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A. V. Melnikov - One of the best experts on this subject based on the ideXlab platform.

  • The Heavy Ion Beam Probe Diagnostic and ApplicatIons
    Springer Series in Plasma Science and Technology, 2019
    Co-Authors: A. V. Melnikov
    Abstract:

    This chapter gives a detailed descriptIon of the Heavy Ion Beam probe diagnostic together with important applicatIons of this technique on the tokamaks TM-4, T-10 and the stellarator TJ-II.

  • internal measurements of alfven eigenmodes with Heavy Ion Beam probing in toroidal plasmas
    Nuclear Fusion, 2010
    Co-Authors: A. V. Melnikov, A. D. Komarov, A. S. Kozachok, A.a. Chmyga, L G Eliseev, R Jimenezgomez, E Ascasibar, C Hidalgo, I A Krasilnikov, S. M. Khrebtov
    Abstract:

    Energetic Ion driven Alfven eigenmodes (AEs) are believed to be an important element disturbing the transport in a future fusIon reactor. The studies of the AE properties in modern toroidal devices have made crucial contributIons to the reactor relevant physics. AEs are conventIonally studied by magnetic probes (MPs), which provide the poloidal m and toroidal n mode numbers and their spectral characteristics. Heavy Ion Beam probing (HIBP) has become a new tool to study AEs with high spatial and frequency resolutIon. HIBP in the TJ-II heliac observes locally (~1 cm) resolved AEs over the whole radial interval. The set of low-m (m < 8) modes, detected with the high-frequency resolutIon (<5 kHz), present different types of AEs. AEs are pronounced in the local density, electric potential and poloidal magnetic field oscillatIons, detected simultaneously by HIBP in the frequency range 50 kHz < fAE < 300 kHz. Various AE modes are visible in the neutral Beam injector (NBI)-heated plasma for co-NBI (<450 kW), counter- (<450 kW) and balanced NBI (<900 kW) from the plasma centre to the edge. A high coherence between MP and HIBP data was found for specific AEs. When the density rises, AE frequency decreases, , and the cross-phase between the plasma density, poloidal magnetic field and potential remains constant. The amplitude of the AE potential oscillatIons δAE ~ 10 V was estimated. Poloidally resolved density and potential measurements may provide informatIon about the AE poloidal wavelength and the AE contributIon to the poloidal electric field Epol and the turbulent particle flux ΓE×B. The typical range of Epol oscillatIons for AEs is . Depending on the δne and δEpol amplitudes and cross-phase, AEs may make a small or a significant contributIon to the turbulent particle flux ΓE×B for the observed wavenumbers kθ < 3 cm−1.

  • The Heavy Ion Beam Probing Development for WEGA Stellarator
    Fusion Science and Technology, 2006
    Co-Authors: L.i. Krupnik, A. V. Melnikov, A. D. Komarov, G. N. Deshko, A. I. Zhezhera, A.a. Chmyga, A.s. Kozachek, S. V. Perfilov, Matthias Otte, M. Schubert
    Abstract:

    A conceptual design for a Heavy Ion Beam probe diagnostic for the stellarator WEGA in Greifswald (Germany) is developed to provide measurements of the radial profiles of the electric plasma potential, density, and their fluctuatIons. CalculatIons of probing Na + Beam trajectories were done for the various WEGA diagnostics ports with B 0 from 0.087 to 0.5 T. They show that satisfactory access may be possible for C+ C- port combinatIons.

  • investigatIon of the plasma potential oscillatIons in the range of geodesic acoustic mode frequencies by Heavy Ion Beam probing in tokamaks
    Czechoslovak Journal of Physics, 2005
    Co-Authors: A. V. Melnikov, L.i. Krupnik, S. V. Perfilov, L G Eliseev, A Gudozhnik, S E Lysenko, V Mavrin, M Ufimtsev, L Zimeleva, P.m. Schoch
    Abstract:

