics Data System (ADS)

    J. Mu, X.; Ghergherehchi, M.; H. Yeon, Y.; W. Kim, J.; S. Chai, J.

    2014-12-01

    In this paper, we focus on a PIG source for producing intense H-ions inside a 9 MeV cyclotron. The properties of the PIG ion source were simulated for a variety of electric field distributions and magnetic field strengths using a CST particle studio. After analyzing the secondary electron emission (SEE) as a function of both magnetic and electric field strengths, we found that for the modeled PIG geometry, a magnetic field strength of 0.2 T provided the best results in terms of the number of secondary electrons. Furthermore, at 0.2 T, the number of secondary electrons proved to be greatest regardless of the cathode potential. Also, the modified PIG ion source with quartz insulation tubes was tested in a KIRAMS-13 cyclotron by varying the gas flow rate and arc current, respectively. The capacity of the designed ion source was also demonstrated by producing plasma inside the constructed 9 MeV cyclotron. As a result, the ion source is verified as being capable of producing an intense H- beam and high ion beam current for the desired 9 MeV cyclotron. The simulation results provide experimental constraints for optimizing the strength of the plasma and final ion beam current at a target inside a cyclotron.

  19. Assessment of the ITER electron cyclotron upper launcher capabilities in view of an optimized design

    NASA Astrophysics Data System (ADS)

    Figini, L.; Farina, D.; Henderson, M.; Mariani, A.; Poli, E.; Saibene, G.

    2015-05-01

    The 24 MW ITER electron cyclotron (EC) heating and current drive (H and CD) system, operating at 170 GHz, consists of one equatorial and four upper launchers (UL). The main task of the UL will be the control of magneto-hydrodynamic activity such as neoclassical tearing modes (NTMs) at the q = 3/2 and q = 2 surfaces and sawteeth at q = 1, but it will also be needed for current profile tailoring in advanced scenarios and to assist plasma break-down and L- to H-mode transition. Moreover, it is required to be effective both when ITER will operate at nominal and reduced magnetic field magnitude. Here the performance of the UL has been assessed through the study of the full temporal evolution of different scenarios, including the reference ITER 15 MA H-mode plasma, a half-field case at 2.65 T and a steady state scenario. The ECCD efficiency has been evaluated for a wide range of injection angles, deriving the optimal angles and the power required for NTMs stabilization with simplified criteria. An injected power ranging from 3 MW to 9 MW should be sufficient to control NTMs in the flat-top phase of the scenarios considered here. The result of the analysis shows that the EC system maintains a good performance level even at intermediate values of the magnetic field, between the nominal and the half-field value. The analysis has also allowed to evaluate the adequateness of the available steering range for reaching the rational surfaces during all the phases of the discharge and to quantify the steering sensitivity to shifts of the target or aiming errors. The result is an assessment of the UL design requirements to achieve the desired functionalities, which will be used to drive the optimization and finalization of the UL design.

  20. Simultaneous excitation of broadband electrostatic noise and electron cyclotron waves in the plasma sheet

    NASA Technical Reports Server (NTRS)

    Berchem, Jean P.; Schriver, David; Ashour-Abdalla, Maha

    1991-01-01

    Electron cyclotron harmonics and broadband electrostatic noise (BEN) are often observed in the earth's outer plasma sheet. While it is well known that ion beams in the plasma sheet boundary layer can generate BEN, new two-dimensional electrostatic simulations show that field-aligned ion beams with a small perpendicular ring distribution can drive not only BEN, but also electron cyclotron harmonic (ECH) waves simultaneously. Simulation results are presented here using detailed diagnostics of wave properties, including dispersion relations of all wave modes.

  1. 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.

  2. Bragg Resonator Cyclotron Resonance Maser Experiments Driven by a Microsecond, Intense Electron Beam Accelerator

    NASA Astrophysics Data System (ADS)

    Choi, Jin Joo

    The cyclotron resonance maser (CRM) has proven to be attractive for many high power microwave applications such as fusion plasma heating, radar/communications, and high gradient RF accelerators. Most of the previous CRM experiments with MV electron beams have been conducted with short (<0.1 musec) pulses. The present work contains the first comprehensive experimental study on mode competition in a high-Q Bragg resonator CRM employing a microsecond, relativistic electron beam. We have designed and fabricated a high-Q sinusoidal Bragg resonator designed to excite high frequency CARM oscillation of the TE_{31} cylindrical cavity mode at 18.9 GHz. The measured reflectivity of the TE_{31} mode is consistent with the prediction of uncoupled single mode theory. A high quality annular electron beam with low velocity spread and energy spread is produced through an apertured mask-anode. The apertured electron beam has been characterized by the use of glass plate diagnostics. The measured beam velocity ratio, v_{| }/v_{|}, was shown to be in agreement with computer simulation results and the theoretical predictions. Experiments have been performed for 4 cases: (1) Bragg resonator with ripples half-inward, (2) large diameter smooth tube without Bragg resonator, (3) Bragg resonator with ripples fully-outward, and (4) small diameter smooth tube without Bragg resonator. The Bragg resonator with ripples half-inward generated high power microwave radiation from TE_ {11} gyro-BWO interactions, TE _{21} absolute instability, and high harmonic gyrotron modes. Considerably less power from the TE_{11} gyro -BWO was observed for the Bragg resonator with ripples fully -outward. The microwave emission from the TE_ {21} absolute instability in the Bragg resonator with ripples fully-outward was successfully suppressed by lowering the cavity magnetic field. These three undesired oscillations, (TE _{21} absolute instability, TE _{11} gyro-BWO, TE _{51} second and third harmonic), were the most

  3. 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

  4. 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.

  5. 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)].

  6. Electron and hole microwave cyclotron resonance in photoexcited undoped GaAs/Al0.3Ga0.7As multiple quantum wells

    NASA Astrophysics Data System (ADS)

    Kozhevnikov, M.; Cohen, E.; Ron, Arza; Shtrikman, Hadas

    1999-12-01

    We studied the microwave cyclotron resonance (CR) of photoexcited free and weakly localized electrons and holes in undoped GaAs/Al0.3Ga0.7As multiple quantum wells (MQW's) of various well widths. The photoinduced microwave absorption was measured at a frequency of ωmw=35.6 GHz and at various lattice temperatures in the range of TL=4.2-300 K. The interband excitation intensity was very low, so that the density of photogenerated electrons and holes was of the order of n<=108 cm-2. In all the studied QW's, an electron CR was observed, while a heavy hole CR was measured only in narrow QW's. By model fitting the CR line shape, the electron and hole cyclotron masses and the electron scattering rate dependence on TL and on the microwave power were obtained. Assuming that the electron in-plane mobility at ωmw is proportional to the inverse scattering rate, we find that it varies in the range of (0.8-8)×105 cm2V-1 sec-1 for 100 Å and 200 Å MQW's. This is less than the mobility measured in modulation doped QW's of similar widths. We present a detailed analysis of the temperature dependence of the electron scattering rate by combining the electron-phonon, electron-impurity, and electron-interface roughness scattering rates. The latter is found to be an important scattering mechanism in undoped MQW's at low temperatures. The CR analysis also shows that the electron cyclotron mass varies (in the range of 0.055-0.070m0) with increasing either TL or the microwave power. These variations are interpreted in terms of weak electron localization in large area, in-plane potential fluctuations arising from interface roughness.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Superconducting magnets for the RAON electron cyclotron resonance ion source.

    PubMed

    Choi, S; Kim, Y; Hong, I S; Jeon, D

    2014-02-01

    The RAON linear accelerator of Rare Isotope Science Project has been developed since 2011, and the superconducting magnet for ECRIS was designed. The RAON ECR ion source was considered as a 3rd generation source. The fully superconducting magnet has been designed for operating using 28 GHz radio frequency. The RAON ECRIS operates in a minimum B field configuration which means that a magnetic sextupole field for radial confinement is superimposed with a magnetic mirror field for axial confinement. The highest field strength reaches 3.5 T on axis and 2 T at the plasma chamber wall for operating frequency up to 28 GHz. In this paper, the design results are presented of optimized superconducting magnet consisting of four solenoids and sextupole. The prototype magnet for ECRIS was fabricated and tested to verify the feasibility of the design. On the basis of test results, a fully superconducting magnet will be fabricated and tested. PMID:24593485

  12. 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.

  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. 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.

  15. 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.

  16. Dynamic cyclotron resonance in relativistic microwave devices with linear electron beams

    SciTech Connect

    Vlasov, A.N.; Kornienko, V.N.; Cherepenin, V.A. |

    1995-12-31

    In the present work the authors analyze theoretically and by numerical simulation dependencies of output radiation versus magnitude of focusing magnetic field when magnetic field magnitude is sufficiently smaller than value corresponding to cyclotron absorption. The high frequency electromagnetic field amplitude is high for optimum regimes with high efficiency level. In this case some electrons are accelerated and different electrons are decelerated during interaction inside device. As a result, cyclotron resonance conditions are different for different electron groups. The authors have found theoretically condition of dynamic cyclotron resonance when it is possible to improve efficiency of interaction in devices with distributed interaction such as TWT, BWO, generator of diffractional radiation by combination of Cherenkov and cyclotron interactions in strong nonlinear regimes with optimum efficiency levels. The numerical simulation of the interaction between initially linear electron beam and electromagnetic field show that there are regions of efficiency improvement up to 50 and amplitude of high-frequency electromagnetic field. One of the important features of such combined interaction is dependence on relativistic factor. They have found optimum region of relativistic factors by numerical simulation. The results of numerical simulation were compared with experimental data refer to relativistic diffractional generators and multiwave Cherenkov generators. Good agreement in value of optimum magnitude of guiding magnetic field was obtained.

  17. 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

  18. Investigation of an electronically tuned 100 GHz superconducting phase shifter

    SciTech Connect

    Tvack, E.K.; Shen, Z.Y.; Dang, H.; Radparvar, M.; Faris, S.M. )

    1991-03-01

    This paper presents the results of an investigation aimed at realizing a tunable superconducting mm-wave phase shifter. The tuning mechanism is based on inductance modulation of NbN microstrips by excess quasiparticle injection. When measured by a dc method, using the interference patterns and resonances of specially designed dc SQUIDs, the inductance of NbN microstrips can be varied by up to 300%. Based on these results, we have designed and fabricated superconducting microstrip interferometers to operate as low power 100 GHz phase shifters. The 100 GHZ signal is coupled into and out of the interferometers by finline antennas. Amplitude modulation of the output is used as the criterion for phase shift in one of the interferometer branches.

  19. Cyclotron resonance spectroscopy in a high mobility two dimensional electron gas using characteristic matrix methods.

    PubMed

    Hilton, David J

    2012-12-31

    We develop a new characteristic matrix-based method to analyze cyclotron resonance experiments in high mobility two-dimensional electron gas samples where direct interference between primary and satellite reflections has previously limited the frequency resolution. This model is used to simulate experimental data taken using terahertz time-domain spectroscopy that show multiple pulses from the substrate with a separation of 15 ps that directly interfere in the time-domain. We determine a cyclotron dephasing lifetime of 15.1 ± 0.5 ps at 1.5 K and 5.0 ± 0.5 ps at 75 K.

  20. Cyclotron resonance spectroscopy in a high mobility two dimensional electron gas using characteristic matrix methods.

    PubMed

    Hilton, David J

    2012-12-31

    We develop a new characteristic matrix-based method to analyze cyclotron resonance experiments in high mobility two-dimensional electron gas samples where direct interference between primary and satellite reflections has previously limited the frequency resolution. This model is used to simulate experimental data taken using terahertz time-domain spectroscopy that show multiple pulses from the substrate with a separation of 15 ps that directly interfere in the time-domain. We determine a cyclotron dephasing lifetime of 15.1 ± 0.5 ps at 1.5 K and 5.0 ± 0.5 ps at 75 K. PMID:23388799

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Two dimensional electron cyclotron emission imaging study of electron temperature profiles and fluctuations in Tokamak plasmas

    NASA Astrophysics Data System (ADS)

    Deng, Bihe

    An innovative plasma diagnostic technique, electron cyclotron emission imaging (ECEI), was successfully developed and implemented on the TEXT-U and RTP tokamaks for the study of plasma electron temperature profiles and fluctuations. Due to the high spatial and temporal resolution of this new diagnostic, plasma filamentation was observed during high power electron cyclotron resonance heating (ECRH) in TEXT-U, and was identified as multiple rotating magnetic islands. In RTP, under special plasma conditions, evidence for magnetic bubbling was first observed, which is characterized by the flattening of the electron temperature and pressure profiles over a small annular region of about 1-2 cm extent near the q = 2 surface. More important results arose from the detailed study of the broadband plasma turbulence in TEXT-U and RTP. With the first measurements of poloidal wavenumbers and dispersion relations, turbulent Te fluctuations in the confinement region of TEXT-U plasmas were identified as electron drift wave turbulence. The fluctuation amplitude is found to follow the mixing length scaling, and the fluctuation-induced conducted- heat flux can account for the observed anomalous energy transport in TEXT-U. In RTP, detailed ECEI study of broadband Te fluctuations has shown that many characteristics of the observed fluctuations are consistent with the predictions of toroidal ηi mode theory. These include the global dependence of the fluctuation frequency and amplitude on the plasma density and current. The measured isotope and impurity scalings quantitatively match the predictions of toroidal ηi mode theory. The ECEI measurements in combination with ECRH modification of T e profiles argue against the Te gradients serving as the driving force of the turbulence. With the detailed 2- D measurements of the fluctuation distribution over the plasma minor cross-section, large scale, coherent structures similar to the eigenmode structures predicted by toroidal ηi mode theory

  7. New electron cyclotron emission diagnostic for measurement of temperature based upon the electron Bernstein wave

    NASA Astrophysics Data System (ADS)

    Efthimion, P. C.; Hosea, J. C.; Kaita, R.; Majeski, R.; Taylor, G.

    1999-01-01

    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 (e.g., ωp≫Ωc in spherical tokamaks) or they do not have sufficient density and temperature to reach the blackbody condition (τ>2). 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 ki. For example, the National Spherical Torus Experiment (NSTX) will have an optical thickness τ≈3000 and CDX-U will have τ≈300. One can reach the blackbody condition with a plasma density ≈1011cm-3 and Te≈1 eV. This makes it attractive to most plasma devices. The serious issue with using EBW is the wave accessibility for the emission measurement. Simple accessibility arguments indicate the wave may be accessible by either direct coupling or mode conversion through an extremely narrow layer (≈1-2 mm). EBW experiments on the Current Drive Experiment-Upgrade (CDX-U) will test the accessibility properties of the spherical tokamak configuration.

  8. New electron cyclotron emission diagnostic for measurement of temperature based upon the electron Bernstein wave

    SciTech Connect

    Efthimion, P.C.; Hosea, J.C.; Kaita, R.; Majeski, R.; Taylor, G.

    1999-01-01

    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 (e.g., {omega}{sub p}{gt}{Omega}{sub c} in spherical tokamaks) or they do not have sufficient density and temperature to reach the blackbody condition ({tau}{gt}2). 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{sub i}. For example, the National Spherical Torus Experiment (NSTX) will have an optical thickness {tau}{approx}3000 and CDX-U will have {tau}{approx}300. One can reach the blackbody condition with a plasma density {approx}10{sup 11}thinspcm{sup {minus}3} and T{sub e}{approx}1thinspeV. This makes it attractive to most plasma devices. The serious issue with using EBW is the wave accessibility for the emission measurement. Simple accessibility arguments indicate the wave may be accessible by either direct coupling or mode conversion through an extremely narrow layer ({approx}1{endash}2 mm). EBW experiments on the Current Drive Experiment-Upgrade (CDX-U) will test the accessibility properties of the spherical tokamak configuration. {copyright} {ital 1999 American Institute of Physics.}

  9. 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.

  10. 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.

  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. 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. PMID:25933856

  13. 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

  14. Dependence of synergy current driven by lower hybrid wave and electron cyclotron wave on the frequency and parallel refractive index of electron cyclotron wave for Tokamaks

    SciTech Connect

    Huang, J.; Chen, S. Y. Tang, C. J.

    2014-01-15

    The physical mechanism of the synergy current driven by lower hybrid wave (LHW) and electron cyclotron wave (ECW) in tokamaks is investigated using theoretical analysis and simulation methods in the present paper. Research shows that the synergy relationship between the two waves in velocity space strongly depends on the frequency ω and parallel refractive index N{sub //} of ECW. For a given spectrum of LHW, the parameter range of ECW, in which the synergy current exists, can be predicted by theoretical analysis, and these results are consistent with the simulation results. It is shown that the synergy effect is mainly caused by the electrons accelerated by both ECW and LHW, and the acceleration of these electrons requires that there is overlap of the resonance regions of the two waves in velocity space.

  15. 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.

  16. Superconductive hot-electron-bolometer mixer receiver for 800-GHz operation

    NASA Astrophysics Data System (ADS)

    Kawamura, J.; Blundell, R.; Tong, C.-Y. E.; Papa, D. C.; Hunter, T. R.; Paine, S. N.; Patt, F.; Gol'Tsman, G.; Cherednichenko, S.; Voronov, B.; Gershenzon, E.

    2000-04-01

    In this paper, we describe a superconductive hot-electron-bolometer mixer receiver designed to operate in the partially transmissive 350-μm atmospheric window. The receiver employs an NbN thin-film microbridge as the mixer element, in which the main cooling mechanism of the hot electrons is through electron-phonon interaction. At a local-oscillator frequency of 808 GHz, the measured double-sideband receiver noise temperature is Trx=970 K, across a 1-GHz intermediate-frequency bandwidth centered at 1.8 GHz. We have measured the linearity of the receiver and the amount of local-oscillator power incident on the mixer for optimal operation, which is PLO ≈ 1 microwatt. This receiver was used in making observations as a facility instrument at the Heinrich Hertz Telescope, Mt. Graham, AZ, during the 1998-1999 winter observing season.

  17. 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.

  18. 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.

  19. Advancements in electron cyclotron emission imaging demonstrated by the TEXTOR ECEI diagnostic upgrade.

    PubMed

    Tobias, B; Kong, X; Liang, T; Spear, A; Domier, C W; Luhmann, N C; Classen, I G J; Boom, J E; van de Pol, M J; Jaspers, R; Donné, A J H; Park, H K; Munsat, T

    2009-09-01

    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.

  20. 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.

  1. Studies on a Q/A selector for the SECRAL electron cyclotron resonance ion source

    SciTech Connect

    Yang, Y.; Sun, L. T.; Feng, Y. C.; Fang, X.; Lu, W.; Zhang, W. H.; Cao, Y.; Zhang, X. Z.; Zhao, H. W.

    2014-08-15

    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.

  2. Cerenkov and cyclotron Cerenkov instabilities in a dielectric loaded parallel plate waveguide sheet electron beam system

    SciTech Connect

    Zhao Ding; Ding Yaogen

    2011-09-15

    A dielectric loaded parallel plate waveguide sheet electron beam system can be taken as a reliable model for the practical dielectric loaded rectangular waveguide sheet beam system that has a transverse cross section with a large width to height ratio. By using kinetic theory, the dispersion equations for Cerenkov and cyclotron Cerenkov instabilities in the parallel plate waveguide sheet beam system have been obtained rigorously. The dependences of the growth rate of both instabilities on the electric and structural parameters have also been investigated in detail through numerical calculations. It is worthwhile to point out that adopting an electron beam with transverse velocity can evidently improve the growth rate of Cerenkov instability, which seems like the case of cyclotron Cerenkov instability.

