Science.gov

Sample records for frequency cyclotron

  1. Resonant Plasma Heating Below the Cyclotron Frequency

    SciTech Connect

    Roscoe White; Liu Chen; Zhihong Lin

    2001-11-26

    Resonant heating of a magnetized plasma by low-frequency waves of large amplitude is considered. It is shown that the magnetic moment can be changed nonadiabatically by a single large amplitude wave, even at frequencies normally considered nonresonant. Two examples clearly demonstrate the existence of the resonances leading to chaos and the generic nature of heating below the cyclotron frequency. First, the classical case of an electrostatic wave of large amplitude propagating across a confining uniform magnetic field, and second, a large amplitude Alfvén wave, propagating obliquely across the magnetic field. Waves with frequencies a small fraction of the cyclotron frequency are shown to produce significant heating; bringing, in the case of Alfvén waves, particles to speeds comparable to the Alfvén velocity in a few hundred cyclotron periods. Stochastic threshold for heating occurs at significantly lower amplitude with a perturbation spectrum consisting of a number of modes. This phenomenon may have relevance for the heating of ions in the solar corona as well as for ion heating in some toroidal confinement fusion devices.

  2. Transparency of Magnetized Plasma at Cyclotron Frequency

    SciTech Connect

    G. Shvets; J.S. Wurtele

    2002-03-14

    Electromagnetic radiation is strongly absorbed by a magnetized plasma if the radiation frequency equals the cyclotron frequency of plasma electrons. It is demonstrated that absorption can be completely canceled in the presence of a magnetostatic field of an undulator or a second radiation beam, resulting in plasma transparency at the cyclotron frequency. This effect is reminiscent of the electromagnetically induced transparency (EIT) of the three-level atomic systems, except that it occurs in a completely classical plasma. Unlike the atomic systems, where all the excited levels required for EIT exist in each atom, this classical EIT requires the excitation of the nonlocal plasma oscillation. The complexity of the plasma system results in an index of refraction at the cyclotron frequency that differs from unity. Lagrangian description was used to elucidate the physics and enable numerical simulation of the plasma transparency and control of group and phase velocity. This control naturally leads to applications for electromagnetic pulse compression in the plasma and electron/ion acceleration.

  3. 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

  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. 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.

  6. Electrostatic hydrogen-cyclotron wave emission below the hydrogen-cyclotron frequency in the auroral acceleration region

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

    A mechanism is suggested for the excitation of electrostatic ion-cyclotron waves at frequencies below the ion-cyclotron frequency in the midst of the auroral acceleration region, which is assumed to consist of downward moving double layers. The mechanism involves upward flowing ions interacting with a downward flowing background plasma. The upward flowing ions are the ion beams accelerated by the double layer. The downward motion of the background plasma corresponds to a plasma expansion into the density cavity that develops in connection with double layer formation in the acceleration region. The ion-cyclotron waves excited by the counterstreaming flows are doppler shifted to frequencies below the harmonics of the ion cyclotron frequency. It is suggested that such wave emissions could account for some very narrow-banded waves at frequencies below the hydrogen cyclotron frequency that were observed by the S3-3 satellite.

  7. Heating by waves in the ion cyclotron frequency range

    SciTech Connect

    Koch, R.

    1996-03-01

    The main aspects of heating with the fast wave in the ion cyclotron range of frequencies (ICRF) are reviewed. First, the ion cyclotron resonance mechanism, fundamental and harmonics, is examined. Then the properties of fast wave dispersion are reviewed, and the principles of minority and higher cylcotron harmonic heating are discussed. An elementary coupling model is worked out in order to outline the computation of the electrical properties of ICRF antennas. Using the simple model, the antenna radiation pattern inside the plasma is computed and the effect of phasing on the k spectrum and on the antenna radiation properties is illustrated. The quasi linear-Fokker-Planck computation of the deformation of distribution functions due to Radio-Frequency (RF) and tail formation are briefly discussed. 11 refs., 5 figs.