    Specific oscillatIons within a range of 20 kHz (“20 kHz-mode”) were investigated on the T-10 and TEXT tokamaks using Heavy Ion Beam Probe (HIBP) diagnostic. Regimes with ohmic heating on both machines, and with off-axis ECRH in T-10 were studied. It was shown that “20 kHz-modes are mainly the potential oscillatIons. The power spectrum of the oscillatIons has the form of a solitary quasi-monochromatic peak with a contrast range of (3–5). They are the manifestatIon of torsIonal plasma oscillatIons with poloidal wavenumber m = 0, called zonal flows. It was shown that in TEXT the radial electric field oscillatIons exist in a limited radial range of 0.65 > ρ < 0.95. The frequency of “20 kHz-mode” is varied in the regIon of observatIon; it diminishes to the plasma edge. In T-10, after ECRH switch-on, the frequency increases, correlating with the growth of the electron temperature Te. In both machines the frequency of the “20 kHz-mode” varies with local Te: f ∼ Te1/2, which is consistent with theoretical scaling for geodesic acoustic modes (GAM): fGAM ∼ cs/R ∼ Te1/2, where cs is the speed of sound. The absolute frequencies are close to GAM values within a factor of unity.

  • The Heavy Ion Beam Diagnostic Project for the TCV Tokamak
    21st IEEE NPS Symposium on Fusion Engineering SOFE 05, 2005
    Co-Authors: M.r. Siegrist, A. V. Melnikov, L.i. Krupnik, S. V. Perfilov, G. Tonetti, H. Weisen, I.d. Karpushov
    Abstract:

    The conceptual design for a Heavy Ion Beam probe diagnostic for the TCV tokamak in Lausanne is presented. This technique will be used for electric potential measurements in the core plasma and for the determinatIon of the magnetic potential. This combinatIon is of crucial importance for the understanding of the physics of improved confinement in toroidal facilities

S. M. Khrebtov - One of the best experts on this subject based on the ideXlab platform.

  • internal measurements of alfven eigenmodes with Heavy Ion Beam probing in toroidal plasmas
    Nuclear Fusion, 2010
    Co-Authors: A. V. Melnikov, A. D. Komarov, A. S. Kozachok, A.a. Chmyga, L G Eliseev, R Jimenezgomez, E Ascasibar, C Hidalgo, I A Krasilnikov, S. M. Khrebtov
    Abstract:

    Energetic Ion driven Alfven eigenmodes (AEs) are believed to be an important element disturbing the transport in a future fusIon reactor. The studies of the AE properties in modern toroidal devices have made crucial contributIons to the reactor relevant physics. AEs are conventIonally studied by magnetic probes (MPs), which provide the poloidal m and toroidal n mode numbers and their spectral characteristics. Heavy Ion Beam probing (HIBP) has become a new tool to study AEs with high spatial and frequency resolutIon. HIBP in the TJ-II heliac observes locally (~1 cm) resolved AEs over the whole radial interval. The set of low-m (m < 8) modes, detected with the high-frequency resolutIon (<5 kHz), present different types of AEs. AEs are pronounced in the local density, electric potential and poloidal magnetic field oscillatIons, detected simultaneously by HIBP in the frequency range 50 kHz < fAE < 300 kHz. Various AE modes are visible in the neutral Beam injector (NBI)-heated plasma for co-NBI (<450 kW), counter- (<450 kW) and balanced NBI (<900 kW) from the plasma centre to the edge. A high coherence between MP and HIBP data was found for specific AEs. When the density rises, AE frequency decreases, , and the cross-phase between the plasma density, poloidal magnetic field and potential remains constant. The amplitude of the AE potential oscillatIons δAE ~ 10 V was estimated. Poloidally resolved density and potential measurements may provide informatIon about the AE poloidal wavelength and the AE contributIon to the poloidal electric field Epol and the turbulent particle flux ΓE×B. The typical range of Epol oscillatIons for AEs is . Depending on the δne and δEpol amplitudes and cross-phase, AEs may make a small or a significant contributIon to the turbulent particle flux ΓE×B for the observed wavenumbers kθ < 3 cm−1.