  3. Electron Cyclotron Heating and Current Drive for Maintaining Minimum q in Negative Central Shear Discharges

    SciTech Connect

    Casper, T A; Kaiser, T B; Jong, R A; LoDestro, L L; Moller, J; Pearlstein, L D; Dodge, T

    2003-04-24

    Toroidal plasmas created with negative magnetic shear in the core region offer advantages in terms of MHD stability properties. These plasmas, transiently created in several tokamaks, have exhibited high performance as measured by normalized stored energy and neutron production rates. A critical issue with extending the duration of these plasmas is the need to maintain the off-axis-peaked current distribution required to support the minimum in the safety factor q at large radii. We present equilibrium and transport simulations that explore the use of electron cyclotron heating and current drive to maintain this negative shear configuration. Using parameters consistent with DIII-D tokamak operation, we find that with sufficiently high injected power, it is possible to achieve steady-state conditions employing well aligned electron cyclotron and bootstrap current drive in fully non-inductively current-driven configurations.

  4. Advancements in electron cyclotron emission imaging demonstrated by the TEXTOR ECEI diagnostic upgrade

    NASA Astrophysics Data System (ADS)

    Tobias, B.; Kong, X.; Liang, T.; Spear, A.; Domier, C. W.; Luhmann, N. C.; Classen, I. G. J.; Boom, J. E.; van de Pol, M. J.; Jaspers, R.; Donné, A. J. H.; Park, H. K.; Munsat, T.

    2009-09-01

    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.

  5. Stimulated electromagnetic emissions during pump frequency sweep through fourth electron cyclotron harmonic

    NASA Astrophysics Data System (ADS)

    Carozzi, T. D.; Thidé, B.; Grach, S. M.; Leyser, T. B.; Holz, M.; Komrakov, G. P.; Frolov, V. L.; Sergeev, E. N.

    2002-09-01

    The frequency of a high-power HF radio wave incident on the ionosphere was swept, using a computer-controlled transmitter signal, in <10 s within a 60-kHz-wide frequency band approximately centered on the fourth harmonic of the electron cyclotron frequency. Measurements of the spectral behavior of stimulated electromagnetic emissions (SEE) across this harmonic after preconditioning could thereby be made with unprecedented resolution, speed, and ionospheric stability. Comparison of local electron cyclotron frequency estimations based on the experimental data reveals discrepancies between certain downshifted maximum models and the empirical broad upshifted maximum (BUM) feature formula ΔfBUM = f0 - nfce. Weak emissions related to the BUM were discovered below the nominal BUM cutoff frequency. Finally, we observed that the intensity of certain SEE components differed depending on the whether the pump frequency sweep was ascending or descending.

  6. 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. PMID:25173256

  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. Collective Thomson scattering of a high power electron cyclotron resonance heating beam in LHD (invited).

    PubMed

    Kubo, S; Nishiura, M; Tanaka, K; Shimozuma, T; Yoshimura, Y; Igami, H; Takahash, H; Mutoh, T; Tamura, N; Tatematsu, Y; Saito, T; Notake, T; Korsholm, S B; Meo, F; Nielsen, S K; Salewski, M; Stejner, M

    2010-10-01

    Collective Thomson scattering (CTS) system has been constructed at LHD making use of the high power electron cyclotron resonance heating (ECRH) system in Large Helical Device (LHD). The necessary features for CTS, high power probing beams and receiving beams, both with well defined Gaussian profile and with the fine controllability, are endowed in the ECRH system. The 32 channel radiometer with sharp notch filter at the front end is attached to the ECRH system transmission line as a CTS receiver. The validation of the CTS signal is performed by scanning the scattering volume. A new method to separate the CTS signal from background electron cyclotron emission is developed and applied to derive the bulk and high energy ion components for several combinations of neutral beam heated plasmas.

  9. 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.

  10. 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. PMID:22380181

  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. Effect of flux surface curvature on the linear coupling of electron cyclotron waves in tokamak plasmas

    NASA Astrophysics Data System (ADS)

    Khusainov, T. A.; Gospodchikov, E. D.; Shalashov, A. G.

    2012-02-01

    Specific features of the linear interaction of ordinary and extraordinary electromagnetic waves in the electron cyclotron frequency range in a nonuniform plasma confined in a toroidal magnetic trap are considered. Reduced wave equations taking into account the curvature of the cut-off surfaces in toroidal geometry are formulated. Using these equations, the distributions of the wave fields in the coupling region are analyzed. A method for calculating quasi-optical beams passed through the region of linear wave interaction is proposed.

  13. 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.

  14. 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.

  15. Development of Compact Electron Cyclotron Resonance Ion Source with Permanent Magnets for High-Energy Carbon-Ion Therapy

    SciTech Connect

    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.

    2008-11-03

    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 C{sup 4+} 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 C{sup 4+} was obtained to be 618 e{mu}A 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.

  16. Effect of resonant-to-bulk electron momentum transfer on the efficiency of electron-cyclotron current drive

    SciTech Connect

    Matsuda, Y.; Smith, G.R.; Cohen, R.H.

    1988-01-01

    Efficiency of current drive by electron-cyclotron waves is investigated numerically by a bounce-average Fokker-Planck code to elucidate the effects of momentum transfer from resonant to bulk electrons, finite bulk temperature relative to the energy of resonant electrons, and trapped electrons. Comparisons are made with existing theories to assess their validity and quantitative difference between theory and code results. Difference of nearly a factor of 2 was found in efficiency between some theory and code results. 4 refs., 4 figs.

  17. Design and investigations of the superconducting magnet system for the multipurpose superconducting electron cyclotron resonance ion source

    SciTech Connect

    Tinschert, K.; Lang, R.; Maeder, J.; Rossbach, J.; Spaedtke, P.; Komorowski, P.; Meyer-Reumers, M.; Krischel, D.; Fischer, B.; Ciavola, G.; Gammino, S.; Celona, L.

    2012-02-15

    The production of intense beams of heavy ions with electron cyclotron resonance ion sources (ECRIS) is an important request at many accelerators. According to the ECR condition and considering semi-empirical scaling laws, it is essential to increase the microwave frequency together with the magnetic flux density of the ECRIS magnet system. A useful frequency of 28 GHz, therefore, requires magnetic flux densities above 2.2 T implying the use of superconducting magnets. A cooperation of European institutions initiated a project to build a multipurpose superconducting ECRIS (MS-ECRIS) in order to achieve an increase of the performances in the order of a factor of ten. After a first design of the superconducting magnet system for the MS-ECRIS, the respective cold testing of the built magnet system reveals a lack of mechanical performance due to the strong interaction of the magnetic field of the three solenoids with the sextupole field and the magnetization of the magnetic iron collar. Comprehensive structural analysis, magnetic field calculations, and calculations of the force pattern confirm thereafter these strong interactions, especially of the iron collar with the solenoidal fields. The investigations on the structural analysis as well as suggestions for a possible mechanical design solution are given.

  18. 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.

  19. 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.

  20. 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.

  1. 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. PMID:26932084

  2. 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.

  3. 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.

  4. MFTF-B electron-cyclotron-resonance heating system

    SciTech Connect

    Krause, K.H.; Pollock, G.G.; Yugo, J.J.

    1981-10-22

    The MFTF-B ECRH system will provide 1.6-MW of microwave power for heating of electrons within the thermal barrier and potential maximum regions of the plasma end-plugs. Absorption of this radiation increases the resonant electron energy which locally alters the electrostatic confining potential within the plasma. The result is a thermal barrier which will isolate end-plug electrons from those in the solenoid thus increasing the plasma confinement time. Microwave energy will be generated by eight 200 kW gyrotrons located outside the vacuum vessel at strategic positions near each end-plug. High voltage dc power will be obtained from a -90 kV, 90 A power supply. A compensation network will condition the dc power and channel it to eight independent pulse power regulatory/isolation networks. Each of these networks will, on command, provide -80 kV, 8 A of dc power to its attendant gyrotron cabinet positioned within the vault. Each gyrotron will interface to a quasi-optical waveguide which will transport microwave power to an antenna system located inside the vacuum vessel. The antenna systems will direct the microwave radiation into the resonant heating zones of the plasma. A local control and monitoring system will interface to the MFTF-B Supervisory Control and Diagnostics System. This will permit operation and monitoring of the entire ECRH system from either the central control room or the local control system.

  5. Electrostatic Electron Cyclotron Waves Observed by the Plasma Wave Instrument on Board Polar

    NASA Technical Reports Server (NTRS)

    Menietti, J. D.; Pickett, J. S.; Gurnett, D. A.; Scudder, J. D.

    2001-01-01

    We report the results of an investigation of waves observed by the Polar spacecraft at high altitudes and latitudes and at frequencies just above the cyclotron frequency. These observations are made frequently when the spacecraft is over the polar cap as well as near the dayside cusp and near the nightside auroral region, and observations are made for ratios of plasma frequency to cyclotron frequency, f(sub p)/f(sub c) = 1. Using the six-channel high-frequency waveform receiver (HFWR) on board the spacecraft, which can provide three-axis electric and three-axis magnetic field measurements, we attempt to identify the wavemode of these emissions and investigate possible source mechanisms including low-energy electron beams. We further observe electromagnetic emission associated with upper hybrid waves near and within the plasmasphere. This emission is consistent with both Z and O modes.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Highly charged ion X-rays from Electron Cyclotron Resonance Ion Sources

    NASA Astrophysics Data System (ADS)

    Indelicato, P.; Boucard, S.; Covita, D. S.; Gotta, D.; Gruber, A.; Hirtl, A.; Fuhrmann, H.; Le Bigot, E.-O.; Schlesser, S.; dos Santos, J. M. F.; Simons, L. M.; Stingelin, L.; Trassinelli, M.; Veloso, J.; Wasser, A.; Zmeskal, J.

    2007-09-01

    Radiation from the highly charged ions contained in the plasma of Electron-Cyclotron Resonance Ion Sources (ECRISs) constitutes a very bright source of X-rays. Because the ions have a relatively low kinetic energy (≈1 eV) transitions can be very narrow, containing only a small Doppler broadening. We describe preliminary accurate measurements of two and three-electron ions with Z=16-18. We show how these measurement can test sensitively many-body relativistic calculations or can be used as X-ray standards for precise measurements of X-ray transitions in exotic atoms.

  12. Strong Coupling of the Cyclotron Motion of Surface Electrons on Liquid Helium to a Microwave Cavity.

    PubMed

    Abdurakhimov, L V; Yamashiro, R; Badrutdinov, A O; Konstantinov, D

    2016-07-29

    The strong coupling regime is observed in a system of two-dimensional electrons whose cyclotron motion is coupled to an electromagnetic mode in a Fabry-Perot cavity resonator. Rabi splitting of eigenfrequencies of the coupled motion is observed both in the cavity reflection spectrum and ac current of the electrons, the latter probed by measuring their bolometric photoresponse. Despite the fact that similar observations of Rabi splitting in many-particle systems have been described as a quantum-mechanical effect, we show that the observed splitting can be explained completely by a model based on classical electrodynamics.

  13. 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.

  14. 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.

  15. Strong Coupling of the Cyclotron Motion of Surface Electrons on Liquid Helium to a Microwave Cavity.

    PubMed

    Abdurakhimov, L V; Yamashiro, R; Badrutdinov, A O; Konstantinov, D

    2016-07-29

    The strong coupling regime is observed in a system of two-dimensional electrons whose cyclotron motion is coupled to an electromagnetic mode in a Fabry-Perot cavity resonator. Rabi splitting of eigenfrequencies of the coupled motion is observed both in the cavity reflection spectrum and ac current of the electrons, the latter probed by measuring their bolometric photoresponse. Despite the fact that similar observations of Rabi splitting in many-particle systems have been described as a quantum-mechanical effect, we show that the observed splitting can be explained completely by a model based on classical electrodynamics. PMID:27517786

  16. Dual array 3D electron cyclotron emission imaging at ASDEX Upgrade.

    PubMed

    Classen, I G J; Domier, C W; Luhmann, N C; Bogomolov, A V; Suttrop, W; Boom, J E; Tobias, B J; Donné, A J H

    2014-11-01

    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. PMID:25430246

  17. Commissioning of electron cyclotron emission imaging instrument on the DIII-D tokamak and first dataa)

    NASA Astrophysics Data System (ADS)

    Tobias, B.; Domier, C. W.; Liang, T.; Kong, X.; Yu, L.; Yun, G. S.; Park, H. K.; Classen, I. G. J.; Boom, J. E.; Donné, A. J. H.; Munsat, T.; Nazikian, R.; Van Zeeland, M.; Boivin, R. L.; Luhmann, N. C.

    2010-10-01

    A new electron cyclotron emission imaging diagnostic has been commissioned on the DIII-D tokamak. Dual detector arrays provide simultaneous two-dimensional images of Te fluctuations over radially distinct and reconfigurable regions, each with both vertical and radial zoom capability. A total of 320 (20 vertical×16 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.

  18. Fast Ion Induced Shearing of 2D Alfven Eigenmodes Measured by Electron Cyclotron Emission Imaging

    SciTech Connect

    Tobias, Ben; Classen, I.G.J.; Domier, C. W.; Heidbrink, W.; Luhmann, N.C.; Nazikian, Raffi; Park, H.K.; Spong, Donald A; Van Zeeland, Michael

    2011-01-01

    Two-dimensional images of electron temperature perturbations are obtained with electron cyclotron emission imaging (ECEI) on the DIII-D tokamak and compared to Alfven eigenmode structures obtained by numerical modeling using both ideal MHD and hybrid MHD-gyrofluid codes. While many features of the observations are found to be in excellent agreement with simulations using an ideal MHD code (NOVA), other characteristics distinctly reveal the influence of fast ions on the mode structures. These features are found to be well described by the nonperturbative hybrid MHD-gyrofluid model TAEFL.

  19. Strong Coupling of the Cyclotron Motion of Surface Electrons on Liquid Helium to a Microwave Cavity

    NASA Astrophysics Data System (ADS)

    Abdurakhimov, L. V.; Yamashiro, R.; Badrutdinov, A. O.; Konstantinov, D.

    2016-07-01

    The strong coupling regime is observed in a system of two-dimensional electrons whose cyclotron motion is coupled to an electromagnetic mode in a Fabry-Perot cavity resonator. Rabi splitting of eigenfrequencies of the coupled motion is observed both in the cavity reflection spectrum and ac current of the electrons, the latter probed by measuring their bolometric photoresponse. Despite the fact that similar observations of Rabi splitting in many-particle systems have been described as a quantum-mechanical effect, we show that the observed splitting can be explained completely by a model based on classical electrodynamics.

  20. Magnetic mirror trap with electron-cyclotron plasma heating as a source of multiply charged ions

    SciTech Connect

    Golovanivskii, K.S.

    1986-03-01

    This paper presents the physical operating principles of sources of multiply charged ions using electron cyclotron resonance. It is shown that the conditions that must be satisfied for multiple ionization are well matched to the conditions of effective plasma confinement in a magnetic mirror trap when a collision mode of confinement is provided. Plasma stability with hot electrons in the mirror magnetic trap and the mechanisms of plasma heating by highfrequency fields are analyzed. Two sources of multiply charged ions with ECR plasma heating are examined. Evaluations of the future of this area are given.

  1. 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.

  2. 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.

  3. Post calibration of the two-dimensional electron cyclotron emission imaging instrument with electron temperature characteristics of the magnetohydrodynamic instabilities.

    PubMed

    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.

  4. 60 GHz ecrh system for the PPL PDX machine

    SciTech Connect

    Bowen, N.; Doane, J.; Newman, W.

    1981-01-01

    A 60-GHz kW Electron Cyclotron Resonance (ECR) heating system for the PDX machine is now under construction. It will use two of the pulse-type 60 GHz gyrotrons now being developed by Varian for the U.S. Department of Energy under a subcontract for Oak Ridge National Laboratory. The system will be used for various temperature profile, start-up, and heating experiments. This paper describes the design of the system and its physical configuration.

  5. 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.

  6. 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.

  7. Experimental evidence for the acceleration of thermal electrons by ion cyclotron waves in the magnetosphere

    NASA Technical Reports Server (NTRS)

    Norris, A. J.; Sojka, J. J.; Wrenn, G. L.; Johnson, J. F. E.; Cornilleau-Wehrlin, N.; Perraut, S.; Roux, A.

    1983-01-01

    Experimental evidence is presented for the acceleration of thermal electrons by large amplitude ion cyclotron waves (ICWs). The wave power in the ULF range near the helium gyrofrequency is compared with the distribution function of low energy electrons measured by GEOS satellite instruments. This comparison shows that electrons are accelerated near the geomagnetic equator along field lines, at times when the ICW energy is large and the cold plasma density is below a threshold value. It is suggested that these accelerated electrons can account for the ELF emissions, modulated at the ICW frequency, observed by Wehrlin (1981). A very efficient acceleration of thermal electrons along field lines results from other ULF events having frequencies close to the proton gyrofrequency. Evidence for this lies in the fact that medium energy protons having large temperature anisotropies in the 100-500 eV range are responsible for the ICW wave generation.

  8. 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.

  9. 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.

  10. Instability of field-aligned electron-cyclotron waves in a magnetic mirror plasma with anisotropic temperature

    NASA Astrophysics Data System (ADS)

    Grishanov, N. I.; Azarenkov, N. A.

    2016-08-01

    > Dispersion characteristics have been analysed for field-aligned electron-cyclotron waves (also known as right-hand polarized waves, extraordinary waves or whistlers) in a cylindrical magnetic mirror plasma including electrons with anisotropic temperature. It is shown that the instability of these waves is possible only in the range below the minimal electron-cyclotron frequency, which is much lower than the gyrotron frequency used for electron-cyclotron resonance power input into the plasma, under the condition where the perpendicular temperature of the resonant electrons is larger than their parallel temperature. The growth rates of whistler instability in the two magnetized plasma models, where the stationary magnetic field is either uniform or has a non-uniform magnetic mirror configuration, are compared.

  11. Coherent and Tunable Terahertz Radiation from Graphene Surface Plasmon Polarirons Excited by Cyclotron Electron Beam.

    PubMed

    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 10(5) W/cm(2). 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

  12. Turbulence of electrostatic electron cyclotron harmonic waves observed by Ogo 5.

    NASA Technical Reports Server (NTRS)

    Oya, H.

    1972-01-01

    Analysis of VLF emissions that have been observed near 3/2, 5/2, and 7/2 f sub H by Ogo 5 in the magnetosphere (f sub H is the electron cyclotron frequency) in the light of the mechanism used for the diffuse plasma resonance f sub Dn observed by Alouette 2 and Isis 1. The VLF emission is considered to be generated by nonlinear coupling mechanisms in certain portions of the observation as the f sub Dn is enhanced by its association with nonlinear wave-particle interaction of the electrostatic electron cyclotron harmonic wave, including the instability due to the nonlinear inverse Landau damping mechanism in the turbulence. The difference between the two observations is in the excitation mechanism of the turbulence; the turbulence in the plasma trough detected by Ogo 5 is due to natural origins, whereas the ionospheric topside sounder makes the plasma wave turbulence artificially by submitting strong stimulation pulses. Electron density values in the plasma trough are deduced by applying the f sub Dn-f sub N/f sub H relationship obtained from the Alouette 2 experiment as well as by applying the condition for the wave-particle nonlinear interactions. The electron density values reveal good agreement with the ion density values observed simultaneously by the highly sensitive ion mass spectrometer.

  13. 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

  14. Coherent and Tunable Terahertz Radiation from Graphene Surface Plasmon Polarirons Excited by Cyclotron Electron Beam.