  8. Electromagnetic cyclotron waves near the proton cyclotron frequency in the solar wind

    NASA Astrophysics Data System (ADS)

    Jian, Lan K.; Boardsen, Scott; Moya, Pablo; Stevens, Michael; Alexander, Robert; Vinas, Adolfo

    2015-04-01

    Strong narrow-band electromagnetic waves around the proton cyclotron frequency (fpc) have been found sporadically in the solar wind from 0.3 to 0.7 AU during MESSENGER spacecraft’s cruise phase. These waves are transverse and circularly polarized, and they propagate in directions quasi-parallel to the magnetic field. The wave power decreases quadratically with heliocentric distance, faster than the trend if assuming the conservation of Poynting flux for wave packets, suggesting there is energy dissipation from the waves, which could contribute to the heating and acceleration of solar wind plasma. Although the wave frequency is a few times of fpc in the spacecraft frame, it is a fraction of fpc in the solar wind plasma frame after removing the Doppler shift effect. In this frequency range, the waves can be left-hand (LH) polarized ion cyclotron waves or right-hand (RH) polarized magnetosonic waves. Because the waves are LH or RH polarized in the spacecraft frame with otherwise nearly identical characteristics, they could be due to Doppler shift of a same type of waves or a mixture of waves with intrinsically different polarizations. Through the assistance of audification, we have studied the long-lasting wave events in 2005 using high-cadence magnetic field data from the Wind mission. Statistically, in contrast with general solar wind, the protons at these waves are distributed closer to the proton instability thresholds, while the alpha particles at these waves are distributed further away from the alpha instability thresholds. For selected events of extensive waves, the ion distribution is analyzed in detail. A mixture of temperature anisotropies for core protons, beam protons, and alpha particles, as well as proton beam drift are often found in such events. We conduct linear wave dispersion analysis using these ion moments to examine whether these waves can be explained by the local generation of kinetic instabilities such as the LH ion cyclotron, the RH

  9. 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.

  10. Electromagnetic Waves near the Proton Cyclotron Frequency: STEREO Observations

    NASA Astrophysics Data System (ADS)

    Jian, L. K.; Wei, H. Y.; Russell, C. T.; Luhmann, J. G.; Klecker, B.; Omidi, N.; Isenberg, P. A.; Goldstein, M. L.; Figueroa-Viñas, A.; Blanco-Cano, X.

    2014-05-01

    Transverse, near-circularly polarized, parallel-propagating electromagnetic waves around the proton cyclotron frequency were found sporadically in the solar wind throughout the inner heliosphere. They could play an important role in heating and accelerating the solar wind. These low-frequency waves (LFWs) are intermittent but often occur in prolonged bursts lasting over 10 minutes, named "LFW storms." Through a comprehensive survey of them from Solar Terrestrial Relations Observatory A using dynamic spectral wave analysis, we have identified 241 LFW storms in 2008, present 0.9% of the time. They are left-hand (LH) or right-hand (RH) polarized in the spacecraft frame with similar characteristics, probably due to Doppler shift of the same type of waves or waves of intrinsically different polarities. In rare cases, the opposite polarities are observed closely in time or even simultaneously. Having ruled out interplanetary coronal mass ejections, shocks, energetic particles, comets, planets, and interstellar ions as LFW sources, we discuss the remaining generation scenarios: LH ion cyclotron instability driven by greater perpendicular temperature than parallel temperature or by ring-beam distribution, and RH ion fire hose instability driven by inverse temperature anisotropy or by cool ion beams. The investigation of solar wind conditions is compromised by the bias of the one-dimensional Maxwellian fit used for plasma data calibration. However, the LFW storms are preferentially detected in rarefaction regions following fast winds and when the magnetic field is radial. This preference may be related to the ion cyclotron anisotropy instability in fast wind and the minimum in damping along the radial field.

  11. Electromagnetic waves near the proton cyclotron frequency: Stereo observations

    SciTech Connect

    Jian, L. K.; Wei, H. Y.; Russell, C. T.; Luhmann, J. G.; Klecker, B.; Omidi, N.; Isenberg, P. A.; Goldstein, M. L.; Figueroa-Viñas, A.; Blanco-Cano, X.

    2014-05-10

    Transverse, near-circularly polarized, parallel-propagating electromagnetic waves around the proton cyclotron frequency were found sporadically in the solar wind throughout the inner heliosphere. They could play an important role in heating and accelerating the solar wind. These low-frequency waves (LFWs) are intermittent but often occur in prolonged bursts lasting over 10 minutes, named 'LFW storms'. Through a comprehensive survey of them from Solar Terrestrial Relations Observatory A using dynamic spectral wave analysis, we have identified 241 LFW storms in 2008, present 0.9% of the time. They are left-hand (LH) or right-hand (RH) polarized in the spacecraft frame with similar characteristics, probably due to Doppler shift of the same type of waves or waves of intrinsically different polarities. In rare cases, the opposite polarities are observed closely in time or even simultaneously. Having ruled out interplanetary coronal mass ejections, shocks, energetic particles, comets, planets, and interstellar ions as LFW sources, we discuss the remaining generation scenarios: LH ion cyclotron instability driven by greater perpendicular temperature than parallel temperature or by ring-beam distribution, and RH ion fire hose instability driven by inverse temperature anisotropy or by cool ion beams. The investigation of solar wind conditions is compromised by the bias of the one-dimensional Maxwellian fit used for plasma data calibration. However, the LFW storms are preferentially detected in rarefaction regions following fast winds and when the magnetic field is radial. This preference may be related to the ion cyclotron anisotropy instability in fast wind and the minimum in damping along the radial field.