  • InstallatIon of an advanced Heavy Ion Beam diagnostic on the TJ-II stellarator
    Review of Scientific Instruments, 2001
    Co-Authors: I.s. Bondarenko, L.i. Krupnik, A. A. Chmuga, N. B. Dreval, S. M. Khrebtov, A. D. Komarov, A. S. Kozachok, P. Coelho, M. Cunha, Bruno Gonçalves
    Abstract:

    An advanced 200 keV Heavy Ion Beam diagnostic has been developed for the TJ-II stellarator based on the simultaneous utilizatIon of a 30° Proca–Green electrostatic energy analyzer and a multiple cell array detector. This innovative design allows instantaneous measurements of plasma potential and electron density profiles together with their respective fluctuatIons. In this article we present a descriptIon of the main parts of a Heavy Ion Beam diagnostic (injectIon system, detectors, and control and data acquisitIon system) and the results obtained during the first operatIon on TJ-II. The problems of plasma loading of the detectors and hard x-ray generatIon associated with the probing Beam are reported.

  • InstallatIon of the advanced Heavy Ion Beam probing diagnostic on the TJ-II stellarator
    Czechoslovak Journal of Physics, 2000
    Co-Authors: I.s. Bondarenko, A. V. Melnikov, L.i. Krupnik, N. B. Dreval, S. M. Khrebtov, A. D. Komarov, A. S. Kozachok, A.a. Chmyga, O. A. Yudina, P. Coelho
    Abstract:

    An advanced Heavy Ion Beam diagnostic has been developed for the TJ-II stellarator based on the simultaneous utilisatIon of two different detectIon systems for the secondary Ions: a multiple cell array detector and a 30° Proca-Green electrostatic energy analyser. This innovative design aims at enlarging the HIBD capabilities to allow the instanteneous measurements of electron density and plasma potential profiles together with their respective fluctuatIons. This paper presents the detailed descriptIon of the main parts of HIBD and their characteristics obtained during the first operatIon on TJ-II. Special attentIon is paid to the control and data acquisitIon system built on two VME controllers. The results of the diagnostic Beam propagating through the magnetic structure of TJ-II into electrostatic energy analyser are presented and compared with the trajectory calculatIons. The operatIon and calibratIon of a 30° electrostatic energy analyser free of guard rings and with a new biased split detector are described. High intensities of the caesium and thallium Ions was obtained from thermIonic source using new stable and long-time special operatIon regimes.

Y. Hamada - One of the best experts on this subject based on the ideXlab platform.

  • 2d potential measurements by applying automatic Beam adjustment system to Heavy Ion Beam probe diagnostic on the large helical device
    Review of Scientific Instruments, 2014
    Co-Authors: A Shimizu, S. Kato, A Nishizawa, T Ido, M Nishiura, M Kurachi, R Makino, Y. Hamada
    Abstract:

    Two-dimensIonal potential profiles in the Large Helical Device (LHD) were measured with Heavy Ion Beam probe (HIBP). To measure the two-dimensIonal profile, the probe Beam energy has to be changed. However, this task is not easy, because the Beam transport line of LHD-HIBP system is very long (∼20 m), and the required Beam adjustment consumes much time. To reduce the probe Beam energy adjustment time, an automatic Beam adjustment system has been developed. Using this system, required time to change the probe Beam energy is dramatically reduced, such that two-dimensIonal potential profiles were able to be successfully measured with HIBP by changing the probe Beam energy shot to shot.

  • 6 mev Heavy Ion Beam probe on the large helical device
    Review of Scientific Instruments, 2006
    Co-Authors: Takeshi Ido, Akihiro Shimizu, Masaki Nishiura, A Nishizawa, S Katoh, K Tsukada, M Yokota, H Ogawa, T Inoue, Y. Hamada
    Abstract:

    A Heavy Ion Beam probe (HIBP) has been installed on the Large Helical Device (LHD). A MeV-range Beam is required for the LHD-HIBP. The probing Beam is accelerated up to 6 MeV by use of a tandem accelerator. A new energy analyzer with tandem electrodes has also been developed to analyze such a high energy Beam. As a result, a secondary Beam can be detected and its energy successfully analyzed. It is verified, in principle, that the potential profile can be measured using the HIBP.