    PubMed

    Zhao, Tao; Gong, Sen; Hu, Min; Zhong, Renbin; Liu, Diwei; Chen, Xiaoxing; Zhang, Ping; Wang, Xinran; Zhang, Chao; Wu, Peiheng; Liu, Shenggang

    2015-11-03

    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 10(5) W/cm(2). 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.

  15. Modulated electron cyclotron drift instability in a high-power pulsed magnetron discharge.

    PubMed

    Tsikata, Sedina; Minea, Tiberiu

    2015-05-01

    The electron cyclotron drift instability, implicated in electron heating and anomalous transport, is detected in the plasma of a planar magnetron. Electron density fluctuations associated with the mode are identified via an adapted coherent Thomson scattering diagnostic, under direct current and high-power pulsed magnetron operation. Time-resolved analysis of the mode amplitude reveals that the instability, found at MHz frequencies and millimeter scales, also exhibits a kHz-scale modulation consistent with the observation of larger-scale plasma density nonuniformities, such as the rotating spoke. Sharply collimated axial fluctuations observed at the magnetron axis are consistent with the presence of escaping electrons in a region where the magnetic and electric fields are antiparallel. These results distinguish aspects of magnetron physics from other plasma sources of similar geometry, such as the Hall thruster, and broaden the scope of instabilities which may be considered to dictate magnetron plasma features. PMID:26001007

  16. Modulated Electron Cyclotron Drift Instability in a High-Power Pulsed Magnetron Discharge

    NASA Astrophysics Data System (ADS)

    Tsikata, Sedina; Minea, Tiberiu

    2015-05-01

    The electron cyclotron drift instability, implicated in electron heating and anomalous transport, is detected in the plasma of a planar magnetron. Electron density fluctuations associated with the mode are identified via an adapted coherent Thomson scattering diagnostic, under direct current and high-power pulsed magnetron operation. Time-resolved analysis of the mode amplitude reveals that the instability, found at MHz frequencies and millimeter scales, also exhibits a kHz-scale modulation consistent with the observation of larger-scale plasma density nonuniformities, such as the rotating spoke. Sharply collimated axial fluctuations observed at the magnetron axis are consistent with the presence of escaping electrons in a region where the magnetic and electric fields are antiparallel. These results distinguish aspects of magnetron physics from other plasma sources of similar geometry, such as the Hall thruster, and broaden the scope of instabilities which may be considered to dictate magnetron plasma features.

  17. 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.

  18. Superradiant decay of cyclotron resonance of two-dimensional electron gases.

    PubMed

    Zhang, Qi; Arikawa, Takashi; Kato, Eiji; Reno, John L; Pan, Wei; Watson, John D; Manfra, Michael J; Zudov, Michael A; Tokman, Mikhail; Erukhimova, Maria; Belyanin, Alexey; Kono, Junichiro

    2014-07-25

    We report on the observation of collective radiative decay, or superradiance, of cyclotron resonance (CR) in high-mobility two-dimensional electron gases in GaAs quantum wells using time-domain terahertz magnetospectroscopy. The decay rate of coherent CR oscillations increases linearly with the electron density in a wide range, which is a hallmark of superradiant damping. Our fully quantum mechanical theory provides a universal formula for the decay rate, which reproduces our experimental data without any adjustable parameter. These results firmly establish the many-body nature of CR decoherence in this system, despite the fact that the CR frequency is immune to electron-electron interactions due to Kohn's theorem. PMID:25105654

  19. Electron cyclotron resonance near the axis of the gas-dynamic trap

    SciTech Connect

    Bagulov, D. S.; Kotelnikov, I. A.

    2012-08-15

    Propagation of an extraordinary electromagnetic wave in the vicinity of electron cyclotron resonance surface in an open linear trap is studied analytically, taking into account inhomogeneity of the magnetic field in paraxial approximation. Ray trajectories are derived from a reduced dispersion equation that makes it possible to avoid the difficulty associated with a transition from large propagation angles to the case of strictly longitudinal propagation. Our approach is based on the theory, originally developed by Zvonkov and Timofeev [Sov. J. Plasma Phys. 14, 743 (1988)], who used the paraxial approximation for the magnetic field strength, but did not consider the slope of the magnetic field lines, which led to considerable error, as has been recently noted by Gospodchikov and Smolyakova [Plasma Phys. Rep. 37, 768-774 (2011)]. We have found ray trajectories in analytic form and demonstrated that the inhomogeneity of both the magnetic field strength and the field direction can qualitatively change the picture of wave propagation and significantly affect the efficiency of electron cyclotron heating of a plasma in a linear magnetic trap. Analysis of the ray trajectories has revealed a criterion for the resonance point on the axis of the trap to be an attractor for the ray trajectories. It is also shown that a family of ray trajectories can still reach the resonance point on the axis if the latter generally repels the ray trajectories. As an example, results of general theory are applied to the electron cyclotron resonance heating experiment which is under preparation on the gas dynamic trap in the Budker Institute of Nuclear Physics [Shalashov et al., Phys. Plasmas 19, 052503 (2012)].

  20. Effect of electron-beam momentum spread on cyclotron resonance maser operation at two resonant frequencies

    NASA Astrophysics Data System (ADS)

    Hunter, G. J.; McNeil, B. W. J.; Robb, G. R. M.

    2001-09-01

    We present a theoretical analysis of cyclotron resonance maser (CRM) operation at two resonant frequencies including the effects of momentum spread in the electron beam. A linear analysis of the system equations is presented in the limit of small momentum spreads. Numerical solutions to the system equations are also given and are in agreement with the linear theory. The results predict that for realistic momentum spreads, operation of the CRM at the higher of the two resonant frequencies should be possible, extending its operating frequency range. An experiment currently under development at Strathclyde University is described and modeled numerically.

  1. Plasma Measurement of Electron Cyclotron Resonance Ion Source for New Materials Production

    NASA Astrophysics Data System (ADS)

    Tanaka, Kiyokatsu; Uchida, Takashi; Minezaki, Hidekazu; Uchiyama, Hidefumi; Asaji, Toyohisa; Muramatsu, Masayuki; Kitagawa, Atsushi; Kato, Yushi; Yoshida, Yoshikazu

    An electron cyclotron resonance ion source (ECRIS) has been designed and developed for a synthesis of new materials such as endohedral metallofullerenes. The plasma chamber diameter is 140 mm in order to produce large m/q ions, like singly charged C60 ions effectively. In this study, we examined the performance of our ECRIS by plasma measurements using a Langmuir probe. The plasma density increased with increasing Ar pressure and reached to 6.1×1017 m-3 at a pressure of 5.0×10-3 Pa. The plasma was produced over a large volume compared with conventional ECRISs.

  2. 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.

  3. Scattering of diffracting beams of electron cyclotron waves by random density fluctuations in inhomogeneous plasmas

    NASA Astrophysics Data System (ADS)

    Weber, Hannes; Maj, Omar; Poli, Emanuele

    2015-03-01

    The physics and first results of the new WKBeam code for electron cyclotron beams in tokamak plasmas are presented. This code is developed on the basis of a kinetic radiative transfer model which is general enough to account for the effects of diffraction and density fluctuations on the beam. Our preliminary numerical results show a significant broadening of the power deposition profile in ITER due to scattering from random density fluctuations at the plasma edge, while such scattering effects are found to be negligible in medium-size tokamaks like ASDEX upgrade.

  4. Closure of the single fluid magnetohydrodynamic equations in presence of electron cyclotron current drive

    NASA Astrophysics Data System (ADS)

    Westerhof, E.; Pratt, J.; Ayten, B.

    2015-03-01

    In the presence of electron cyclotron current drive (ECCD), the Ohm's law of single fluid magnetohydrodynamics (MHD) is modified as E + v × B = η(J - JECCD). 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.

  5. 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.

  6. Status of the Bio-Nano electron cyclotron resonance ion source at Toyo University

    SciTech Connect

    Uchida, T.; Minezaki, H.; Ishihara, S.; Muramatsu, M.; Kitagawa, A.; Drentje, A. G.; Rácz, R.; Biri, S.; Asaji, T.; Kato, Y.; Yoshida, Y.

    2014-02-15

    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 C{sub 60} 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.

  7. 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.

  8. Electron cyclotron resonance plasma etching of native TiO{sub 2} on TiN

    SciTech Connect

    Day, M.E.; Delfino, M.

    1996-01-01

    Thin-film polycrystalline Tin with an approximate 2 nm thick native TiO{sub 2} overlayer is bombarded with 50 to 200 eV Ar ions in an electron cyclotron resonance plasma. In situ X-ray photoelectron spectroscopy and static secondary ion mass spectrometry suggest complete removal of oxygen from the planar surface, independent of ion energy, with TiO{sub 2} remaining on the columnar grain boundaries. The TiN etching rate increases from 6 to 14 nm/min as the ion energy is raised from 100 to 200 eV. The TiN stoichiometry does not change with ion bombardment.

  9. Linear theory of electron cyclotron instability of electromagnetic waves in a magnetoactive plasma waveguide

    SciTech Connect

    Zaginaylov, G. I.; Shcherbinin, V. I.; Schuenemann, K.

    2007-08-15

    The linear stage of electron cyclotron instability of quasi-TE modes in a waveguide filled with a magnetoactive plasma is studied using a kinetic approach. The dispersion relation of the instability is derived analytically. It is shown that the presence of the plasma can reduce both the linear instability growth rate and the instability region; in this case, the maximum of the growth rate is displaced toward lower frequencies. The results obtained are compared with the available experimental observations. They can be useful for optimizing the operating regimes of high-power continuous-wave gyrotrons.

  10. 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.

  11. Stability study of all-permanent-magnet electron cyclotron resonance ion source.

    PubMed

    Yoshida, K; Nara, T; Saitoh, Y; Yokota, W

    2010-02-01

    Beam intensity fluctuation was investigated using an electron cyclotron resonance ion source of an all-permanent-magnet type under development for highly stable beam intensity. While the source achieved a stability of better than 3.2% by strict regulation of the coolant temperature change within +/-0.1 degrees C, the intensity varies strongly with intentional changes in the temperature of the plasma chamber coolant. The influence of the temperature on chamber expansion, magnetic field strength, and vacuum was measured or estimated in detail. The result shows that a slight change in vacuum and magnetic field strength has considerable influence on the intensity fluctuation.

  12. 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.

  13. 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.

  14. 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.

  15. 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+.

  16. Phase-resolved optical emission spectroscopy for an electron cyclotron resonance etcher

    SciTech Connect

    Milosavljevic, Vladimir; MacGearailt, Niall; Daniels, Stephen; Turner, Miles M.; Cullen, P. J.

    2013-04-28

    Phase-resolved optical emission spectroscopy (PROES) is used for the measurement of plasma products in a typical industrial electron cyclotron resonance (ECR) plasma etcher. In this paper, the PROES of oxygen and argon atoms spectral lines are investigated over a wide range of process parameters. The PROES shows a discrimination between the plasma species from gas phase and those which come from the solid phase due to surface etching. The relationship between the micro-wave and radio-frequency generators for plasma creation in the ECR can be better understood by the use of PROES.

  17. 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+}.

  18. Progress in design and integration of the ITER Electron Cyclotron H&CD system

    SciTech Connect

    Darbos, Caroline; Henderson, Mark; Kobayashi, N.; Albajar, F.; Bonicelli, T.; Saibene, G.; Bigelow, Timothy S; Rasmussen, David A; Chavan, R.; Fasel, D.; Hogge, J. P.; Denisov, G. G.; Heidinger, R.; Piosczyk, B.; Thumm, M.; Rao, S. L.; Sakamoto, K.; Takahaski, K.; Thumm, M.

    2009-06-01

    The Electron Cyclotron system for ITER is an in-kind procurement shared between five parties and the total installed power will be 24 MW, corresponding to a nominal injected power of 20 MW to the plasma, with a possible upgrade up to 48 MW (corresponding to 40 MW injected). Some critical issues have been raised and changes are proposed to simplify these procurements and to facilitate the integration into ITER. The progress in the design and the integration of the EC system into the whole project is presented in this paper, as well as some issues still under studies and some recommendations made by external expert committees.

  19. Nonlinear electron acoustic cyclotron waves in presence of uniform magnetic field

    SciTech Connect

    Dutta, Manjistha; Khan, Manoranjan; Ghosh, Samiran; Roychoudhury, Rajkumar; Chakrabarti, Nikhil

    2013-04-15

    Nonlinear electron acoustic cyclotron waves (EACW) are studied in a quasineutral plasma in presence of uniform magnetic field. The fluid model is used to describe the dynamics of two temperature electron species in a stationary charge neutral inhomogeneous background. In long wavelength limit, it is shown that the linear electron acoustic wave is modified by the uniform magnetic field similar to that of electrostatic ion cyclotron wave. Nonlinear equations for these waves are solved by using Lagrangian variables. Results show that the spatial solitary wave-like structures are formed due to nonlinearities and dispersions. These structures transiently grow to larger amplitude unless dispersive effect is actively operative and able to arrest this growth. We have found that the wave dispersion originated from the equilibrium inhomogeneity through collective effect and is responsible for spatiotemporal structures. Weak dispersion is not able to stop the wave collapse and singular structures of EACW are formed. Relevance of the results in the context of laboratory and space plasmas is discussed.

  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.

    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.

  1. Cyclotron Maser Emission from Power-law Electrons with Strong Pitch-angle Anisotropy

    NASA Astrophysics Data System (ADS)

    Zhao, G. Q.; Feng, H. Q.; Wu, D. J.; Chen, L.; Tang, J. F.; Liu, Q.

    2016-05-01

    Energetic electrons with power-law spectra are commonly observed in astrophysics. This paper investigates electron cyclotron maser emission (ECME) from the power-law electrons, in which strong pitch-angle anisotropy is emphasized. The electron distribution function proposed in this paper can describe various types of pitch-angle anisotropy. Results show that the emission properties of ECME, including radiation growth, propagation, and frequency properties, depend considerably on the types of electron pitch-angle anisotropy, and different wave modes show different dependences on the pitch angle of electrons. In particular, the maximum growth rate of the X2 mode rapidly decreases with respect to the electron pitch-angle cosine μ 0 at which the electron distribution peaks, while the growth rates for other modes (X1, O1, O2) initially increase before decreasing as μ 0 increases. Moreover, the O mode, as well as the X mode, can be the fastest growth mode, in terms of not only the plasma parameter but also the type of electron pitch-angle distribution. This result presents a significant extension of the recent researches on ECME driven by the lower energy cutoff of power-law electrons, in which the X mode is generally the fastest growth mode.

  2. Pierce-Wiggler electron beam system for 250 GHz GYRO-BWO: Final report

    SciTech Connect

    Pirkle, D.R.; Alford, C.W.; Anderson, M.H.; Garcia, R.F.; Legarra, J.R.; Nordquist, A.L.

    1989-01-01

    This final report summarizes the design and performance of the VUW-8028 Pierce-Wiggler electron beam systems, which can be used to power high frequency gyro-BWO's. The operator's manual for this gyro-BWO beamstick is included as appendix A. Researchers at Lawrence Livermore National Laboratory (LLNL) are developing a gyro-BWO with a center frequency of 250 GHz, 6% bandwidth, and 10 kV peak output power. The gyro-BWO will be used to drive a free electron laser amplifier at LLNL. The electron beam requirements of the gyro-BWO application are: Small beam size, .100 inch at 2500 gauss axial magnetic field; a large fraction of the electron energy in rotational velocity; ability to vary the electrons' axial velocity easily, for electronic tuning; and low velocity spread i.e. little variation in the axial velocities of the electrons in the interaction region. 1 ref., 13 figs.

  3. 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.

  4. 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.

  5. 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.

  6. Experiment study of an electron cyclotron resonant ion source based on a tapered resonance cavity

    NASA Astrophysics Data System (ADS)

    Yang, Juan; Shi, Feng; Jin, Yizhou; Wang, Yunmin; Komurasaki, Kimiya

    2013-12-01

    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 × 1016-4.8 × 1017 m-3, respectively.

  7. Instability of surface electron cyclotron TM-modes influenced by non-monochromatic alternating electric field

    NASA Astrophysics Data System (ADS)

    Girka, I. O.; Girka, V. O.; Sydora, R. D.; Thumm, M.

    2016-06-01

    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.

  8. 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.

  9. 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.

  10. 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.

  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. 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.

  13. 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.

  14. 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.

  15. Design of a correlation electron cyclotron emission diagnostic for Alcator C-Mod.

    PubMed

    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 k(θ) ≤ 4.8 cm(-1) (k(θ)ρ(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.

  16. Nonlinear evolution of the electromagnetic electron-cyclotron instability in bi-Kappa distributed plasma

    NASA Astrophysics Data System (ADS)

    Eliasson, B.; Lazar, M.

    2015-06-01

    This paper presents a numerical study of the linear and nonlinear evolution of the electromagnetic electron-cyclotron (EMEC) instability in a bi-Kappa distributed plasma. Distributions with high energy tails described by the Kappa power-laws are often observed in collision-less plasmas (e.g., solar wind and accelerators), where wave-particle interactions control the plasma thermodynamics and keep the particle distributions out of Maxwellian equilibrium. Under certain conditions, the anisotropic bi-Kappa distribution gives rise to plasma instabilities creating low-frequency EMEC waves in the whistler branch. The instability saturates nonlinearly by reducing the temperature anisotropy until marginal stability is reached. Numerical simulations of the Vlasov-Maxwell system of equations show excellent agreement with the growth-rate and real frequency of the unstable modes predicted by linear theory. The wave-amplitude of the EMEC waves at nonlinear saturation is consistent with magnetic trapping of the electrons.

  17. 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.

  18. Effect of magnetic field profile on the uniformity of a distributed electron cyclotron resonance plasma

    SciTech Connect

    Huang, C. C.; Chou, S. F.; Chang, T. H.; Chao, H. W.; Chen, C. C.

    2013-07-15

    This study extensively measured the uniformity of an electron cyclotron resonance (ECR) plasma versus the magnetic field distribution. The influence of magnetic field distribution on the generation of uniform ECR plasma was examined. It is suggested that in addition to the uniformity of the magnetic field distribution at ECR zone and at the downstream zone near the substrate, the transition of the magnetic field between these two zones is also crucial. A uniform ECR plasma with the electron density uniformity of ±7.7% over 500 × 500 mm{sup 2} was measured at the downstream. The idea of generating uniform ECR plasma can be scaled up to a much larger area by using an n × n microwave input array and a well-designed magnetic system.

  19. Nonlinear evolution of the electromagnetic electron-cyclotron instability in bi-Kappa distributed plasma

    SciTech Connect

    Eliasson, B.; Lazar, M.

    2015-06-15

    This paper presents a numerical study of the linear and nonlinear evolution of the electromagnetic electron-cyclotron (EMEC) instability in a bi-Kappa distributed plasma. Distributions with high energy tails described by the Kappa power-laws are often observed in collision-less plasmas (e.g., solar wind and accelerators), where wave-particle interactions control the plasma thermodynamics and keep the particle distributions out of Maxwellian equilibrium. Under certain conditions, the anisotropic bi-Kappa distribution gives rise to plasma instabilities creating low-frequency EMEC waves in the whistler branch. The instability saturates nonlinearly by reducing the temperature anisotropy until marginal stability is reached. Numerical simulations of the Vlasov-Maxwell system of equations show excellent agreement with the growth-rate and real frequency of the unstable modes predicted by linear theory. The wave-amplitude of the EMEC waves at nonlinear saturation is consistent with magnetic trapping of the electrons.