  12. Solar cycle dependence of ion cyclotron wave frequencies

    NASA Astrophysics Data System (ADS)

    Lessard, Marc R.; Lindgren, Erik A.; Engebretson, Mark J.; Weaver, Carol

    2015-06-01

    Electromagnetic ion cyclotron (EMIC) waves have been studied for decades, though remain a fundamentally important topic in heliospheric physics. The connection of EMIC waves to the scattering of energetic particles from Earth's radiation belts is one of many topics that motivate the need for a deeper understanding of characteristics and occurrence distributions of the waves. In this study, we show that EMIC wave frequencies, as observed at Halley Station in Antarctica from 2008 through 2012, increase by approximately 60% from a minimum in 2009 to the end of 2012. Assuming that these waves are excited in the vicinity of the plasmapause, the change in Kp in going from solar minimum to near solar maximum would drive increased plasmapause erosion, potentially shifting the generation region of the EMIC to lower L and resulting in the higher frequencies. A numerical estimate of the change in plasmapause location, however, implies that it is not enough to account for the shift in EMIC frequencies that are observed at Halley Station. Another possible explanation for the frequency shift, however, is that the relative density of heavier ions in the magnetosphere (that would be associated with increased solar activity) could account for the change in frequencies. In terms of effects on radiation belt dynamics, the shift to higher frequencies tends to mean that these waves will interact with less energetic electrons, although the details involved in this process are complex and depend on the specific plasma and gyrofrequencies of all populations, including electrons. In addition, the change in location of the generation region to lower L shells means that the waves will have access to higher number fluxes of resonant electrons. Finally, we show that a sunlit ionosphere can inhibit ground observations of EMIC waves with frequencies higher than ˜0.5 Hz and note that the effect likely has resulted in an underestimate of the solar-cycle-driven frequency changes described here.

  13. Precision phase control for the radio frequency system of K500 superconducting cyclotron at Variable Energy Cyclotron Centre, Kolkata.

    PubMed

    Som, Sumit; Ghosh, Surajit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Roy, Suprakash

    2013-11-01

    Variable Energy Cyclotron Centre (VECC) has commissioned K500 Superconducting cyclotron (SCC) based on MSU and Texas A&M university cyclotrons. The radio frequency (RF) system of SCC has been commissioned with the stringent requirement of various RF parameters. The three-phase RF system of Superconducting cyclotron has been developed in the frequency range 9-27 MHz with amplitude and phase stability of 100 ppm and ±0.1°, respectively. The phase control system has the option to change the relative phase difference between any two RF cavities and maintain the phase stability within ±0.1° during round-the-clock cyclotron operation. The said precision phase loop consists of both analogue In-phase∕Quadrature modulator to achieve faster response and also Direct Digital Synthesis based phase shifter to achieve wide dynamic range as well. This paper discusses detail insights into the various issues of phase control for the K500 SCC at VECC, Kolkata.

  14. Precision phase control for the radio frequency system of K500 superconducting cyclotron at Variable Energy Cyclotron Centre, Kolkata

    SciTech Connect

    Som, Sumit; Ghosh, Surajit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Roy, Suprakash

    2013-11-15

    Variable Energy Cyclotron Centre (VECC) has commissioned K500 Superconducting cyclotron (SCC) based on MSU and Texas A and M university cyclotrons. The radio frequency (RF) system of SCC has been commissioned with the stringent requirement of various RF parameters. The three-phase RF system of Superconducting cyclotron has been developed in the frequency range 9–27 MHz with amplitude and phase stability of 100 ppm and ±0.1°, respectively. The phase control system has the option to change the relative phase difference between any two RF cavities and maintain the phase stability within ±0.1° during round-the-clock cyclotron operation. The said precision phase loop consists of both analogue In-phase/Quadrature modulator to achieve faster response and also Direct Digital Synthesis based phase shifter to achieve wide dynamic range as well. This paper discusses detail insights into the various issues of phase control for the K500 SCC at VECC, Kolkata.

  15. 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.