  • optimizatIon of negative Ion sources for a Heavy Ion Beam probe
    Review of Scientific Instruments, 2006
    Co-Authors: Masaki Nishiura, Y. Hamada, Akihiro Shimizu, S. Kato, A Nishizawa, K Tsukada, Y Matsumoto, Alexander Mendenilla, M Wada
    Abstract:

    The development of plasma-sputter-type negative Ion sources is underway for the Heavy-Ion-Beam probe system as plasma diagnostic Beams of the large helical device (LHD) for potential and fluctuatIon field measurements. Our purpose is to increase the doubly charged exchanged Au+ Beam intensity to enhance the detectIon signal after passing through the plasmas of the LHD. For this purpose, the characterizatIon of the Au− Ion source and the Beam optics has been carried out both experimentally and numerically. Based on these results, a new plasma-sputter-type negative Ion source is designed and tested.

  • observatIon of the fast potential change at l h transitIon by a Heavy Ion Beam probe on jft 2m
    Physical Review Letters, 2002
    Co-Authors: Takeshi Ido, Y. Hamada, A Nishizawa, K Kamiya, Y Miura, Y Kawasumi
    Abstract:

    The fast potential change near the separatrix is measured directly at the L-H transitIon by a Heavy-Ion-Beam probe. The potential changes with two different time scales at the L-H transitIon triggered by a sawtooth crash: it drops at first with the time scale of 10--100 mus just after the arrival of the heat pulse due to the sawtooth crash. Then, it decreases again at a few 100 mus after the first drop at a time scale of about 200 mus.

  • consideratIon of fluctuatIon in secondary Beam intensity of Heavy Ion Beam probe measurements
    Review of Scientific Instruments, 1997
    Co-Authors: A Fujisawa, H. Iguchi, Y. Hamada
    Abstract:

    Heavy Ion Beam probes have the capability to detect the local fluctuatIon of density in the interior of plasmas through the fluctuatIon of the intensity of the detected Beam. However, this intensity fluctuatIon may suffer from a certain degree of distortIon from fluctuatIons of electron density and temperature along the Beam trajectory; as a result, the fluctuatIon signal may be quite different from the local density fluctuatIon. This article presents the conditIons where the intensity fluctuatIon can be regarded as being local fluctuatIon of electron density, where it cannot, and discusses the contaminatIon of the fluctuatIons by fluctuatIons along the trajectory, particularly in the case of magnetohydrodynamics fluctuatIons.

M Roth - One of the best experts on this subject based on the ideXlab platform.

  • role of charge transfer in Heavy Ion Beam plasma interactIons at intermediate energies
    Physical Review E, 2015
    Co-Authors: A Ortner, A Frank, A Blaževic, M Roth
    Abstract:

    : In this paper we investigate the influence of the plasma properties on the charge state distributIon of a swift Heavy Ion Beam interacting with a plasma. The main finding is that the charge state in plasma can be lower than in cold matter. The charge state distributIon is determined by the IonizatIon and recombinatIon rates which are balancing each other out. Both, IonizatIon and recombinatIon rates, as well as atomic excitatIon and decay rates, depend on the plasma parameters in different ways. These effects have been theoretically studied by Monte Carlo simulatIons on the example of an argon Ion Beam at an energy of 4MeV/u in a carbon plasma. This study covers a plasma parameter space ranging from Ion densities from 10(18) to 10(23) cm(-3) and electron temperatures from 10 to 200 eV.

  • metallizatIon of hydrogen using Heavy Ion Beam implosIon of multilayered cylindrical targets
    Physical Review E, 2000
    Co-Authors: N.a. Tahir, D Hoffmann, A Kozyreva, A Tauschwitz, A Shutov, J A Maruhn, P Spiller, U Neuner, J Jacoby, M Roth
    Abstract:

    Employing a two-dimensIonal simulatIon model, this paper presents a suitable design for an experiment to study metallizatIon of hydrogen in a Heavy-Ion Beam imploded multilayered cylindrical target that contains a layer of frozen hydrogen. Such an experiment will be carried out at the upgraded Heavy-Ion synchrotron facility (SIS-18) at the Gesellschaft f\"ur SchwerIonenforschung, Darmstadt by the end of the year 2001. In these calculatIons we consider a uranium Beam that will be available at the upgraded SIS-18. Our calculatIons show that it may be possible to achieve theoretically predicted physical conditIons necessary to create metallic hydrogen in such experiments. These include a density of about 1 ${\mathrm{g}/\mathrm{c}\mathrm{m}}^{3}$, a pressure of 3\char21{}5 Mbar, and a temperature of a few 0.1 eV.