  20. Stability of vacuum-ultraviolet radiometric transfer standards: Electron cyclotron resonance versus hollow cathode source

    SciTech Connect

    Gottwald, Alexander; Richter, Mathias; Ulm, Gerhard; Schuehle, Udo

    2005-02-01

    Established transfer standards such as Penning and hollow cathode discharge sources suffer from limited spectral range and, in particular, a limited lifetime and stability due to electrode erosion. The development of a vacuum-ultraviolet radiation source based on an electron cyclotron resonance (ECR)-created plasma might overcome these limitations. To test such a source with regard to its usefulness as radiometric transfer standard, the emission intensity of a Ne plasma was monitored over an operation period of 180 days, with regard to stability and reproducibility in the 50-75 nm wavelength range. For comparison and calibration, a hollow cathode was used as transfer standard traceable to the electron storage ring BESSY II as primary standard. It was found that the ECR source exceeded the lifetime of the hollow cathode source by far, offering a more balanced spectral emission line variety with similar stability.

  1. Electron cyclotron resonance heating by magnetic filter field in a negative hydrogen ion source.

    PubMed

    Kim, June Young; Cho, Won-Hwi; Dang, Jeong-Jeung; Chung, Kyoung-Jae; Hwang, Y S

    2016-02-01

    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(-) 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(-) ion generation in volume-produced negative hydrogen ion sources. PMID:26931999

  2. Electron cyclotron resonance heating by magnetic filter field in a negative hydrogen ion source.

    PubMed

    Kim, June Young; Cho, Won-Hwi; Dang, Jeong-Jeung; Chung, Kyoung-Jae; Hwang, Y S

    2016-02-01

    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(-) 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(-) ion generation in volume-produced negative hydrogen ion sources.

  3. Free-electron laser as a driver for a resonant cavity at 35 GHz

    PubMed

    Lefevre; Gardelle; Rullier; Vermare; Donohue; Meurdesoif; Lidia

    2000-02-01

    An intense beam of relativistic electrons (800 A, 6.7 MeV) has been bunched at 35 GHz by a free-electron laser, in which output power levels exceeding 100 MW were obtained. The beam was then extracted and transported through a resonant cavity, which was excited by its passage. Microwave power levels of 10 MW were extracted from the cavity, in reasonable agreement with the simple formula which relates power to known properties of both the beam and the cavity.

  4. On the role of electron energy distribution function in double frequency heating of electron cyclotron resonance ion source plasmas

    SciTech Connect

    Schachter, L. Dobrescu, S.; Stiebing, K. E.

    2014-02-15

    Double frequency heating (DFH) is a tool to improve the output of highly charged ions particularly from modern electron cyclotron resonance ion source installations with very high RF-frequencies. In order to gain information on the DFH-mechanism and on the role of the lower injected frequency we have carried out a series of dedicated experiments where we have put emphasis on the creation of a discrete resonance surface also for this lower frequency. Our well-established method of inserting an emissive MD (metal-dielectric) liner into the plasma chamber of the source is used in these experiments as a tool of investigation. In this way, the electron temperature and density for both ECR zones is increased in a controlled manner, allowing conclusions on the role of the change of the electron-energy-distribution function with and without DFH.

  5. On the role of electron energy distribution function in double frequency heating of electron cyclotron resonance ion source plasmas.

    PubMed

    Schachter, L; Stiebing, K E; Dobrescu, S

    2014-02-01

    Double frequency heating (DFH) is a tool to improve the output of highly charged ions particularly from modern electron cyclotron resonance ion source installations with very high RF-frequencies. In order to gain information on the DFH-mechanism and on the role of the lower injected frequency we have carried out a series of dedicated experiments where we have put emphasis on the creation of a discrete resonance surface also for this lower frequency. Our well-established method of inserting an emissive MD (metal-dielectric) liner into the plasma chamber of the source is used in these experiments as a tool of investigation. In this way, the electron temperature and density for both ECR zones is increased in a controlled manner, allowing conclusions on the role of the change of the electron-energy-distribution function with and without DFH.

  6. 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.

  7. 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.

  8. Ray tracing and absorption of electron cyclotron waves in the L-2 stellarator

    SciTech Connect

    Goldfinger, R.C. ); Likin, K.M. . Inst. Obshchey Fiziki); Ochirov, B.D. . Inst. Avtomatiki i Ehlektrometrii)

    1991-01-01

    The absorption of electron cyclotron waves in L-2 stellarator plasmas has been investigated by adapting the RAYS geometrical optics code developed at Oak Ridge National Laboratory to the parameters of L-2. Two heating schemes were considered: Low-field launching of the ordinary wave at the fundamental resonance and low-field launching of the extraordinary wave at the second harmonic. Significant power absorption (up to 100%) of the extraordinary mode at the second harmonic resonance was obtained. A multipass absorption model was used to estimate the contribution to plasma heating of the power that remains after the first pass which is subsequently reflected from the vessel walls. Finally, results obtained with the RAYS code and with a code developed at the Institute of Automation and Electrometry were compared and found to be in good agreement. 6 refs., 4 figs.

  9. Investigations on the structure of the extracted ion beam from an electron cyclotron resonance ion source

    SciTech Connect

    Spaedtke, P.; Lang, R.; Maeder, J.; Rossbach, J.; Tinschert, K.; Maimone, F.

    2012-02-15

    Using improved beam diagnostic tools, the structure of an ion beam extracted from an electron cyclotron resonance ion source (ECRIS) becomes visible. Especially viewing targets to display the beam profile and pepper pot devices for emittance measurements turned out to be very useful. On the contrary, diagnostic tools integrating over one space coordinate like wire harps for profile measurements or slit-slit devices, respectively slit-grid devices to measure the emittance might be applicable for beam transport investigations in a quadrupole channel, but are not very meaningful for investigations regarding the given ECRIS symmetry. Here we try to reproduce the experimentally found structure on the ion beam by simulation. For the simulation, a certain model has to be used to reproduce the experimental results. The model is also described in this paper.

  10. Innovations in optical coupling of the KSTAR electron cyclotron emission imaging diagnostic

    SciTech Connect

    Liang, T.; Tobias, B.; Kong, X.; Domier, C. W.; Luhmann, N. C. Jr.; Lee, W.; Yun, G. S.; Park, H. K.

    2010-10-15

    The installation of a new electron cyclotron emission imaging diagnostic for the Korea Superconducting Tokamak Advanced Research (KSTAR) is underway, making use of a unique optical port cassette design, which allows placement of refractive elements inside the cryostat region without adverse effects. The result is unprecedented window access for the implementation of a state of the art imaging diagnostic. A dual-array optical design has been developed, capable of simultaneously imaging the high and low field sides of the plasma with independent features of focal plane translation, vertical zoom, and radial channel spacing. The number of translating optics has been minimized by making use of a zoom lens triplet and parabolic plasma facing lens for maximum channel uniformity over a continuous vertical zoom range of 3:1. The simulated performance of this design is presented along with preliminary laboratory characterization data.

  11. Data acquisition and processing system of the electron cyclotron emission imaging system of the KSTAR tokamak

    SciTech Connect

    Kim, J. B.; Lee, W.; Yun, G. S.; Park, H. K.; Domier, C. W.; Luhmann, N. C. Jr.

    2010-10-15

    A new innovative electron cyclotron emission imaging (ECEI) diagnostic system for the Korean Superconducting Tokamak Advanced Research (KSTAR) produces a large amount of data. The design of the data acquisition and processing system of the ECEI diagnostic system should consider covering the large data production and flow. The system design is based on the layered structure scalable to the future extension to accommodate increasing data demands. Software architecture that allows a web-based monitoring of the operation status, remote experiment, and data analysis is discussed. The operating software will help machine operators and users validate the acquired data promptly, prepare next discharge, and enhance the experiment performance and data analysis in a distributed environment.

  12. Innovations in optical coupling of the KSTAR electron cyclotron emission imaging diagnostic.

    PubMed

    Liang, T; Tobias, B; Kong, X; Domier, C W; Luhmann, N C; Lee, W; Yun, G S; Park, H K

    2010-10-01

    The installation of a new electron cyclotron emission imaging diagnostic for the Korea Superconducting Tokamak Advanced Research (KSTAR) is underway, making use of a unique optical port cassette design, which allows placement of refractive elements inside the cryostat region without adverse effects. The result is unprecedented window access for the implementation of a state of the art imaging diagnostic. A dual-array optical design has been developed, capable of simultaneously imaging the high and low field sides of the plasma with independent features of focal plane translation, vertical zoom, and radial channel spacing. The number of translating optics has been minimized by making use of a zoom lens triplet and parabolic plasma facing lens for maximum channel uniformity over a continuous vertical zoom range of 3:1. The simulated performance of this design is presented along with preliminary laboratory characterization data.

  13. Investigations on the structure of the extracted ion beam from an electron cyclotron resonance ion source.

    PubMed

    Spädtke, P; Lang, R; Mäder, J; Maimone, F; Rossbach, J; Tinschert, K

    2012-02-01

    Using improved beam diagnostic tools, the structure of an ion beam extracted from an electron cyclotron resonance ion source (ECRIS) becomes visible. Especially viewing targets to display the beam profile and pepper pot devices for emittance measurements turned out to be very useful. On the contrary, diagnostic tools integrating over one space coordinate like wire harps for profile measurements or slit-slit devices, respectively slit-grid devices to measure the emittance might be applicable for beam transport investigations in a quadrupole channel, but are not very meaningful for investigations regarding the given ECRIS symmetry. Here we try to reproduce the experimentally found structure on the ion beam by simulation. For the simulation, a certain model has to be used to reproduce the experimental results. The model is also described in this paper.

  14. Amorphous silicon-carbon alloys deposited by electron-cyclotron resonance PECVD

    SciTech Connect

    Chu, V.; Conde, J.P.

    1996-12-31

    Hydrogenated amorphous silicon-carbon alloys are prepared using electron-cyclotron resonance (ECR) plasma-enhanced chemical-vapor deposition. Hydrogen is used as the excitation gas in the resonance chamber while silane and methane (or ethylene) are introduced in the main chamber. A minimum of 95% hydrogen dilution is used. The microwave power is kept constant at 150 W. The effect of the type of carbon source gas, silane to carbon source gas ratio, deposition pressure, substrate temperature and hydrogen dilution on the deposition rate, bandgap and Urbach energy are studied. The photoconductivity and the Urbach energy of the ECR-deposited films are compared to those prepared with glow discharge with the same bandgap.

  15. Emittance and proton fraction measurement in High current electron cyclotron resonance proton ion source

    NASA Astrophysics Data System (ADS)

    Roychowdhury, P.; Kewlani, H.; Mishra, L.; Gharat, S.; Rajawat, R. K.

    2015-09-01

    The beam characterization studies in terms of emittance and proton fraction have been carried out in the high current Electron Cyclotron Resonance (ECR) proton ion source developed for Low Energy High Intensity Proton Accelerator (LEHIPA). The beam emittance was measured using two slit emittance measurement units (EMU). The emittance was measured at three locations (1) after beam extraction at ion source end, (2) after focusing the beam using solenoid magnet and (3) after focusing and separating H+ using solenoid magnet and analyzing magnet. The beam emittance measured in all three cases was found to be less than 0.2π mm-mrad (rms-normalized). The proton fraction in the beam measured using analyzing magnet was found to be more than 90%. The variations of beam emittance and proton fraction have been studied as a function of microwave power and neutral gas pressure.

  16. Multiaperture ion beam extraction from gas-dynamic electron cyclotron resonance source of multicharged ions.

    PubMed

    Sidorov, A; Dorf, M; Zorin, V; Bokhanov, A; Izotov, I; Razin, S; Skalyga, V; Rossbach, J; Spädtke, P; Balabaev, A

    2008-02-01

    Electron cyclotron resonance ion source with quasi-gas-dynamic regime of plasma confinement (ReGIS), constructed at the Institute of Applied Physics, Russia, provides opportunities for extracting intense and high-brightness multicharged ion beams. Despite the short plasma lifetime in a magnetic trap of a ReGIS, the degree of multiple ionization may be significantly enhanced by the increase in power and frequency of the applied microwave radiation. The present work is focused on studying the intense beam quality of this source by the pepper-pot method. A single beamlet emittance measured by the pepper-pot method was found to be approximately 70 pi mm mrad, and the total extracted beam current obtained at 14 kV extraction voltage was approximately 25 mA. The results of the numerical simulations of ion beam extraction are found to be in good agreement with experimental data.

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

    NASA Astrophysics Data System (ADS)

    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.

  18. 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.

  19. Mass Spectrometry Investigation on Decamethylcyclopentasiloxane Electron Cyclotron Resonance Plasma for SiCOH Film Deposition

    NASA Astrophysics Data System (ADS)

    Zhang, Hai-Yan; Ye, Chao; Ning, Zhao-Yuan

    2008-02-01

    We investigate the fragmentation behaviour of decamethylcyclopentasiloxane (DMCPS) plasma using a quadrupole mass spectrometry, which is used as the precursor to deposit SiCOH film in an electron cyclotron resonance (ECR) plasma system. The structure of DMCPS molecules comprises a fivefold Si-O ring and ten -CH3 groups bonded at five Si atoms. In ECR discharge plasma, the main fragmentation behaviour of DMCPS includes two stages. One is the breaking of fivefold Si-O rings and then the formation of threefold Si-O rings and Si-O chain species. The other is the decomposing of hydrocarbon groups from Si atoms and then the crosslink of hydrocarbon species. Combined with the bonding configuration of SiCOH films, the relation between species in ECR plasma and films structures is analysed.

  20. Multiaperture ion beam extraction from gas-dynamic electron cyclotron resonance source of multicharged ions

    SciTech Connect

    Sidorov, A.; Dorf, M.; Zorin, V.; Bokhanov, A.; Izotov, I.; Razin, S.; Skalyga, V.; Rossbach, J.; Spaedtke, P.; Balabaev, A.

    2008-02-15

    Electron cyclotron resonance ion source with quasi-gas-dynamic regime of plasma confinement (ReGIS), constructed at the Institute of Applied Physics, Russia, provides opportunities for extracting intense and high-brightness multicharged ion beams. Despite the short plasma lifetime in a magnetic trap of a ReGIS, the degree of multiple ionization may be significantly enhanced by the increase in power and frequency of the applied microwave radiation. The present work is focused on studying the intense beam quality of this source by the pepper-pot method. A single beamlet emittance measured by the pepper-pot method was found to be {approx}70 {pi} mm mrad, and the total extracted beam current obtained at 14 kV extraction voltage was {approx}25 mA. The results of the numerical simulations of ion beam extraction are found to be in good agreement with experimental data.

  1. The saturation of the electron-cyclotron maser instability and the interpretation of solar millisecond spikes

    NASA Technical Reports Server (NTRS)

    Aschwanden, M. J.

    1990-01-01

    A self-consistent numeric two-dimensional code of the kinetic wave-particle equations developed to investigate the maser dynamics in the solar context is applied to solar millisecond-spike observations in order to improve the diagnostic capabilities of the theory of the electron-cyclotron maser instablitity. Attention is given to the inhomogeneity of the magnetic field selecting magneto-ionic modes with relatively short saturation lengths and suppressing mechanisms such as collisional deflection, free-free absorption, and gyroresonance absorption. The time scales of maser saturation in respect to time scales of global particle changes in a magnetic loop are covered, relevant observations of solar millisecond spikes are described, and the interpretation in terms of physical parameters deduced from the quasi-linear maser simulations are presented. It is demonstrated that the quasi-linear simulations make it possible to constrain the physical parameters from the observed time scale and frequency.

  2. Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS.

    PubMed

    Thomae, R; Conradie, J; Fourie, D; Mira, J; Nemulodi, F; Kuechler, D; Toivanen, V

    2016-02-01

    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.

  3. Hard boron oxide thin-film deposition using electron cyclotron resonance microwave plasmas

    NASA Astrophysics Data System (ADS)

    Gorbatkin, S. M.; Rhoades, R. L.; Tsui, T. Y.; Oliver, W. C.

    1994-11-01

    Hard boron suboxide thin films were deposited in an electron cyclotron resonance (ECR) microwave plasma system at substrate temperatures below 300 °C. A high-temperature effusion cell, operated at 2200°-2250 °C, was used for injection of boron downstream of an Ar/O2 ECR plasma. B ion bombardment is estimated to have been up to 6% of the total boron flux, and Ar ion bombardment is estimated to have contributed ˜100 eV/deposited atom. Boron suboxide films with oxygen concentrations of 11% exhibited hardnesses up to 30 GPa, equal to sapphire and near that of pure boron. The hardness/modulus ratio was 0.1, significantly better than that of sapphire (0.067) or solid boron (0.074), indicating these films may be of interest for a variety of tribological applications.

  4. Hard boron oxide thin-film deposition using electron cyclotron resonance microwave plasmas

    SciTech Connect

    Gorbatkin, S.M.; Rhoades, R.L.; Tsui, T.Y.; Oliver, W.C. )

    1994-11-21

    Hard boron suboxide thin films were deposited in an electron cyclotron resonance (ECR) microwave plasma system at substrate temperatures below 300 [degree]C. A high-temperature effusion cell, operated at 2200[degree]--2250 [degree]C, was used for injection of boron downstream of an Ar/O[sub 2] ECR plasma. B ion bombardment is estimated to have been up to 6% of the total boron flux, and Ar ion bombardment is estimated to have contributed [similar to]100 eV/deposited atom. Boron suboxide films with oxygen concentrations of 11% exhibited hardnesses up to 30 GPa, equal to sapphire and near that of pure boron. The hardness/modulus ratio was 0.1, significantly better than that of sapphire (0.067) or solid boron (0.074), indicating these films may be of interest for a variety of tribological applications.

  5. 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.

  6. On the criteria guiding the design of the upper electron-cyclotron launcher for ITER

    NASA Astrophysics Data System (ADS)

    Poli, E.; Angioni, C.; Casson, F. J.; Farina, D.; Figini, L.; Goodman, T. P.; Maj, O.; Sauter, O.; Weber, H.; Zohm, H.; Saibene, G.; Henderson, M. A.

    2015-03-01

    Electron cyclotron waves injected from an antenna located in the upper part of the vessel will be employed in ITER to controlMHD instabilities, particularly neoclassical tearingmodes (NTMs). The derivation of the NTM stabilization criteria used up to now to guide the optimization of the launcher is reviewed in this paper and their range of validity elucidated. Possible effects leading to a deterioration of the predicted performance through a broadening of the EC deposition profile are discussed. The most detrimental effect will likely be the scattering of the EC beams from density fluctuations, resulting in a beam broadening in the 100% range. The combined impact of these effects with that of beam misalignment (with respect to the targeted surface) is discussed for a time slice of the standard Q = 10 H-mode scenario.

  7. Reversed Shear Alfv'en Eigenmode Stabilization by Localized Electron Cyclotron Heating

    NASA Astrophysics Data System (ADS)

    van Zeeland, M. A.; Lohr, J.; Heidbrink, W. W.; Nazikian, R.; Solomon, W. M.; Gorelenkov, N. N.; Kramer, G. J.; Austin, M. E.; Rhodes, T. L.; Holcomb, C.; Makowski, M. A.; McKee, G. R.; Sharapov, S. E.

    2007-11-01

    Reversed shear Alfv'en eigenmode (RSAE) activity in DIII-D is observed to be stabilized by electron cyclotron heating (ECH) near the minimum of the safety factor (qmin) in neutral beam heated discharges with reversed magnetic shear. The degree of RSAE stabilization and the volume averaged neutron production (Sn) are highly dependent on ECH deposition location relative to qmin. Ideal MHD simulations predict RSAE existence during ECH, indicating that the mode disappearance is due to kinetic effects not taken into account by the ideal MHD model. While discharges with ECH stabilization of RSAEs have higher Sn than discharges with significant RSAE activity, neutron production remains strongly reduced (up to 60%), indicating the bulk of the deficit is not due to RSAEs alone.