  16. Absorption and emission of extraordinary-mode electromagnetic waves near cyclotron frequency in nonequilibrium plasmas

    NASA Technical Reports Server (NTRS)

    Wu, C. S.; Lin, C. S.; Wong, H. K.; Tsai, S. T.; Zhou, R. L.

    1981-01-01

    An investigation is presented of two cases: (1) weakly relativistic electrons with a loss-cone type distribution, and (2) electrons with a drift velocity parallel to the ambient magnetic field. Numerical computations are given for physical parameters close to those in the polar region of the earth magnetosphere and laboratory experiments, with attention to the fast extraordinary-mode radiation whose frequency is near that of the electron cyclotron frequency. The fast extraordinary mode can escape from a strong field region to the weaker field region and may therefore be measured outside the plasma. It is found that the X mode radiation can be amplified by means of a cyclotron maser effect when the electrons have a loss-cone distribution, and it is concluded that, when the electron energy is sufficiently high, the X mode cutoff frequency may be lower than the cyclotron frequency.

  17. Observation of upper drift modes in radio frequency produced magnetized plasmas with frequency above ion cyclotron frequency

    NASA Astrophysics Data System (ADS)

    Ghosh, Abhijit; Saha, S. K.; Chowdhury, S.; Janaki, M. S.

    2015-12-01

    In a RF produced magnetized argon plasma expanding into a larger expansion chamber, electrostatic modes propagating azimuthally in the direction of the electron diamagnetic drift and frequency greater than the ion cyclotron frequency are observed. In the radial direction, the mode amplitude peaks at a location where the radial density gradient is maximum. The modes are detected at axial locations up to 16 cm away from the entrance aperture. For fixed values of the neutral pressure and magnetic field, the mode frequency is found to be independent of the location at which it is measured. The modes exhibit drift wave characteristics revealing a radial structure with the azimuthal mode number m = 1 at the lower radial locations (r ˜ 3.0 cm) while the m = 2 mode is located in the outer region. Theoretical modeling using a local dispersion relation based on the fluid equations predicts destabilization of the modes with frequency greater than the ion-cyclotron frequency by electron-neutral collisions and exhibiting other drift wave features.

  18. Observation of upper drift modes in radio frequency produced magnetized plasmas with frequency above ion cyclotron frequency

    SciTech Connect

    Ghosh, Abhijit; Saha, S. K.; Chowdhury, S.; Janaki, M. S.

    2015-12-15

    In a RF produced magnetized argon plasma expanding into a larger expansion chamber, electrostatic modes propagating azimuthally in the direction of the electron diamagnetic drift and frequency greater than the ion cyclotron frequency are observed. In the radial direction, the mode amplitude peaks at a location where the radial density gradient is maximum. The modes are detected at axial locations up to 16 cm away from the entrance aperture. For fixed values of the neutral pressure and magnetic field, the mode frequency is found to be independent of the location at which it is measured. The modes exhibit drift wave characteristics revealing a radial structure with the azimuthal mode number m = 1 at the lower radial locations (r ∼ 3.0 cm) while the m = 2 mode is located in the outer region. Theoretical modeling using a local dispersion relation based on the fluid equations predicts destabilization of the modes with frequency greater than the ion-cyclotron frequency by electron-neutral collisions and exhibiting other drift wave features.

  19. 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.

  20. Comments on finite Larmor radius models for ion cyclotron range of frequencies heating in tokamaks

    SciTech Connect

    Phillips, C.K.; Wilson, J.R.; Hosea, J.C.; Majeski, R.; Smithe, D.N.

    1994-06-01

    The accuracy of standard finite Larmor radius (FLR) models for wave propagation in the ion cyclotron range of frequencies (ICRF) is compared against full hot plasma models. For multiple ion species plasmas, the FLR model is shown to predict the presence of a spurious second harmonic ion-ion type resonance between the second harmonic cyclotron layers of two ion species. It is shown explicitly here that the spurious resonance is an artifact of the FLR models and that no absorption occurs in the plasma as a result of this ``resonance.``

  1. Cyclotron mode frequencies and resonant absorption in multi-species ion plasmas

    SciTech Connect

    Affolter, M.; Anderegg, F.; Dubin, D. H. E.; Driscoll, C. F.