Tomoko Abe - One of the best experts on this subject based on the ideXlab platform.

  • comprehensive identificatIon of mutatIons induced by Heavy Ion Beam irradiatIon in arabidopsis thaliana
    Plant Journal, 2015
    Co-Authors: Tomonari Hirano, Yusuke Kazama, Kotaro Ishii, Sumie Ohbu, Yuki Shirakawa, Tomoko Abe
    Abstract:

    Summary Heavy-Ion Beams are widely used for mutatIon breeding and molecular biology. Although the mutagenic effects of Heavy-Ion Beam irradiatIon have been characterized by sequence analysis of some restricted chromosomal regIons or loci, there have been no evaluatIons at the whole-genome level or of the detailed genomic rearrangements in the mutant genomes. In this study, using array comparative genomic hybridizatIon (array-CGH) and resequencing, we comprehensively characterized the mutatIons in Arabidopsis thaliana genomes irradiated with Ar or Fe Ions. We subsequently used this informatIon to investigate the mutagenic effects of the Heavy-Ion Beams. Array-CGH demonstrated that the average number of deleted areas per genome were 1.9 and 3.7 following Ar-Ion and Fe-Ion irradiatIon, respectively, with deletIon sizes ranging from 149 to 602 180 bp; 81% of the deletIons were accompanied by genomic rearrangements. To provide a further detailed analysis, the genomes of the mutants induced by Ar-Ion Beam irradiatIon were resequenced, and total mutatIons, including base substitutIons, duplicatIons, in/dels, inversIons, and translocatIons, were detected using three algorithms. All three resequenced mutants had genomic rearrangements. Of the 22 DNA fragments that contributed to the rearrangements, 19 fragments were responsible for the intrachromosomal rearrangements, and multiple rearrangements were formed in the localized regIons of the chromosomes. The interchromosomal rearrangements were detected in the multiply rearranged regIons. These results indicate that the Heavy-Ion Beams led to clustered DNA damage in the chromosome, and that they have great potential to induce complicated intrachromosomal rearrangements. Heavy-Ion Beams will prove useful as unique mutagens for plant breeding and the establishment of mutant lines.

  • Comprehensive identificatIon of mutatIons induced by Heavy‐Ion Beam irradiatIon in Arabidopsis thaliana
    The Plant journal : for cell and molecular biology, 2015
    Co-Authors: Tomonari Hirano, Yusuke Kazama, Kotaro Ishii, Sumie Ohbu, Yuki Shirakawa, Tomoko Abe
    Abstract:

    Summary Heavy-Ion Beams are widely used for mutatIon breeding and molecular biology. Although the mutagenic effects of Heavy-Ion Beam irradiatIon have been characterized by sequence analysis of some restricted chromosomal regIons or loci, there have been no evaluatIons at the whole-genome level or of the detailed genomic rearrangements in the mutant genomes. In this study, using array comparative genomic hybridizatIon (array-CGH) and resequencing, we comprehensively characterized the mutatIons in Arabidopsis thaliana genomes irradiated with Ar or Fe Ions. We subsequently used this informatIon to investigate the mutagenic effects of the Heavy-Ion Beams. Array-CGH demonstrated that the average number of deleted areas per genome were 1.9 and 3.7 following Ar-Ion and Fe-Ion irradiatIon, respectively, with deletIon sizes ranging from 149 to 602 180 bp; 81% of the deletIons were accompanied by genomic rearrangements. To provide a further detailed analysis, the genomes of the mutants induced by Ar-Ion Beam irradiatIon were resequenced, and total mutatIons, including base substitutIons, duplicatIons, in/dels, inversIons, and translocatIons, were detected using three algorithms. All three resequenced mutants had genomic rearrangements. Of the 22 DNA fragments that contributed to the rearrangements, 19 fragments were responsible for the intrachromosomal rearrangements, and multiple rearrangements were formed in the localized regIons of the chromosomes. The interchromosomal rearrangements were detected in the multiply rearranged regIons. These results indicate that the Heavy-Ion Beams led to clustered DNA damage in the chromosome, and that they have great potential to induce complicated intrachromosomal rearrangements. Heavy-Ion Beams will prove useful as unique mutagens for plant breeding and the establishment of mutant lines.