  8. 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.

  9. 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. PMID:26931928

  10. Review of highly charged heavy ion production with electron cyclotron resonance ion source (invited)

    SciTech Connect

    Nakagawa, T.

    2014-02-15

    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.

  11. Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS.

    PubMed

    Thomae, R; Conradie, J; Fourie, D; Mira, J; Nemulodi, F; Kuechler, D; Toivanen, V

    2016-02-01

    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. PMID:26931949

  12. Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS

    NASA Astrophysics Data System (ADS)

    Thomae, R.; Conradie, J.; Fourie, D.; Mira, J.; Nemulodi, F.; Kuechler, D.; Toivanen, V.

    2016-02-01

    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.

  13. 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.

  14. ECR (electron cyclotron resonance) ion sources and applications with heavy-ion linacs

    SciTech Connect

    Pardo, R.C.

    1990-01-01

    The electron cyclotron resonance (ECR) ion source has been developed in the last few years into a reliable source of high charge-state heavy ions. The availability of heavy ions with relatively large charge-to-mass ratios (0.1--0.5) has made it possible to contemplate essentially new classes of heavy-ion linear accelerators. In this talk, I shall review the state-of-the-art in ECR source performance and describe some of the implications this performance level has for heavy-ion linear accelerator design. The present linear accelerator projects using ECR ion sources will be noted and the performance requirements of the ECR source for these projects will be reviewed. 30 refs., 3 figs.

  15. Self-consistent simulation of a planar electron-cyclotron-wave-resonance discharge

    SciTech Connect

    Krimke, R.; Urbassek, H.M.

    1997-06-01

    A discharge heated inductively by resonant absorption of electron cyclotron waves discharge is modeled in a planar geometry. The simulation algorithm is based on a kinetic particle-in-cell (PIC/MC) simulation of the plasma properties; the electromagnetic field is calculated macroscopically using the Appleton{endash}Hartree theory for the dielectric tensor. The results are checked against a simplified analytical theory and experimental data by B. Pfeiffer [J. Appl. Phys. {bold 37}, 1624,1628 (1966)] for a 15 mTorr argon discharge. As a result, we show that an inhomogeneous density profile in the discharge strongly affects the electromagnetic fields in the plasma. Power deposition is calculated both in and outside of the resonance. {copyright} {ital 1997 American Institute of Physics.}

  16. Simulations of peeling-ballooning modes with electron cyclotron resonance heating

    NASA Astrophysics Data System (ADS)

    Huang, J.; Chen, S. Y.; Tang, C. J.

    2016-05-01

    The effects of the deposited power and deposited position of Electron Cyclotron Resonance Heating (ECRH) on Peeling-Ballooning (P-B) modes are simulated using BOUT++ code in this paper. The simulation results show that as the deposited position moves from the top to the bottom of the pedestal, the edge localized mode (ELM) size decreases first and then increases, finally decreases again. For ECRH with different deposited power, the effects on P-B modes are similar if they have the same peak value of the power deposition profile. These results show that the effects of ECRH on P-B modes are primarily determined by the change in pressure profile caused by ECRH. As long as ECRH can lead to large enough change in pressure profile, ECRH can efficiently affect the dynamics of P-B modes.

  17. 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.

  18. 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.

  19. Electron Cyclotron / Bernstein Wave Heating and Current Drive Experiments using Phased-array Antenna in QUEST

    SciTech Connect

    Idei, H.; Zushi, H.; Hanada, K.; Nakamura, K.; Fujisawa, A.; Hasegawa, M.; Yoshida, N.; Watanebe, H.; Tokunaga, K.; Nagashima, Y.; Kawasaki, S.; Nakashima, H.; Higashijima, A.; Sakamoto, M.; Ejiri, A.; Takase, Y.; Sakaguchi, M.; Kalinnikova, E.; Ishiguro, M.; Tashima, S.

    2011-12-23

    The phased-array antenna system for Electron Cyclotron/Bernstein Wave Heating and Current Drive experiments has been developed in the QUEST. The antenna was designed to excite a pure O-mode wave in the oblique injection for the O-X-B mode conversion experiments, and its good performances were confirmed at a low power level. The plasma current (<{approx}15 kA) with an aspect ratio of 1.5 was started up and sustained by only RF injection in the low-density operations. The long pulse discharge of 10 kA was also attained for 37 s. The new density window to sustain the plasma current was observed in the high-density plasmas. The single-null divertor configuration with the high plasma current (<{approx}25 kA) was attained in the 17 s plasma sustainment.

  20. Roadmap for the design of a superconducting electron cyclotron resonance ion source for Spiral2

    SciTech Connect

    Thuillier, T.; Angot, J.; Lamy, T.; Peaucelle, C.

    2012-02-15

    A review of today achieved A/Q = 3 heavy ions beams is proposed. The daily operation A/Q = 3 ion beam intensities expected at Spiral2 are at the limit or above best record 3rd generation electron cyclotron resonance ion source (ECRIS) intensities. The necessity to build a new fully superconducting to fulfill these requirements is outlined. A discussion on the volume of the future source is proposed and the minimum value of 12 liters is derived. An analysis of the x-ray absorption superconducting ECRIS is presented based on VENUS experimental data and geometry. This study underlines the necessity to include a complete x-ray study at the time of source conception. The specifications foreseen for the new ECRIS are presented, followed with the roadmap for the design.

  1. New compact and efficient local oscillator optic system for the KSTAR electron cyclotron emission imaging system

    NASA Astrophysics Data System (ADS)

    Nam, Y. B.; Lee, D. J.; Lee, J.; Kim, C.; Yun, G. S.; Lee, W.; Park, H. K.

    2016-11-01

    Electron cyclotron emission imaging (ECEI) diagnostic on Korean Superconducting Tokamak Advanced Research utilizes quasi-optical heterodyne-detection method to measure 2D (vertical and radial) Te 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.

  2. ORIGIN OF ELECTRON CYCLOTRON MASER INDUCED RADIO EMISSIONS AT ULTRACOOL DWARFS: MAGNETOSPHERE-IONOSPHERE COUPLING CURRENTS

    SciTech Connect

    Nichols, J. D.; Burleigh, M. R.; Casewell, S. L.; Cowley, S. W. H.; Wynn, G. A.; Clarke, J. T.; West, A. A.

    2012-11-20

    A number of ultracool dwarfs emit circularly polarized radio waves generated by the electron cyclotron maser instability. In the solar system such radio is emitted from regions of strong auroral magnetic-field-aligned currents. We thus apply ideas developed for Jupiter's magnetosphere, being a well-studied rotationally dominated analog in our solar system, to the case of fast-rotating UCDs. We explain the properties of the radio emission from UCDs by showing that it would arise from the electric currents resulting from an angular velocity shear in the fast-rotating magnetic field and plasma, i.e., by an extremely powerful analog of the process that causes Jupiter's auroras. Such a velocity gradient indicates that these bodies interact significantly with their space environment, resulting in intense auroral emissions. These results strongly suggest that auroras occur on bodies outside our solar system.

  3. 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.

  4. Electron field emission characteristics of nano-catkin carbon films deposited by electron cyclotron resonance microwave plasma chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Gu, Guang-Rui; Wu, Bao-Jia; Jin, Zhe; Ito, Toshimichi

    2008-02-01

    This paper reported that the nano-catkin carbon films were prepared on Si substrates by means of electron cyclotron resonance microwave plasma chemical vapour deposition in a hydrogen and methane mixture. The surface morphology and the structure of the fabricated films were characterized by using scanning electron microscopes and Raman spectroscopy, respectively. The stable field emission properties with a low threshold field of 5V/μm corresponding to a current density of about 1μA/cm2 and a current density of 3.2mA/cm2 at an electric field of 10V/μm were obtained from the carbon film deposited at CH4 concentration of 8%. The mechanism that the threshold field decreased with the increase of the CH4 concentration and the high emission current appeared at the high CH4 concentration was explained by using the Fowler-Nordheim theory.

  5. Excitation of the surface flute waves in electron cyclotron frequency range by internal rotating electron beam in a coaxial waveguide

    NASA Astrophysics Data System (ADS)

    Blednov, O.; Girka, I.; Girka, V.; Pavlenko, I.; Sydora, R.

    2014-12-01

    The initial stage of interaction between a gyrating beam of electrons, which move along Larmor orbits in a narrow gap between a cylindrical plasma layer and an internal screen of a metal coaxial waveguide and electromagnetic eigen waves, is studied theoretically. These waves are extraordinary polarized ones; they propagate along the azimuthal angle across an axial external steady magnetic field in the electron cyclotron frequency range. The numerical analysis shows that the excitation process is stable enough in respect to changing plasma waveguide parameters. The wider the plasma layer, the broader the range of plasma waveguide parameters within which effective wave excitation takes place. The main influence on the excitation of these modes is performed by the applied axial magnetic field, namely: its increase leads to an increase of growth rate and a broadening of the range of the waveguide parameters within which wave excitation is effective.

  6. Comparison of Fine Structures of Electron Cyclotron Harmonic Emissions in Aurora

    NASA Astrophysics Data System (ADS)

    Labelle, J. W.; Dundek, M.

    2015-12-01

    Recent discoveries of emissions at four and five times the electron cyclotron frequency in aurora occuring under daylit conditions motivated the modification of radio receivers at South Pole Station, Antarctica, to measure fine structure of such emissions during two consecutive austral summers, 2013-4 and 2014-5. The experiment recorded 347 emission events over 376 days of observation. The seasonal distribution of these events revealed that successively higher harmonics require higher solar zenith angles for occurrence, as expected if they are generated at locations where the upper hybrid frequency matches the cyclotron harmonic, which for higher harmonics requires higher electron densities which are associated with higher solar zenith angles. Detailed examination of 21 cases in which two harmonics occur simultaneously showed that only rarely, about ten percent of the time, are the frequencies of the fine structures of the emissions in exact integer ratio (e.g., 3:2, 4:3, or 5:4 depending on which combination of harmonics is observed). In the remaining approximately ninety percent of the cases, the higher harmonic occurred at a lower ratio than the appropriate integer ratio, as expected if the harmonics are generated independently at their separate matching conditions in the bottomside ionosphere, where the upper hybrid frequency increases with altitude while the gyroharmonics decrease with altitude. (The bottomside is the most likely source of the emissions, since from there the mode converted Z-modes have access to ground-level.) Taken together, these results suggest that the dominant mechanism for the higher harmonics is independent generation at locations where the upper hybrid frequency matches each harmonic, i.e., at a separate source altitude for each harmonic. Generation of higher harmonics through coalescence of lower harmonic waves explains at most a small minority of events.

  7. 2.4 GHz wireless sensor network for smart electronic shirts

    NASA Astrophysics Data System (ADS)

    Carmo, J. P.; Mendes, P. M.; Couto, C.; Correia, J. H.

    2005-07-01

    This paper presents a wireless sensor network for smart electronic shirts. This allows the monitoring of individual biomedical data, such the cardio-respiratory function. The solution chosen to transmit the body's measured signals for further processing was the use of a wireless link, working at the 2.4 GHz ISM band. A radio-frequency transceiver chip was designed in a UMC RF 0.18 μm CMOS process. The power supply of the transceiver is 1.8 V. Simulations show a power consumption of 12.9 mW. Innovative topics concerning efficient power management was taken into account during the design of the transceiver.

  8. A Compact 600 GHz Electronically Tunable Vector Measurement System for Submillimeter Wave Imaging

    NASA Technical Reports Server (NTRS)

    Dengler, Robert J.; Maiwald, Frank; Siegel, Peter H.

    2006-01-01

    A compact submillimeter wave transmission / reflection measurement system has been demonstrated at 560-635 GHz, with electronic tuning over the entire band. Maximum dynamic range measured at a single frequency is 90 dB (60 dB typical), and phase noise is less than +/- 2(deg). By using a frequency steerable lens at the source output and mixer input, the frequency agility of the system can be used to scan the source and receive beams, resulting in near real-time imaging capability using only a single pixel.

  9. Physics and Engineering Design of the ITER Electron Cyclotron Emission Diagnostic

    NASA Astrophysics Data System (ADS)

    Rowan, W. L.; Austin, M. E.; Houshmandyar, S.; Phillips, P. E.; Beno, J. H.; Ouroua, A.; Weeks, D. A.; Hubbard, A. E.; Stillerman, J. A.; Feder, R. E.; Khodak, A.; Taylor, G.; Pandya, H. K.; Danani, S.; Kumar, R.

    2015-11-01

    Electron temperature (Te) measurements and consequent electron thermal transport inferences will be critical to the non-active phases of ITER operation and will take on added importance during the alpha heating phase. Here, we describe our design for the diagnostic that will measure spatial and temporal profiles of Te using electron cyclotron emission (ECE). Other measurement capability includes high frequency instabilities (e.g. ELMs, NTMs, and TAEs). Since results from TFTR and JET suggest that Thomson Scattering and ECE differ at high Te due to driven non-Maxwellian distributions, non-thermal features of the ITER electron distribution must be documented. The ITER environment presents other challenges including space limitations, vacuum requirements, and very high-neutron-fluence. Plasma control in ITER will require real-time Te. The diagnosic design that evolved from these sometimes-conflicting needs and requirements will be described component by component with special emphasis on the integration to form a single effective diagnostic system. Supported by PPPL/US-DA via subcontract S013464-C to UT Austin.

  10. Electron cyclotron maser emission in coronal arches and solar radio type V bursts

    SciTech Connect

    Tang, J. F.; Wu, D. J.; Tan, C. M.

    2013-12-10

    Solar radio type V bursts were classified as a special spectral class based on their moderately long duration, wide bandwidth, and sense of polarization opposite of associated type III bursts. However, type V bursts are also closely related to the preceding type III bursts. They have an approximately equal source height and the same dispersion of position with frequency. Electron cyclotron maser (ECM) instability driven by beam electrons has been used to explain type III bursts in recent years. We propose ECM emission as the physical process of type V solar radio bursts. According to the observed properties of type V and III bursts, we propose that energetic electrons in excited type V continuum are trapped in coronal loops, which are adjacent to the open field lines traced by type III electrons. With the proposed magnetic field configuration and the ECM emission mechanism, the observed properties of type V bursts, such as long duration, wide bandwidth, and opposite sense of polarization can be reasonably explained by our model.

  11. The effect of electron beams on cyclotron maser emission excited by lower-energy cutoffs

    NASA Astrophysics Data System (ADS)

    Zhao, G. Q.; Feng, H. Q.; Wu, D. J.

    2016-05-01

    Electron-cyclotron maser (ECM) is one of the most important emission mechanisms in astrophysics and can be excited efficiently by lower-energy cutoffs of power-law electrons. These non-thermal electrons probably propagate as a directed collimated beam along ambient magnetic fields. This paper investigates the ECM, in which the effect of electron beams is emphasized. Results show the dependence of emission properties of the ECM on the beam feature. The maximum growth rate of the extraordinary mode (X2) rapidly decreases as the beam momentum increases, while the growth rate of the ordinary mode (O1) changes slightly. In particular, the ordinary mode can overcome the extraordinary mode and becomes the fastest growth mode once the beam momentum is large enough. This research presents an extension of the conventional studies on ECM driven by lower-energy cutoffs and may be helpful to understand better the emission process of solar type I radio bursts, which are dominated by the ordinary mode emission.

  12. Study of plasma start-up initiated by second harmonic electron cyclotron resonance heating on WEGA experiment

    SciTech Connect

    Preynas, M.; Laqua, H. P.; Otte, M.; Stange, T.; Aßmus, D.; Wauters, T.

    2014-02-12

    Although both 1st harmonic ordinary mode (O1) and 2nd harmonic extra-ordinary mode (X2) have been successfully used to initiate pre-ionization and breakdown in many devices, a complete theoretical model is still missing to explain the success of this method. Moreover, some experimental observations are not completely understood, such as what occurs during the delay time between the turn-on of ECRH power and first signals of density or light measurements. Since during this free period the ECRH power has to be absorbed by in-vessel components, it is of prime importance to know what governs this delay time. Recently, dedicated start-up experiments have been performed on WEGA, using a 28 GHz ECRH system in X2-mode. This machine has the interesting capability to be run also as a tokamak allowing comparative experiments between stellarator (ι/2π > 0) and tokamak (ι/2π = 0) configurations. Different scans in heating power, neutral gas pressure, and rotational transform (ι) show clearly that the start-up is a two step process. A first step following the turn-on of the ECRH power during which no measurable electron density (or just above the noise level in some cases), ECE and radiated power is detected. Its duration depends strongly on the level of injected power. The second step corresponds to the gas ionization and plasma expansion phase, with a velocity of density build-up and filling-up of the vessel volume depending mainly on pressure, gas and rotational transform. Moreover, an interesting scenario of ECRH pre-ionization without loop voltage in tokamak configuration by applying a small optimal vertical field is relevant for start-up assistance on future experiments like ITER. The results from this experimental parametric study are useful for the modeling of the start-up assisted by the second harmonic electron cyclotron resonance heating. The aim of this work is to establish predictive scenarios for both ITER and W7-X operation.

  13. Anomalous conductivity in Hall thrusters: Effects of the non-linear coupling of the electron-cyclotron drift instability with secondary electron emission of the walls

    SciTech Connect

    Héron, A.; Adam, J. C.

    2013-08-15

    With the help of an implicit particle-in-cell code, we have shown in a previous paper that the electron-cyclotron drift instability was able to induce anomalous conductivity as well as anomalous heating. As such it can be a major actor among the mechanisms involved in the operation of Hall thrusters. However, experimental results show that the nature of wall material has a significant effect on the behavior of the thruster. The purpose of this paper is to study the plasma-wall interaction in the case where the plasma is heated self-consistently by electrostatic fluctuations induced by the electron-cyclotron drift instability.

  14. Ion and electron cyclotron wall conditioning in stellarator and tokamak magnetic field configuration on WEGA

    SciTech Connect

    Wauters, T.; Louche, F.; Urlings, P.

    2014-02-12

    Discharge wall conditioning is an effective tool to improve plasma performance in tokamaks and stellarators. RF Discharge Conditioning (RFDC) techniques are envisaged for use during operational campaigns on superconducting devices like the ITER tokamak and W7-X stellarator, as alternative to DC Glow Discharge Conditioning which is inefficient in presence of magnetic fields. This contribution investigates RFDC in both the ion and electron cyclotron range of frequencies (ICRF and ECRF) on the WEGA device (Max-Planck-Institute for Plasma Physics, Greifswald, Germany) as preparation for W7-X operation. ECRF discharges produced by localised absorption of RF power at EC resonance layers suffer from poor radial discharge homogeneity in the tokamak vacuum magnetic field configuration, severely limiting the plasma wetted wall areas and consequently the conditioning efficiency. The non-localised production of ICRF discharges by collisional RF power absorption features much improved discharge homogeneity making Ion Cyclotron Wall Conditioning (ICWC) the favoured RFDC technique for superconducting tokamaks. RFDC with the stellarator vacuum magnetic field needs to aim at sufficient plasma densities at and outside the last closed flux surface (LCFS), maximising the convective plasma flux along the open field lines to the wall. Whereas for ICRF discharges this condition is easily fulfilled, on WEGA for He-ECRF discharges this could be achieved as well by off axis heating close to the LCFS. In stellarator magnetic field configuration it is found that He-ICWC for wall desaturation is at least one order of magnitude more efficient than He-ECWC. Novel ECWC methods are proposed that can decrease this efficiency gap with ICWC to a factor 2-3. The efficiency difference is less pronounced in case of H{sub 2}-ICWC and ECWC for isotopic exchange.