    2015-05-15

    Cyclotron mode frequencies are studied on trapped rigid-rotor multi-species ion plasmas. Collective effects and radial electric fields shift the mode frequencies away from the “bare” cyclotron frequencies 2πF{sub c}{sup (s)}≡(q{sub s}B/M{sub s}c) for each species s. These frequency shifts are measured on the distinct cyclotron modes (m=0,1, and 2) with cos(mθ) azimuthal dependence. We find that for radially uniform plasmas the frequency shifts corroborate a simple theory expression, in which collective effects enter only through the E × B rotation frequency f{sub E} and the species fraction δ{sub s}. The m = 1 center-of-mass mode is in agreement with a simple “clump” model. Additionally, ultra-cold ion plasmas exhibit centrifugal separation by mass, and additional frequency shifts are observed, in agreement with a more general theory.

  2. 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.

  3. Ion cyclotron range of frequencies heating of plasma with small impurity production

    DOEpatents

    Ohkawa, Tihiro

    1987-01-01

    Plasma including plasma ions is magnetically confined by a magnetic field. The plasma has a defined outer surface and is intersected by resonance surfaces of respective common ion cyclotron frequency of a predetermined species of plasma ions moving in the magnetic field. A radio frequency source provides radio frequency power at a radio frequency corresponding to the ion cyclotron frequency of the predetermined species of plasma ions moving in the field at a respective said resonance surface. RF launchers coupled to the radio frequency source radiate radio frequency energy at the resonance frequency onto the respective resonance surface within the plasma from a plurality of locations located outside the plasma at such respective distances from the intersections of the respective resonance surface and the defined outer surface and at such relative phases that the resulting interference pattern provides substantially null net radio frequency energy over regions near and including substantial portions of the intersections relative to the radio frequency energy provided thereby at other portions of the respective resonance surface within the plasma.

  4. Oscillating two stream instability of electromagnetic pump in the ion cyclotron range of frequency in a plasma

    SciTech Connect

    Ahmad, Nafis; Tripathi, V. K.; Rafat, M.; Husain, Mudassir M.

    2009-06-15

    An analytical formalism of oscillating two stream instability of a large amplitude electromagnetic wave in the ion cyclotron range of frequency in a plasma is developed. The instability produces electrostatic ion cyclotron sidebands and a driven low frequency mode. The nonlinear coupling arises primarily due to the motion of ions and is strong when the pump frequency is close to ion cyclotron frequency and the oscillatory ion velocity is a significant fraction of acoustic speed. For propagation perpendicular to the ambient magnetic field, the X-mode pump wave produces flute type perturbation with maximum growth rate at some specific wavelengths, which are three to four times larger than the ion Larmor radius. For propagation at oblique angles to ambient magnetic field, the ion cyclotron O-mode, the growth rate increases with the wave number of the low frequency mode.

  5. 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.

  6. HIGH FREQUENCY POWER TRANSMISSION LINE FOR CYCLOTRONS AND THE LIKE

    DOEpatents

    Armstrong, W.J.

    1954-04-20

    High-frequency power transmission systems, particularly a stacked capacitance alternating power current transmission line wherein maximum utilization of the effective conductios skin of the line conductors is achieved while enabling a low impedance to be obtained are reported. The transmission line consists of a number of flat metal strips with interleaved dielectric strips. The metal dielectric strips are coiled spirally with the axis of the spiral extending along the length of the strips, and the alternating metal strips at the output end have outwardly extending aligned lugs which are directly strapped together and connected to the respective terminals on the load. At the input end of the transmission line, similarly, the alternate metal strips are directly strapped together and connected to an altereating current source. With the arrangement described each metal strip conducts on both sides, so that the metal strips are designed to have a thickness corresponding to twice the depth of the "skin effect" conducting lamina of each conductor at the source frequency.

  7. Frequency shifts and modulation effects due to solenoidal magnetic field inhomogeneities in ion cyclotron mass spectrometry

    NASA Astrophysics Data System (ADS)

    Mitchell, Dale W.; Rockwood, Alan L.; Smith, Richard D.

    1995-02-01

    Solenoidal (i.e. axially symmetric) magnetic field inhomogeneities, which in addition have symmetry under the operation z --> -z are the most important to Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometry since they introduce frequency shifts at first-order in perturbation theory. Frequency shifts for all three fundamental modes are derived for the leading second-order and fourth-order solenoidal inhomogeneities without any restrictions on the initial conditions. The analytical frequency shifts agree very well with frequency shifts obtained from numerical trajectory calculations using the exact classical equations of motion. The effect of the inhomogeneity on the ion trajectory is solved analytically. For a strong magnetic bottle field, the cyclotron motion is frequency modulated at twice the z-oscillation frequency resulting in sidebands. However, the amplitude of these sidebands is negligibly small for typical inhomogeneity strengths. The effect of a magnetized ICR trap on the homogeneity of the magnetic field is studied by analytical methods. We find that the leading magnetic bottle field decreases as d-3, where d is the cylindrical ion trap diameter.