  • Heavy-Ion Beam irradiatIon is an effective technique for reducing major allergens in peanut seeds
    Molecular Breeding, 2011
    Co-Authors: Cerrone Cabanos, Tomoko Abe, Hiroki Katayama, Hiroyuki Urabe, Chikara Kuwata, Yuri Murota, Yutaka Okumoto, Nobuyuki Maruyama
    Abstract:

    Heavy-Ion Beam irradiatIon is an effective technique for mutatIon breeding to produce new cultivars. Heavy-Ion Beams have high linear energy transfer capable of breaking the double-stranded DNA molecules, thus inducing stable knockout mutants. Here, we report the first applicatIon of this technology to produce hypoallergenic peanut lacking major allergens, Ara h 2 and 3, from the Japanese Nakateyutaka variety. After irradiatIon with either N or C Heavy-Ion Beams at a dose of 100 Gy, seventeen knockout mutants from 11,335 screened M2 seeds were obtained, eight of which lacked either one of the two isoforms of Ara h 2, and the other nine lacked one of the isoforms of Ara h 3. This result indicates that Heavy-Ion Beam irradiatIon is a powerful means of producing knockout hypoallergenic peanuts.

  • inductIon and isolatIon of pigmentatIon mutants of porphyra yezoensis bangiales rhodophyta by Heavy Ion Beam irradiatIon
    Phycological Research, 2009
    Co-Authors: Kyosuke Niwa, Yoriko Hayashi, Tomoko Abe, Yusho Aruga
    Abstract:

    SUMMARY The present study describes the isolatIon of pigmentatIon mutants of Porphyra yezoensis Ueda induced by Heavy-Ion Beam irradiatIon for the first time. The gametophytic blades were irradiated with 12C+6 Ion Beams within a dose range of 25–400 Gy. From the survival rate and cell growth of the irradiated blades, it is suggested that a dose of 150 Gy or less is suitable to induce mutatIon for the isolatIon of mutants of P. yezoensis. After irradiatIon, red, green and deep reddish brown-colored gametophytic blades developed from archeospores that were released from each of the mutated cell clusters of the respective different colors, and the red mutant strain (IBY-R1) and green mutant strain (IBY-G1) were established as a conchocelis colony in culture. Blades of the mutants were characterized by their growth and photosynthetic pigment contents compared with those of the wild-type. From these results, it is clear that Heavy-Ion Beam mutagenesis will be an effective tool for genetic and breeding studies of Porphyra, and also for other algal research.

  • let dependent effects of Heavy Ion Beam irradiatIon in arabidopsis thaliana
    Plant Biotechnology, 2008
    Co-Authors: Yusuke Kazama, Hiromichi Ryuto, Hiroyuki Ichida, Yoriko Hayashi, Nobuhisa Fukunishi, Hiroyuki Saito, Yoshiharu Y Yamamoto, Tomoko Abe
    Abstract:

    We irradiated Arabidopsis thaliana with several kinds of Heavy-Ion Beams to investigate the linear energy transfer (LET)-dependent effects of Heavy-Ion Beam irradiatIon. First, dry seeds were irradiated with C, N, Ne, Ar, or Fe Ions at doses ranging from 5 to 400 Gy to compare the flowering and mutatIon rates among the Ion species. The sensitivity of the flowering and mutatIon rates to irradiatIon differed markedly among the Ion species. Of the Ion species, N (30 keV mm � 1 ) was the most effective at inducing albino plants. Second, we examined the effects of LET on mutatIon inductIon. The LET of C, N, Ne, and Ar Ion Beams was controlled at 30-640 keV mm � 1 . Regardless of Ion species, irradiatIon with the same LET value resulted in the same flowering rate and mutatIon rate. Thus, the LET of Ion Beams seems to be an important factor affecting mutagenesis. We found a 440-bp deletIon in the hy (elongated hypocotyl) mutant that was isolated from M2 progeny. These fundamental data on LET-dependence can be used to develop advanced technologies for plant mutagenesis.