  15. An inverted cylindrical sputter magnetron as metal vapor supply for electron cyclotron resonance ion sources

    SciTech Connect

    Weichsel, T. Hartung, U.; Kopte, T.; Zschornack, G.; Kreller, M.; Silze, A.

    2014-05-15

    An inverted cylindrical sputter magnetron device has been developed. The magnetron is acting as a metal vapor supply for an electron cyclotron resonance (ECR) ion source. FEM simulation of magnetic flux density was used to ensure that there is no critical interaction between both magnetic fields of magnetron and ECR ion source. Spatially resolved double Langmuir probe and optical emission spectroscopy measurements show an increase in electron density by one order of magnitude from 1 × 10{sup 10} cm{sup −3} to 1 × 10{sup 11} cm{sup −3}, when the magnetron plasma is exposed to the magnetic mirror field of the ECR ion source. Electron density enhancement is also indicated by magnetron plasma emission photography with a CCD camera. Furthermore, photographs visualize the formation of a localized loss-cone - area, when the magnetron is operated at magnetic mirror field conditions. The inverted cylindrical magnetron supplies a metal atom load rate of R > 1 × 10{sup 18} atoms/s for aluminum, which meets the demand for the production of a milliampere Al{sup +} ion beam.

  16. Quasilinear analysis of loss-cone driven weakly relativistic electron cyclotron maser instability

    SciTech Connect

    Ziebell, L.F.; Yoon, P.H.

    1995-04-01

    This paper presents a quasilinear analysis of the relativistic electron cyclotron maser instability. Two electron populations are assumed: a low-temperature background component and a more energetic loss-cone population. The dispersion relation is valid for any ratio of the energetic to cold populations, and includes thermal and relativistic effects. The quasilinear analysis is based upon an efficient kinetic moment method, in which various moment equations are derived from the particle kinetic equation. A model time-dependent loss-cone electron distribution function is assumed, which allows one to evaluate the instantaneous linear growth rate as well as the moment kinetic equations. These moment equations along with the wave kinetic equation form a fully self-consistent set of equations which governs the evolution of the particles as well as unstable waves. This set of equations is solved with physical parameters typical of the earth`s auroral zone plasma. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  17. Electron cyclotron heating and core intrinsic rotation reversal in DIII-D

    SciTech Connect

    Grassie, J. S. de; Boedo, J. A.; Grierson, B. A.

    2015-12-10

    The effect of electron cyclotron heating (ECH) on the intrinsic rotation profile in DIII-D is shown experimentally. Former DIII-D experiments have shown that ECH tends to cause an interior reduction in the normally co-Ip directed intrinsic rotation profile, and this core rotation can be fully reversed to the opposite direction. This effect is due to a turbulent rearrangement of the interior rotation profile. Here, we show results that there is more than one mechanism causing this. We compare two low density L-mode discharges where the only operational difference is the location of the ECH deposition. At low ECH power, comparable to the Ohmic power, the primary change is in the q-profile accompanied by a reversal of the core intrinsic rotation direction for the more off-axis deposition. The change in the shear of the q-profile fits well with a recent theoretical prediction for this rotation reversal. At higher ECH power, the primary change is in the core electron temperature, Te, accompanied by a hollowing of the rotation profile near the magnetic axis. This effect appears to be due to the change in electron collisionality, consistent with another theoretical, gyrokinetic prediction. The variety of phenomena that could allow ECH to modify the intrinsic rotation profile give some expectation that regions of large velocity shear in the interior could be generated, with the possibility of triggering internal transport barriers.

  18. Characterization of plasma parameters, first beam results, and status of electron cyclotron resonance source

    SciTech Connect

    Jain, S. K.; Jain, Akhilesh; Hannurkar, P. R.; Kotaiah, S.

    2007-05-15

    Electron cyclotron resonance (ECR) plasma source at 50 keV, 30 mA proton current has been designed, fabricated, and assembled. Its plasma study has been done. Plasma chamber was excited with 350 W of microwave power at 2450 MHz, along with nitrogen and hydrogen gases. Microwave power was fed to the plasma chamber through waveguide. Plasma density and electron temperature were studied under various operating conditions, such as magnetic field, gas pressure, and transversal distance. Langmuir probe was used for plasma characterization using current-voltage variation. The nitrogen plasma density calculated was approximately 4.5x10{sup 11} cm{sup -3}, and electron temperatures of 3-10 eV (cold) and 45-85 eV (hot) were obtained. The total ion beam current of 2.5 mA was extracted, with two-electrode extraction geometry, at 15 keV beam energy. The optimization of the source is under progress to extract 30 mA proton beam current at 50 keV beam energy, using three-electrode extraction geometry. This source will be used as an injector to continuous wave radio frequency quadrupole, a part of 100 MeV proton linac. The required root-mean-square normalized beam emittance is less than 0.2{pi} mm mrad. This article presents the study of plasma parameters, first beam results, and status of ECR proton source.

  19. Characterization of plasma parameters, first beam results, and status of electron cyclotron resonance source.

    PubMed

    Jain, S K; Jain, Akhilesh; Hannurkar, P R; Kotaiah, S

    2007-05-01

    Electron cyclotron resonance (ECR) plasma source at 50 keV, 30 mA proton current has been designed, fabricated, and assembled. Its plasma study has been done. Plasma chamber was excited with 350 W of microwave power at 2450 MHz, along with nitrogen and hydrogen gases. Microwave power was fed to the plasma chamber through waveguide. Plasma density and electron temperature were studied under various operating conditions, such as magnetic field, gas pressure, and transversal distance. Langmuir probe was used for plasma characterization using current-voltage variation. The nitrogen plasma density calculated was approximately 4.5 x 10(11) cm(-3), and electron temperatures of 3-10 eV (cold) and 45-85 eV (hot) were obtained. The total ion beam current of 2.5 mA was extracted, with two-electrode extraction geometry, at 15 keV beam energy. The optimization of the source is under progress to extract 30 mA proton beam current at 50 keV beam energy, using three-electrode extraction geometry. This source will be used as an injector to continuous wave radio frequency quadrupole, a part of 100 MeV proton linac. The required root-mean-square normalized beam emittance is less than 0.2pi mm mrad. This article presents the study of plasma parameters, first beam results, and status of ECR proton source.

  20. Phenomenology of intense electron cyclotron emission bursts during high power neutral beam heating on TFTR (abstract)

    NASA Astrophysics Data System (ADS)

    Taylor, G.; Bush, C. E.; Fredrickson, E.; Park, H. K.; Ramsey, A. T.

    1992-10-01

    A 20-channel grating polychromator has been used to study intense bursts of electron cyclotron emission (ECE) from TFTR deuterium plasmas predominantly heated by 90-110-keV neutral beams (Pinj/Poh≳30). The ECE bursts have a duration of 20-150 μs and are usually seen 300-500 ms after the start of neutral beam injection, when the stored energy and neutron production are collapsing or rolling over. In most cases the ECE bursts have Δf/f˜0.2-0.5, if this frequency spread is due entirely to relativistic broadening it implies an electron energy of 10-100 keV (Core electron temperatures in these plasmas are typically 7-12 keV). The ECE bursts are often correlated with ELM activity during limiter H modes and appear to occur at the beginning of the rise in the Dα signal. In some instances the spectral width of the ECE burst is narrow enough (Δf/f˜0.1) to allow identification of the origin of the emission, in these cases the source appears to be within 0.2 m of the plasma edge and the ECE burst exhibits a delay characteristic of an outwardly directed velocity of 2-3×103 m/s. This work is supported by U.S. Department of Energy Contract No. DE-AC02-76-CHO-3073.

  1. Operation and theory of a driven single-mode electron cyclotron maser

    NASA Astrophysics Data System (ADS)

    McCurdy, A. H.; Ganguly, A. K.; Armstrong, C. M.

    1989-08-01

    The general response of an electron cyclotron resonance maser (ECRM) to the application of an external signal, applied both by direct injection of rf into the device and by premodulation of the electron beam, is studied. It is found that phase and frequency control can be achieved over the gyromonotron via phase locking; doing this by premodulating the electron beam produces results that far surpass those of any other locked oscillator system. This premodulation technique allowed phase locking at input power levels 15 dB below that predicted by Adler's theory for a single cavity. A perturbation is used to predict successfully the phase-locking bandwidths for two- and three-cavity systems. Three different regimes of ECRM behavior are examined experimentally and located in the oscillator plane. It is shown that the regime of hard excitation can be accessed by application of a small external signal during the startup of the ECRM. Phase-locking in the hard-excitation regime is also demonstrated.

  2. Modification of electron cyclotron maser operation by application of an external signal

    NASA Astrophysics Data System (ADS)

    McCurdy, Alan H.; Armstrong, C. M.; Bollen, W. M.

    1987-03-01

    Operation of the electron cyclotron resonance maser (ECRM) when subjected to an external rf signal is studied. The signal is introduced both by direct injection through a coupling hole in the oscillator and by modulating the electron beam in separate cavities, upstream of the oscillator. Experiments using both one and two pre bunching cavities are reported. It is found that the gyromonotron, a specific embodiment of the ECRM, can be phase locked by premodulating the electron beam. In this case, the required drive power levels are more than 15 dB below that predicated by Adler's widely applicable theory for single-cavity oscillators. In addition, the same method allows oscillator phase-locked systems, significant reduction of frequency and amplitude noise is observed within the locking band. In signal of a power level 65 dB below that of the oscillator. The general amplitude and frequency response of the ECRM to an applied external signal is also investigated. Three distinct regions of qualitatively different behavior are noted: soft excitation, which is free, self excited oscillation; hard excitation, where the oscillation requires an external impulse for start up; and amplifier, in which the output power level and frequency are linearly related to the drive in the small regime.

  3. Numerical investigation of auroral cyclotron maser processes

    SciTech Connect

    Speirs, D. C.; Ronald, K.; McConville, S. L.; Gillespie, K. M.; Phelps, A. D. R.; Cross, A. W.; Robertson, C. W.; Whyte, C. G.; He, W.; Bingham, R.; Vorgul, I.; Cairns, R. A.; Kellett, B. J.

    2010-05-15

    When a mainly rectilinear electron beam is subject to significant magnetic compression, conservation of magnetic moment results in the formation of a horseshoe shaped velocity distribution. It has been shown that such a distribution is unstable to cyclotron emission and may be responsible for the generation of auroral kilometric radiation--an intense rf emission sourced at high altitudes in the terrestrial auroral magnetosphere. Particle-in-cell code simulations have been undertaken to investigate the dynamics of the cyclotron emission process in the absence of cavity boundaries with particular consideration of the spatial growth rate, spectral output and rf conversion efficiency. Computations reveal that a well-defined cyclotron emission process occurs albeit with a low spatial growth rate compared with waveguide bounded simulations. The rf output is near perpendicular to the electron beam with a slight backward-wave character reflected in the spectral output with a well defined peak at 2.68 GHz, just below the relativistic electron cyclotron frequency. The corresponding rf conversion efficiency of 1.1% is comparable to waveguide bounded simulations and consistent with the predictions of kinetic theory that suggest efficient, spectrally well defined emission can be obtained from an electron horseshoe distribution in the absence of radiation boundaries.

  4. Effect of electron-electron interaction on cyclotron resonance in high-mobility InAs/AlSb quantum wells

    SciTech Connect

    Krishtopenko, S. S. Gavrilenko, V. I.; Ikonnikov, A. V.; Orlita, M.; Sadofyev, Yu. G.; Goiran, M.; Teppe, F.; Knap, W.

    2015-03-21

    We report observation of electron-electron (e-e) interaction effect on cyclotron resonance (CR) in InAs/AlSb quantum well heterostructures. High mobility values allow us to observe strongly pronounced triple splitting of CR line at noninteger filling factors of Landau levels ν. At magnetic fields, corresponding to ν > 4, experimental values of CR energies are in good agreement with single-electron calculations on the basis of eight-band k ⋅ p Hamiltonian. In the range of filling factors 3 < ν < 4 pronounced, splitting of CR line, exceeding significantly the difference in single-electron CR energies, is discovered. The strength of the splitting increases when occupation of the partially filled Landau level tends to a half, being in qualitative agreement with previous prediction by MacDonald and Kallin [Phys. Rev. B 40, 5795 (1989)]. We demonstrate that such behaviour of CR modes can be quantitatively described if one takes into account both electron correlations and the mixing between conduction and valence bands in the calculations of matrix elements of e-e interaction.

  5. DIII-D electron cyclotron heating 2 MW upgrade project. Final report, FY1989--FY1997

    SciTech Connect

    Callis, R.W.

    1997-08-01

    The 2 MW, 110 GHz ECH system was based on the General Atomics Proposal to the Department of Energy: DIII-D Fusion Research Program Vol. I Technical, and Vol. II Cost (GACP-72-166, July 1987 and revised). This proposal was reviewed in August 1987 by a senior technical review committee, who recommended to vigorously pursue increasing the ECH power to 6 MW. The realization of the higher frequency and power ECH on DIII-D was recognized by the committee to be important, not only for the DIII-D program, but also for future devices and the whole ECH area. Subsequently, an engineering cost and schedule review was conducted by DOE-OAK which confirmed the GA costs and schedules and recommended proceeding directly to 10 MW. However, because of budgetary constraints, in the April 1988 Field Task Proposal submission, GA proposed a phased ECH approach, Phase I being 2 MW and Phase II increasing the power to 10 MW. After review, DOE instructed GA to initiate the prototype 2 MW, 110 GHz program. The contract to procure four 500 kW, 110 GHz, 10 s gyrotrons from Varian Associates was initiated in April 1989 with final delivery by November 1990. Because of difficulties in spreading the energy of the electron beam over the collector area, the testing of the first gyrotron delayed its delivery until February 1991. The second gyrotron was able to operate for 1 s at 500 kW and 2 s at 300 kW, but failed when the cavity suffered thermal damage.

  6. Formation of a laminar electron flow for 300 GHz high-power pulsed gyrotron

    SciTech Connect

    Yamaguchi, Yuusuke; Tatematsu, Yoshinori; Saito, Teruo; Ikeda, Ryosuke; Mudiganti, Jagadish C.; Ogawa, Isamu; Idehara, Toshitaka

    2012-11-15

    This paper describes the design of a triode magnetron injection gun for use in a 200 kW, 300 GHz gyrotron. As power and frequency increase, the performance of the gyrotron becomes quite sensitive to the quality of the electron beam. Formation of a laminar electron flow is essential for the realization of a high quality beam with a small velocity spread. In this study, a new method is developed for a quantitative evaluation of the laminarity and is applied to optimize the electrode design. The laminarity depends not only on conventional design parameters such as the cathode slant angle but also on the spatial distribution of the electric field along the beam trajectory. In the optimized design, the velocity pitch factors, {alpha}, larger than 1.2 are obtained at 65 kV, 10 A with spreads, {Delta}{alpha}, less than 5%.

  7. Langmuir probe diagnostics of plasma in high current electron cyclotron resonance proton ion source

    NASA Astrophysics Data System (ADS)

    Roychowdhury, P.; Kewlani, H.; Mishra, L.; Patil, D. S.; Mittal, K. C.

    2013-07-01

    A high current Electron Cyclotron Resonance (ECR) proton ion source has been developed for low energy high intensity proton accelerator at Bhabha Atomic Research Centre. Langmuir probe diagnostics of the plasma generated in this proton ion source is performed using Langmuir probe. The diagnostics of plasma in the ion source is important as it determines beam parameters of the ion source, i.e., beam current, emittance, and available species. The plasma parameter measurement in the ion source is performed in continuously working and pulsed mode using hydrogen as plasma generation gas. The measurement is performed in the ECR zone for operating pressure and microwave power range of 10-4-10-3 mbar and 400-1000 W. An automated Langmuir probe diagnostics unit with data acquisition system is developed to measure these parameters. The diagnostics studies indicate that the plasma density and plasma electron temperature measured are in the range 5.6 × 1010 cm-3 to 3.8 × 1011 cm-3 and 4-14 eV, respectively. Using this plasma, ion beam current of tens of mA is extracted. The variations of plasma parameters with microwave power, gas pressure, and radial location of the probe have been studied.

  8. Langmuir probe diagnostics of plasma in high current electron cyclotron resonance proton ion source

    SciTech Connect

    Roychowdhury, P.; Kewlani, H.; Mishra, L.; Mittal, K. C.; Patil, D. S.

    2013-07-15

    A high current Electron Cyclotron Resonance (ECR) proton ion source has been developed for low energy high intensity proton accelerator at Bhabha Atomic Research Centre. Langmuir probe diagnostics of the plasma generated in this proton ion source is performed using Langmuir probe. The diagnostics of plasma in the ion source is important as it determines beam parameters of the ion source, i.e., beam current, emittance, and available species. The plasma parameter measurement in the ion source is performed in continuously working and pulsed mode using hydrogen as plasma generation gas. The measurement is performed in the ECR zone for operating pressure and microwave power range of 10{sup −4}–10{sup −3} mbar and 400–1000 W. An automated Langmuir probe diagnostics unit with data acquisition system is developed to measure these parameters. The diagnostics studies indicate that the plasma density and plasma electron temperature measured are in the range 5.6 × 10{sup 10} cm{sup −3} to 3.8 × 10{sup 11} cm{sup −3} and 4–14 eV, respectively. Using this plasma, ion beam current of tens of mA is extracted. The variations of plasma parameters with microwave power, gas pressure, and radial location of the probe have been studied.

  9. Finding evidence for density fluctuation effects on electron cyclotron heating deposition profiles on DIII-D

    SciTech Connect

    Brookman, M. W. Austin, M. E.; Petty, C. C.

    2015-12-10

    Theoretical work, computation, and results from TCV [J. Decker “Effect of density fluctuations on ECCD in ITER and TCV,” EPJ Web of Conf. 32, 01016 (2012)] suggest that density fluctuations in the edge region of a tokamak plasma can cause broadening of the ECH deposition profile. In this paper, a GUI tool is presented which is used for analysis of ECH deposition as a first step towards looking for this broadening, which could explain effects seen in previous DIII-D ECH transport studies [K.W. Gentle “Electron energy transport inferences from modulated electron cyclotron heating in DIII-D,” Phys. Plasmas 13, 012311 (2006)]. By applying an FFT to the T{sub e} measurements from the University of Texas’s 40-channel ECE Radiometer, and using a simplified thermal transport equation, the flux surface extent of ECH deposition is determined. The Fourier method analysis is compared with a Break-In-Slope (BIS) analysis and predictions from the ray-tracing code TORAY. Examination of multiple Fourier harmonics and BIS fitting methods allow an estimation of modulated transport coefficients and thereby the true ECH deposition profile. Correlations between edge fluctuations and ECH deposition in legacy data are also explored as a step towards establishing a link between fluctuations and deposition broadening in DIII-D.

  10. Fluctuations in electron cyclotron resonance plasma in a divergent magnetic field

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, Sudeep; Fredriksen, Åshild; Chandra, Sayan

    2016-02-01

    The dependence of fluctuations on electron-neutral collision frequency (νen) and the radial location is investigated in an electron cyclotron resonance plasma in a divergent magnetic field region for a set of magnetic fields. Results indicate that the fluctuations depend strongly on the collision frequency. At lower magnetic fields and νen, the fluctuation levels are small and are observed to peak around 3-5 cm from the central plasma region. Coherent wave modes are found to contribute up to about 30% of the total fluctuation power, and two to three harmonics are present in the power spectra. There are two principal modes present in the discharge: one appears to be a dissipative mode associated with a collisional drift wave instability initiated at a lower pressure (collision frequencies) (˜0.5 mTorr) and is stabilized at a higher pressure (≳3 mTorr). The other mode appears at intermediate pressure (≳1.75 mTorr) and possesses the signature of a flute instability. The fluctuation levels indicate that flute modes are predominant in the discharge at higher pressures ( >1.75 mTorr) and at higher values of the magnetic field (˜540 Gauss).