  8. Theoretical analysis of the EAST 4-strap ion cyclotron range of frequency antenna with variational theory

    NASA Astrophysics Data System (ADS)

    Zhang, Jia-Hui; Zhang, Xin-Jun; Zhao, Yan-Ping; Qin, Cheng-Ming; Chen, Zhao; Yang, Lei; Wang, Jian-Hua

    2016-08-01

    A variational principle code which can calculate self-consistently currents on the conductors is used to assess the coupling characteristic of the EAST 4-strap ion cyclotron range of frequency (ICRF) antenna. Taking into account two layers of antenna conductors without lateral frame but with slab geometry, the antenna impedances as a function of frequency and the structure of RF field excited inside the plasma in various phasing cases are discussed in this paper. Project supported by the National Magnetic Confinement Fusion Science Program, China (Grant No. 2015GB101001) and the National Natural Science Foundation of China (Grant Nos. 11375236 and 11375235).

  9. Theoretical analysis of the EAST 4-strap ion cyclotron range of frequency antenna with variational theory

    NASA Astrophysics Data System (ADS)

    Zhang, Jia-Hui; Zhang, Xin-Jun; Zhao, Yan-Ping; Qin, Cheng-Ming; Chen, Zhao; Yang, Lei; Wang, Jian-Hua

    2016-08-01

    A variational principle code which can calculate self-consistently currents on the conductors is used to assess the coupling characteristic of the EAST 4-strap ion cyclotron range of frequency (ICRF) antenna. Taking into account two layers of antenna conductors without lateral frame but with slab geometry, the antenna impedances as a function of frequency and the structure of RF field excited inside the plasma in various phasing cases are discussed in this paper. Project supported by the National Magnetic Confinement Fusion Science Program, China (Grant No. 2015GB101001) and the National Natural Science Foundation of China (Grant Nos. 11375236 and 11375235).

  10. Low-distortion detection system for frequency-swept ion cyclotron resonance spectrometry

    SciTech Connect

    Wise, M.B.; Freiser, B.S.

    1986-07-01

    A high-performance frequency-swept capacitance bridge detector for ion cyclotron resonance (ICR) spectrometry has been constructed in our laboratory. Although the basic design of the system is similar to that of previously reported bridge circuits, careful design, layout, construction, and component selection have resulted in excellent frequency-swept performance over a bandwidth of 15 kHz to 1 MHz. At a magnetic field strength of 1.0 T, this corresponds to a mass range of 15--1000 Daltons. Problems with base-line drift and frequency-dependent signal distortion common to many other designs have been significantly reduced. Circuit diagrams are included for all parts of the detector and frequency response curves have been included where appropriate. In addition, several simple circuit diagrams for support devices have also been included.

  11. 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.

  12. Numerical analysis of radio-frequency sheath-plasma interactions in the ion cyclotron range of frequencies

    SciTech Connect

    Kohno, H.; Myra, J. R.; D'Ippolito, D. A.

    2012-01-15

    A new finite element numerical scheme for analyzing self-consistent radio-frequency (RF) sheath-plasma interaction problems in the ion cyclotron range of frequencies is applied to various problems represented by simplified models for the tokamak scrape-off layer. The present code incorporates a modified boundary condition, which is called a sheath boundary condition, that couples the radio-frequency waves and sheaths at the material boundaries by treating the sheath as a thin vacuum layer. A series of numerical analyses in one- and two-dimensional domains show several important physical properties, such as the existence of multiple roots, hysteresis effects, presence and characteristics of the sheath-plasma waves, and the phase shift of a reflected slow wave, some of which are newly identified by introducing a spatially varying plasma density and background magnetic field.

  13. 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.

  14. Ion heating in the ion cyclotron range of frequencies in the Wisconsin Tokapole II

    SciTech Connect

    Biddle, A. P.

    1980-06-01

    Ion temperatures of 75 eV, a doubling of the ohmic heating temperature in a normal discharge, have been achieved using the fast magnetosonic wave heating at the second, third, and fourth harmonics of the cyclotron frequency in a single component hydrogen plasma. The wave launching structure is a single turn, shielded, insulated loop which constitutes the inductor of the rf source tank circuit. Power levels of 800 kW have been applied to the plasma for periods of up to 1.1 milliseconds. Good agreement has been found between theory and experiment for loading and wave propagation in the plasma for m = 0 and m = +1 modes. Eigenmodes have been observed by peaking of both the rf wave amplitude and the loading of the oscillator, as well as by oscillator frequency shifts imposed by their passage.

  15. On radio frequency current drive in the ion cyclotron range of frequencies in DEMO and large ignited plasmas

    NASA Astrophysics Data System (ADS)

    Brambilla, Marco; Bilato, Roberto

    2015-02-01

    To explore the possibility of efficient fast wave current drive in an ignited plasma in the ion cyclotron (IC) range of frequency in spite of competition from absorption by ions, we have added to the full-wave toroidal code TORIC a set of subroutines which evaluate absorption by these particles at IC harmonic resonances, using a realistic ‘slowing-down’ distribution function, and taking into account that their Larmor radius is comparable or even larger than the fast wave wavelength. The thermalized population of α-particles is not a serious competitor for power absorption as long as their number density is compatible with maintenance of ignition. By contrast, the energetic slowing down fraction, in spite of its even greater dilution, can absorb from the waves a substantial amount of power at the cyclotron resonance and its harmonics. An extensive exploration both in frequency and in toroidal wavenumbers using the parameters of one of the European versions of DEMO shows that three frequency windows exist in which damping is nevertheless predominantly on the electrons. Designing an antenna capable of shaping the launched spectrum to optimize current drive, however, will not be straightforward. Only in a narrow range when the first IC harmonic of tritium is deep inside the plasma on the high-field side of the magnetic axis, and that of deuterium and helium is still outside on the low-field side, it appears possible to achieve a satisfactory current drive efficiency with a conventional multi-strap antenna, preferentially located in the upper part of the vessel. Exploiting the other two windows at quite low and quite high frequencies is either impossible on first principles, or will demand novel ideas in antenna design.

  16. Wave Heating in Ion Cyclotron Ranges of Frequencies in RT-1

    NASA Astrophysics Data System (ADS)

    Nishiura, M.; Yoshida, Z.; Yano, Y.; Kawazura, Y.; Mushiake, T.; Saitoh, H.; Yamasaki, M.; Kashyap, A.; Takahashi, N.; Nakatsuka, M.; Fukuyama, A.

    2015-11-01

    The magnetosphere plasma device RT-1 has been developed for the studies on magnetosphere and advanced fusion plasmas. A levitated superconducting coil produces magnetic dipole fields that realize a high confinement state. The electron cyclotron resonance heating (ECRH) with 8.2 GHz and 50 kW produces the plasmas with hot electrons in a few ten keV range. We reported that the local electron beta exceeded 1 in RT-1 plasmas. In such situation, the ions still remain cold at a few ten eV. Heating ions is expected to access high ion beta state and to improve the plasma confinement theoretically. Therefore the ion cyclotron range of frequencies (ICRF) heating with 2-4 MHz and 10 kW is being prepared in RT-1. Based on the results of the TASK-WF2 code, the ∩ shape loop antenna was designed for a slow wave excitation, and was implemented in the RT-1. In the ICRF heating experiments, a base plasma was sustained by ECRH. We observed the clear increase in diamagnetic signals and impurity ion temperature (CIII) in helium plasmas at the neutral gas pressure of 3 mPa, if the ICRF power of 10 kW is comparable to the ECRH one. This result is the first time in a magnetosphere plasma device. The results related to the ICRF heating will be presented in detail. JSPS KAKENHI Grant Nos 23224014 and 24360384.

  17. Discrete wave packets at the proton cyclotron frequency at Comet P/Halley

    NASA Astrophysics Data System (ADS)

    Mazelle, C.; Neubauer, F. M.

    1993-01-01

    We present the first experimental evidence for wave packets near the local proton cyclotron frequency in the plasma environment of a comet. The observations have been made by the Giotto magnetometer experiment around Comet P/Halley on both sides of closest approach. The waves are always left-handed in the spacecraft frame, elliptically or nearly circularly polarized, and propagate at small angles from the ambient magnetic field. Their period in the spacecraft frame always closely fits the local proton cyclotron period. The possible generation mechanisms of these waves are discussed. They can be consistently interpreted as waves generated by a resonant helical beam instability fed by the cometary pick-up protons. These waves are intrinsically right-handed waves in the plasma rest frame and are anomalously Doppler-shifted from the plasma frame to the spacecraft frame because their phase velocity is small compared to the local solar wind speed. A generation by a resonance with heavy (water group) ions introducing a temperature effect is also discussed but is less satisfactory.

  18. 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.

  19. Computational study of ion cyclotron frequency stabilization of the m = 1 interchange mode in mirror geometry

    SciTech Connect

    Myra, J.R.; D'Ippolito, D.A.; Francis, G.L.