  11. Microgan electron cyclotron resonance ion source in a Van de Graaff accelerator terminala)

    NASA Astrophysics Data System (ADS)

    Gaubert, G.; Bieth, C.; Bougy, W.; Brionne, N.; Donzel, X.; Sineau, A.; Vallerand, C.; Villari, A. C. C.; Chaves, C.; Gamboni, T.; Geerts, W.; Giorginis, G.; Lövestam, G.; Mondelaers, W.

    2012-02-01

    The Van de Graaff accelerator at IRMM works since many years providing proton, deuteron, and helium beams for nuclear data measurements. The original ion source was of RF type with quartz bottle. This kind of source, as well known, needs regular maintenance for which the accelerator tank must be completely opened. The heavy usage at high currents of the IRMM accelerator necessitated an opening about once every month. In 2010, the full permanent magnet Microgan electron cyclotron resonance (ECR) ion source from PANTECHNIK was installed into a new terminal platform together with a solid state amplifier of 50 W, a dedicated dosing system for 4 gases (with respective gas bottles H2, D2, He, and Ar), and a set of dedicated power supplies and electronic devices for the remote tuning of the source. The new system shows a very stable behaviour of the produced beam allowing running the Van de Graaf without maintenance for several months. This contribution will describe the full installed system in details (working at high pressure in the terminal, spark effects, and optic of the extraction), as well as beam results in dc or pulsed mode.

  12. A study of tearing modes via electron cyclotron emission from tokamak plasmas

    SciTech Connect

    Ren, C.

    1998-07-01

    This thesis studies several tearing mode problems from both theoretical and experimental points of view. A major part of this thesis is to demonstrate that Electron Cyclotron Emission (ECE) is an excellent diagnostic for studying an MHD mode structure and its properties in a tokamak plasma. It is shown that an MHD mode can be detected from the electron temperature fluctuations measured by ECE. The amplitude and phase profiles of the fluctuations contain detailed information about the mode structure. The ECE fluctuation phase profile indicates the magnetic island deformation due to the combination of sheared flow and viscosity. A model is presented to relate qualitatively the observed phase gradient to the local magnetic field, flow velocity shear and viscosity in a 2D slab geometry, using an ideal Ohm`s law and the plasma momentum equation including flow and viscosity. Numerical solution of the resultant Grad-Shafranov-like equation describing the deformed island shows that the experimentally observed value of the phase gradient can be obtained under realistic parameters for the shear in the flow velocity and viscosity. A new approach to the tearing mode stability boundary and saturation level is also presented.

  13. Langmuir probe diagnostics of plasma in high current electron cyclotron resonance proton ion source.

    PubMed

    Roychowdhury, P; Kewlani, H; Mishra, L; Patil, D S; Mittal, K C

    2013-07-01

    A high current Electron Cyclotron Resonance (ECR) proton ion source has been developed for low energy high intensity proton accelerator at Bhabha Atomic Research Centre. Langmuir probe diagnostics of the plasma generated in this proton ion source is performed using Langmuir probe. The diagnostics of plasma in the ion source is important as it determines beam parameters of the ion source, i.e., beam current, emittance, and available species. The plasma parameter measurement in the ion source is performed in continuously working and pulsed mode using hydrogen as plasma generation gas. The measurement is performed in the ECR zone for operating pressure and microwave power range of 10(-4)-10(-3) mbar and 400-1000 W. An automated Langmuir probe diagnostics unit with data acquisition system is developed to measure these parameters. The diagnostics studies indicate that the plasma density and plasma electron temperature measured are in the range 5.6 × 10(10) cm(-3) to 3.8 × 10(11) cm(-3) and 4-14 eV, respectively. Using this plasma, ion beam current of tens of mA is extracted. The variations of plasma parameters with microwave power, gas pressure, and radial location of the probe have been studied.

  14. Scattering of relativistic and ultra-relativistic electrons by obliquely propagating Electromagnetic Ion Cyclotron waves

    NASA Astrophysics Data System (ADS)

    Uzbekov, Bogdan; Shprits, Yuri Y.; Orlova, Ksenia

    2016-10-01

    Electromagnetic Ion Cyclotron (EMIC) waves are transverse plasma waves that are generated in the Earth magnetosphere by ring current protons with temperature anisotropy in three different bands: below the H+, He+ and O+ ion gyrofrequencies. EMIC events are enhanced during the main phase of a geomagnetic storm when intensifications in the electric field result in enhanced injections of ions and are usually confined to high-density regions just inside the plasmapause or within drainage plumes. EMIC waves are capable of scattering radiation belt electrons and thus provide an important link between the intensification of the electric field, ion populations, and radiation belt electrons. Bounce-averaged diffusion coefficients computed with the assumption of parallel wave propagation are compared to the results of the code that uses the full cold plasma dispersion relation taking into account oblique propagation of waves and higher-order resonances. We study the sensitivity of the scattering rates to a number of included higher-order resonances, wave spectral distribution parameters, wave normal angle distribution parameters, ambient plasma density, and ion composition. Inaccuracies associated with the neglect of higher-order resonances and oblique propagation of waves are compared to potential errors introduced by uncertainties in the model input parameters.

  15. Direct determination of the electron effective mass of GaAsN by terahertz cyclotron resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Eßer, F.; Drachenko, O.; Patanè, A.; Ozerov, M.; Winnerl, S.; Schneider, H.; Helm, M.

    2015-08-01

    We use cyclotron resonance THz-spectroscopy in pulsed magnetic fields up to 63 T to measure the electron effective mass in Si-doped GaAsN semiconductor alloys with nitrogen content up to 0.2%. This technique directly probes the transport properties of the N-modified conduction band, particularly the electron effective mass, which has been discussed controversially in the experimental and theoretical literature. We report a slight increase of the electron effective mass and nonparabolicity with N-content for different photon energies in agreement with the two-level band anticrossing model calculations. Furthermore, we show a pronounced electron mobility drop with increasing N-content.

  16. Modification of Electron Cyclotron Maser Operation by Application of AN External Signal.

    NASA Astrophysics Data System (ADS)

    McCurdy, Alan Hugh

    The operation of the electron cyclotron resonance maser (ECRM) when subjected to an external rf signal is studied. The signal is introduced both by direct injection through a coupling hole in the oscillator and by modulating the electron beam in separate cavities, upstream of the oscillator. The gyrotron, a specific embodiment of the ECRM, can be phase locked by premodulating the electron beam. The required drive power levels are more than 15 dB below that predicted by Adler's widely applicable theory for single-cavity oscillators. The phase locking results are compared with a multi-cavity theory in which the free -running gyrotron is perturbed by a small current modulation. The same experimental method allows gyrotron priming, (pulse to pulse phase coherence), at drive-to-oscillator powers 50 dB below that required by magnetrons for equivalent phase control. A lumped circuit theory is used to predict the phase control introduced by the priming signal. The theory agrees with experiment at external signal frequencies within about 5 MHz of the gyrotron frequency. Significant reduction of frequency and amplitude noise is observed within the phase locking band. Reduction of pulse-to-pulse starting time jitter by almost an order of magnitude also occurs. Mechanisms of convective noise growth are investigated by using a technique of noise determination based on the oscillator response to an external signal. The general amplitude-frequency response of the ECRM to an applied external signal is also investigated. Three distinct regions of qualitatively different behavior are noted: soft excitation, hard excitation, and amplification. Control of axial modes in a gyrotron by injection of an external signal is shown for the first time. Finally, it has been verified experimentally, for the first time, that the ECRM is dominated by interaction of the right-hand circularly polarized electromagnetic wave with the electron beam.

  17. Stabilization of Neoclassical Tearing Modes in Tokamaks by Electron Cyclotron Current Drive

    NASA Astrophysics Data System (ADS)

    La Haye, R. J.

    2009-04-01

    Resistive neoclassical tearing modes (NTMs) are anticipated to be the principal limit on stability and performance in ITER as the resulting islands break up the magnetic surfaces confining the plasma. Drag from island-induced eddy currents in the resistive wall can slow plasma rotation, produce locking to the wall, and cause loss of the high-confinement H-mode and disruption. NTMs are destabilized by helical perturbations to the pressure-gradient-driven "bootstrap" current. NTMs can be stabilized by applying co-electron-cyclotron current drive (ECCD) at the island rational surface. Such stabilization and/or preemption is successful in ASDEX Upgrade, DIII-D, and JT-60U, if the peak off-axis current density is comparable to the local bootstrap current density and well-aligned. ASDEX Upgrade has used a feed-forward sweep of the toroidal field to get ECCD alignment on the island. JT-60U has used feed-forward sweeps of the launching mirror for the same purpose, followed up by real-time adjustment of the mirror using the electron cyclotron emission (ECE) diagnostic to locate the island rational surface. In DIII-D, ECCD alignment techniques include applying "search and suppress" real-time control to find and lock onto optimum alignment (adjusting the field or shifting the plasma major radius in equivalent small steps). Most experimental work to date uses narrow, cw ECCD; the relatively wide ECCD in ITER may be less effective if it is also cw: the stabilization effect of replacing the "missing" bootstrap current on the island O-point could be nearly cancelled by the destabilization effect on the island X-point if the ECCD is very broad. Modulating the ECCD so that it is absorbed only on the m/n = 3/2 rotating island O-point is proving successful in recovering ECCD effectiveness in ASDEX Upgrade when the ECCD is configured for wider deposition. The ECCD in ITER is relatively broad, with current deposition full width half maximum almost twice the marginal island width. This

  18. Improved cross-calibration of Thomson scattering and electron cyclotron emission with ECH on DIII-D

    NASA Astrophysics Data System (ADS)

    Brookman, M. W.; Austin, M. E.; McLean, A. G.; Carlstrom, T. N.; Hyatt, A. W.; Lohr, J.

    2016-11-01

    Thomson scattering produces ne profiles from measurement of scattered laser beam intensity. Rayleigh scattering provides a first calibration of the relation ne ∝ ITS, which depends on many factors (e.g., laser alignment and power, optics, and measurement systems). On DIII-D, the ne calibration is adjusted against an absolute ne from the density-driven cutoff of the 48 channel 2nd harmonic X-mode electron cyclotron emission system. This method has been used to calibrate Thomson ne from the edge to near the core (r/a > 0.15). Application of core electron cyclotron heating improves the quality of cutoff and depth of its penetration into the core, and also changes underlying MHD activity, minimizing crashes which confound calibration. Less fueling is needed as "ECH pump-out" generates a plasma ready to take up gas. On removal of gyrotron power, cutoff penetrates into the core as channels fall successively and smoothly into cutoff.

  19. Beam extraction and high stability operation of high current electron cyclotron resonance proton ion source

    NASA Astrophysics Data System (ADS)

    Roychowdhury, P.; Mishra, L.; Kewlani, H.; Patil, D. S.; Mittal, K. C.

    2014-03-01

    A high current electron cyclotron resonance proton ion source is designed and developed for the low energy high intensity proton accelerator at Bhabha Atomic Research Centre. The plasma discharge in the ion source is stabilized by minimizing the reflected microwave power using four stub auto tuner and magnetic field. The optimization of extraction geometry is performed using PBGUNS code by varying the aperture, shape, accelerating gap, and the potential on the electrodes. While operating the source, it was found that the two layered microwave window (6 mm quartz plate and 2 mm boron nitride plate) was damaged (a fine hole was drilled) by the back-streaming electrons after continuous operation of the source for 3 h at beam current of 20-40 mA. The microwave window was then shifted from the line of sight of the back-streaming electrons and located after the water-cooled H-plane bend. In this configuration the stable operation of the high current ion source for several hours is achieved. The ion beam is extracted from the source by biasing plasma electrode, puller electrode, and ground electrode to +10 to +50 kV, -2 to -4 kV, and 0 kV, respectively. The total ion beam current of 30-40 mA is recorded on Faraday cup at 40 keV of beam energy at 600-1000 W of microwave power, 800-1000 G axial magnetic field and (1.2-3.9) × 10-3 mbar of neutral hydrogen gas pressure in the plasma chamber. The dependence of beam current on extraction voltage, microwave power, and gas pressure is investigated in the range of operation of the ion source.

  20. Beam extraction and high stability operation of high current electron cyclotron resonance proton ion source

    SciTech Connect

    Roychowdhury, P. Mishra, L.; Kewlani, H.; Mittal, K. C.; Patil, D. S.

    2014-03-15

    A high current electron cyclotron resonance proton ion source is designed and developed for the low energy high intensity proton accelerator at Bhabha Atomic Research Centre. The plasma discharge in the ion source is stabilized by minimizing the reflected microwave power using four stub auto tuner and magnetic field. The optimization of extraction geometry is performed using PBGUNS code by varying the aperture, shape, accelerating gap, and the potential on the electrodes. While operating the source, it was found that the two layered microwave window (6 mm quartz plate and 2 mm boron nitride plate) was damaged (a fine hole was drilled) by the back-streaming electrons after continuous operation of the source for 3 h at beam current of 20–40 mA. The microwave window was then shifted from the line of sight of the back-streaming electrons and located after the water-cooled H-plane bend. In this configuration the stable operation of the high current ion source for several hours is achieved. The ion beam is extracted from the source by biasing plasma electrode, puller electrode, and ground electrode to +10 to +50 kV, −2 to −4 kV, and 0 kV, respectively. The total ion beam current of 30–40 mA is recorded on Faraday cup at 40 keV of beam energy at 600–1000 W of microwave power, 800–1000 G axial magnetic field and (1.2–3.9) × 10{sup −3} mbar of neutral hydrogen gas pressure in the plasma chamber. The dependence of beam current on extraction voltage, microwave power, and gas pressure is investigated in the range of operation of the ion source.

  1. A quasi-optical electron cyclotron maser for fusion reactor heating

    SciTech Connect

    Morse, E.C.

    1990-01-01

    High power microwave and millimeter sources, such as the quasi-optical electron cyclotron maser (QOECM) are important in fusion research as well as in high-energy physics and in other applications. The interaction between the electromagnetic modes of a Fabry-Perot resonator and an electron beam gyrating through a magnetic field has been studied for both the cases of beams parallel and perpendicular to the resonator. The parallel case was theoretically first studied by Kurin for forward and backward wave interaction, and experimentally by Komlev and Kurin. Kreischer and Temkin reviewed the general case of the linear small signal interaction parallel and perpendicular to the resonator. Sprangle, et al discussed the perpendicular case in a self-consistent linear and nonlinear theoretical study using the Gaussian transverse profile of an open resonator with a single longitudinal mode. Experimental verification of the devices operation was first mentioned in work at the Naval Research Laboratory. Theoretical studies using a time-dependent analysis of a large number of longitudinal modes with similar transverse mode profiles have demonstrated that single longitudinal-mode operation can be achieved at equilibrium and that performance can be enhanced by prebunching the electron beam and tapering the magnetic field. The use of output coupling apertures in the mirrors has been studied theoretically in relation to the structure of the modes for both confocal and nonconfocal resonators by Permnoud; use of an open resonator with stepped mirrors has been studied in order to choose a particular longitudinal mode. Studies at the Naval Research Laboratory mirror used configurations that diffraction couple the energy from around the mirror edges, so that the transverse profile inside the resonator can be selective to the fundamental mode.

  2. A quasi-optical electron cyclotron maser for fusion reactor heating. Final report

    SciTech Connect

    Morse, E.C.

    1990-12-31

    High power microwave and millimeter sources, such as the quasi-optical electron cyclotron maser (QOECM) are important in fusion research as well as in high-energy physics and in other applications. The interaction between the electromagnetic modes of a Fabry-Perot resonator and an electron beam gyrating through a magnetic field has been studied for both the cases of beams parallel and perpendicular to the resonator. The parallel case was theoretically first studied by Kurin for forward and backward wave interaction, and experimentally by Komlev and Kurin. Kreischer and Temkin reviewed the general case of the linear small signal interaction parallel and perpendicular to the resonator. Sprangle, et al discussed the perpendicular case in a self-consistent linear and nonlinear theoretical study using the Gaussian transverse profile of an open resonator with a single longitudinal mode. Experimental verification of the devices operation was first mentioned in work at the Naval Research Laboratory. Theoretical studies using a time-dependent analysis of a large number of longitudinal modes with similar transverse mode profiles have demonstrated that single longitudinal-mode operation can be achieved at equilibrium and that performance can be enhanced by prebunching the electron beam and tapering the magnetic field. The use of output coupling apertures in the mirrors has been studied theoretically in relation to the structure of the modes for both confocal and nonconfocal resonators by Permnoud; use of an open resonator with stepped mirrors has been studied in order to choose a particular longitudinal mode. Studies at the Naval Research Laboratory mirror used configurations that diffraction couple the energy from around the mirror edges, so that the transverse profile inside the resonator can be selective to the fundamental mode.

  3. Impact of magnetic field inhomogeneity on electron cyclotron radiative loss in tokamak reactors

    SciTech Connect

    Kukushkin, A. B.; Minashin, P. V.; Polevoi, A. R.

    2012-03-15

    The potential importance of electron cyclotron (EC) emission in the local electron power balance in the steady-state regimes of ITER operation with high temperatures, as well as in the DEMO reactor, requires accurate calculation of the one-dimensional (over magnetic surfaces) distribution of the net radiated power density, P{sub EC}({rho}). When the central electron temperature increases to {approx}30 keV, the local EC radiative loss comprises a substantial fraction of the heating power from fusion alphas and is close to the total auxiliary NBI heating power, P{sub EC}(0) Asymptotically-Equal-To 0.3P{sub {alpha}}(0) Asymptotically-Equal-To P{sub aux}(0). In the present paper, the model of EC radiative transport in an axisymmetric toroidal plasma is extended to the case of an inhomogeneous magnetic field B(R, Z). The impact of such inhomogeneity on local and total power losses is analyzed in the framework of this model by using the CYNEQ code. It is shown that, for the magnetic field B, temperature T{sub e}, density n{sub e}, and wall reflection coefficient R{sub w} expected in ITER and DEMO, accurate simulations of the EC radiative loss require self-consistent 1.5D transport analysis (i.e., one-dimensional simulations of plasma transport and two-dimensional simulations of plasma equilibrium). It is shown that EC radiative transport can be described with good accuracy in the 1D approximation with the surface-averaged magnetic field, B({rho}) = Left-Pointing-Angle-Bracket B(R, Z) Right-Pointing-Angle-Bracket {sub ms}. This makes it possible to substantially reduce the computational time required for time-dependent self-consistent 1.5D transport analysis. Benchmarking of the CYNEQ results with available results of the RAYTEC, EXACTEC, and CYTRAN codes is performed for various approximations of the magnetic field.

  4. Electron cyclotron emission reconstruction image and m/n=3/2 mode in HT-7 tokamak

    SciTech Connect

    Li Erzhong; Hu Liqun; Ling Bili; Liu Yong; Ti Ang; Chen Kaiyun; Shen Biao; Gao Xiang

    2010-07-15

    Electron cyclotron emission reconstruction image has been used for flux surface reconstruction. The reconstruction image is based on plasma rigid rotation which is obtained from Mirnov diagnostic. From the reconstructed two-dimensional flux surface, the classical m/n=3/2 mode is visualized, which is of similar spatial structure as neoclassical 3/2 mode observed in some other tokamaks [B. Esposito et al., Phys. Rev. Lett. 100, 045006 (2008)].

  5. Reconstruction of high temporal resolution Thomson scattering data during a modulated electron cyclotron resonance heating using conditional averaging.

    PubMed

    Kobayashi, T; Ida, K; Itoh, K; Yoshinuma, M; Moon, C; Inagaki, S; Yamada, I; Funaba, H; Yasuhara, R; Tsuchiya, H; Ohdachi, S; Yoshimura, Y; Igami, H; Shimozuma, T; Kubo, S; Tsujimura, T I

    2016-04-01

    This paper provides a software application of the sampling scope concept for fusion research. The time evolution of Thomson scattering data is reconstructed with a high temporal resolution during a modulated electron cyclotron resonance heating (MECH) phase. The amplitude profile and the delay time profile of the heat pulse propagation are obtained from the reconstructed signal for discharges having on-axis and off-axis MECH depositions. The results are found to be consistent with the MECH deposition.

  6. First principles fluid modelling of magnetic island stabilization by electron cyclotron current drive (ECCD)

    NASA Astrophysics Data System (ADS)

    Février, O.; Maget, P.; Lütjens, H.; Luciani, J. F.; Decker, J.; Giruzzi, G.; Reich, M.; Beyer, P.; Lazzaro, E.; Nowak, S.; the ASDEX Upgrade Team

    2016-04-01

    Tearing modes are MagnetoHydroDynamics (MHD) instabilities that reduce the performance of fusion devices. They can however be controlled and suppressed using electron cyclotron current drive (ECCD) as demonstrated in various tokamaks. In this work, simulations of island stabilization by ECCD-driven current have been carried out using the toroidal nonlinear 3D full MHD code xtor-2f, in which a current source term modeling the ECCD has been implemented. The efficiency parameter, {η\\text{RF}} , has been computed and its variations with respect to source width and location were also computed. The influence of parameters such as current intensity, source width and position with respect to the island was evaluated and compared to the modified Rutherford equation. We retrieved a good agreement between the simulations and the analytical predictions concerning the variations of control efficiency with source width and position. We also show that the 3D nature of the current source term can lead to the onset of an island if the source term is precisely applied on a rational surface. We report the observation of a flip phenomenon in which the O- and X-points of the island rapidly switch their position in order for the island to take advantage of the current drive to grow.

  7. Electron cyclotron resonance deposition of amorphous silicon alloy films and devices

    SciTech Connect

    Shing, Y.H. )

    1992-10-01

    This report describes work to develop a state-of-the-art electron cyclotron resonance (ECR) plasma-enhanced chemical vapor deposition (PECVD) system. The objective was to understand the deposition processes of amorphous silicon (a-Si:H) and related alloys, with a best-effort improvement of optoelectronic material properties and best-effort stabilization of solar cell performance. ECR growth parameters were systematically and extensively investigated; materials characterization included constant photocurrent measurement (CPM), junction capacitance, drive-level capacitance profiling (DLCP), optical transmission, light and dark photoconductivity, and small-angle X-ray scattering (SAXS). Conventional ECR-deposited a-Si:H was compared to a new form, a-Si:(Xe, H), in which xenon gas was added to the ECR plasma. a-Si:(Xe,H) possessed low, stable dark conductivities and high photosensitivites. Light-soaking revealed photodegradation rates about 35% lower than those of comparable radio frequency (rf)-deposited material. ECR-deposited p-type a SiC:H and intrinsic a-Si:H films underwent evaluation as components of p-i-n solar cells with standard rf films for the remaining layers.

  8. He-like argon, chlorine and sulfur spectra measurement from an Electron Cyclotron Resonance Ion Trap

    NASA Astrophysics Data System (ADS)

    Trassinelli, M.; Boucard, S.; Covita, D. S.; Gotta, D.; Hirtl, A.; Indelicato, P.; LeBigot, É.-O.; dos Santos, J. M. F.; Simons, L. M.; Stingelin, L.; Veloso, J. F. C. A.; Wasser, A.; Zmeskal, J.

    2007-03-01

    We present a new measurement on X-ray spectroscopy of multicharged argon, chlorine and sulfur obtained with the Electron Cyclotron Resonance Ion Trap installed at the Paul Scherrer Institut (Villigen, Switzerland). For this purpose, we used a crystal spectrometer with a spherically bent crystal having an energy resolution of about 0.4 eV. High intensity Kα X-ray spectra were obtained from ions with one 1s hole ranging from almost neutral to heliumlike charge states. In particular we observed the 1s2s 3S1 → 1s2 1S0 M1 and 1s2p 3P2 → 1s2 1S0 M2 transitions in He-like argon, chlorine and sulfur with unprecedented statistics and resolution. The preliminary analysis presented here describes a new technique to measure precisely energy differences between transitions using a Johann-type Bragg spectrometer. A recent characterization of the spectrometer will allow for a drastic reduction of the systematic errors.

  9. Observation of plasma instabilities related to dust particle growth mechanisms in electron cyclotron resonance plasmas

    SciTech Connect

    Drenik, A.; Margot, J.

    2013-10-15

    Instabilities are observed in the self-bias voltage measured on a probe immersed in microwave plasma excited at Electron Cyclotron Resonance (ECR). Observed in the MHz range, they were systematically measured in dust-free or dusty plasmas (obtained for different conditions of applied microwave powers and acetylene flow rates). Two characteristic frequencies, well described as lower hybrid oscillations, can be defined. The first one, in the 60–70 MHz range, appears as a sharp peak in the frequency spectra and is observed in every case. Attributed to ions, its position shift observed with the output power highlights that nucleation process takes place in the dusty plasma. Attributed to lower hybrid oscillation of powders, the second broad peak in the 10–20 MHz range leads to the characterization of dust particles growth mechanisms: in the same way as in capacitively coupled plasmas, accumulation of nucleus confined near the probe in the magnetic field followed by aggregation takes place. Then, the measure of electrical instabilities on the self-bias voltage allows characterizing the discharge as well as the chemical processes that take place in the magnetic field region and their kinetics.

  10. An all permanent magnet electron cyclotron resonance ion source for heavy ion therapy

    SciTech Connect

    Cao, Yun Li, Jia Qing; Sun, Liang Ting; Zhang, Xue Zhen; Feng, Yu Cheng; Wang, Hui; Ma, Bao Hua; Li, Xi Xia

    2014-02-15

    A high charge state all permanent Electron Cyclotron Resonance ion source, Lanzhou All Permanent ECR ion source no. 3-LAPECR3, has been successfully built at IMP in 2012, which will serve as the ion injector of the Heavy Ion Medical Machine (HIMM) project. As a commercial device, LAPECR3 features a compact structure, small size, and low cost. According to HIMM scenario more than 100 eμA of C{sup 5+} ion beam should be extracted from the ion source, and the beam emittance better than 75 π*mm*mrad. In recent commissioning, about 120 eμA of C{sup 5+} ion beam was got when work gas was CH{sub 4} while about 262 eμA of C{sup 5+} ion beam was obtained when work gas was C{sub 2}H{sub 2} gas. The design and construction of the ion source and its low-energy transportation beam line, and the preliminary commissioning results will be presented in detail in this paper.

  11. Silicon nitride formation from a silane-nitrogen ECR (electron cyclotron resonance) plasma

    SciTech Connect

    Barbour, J.C.; Stein, H.J. ); Popov, O.A.; Yoder, M. ); Outten, C.A. . Dept. of Nuclear Engineering)

    1990-01-01

    Good quality, low temperature silicon nitride and oxynitride films were deposited downstream from an electron cyclotron resonance (ECR) plasma source using SiH{sub 4} and N{sub 2} gas mixtures. The Si/N ratio and H content in the deposited films were determined using Rutherford backscattering spectrometry (RBS)and elastic recoil detection (ERD). The H concentration was minimum for films with compositions closest to that of stoichiometric Si{sub 3}N{sub 4}. The optimum conditions for producing a stoichiometric Si{sub 3}N{sub 4}were: a SiH{sub 4}/N{sub 2} flow ratio between 0.1 and 0.2, and an electrically isolated sample far from the ECR source. Infrared absorption spectra showed that as the film composition changed from N rich to Si rich the dominant bonds associated with H changed from N-H to Si-H. The addition of O{sub 2} to the background gas formed an oxynitride with a low H content similar to the stoichiometric Si{sub 3}N{sub 4} 10 refs., 4 figs., 2 tabs.

  12. Calculation of plasma dielectric response in inhomogeneous magnetic field near electron cyclotron resonance

    NASA Astrophysics Data System (ADS)

    Evstatiev, Evstati; Svidzinski, Vladimir; Spencer, Andy; Galkin, Sergei

    2014-10-01

    Full wave 3-D modeling of RF fields in hot magnetized nonuniform plasma requires calculation of nonlocal conductivity kernel describing the dielectric response of such plasma to the RF field. In many cases, the conductivity kernel is a localized function near the test point which significantly simplifies numerical solution of the full wave 3-D problem. Preliminary results of feasibility analysis of numerical calculation of the conductivity kernel in a 3-D hot nonuniform magnetized plasma in the electron cyclotron frequency range will be reported. This case is relevant to modeling of ECRH in ITER. The kernel is calculated by integrating the linearized Vlasov equation along the unperturbed particle's orbits. Particle's orbits in the nonuniform equilibrium magnetic field are calculated numerically by one of the Runge-Kutta methods. RF electric field is interpolated on a specified grid on which the conductivity kernel is discretized. The resulting integrals in the particle's initial velocity and time are then calculated numerically. Different optimization approaches of the integration are tested in this feasibility analysis. Work is supported by the U.S. DOE SBIR program.

  13. Effects of electron cyclotron current drive on the evolution of double tearing mode

    SciTech Connect

    Sun, Guanglan Dong, Chunying; Duan, Longfang

    2015-09-15

    The effects of electron cyclotron current drive (ECCD) on the double tearing mode (DTM) in slab geometry are investigated by using two-dimensional compressible magnetohydrodynamics equations. It is found that, mainly, the double tearing mode is suppressed by the emergence of the secondary island, due to the deposition of driven current on the X-point of magnetic island at one rational surface, which forms a new non-complete symmetric magnetic topology structure (defined as a non-complete symmetric structure, NSS). The effects of driven current with different parameters (magnitude, initial time of deposition, duration time, and location of deposition) on the evolution of DTM are analyzed elaborately. The optimal magnitude or optimal deposition duration of driven current is the one which makes the duration of NSS the longest, which depends on the mutual effect between ECCD and the background plasma. Moreover, driven current introduced at the early Sweet-Parker phase has the best suppression effect; and the optimal moment also exists, depending on the duration of the NSS. Finally, the effects varied by the driven current disposition location are studied. It is verified that the favorable location of driven current is the X-point which is completely different from the result of single tearing mode.

  14. Optimization of the ITER electron cyclotron equatorial launcher for improved heating and current drive functional capabilities

    SciTech Connect

    Farina, D.; Figini, L.; Henderson, M.; Saibene, G.

    2014-06-15

    The design of the ITER Electron Cyclotron Heating and Current Drive (EC H and CD) system has evolved in the last years both in goals and functionalities by considering an expanded range of applications. A large effort has been devoted to a better integration of the equatorial and the upper launchers, both from the point of view of the performance and of the design impact on the engineering constraints. However, from the analysis of the ECCD performance in two references H-mode scenarios at burn (the inductive H-mode and the advanced non-inductive scenario), it was clear that the EC power deposition was not optimal for steady-state applications in the plasma region around mid radius. An optimization study of the equatorial launcher is presented here aiming at removing this limitation of the EC system capabilities. Changing the steering of the equatorial launcher from toroidal to poloidal ensures EC power deposition out to the normalized toroidal radius ρ ≈ 0.6, and nearly doubles the EC driven current around mid radius, without significant performance degradation in the core plasma region. In addition to the improved performance, the proposed design change is able to relax some engineering design constraints on both launchers.

  15. Control of composition and crystallinity in hydroxyapatite films deposited by electron cyclotron resonance plasma sputtering

    NASA Astrophysics Data System (ADS)

    Akazawa, Housei; Ueno, Yuko

    2014-01-01

    Hydroxyapatite (HAp) films were deposited by electron cyclotron resonance plasma sputtering under a simultaneous flow of H2O vapor gas. Crystallization during sputter-deposition at elevated temperatures and solid-phase crystallization of amorphous films were compared in terms of film properties. When HAp films were deposited with Ar sputtering gas at temperatures above 460 °C, CaO byproducts precipitated with HAp crystallites. Using Xe instead of Ar resolved the compositional problem, yielding a single HAp phase. Preferentially c-axis-oriented HAp films were obtained at substrate temperatures between 460 and 500 °C and H2O pressures higher than 1×10-2 Pa. The absorption signal of the asymmetric stretching mode of the PO43- unit (ν3) in the Fourier-transform infrared absorption (FT-IR) spectra was the narrowest for films as-crystallized during deposition with Xe, but widest for solid-phase crystallized films. While the symmetric stretching mode of PO43- (ν1) is theoretically IR-inactive, this signal emerged in the FT-IR spectra of solid-phase crystallized films, but was absent for as-crystallized films, indicating superior crystallinity for the latter. The Raman scattering signal corresponding to ν1 PO43- sensitively reflected this crystallinity. The surface hardness of as-crystallized films evaluated by a pencil hardness test was higher than that of solid-phase crystallized films.

  16. Experiments with biased side electrodes in electron cyclotron resonance ion sources

    SciTech Connect

    Drentje, A. G. Kitagawa, A.; Uchida, T.; Rácz, R.; Biri, S.

    2014-02-15

    The output of highly charged ions from an electron cyclotron resonance ion source (ECRIS) consists of ionic losses from a highly confined plasma. Therefore, an increase of the output of the ions of interest always is a compromise between an increase in the confinement and an increase of the losses. One route towards a solution consists of attacking the losses in directions – i.e., radial directions – that do not contribute to the required output. This was demonstrated in an experiment (using the Kei ECRIS at NIRS, Japan) where radial losses were electrostatically reduced by positively biasing one set of six “side” electrodes surrounding the plasma in side-ward directions attached (insulated) to the cylindrical wall of the plasma chamber. Recently new studies were performed in two laboratories using two essentially different ion sources. At the BioNano ECRIS (Toyo University, Japan) various sets of electrodes were used; each of the electrodes could be biased individually. At the Atomki ECRIS (Hungary), one movable, off-axis side electrode was applied in technically two versions. The measurements show indeed a decrease of ionic losses but different effectivities as compared to the biased disk.

  17. Measurements, modelling and electron cyclotron heating modification of Alfven eigenmode activity in DIII-D

    SciTech Connect

    Van Zeeland, Michael; Heidbrink, W.; Nazikian, Raffi; Austin, M. E.; Cheng, C Z; Chu, M. S.; Gorelenkov, Nikolai; Holcomb, C T; Hyatt, A. W.; Kramer, G.; Lohr, J.T.; Mckee, G. R.; Petty, C C.; Prater, R.; Solomon, W. M.; Spong, Donald A

    2009-01-01

    Neutral beam injection into reversed magnetic shear DIII-D plasmas produces a variety of Alfvenic activity including toroidicity and ellipticity induced Alfven eigenmodes (TAE/EAE, respectively) and reversed shear Alfven eigenmodes (RSAE) as well as their spatial coupling. These modes are studied during the discharge current ramp phase when incomplete current penetration results in a high central safety factor and strong drive due to multiple higher order resonances. It is found that ideal MHD modelling of eigenmode spectral evolution, coupling and structure are in excellent agreement with experimental measurements. It is also found that higher radial envelope harmonic RSAEs are clearly observed and agree with modelling. Some discrepancies with modelling such as that due to up/down eigenmode asymmetries are also pointed out. Concomitant with the Alfvenic activity, fast ion (FIDA) spectroscopy shows large reductions in the central fast ion profile, the degree of which depends on the Alfven eigenmode amplitude. Interestingly, localized electron cyclotron heating (ECH) near the mode location stabilizes RSAE activity and results in significantly improved fast ion confinement relative to discharges with ECH deposition on axis. In these discharges, RSAE activity is suppressed when ECH is deposited near the radius of the shear reversal point and enhanced with deposition near the axis. The sensitivity of this effect to deposition power and current drive phasing as well as ECH modulation are presented.

  18. Phosphorus Doping Using Electron Cyclotron Resonance Plasma for Large-Area Polycrystalline Silicon Thin Film Transistors

    NASA Astrophysics Data System (ADS)

    Kakinuma, Hiroaki; Mohri, Mikio; Tsuruoka, Taiji

    1994-01-01

    We have investigated phosphorus doping using an electron cyclotron resonance (ECR) plasma, for application to the poly-Si driving circuits of liquid crystal displays or image sensors. The PH3/He was ionized and accelerated to poly-Si and c-Si substrates with a self bias of -220 V. The P concentration, as detected by secondary ion mass spectroscopy (SIMS), is ˜5×1021 cm-3 at the surface, which decayed to ˜1017 cm-3 within 50 100 nm depth. The surface is found to be etched during doping. The etching is restored by adding a small amount of SiH4 and the sheet resistance R s decreases. The optimized as-irradiated R s is ˜ 1× 105 Ω/\\Box and 1.7× 102 Ω/\\Box for poly-Si and (110) c-Si, respectively. The dependence of R s on the substrates and the anomalous diffusion constants derived from SIMS are also discussed.

  19. Silicon nitride and oxynitride film formation using electron cyclotron resonance plasmas

    SciTech Connect

    Barbour, J.C.

    1994-07-01

    Growth of dielectrics from electron cyclotron resonance (ECR) plasmas can provide for low-temperature surface passivation and gate-quality insulation. Properties of SiN{sub x} and SiN{sub x}O{sub y} were measured on three model substrates: Si, GaAs, and InSb. The hydrogen incorporated into as-grown SiN{sub x} was primarily bonded to nitrogen and the total H content decreased with increasing deposition temperature (100--600 C). A model for the thermal release of H from Si-H bonds and two types of N-H bonds described the energetics of the H stability. A thermally-grown SiO{sub 2} layer improved the interface between ECR-deposited SiN{sub x} and Si, yielding an interface-state density of 1.5 {times} 10{sup 11} cm{sup {minus}2} eV{sup {minus}1} (midgap). The thermal release of H from SiN{sub x} on GaAs passivated non-radiative recombination centers. The difference in adhesion of Si{sub 3}N{sub 4} on InSb and the adhesion of Si{sub 3}ON{sub 2} on InSb was described in terms of the strength of the bonding at the dielectric-InSb interface, and the room-temperature growth of a high-quality dielectric on InSb was demonstrated.

  20. Improved charge breeding efficiency of light ions with an electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Vondrasek, R.; Delahaye, P.; Kutsaev, Sergey; Maunoury, L.

    2012-11-01

    The Californium Rare Isotope Breeder Upgrade is a new radioactive beam facility for the Argonne Tandem Linac Accelerator System (ATLAS). The facility utilizes a 252Cf fission source coupled with an electron cyclotron resonance ion source to provide radioactive beam species for the ATLAS experimental program. The californium fission fragment distribution provides nuclei in the mid-mass range which are difficult to extract from production targets using the isotope separation on line technique and are not well populated by low-energy fission of uranium. To date the charge breeding program has focused on optimizing these mid-mass beams, achieving high charge breeding efficiencies of both gaseous and solid species including 14.7% for the radioactive species 143Ba27+. In an effort to better understand the charge breeding mechanism, we have recently focused on the low-mass species sodium and potassium which up to present have been difficult to charge breed efficiently. Unprecedented charge breeding efficiencies of 10.1% for 23Na7+ and 17.9% for 39K10+ were obtained injecting stable Na+ and K+ beams from a surface ionization source.