    1987-01-01

    A cylindrical plasma model is used to study the stabilizing effect of electromagnetic ion cyclotron frequency range (ICRF) waves on the m = 1 magnetohydrodynamic interchange mode. The fast wave eigenmodes of the column and the near-field antenna pattern are calculated numerically for a diffuse plasma profile when ..omega..>..cap omega../sub i/. The resulting ponderomotive force and sideband contributions to global interchange stability are then determined using a rigid shift trial function. For far-field stabilization it is verified that the direct ponderomotive and sideband contributions cancel exactly as the conducting wall supporting the fast wave eigenmode moves out to infinity. The near-field stabilization effect is related numerically to the driven k/sub parallel/ spectrum of the waves and their radial profiles. The numerical model is employed to calculate threshold ICRF wave amplitudes for the stabilization experiments in the Phaedrus tandem mirror (Phys. Rev. Lett. 51, 1955 (1983)).

  20. Operation of the CAPRICE electron cyclotron resonance ion source applying frequency tuning and double frequency heating

    SciTech Connect

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

    2012-02-15

    The properties of the electromagnetic waves heating the electrons of the ECR ion sources (ECRIS) plasma affect the features of the extracted ion beams such as the emittance, the shape, and the current, in particular for higher charge states. The electron heating methods such as the frequency tuning effect and the double frequency heating are widely used for enhancing the performances of ECRIS or even for the routine operation during the beam production. In order to better investigate these effects the CAPRICE ECRIS has been operated using these techniques. The ion beam properties for highly charged ions have been measured with beam diagnostic tools. The reason of the observed variations of this performance can be related to the different electromagnetic field patterns, which are changing inside the plasma chamber when the frequency is varying.

  1. Operation of the CAPRICE electron cyclotron resonance ion source applying frequency tuning and double frequency heating.

    PubMed

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

    2012-02-01

    The properties of the electromagnetic waves heating the electrons of the ECR ion sources (ECRIS) plasma affect the features of the extracted ion beams such as the emittance, the shape, and the current, in particular for higher charge states. The electron heating methods such as the frequency tuning effect and the double frequency heating are widely used for enhancing the performances of ECRIS or even for the routine operation during the beam production. In order to better investigate these effects the CAPRICE ECRIS has been operated using these techniques. The ion beam properties for highly charged ions have been measured with beam diagnostic tools. The reason of the observed variations of this performance can be related to the different electromagnetic field patterns, which are changing inside the plasma chamber when the frequency is varying.

  2. 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.

  3. 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.

  4. 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.

  5. 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).

  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. 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.

  8. Investigation of electrostatic waves in the ion cyclotron range of frequencies in L-4 and ACT-1

    SciTech Connect

    Ono, Masayuki.

    1993-05-01

    Electrostatic waves in the ion cyclotron range of frequencies (ICRF) were studied in the Princeton L-4 and ACT-1 devices for approximately ten years, from 1975 to 1985. The investigation began in the L-4 linear device, looking for the parametric excitation of electrostatic ion cyclotron waves in multi-ion-species plasmas. In addition, this investigation verified multi-ion-species effects on the electrostatic ion cyclotron wave dispersion religion including the ion-ion hybrid resonance. Finite-Larmor-radius modification of the wave dispersion relation was also observed, even for ion temperatures of T[sub i] [approx] 1/40 eV. Taking advantage of the relatively high field and long device length of L-4, the existence of the cold electrostatic ion cyclotron wave (CES ICW) was verified. With the arrival of the ACT-1 toroidal device, finite-Larmor-radius (FLR) waves were studied in a relatively collisionless warm-ion hydrogen plasma. Detailed investigations of ion Bernstein waves (IBW) included the verification of mode-transformation in their launching, their wave propagation characteristics, their absorption, and the resulting ion heating. This basic physics activity played a crucial role in developing a new reactor heating concept termed ion Bernstein wave heating. Experimental research in the lower hybrid frequency range confirmed the existence of FLR effects near the lower hybrid resonance, predicted by Stix in 1965. In a neon plasma with a carefully placed phased wave exciter, the neutralized ion Bernstein wave was observed for the first time. Using a fastwave ICRF antenna, two parasitic excitation processes for IBW -- parametric instability and density-gradient-driven excitation -- were also discovered. In the concluding section of this paper, a possible application of externally launched electrostatic waves is suggested for helium ash removal from fusion reactor plasmas.

  9. Investigation of electrostatic waves in the ion cyclotron range of frequencies in L-4 and ACT-1

    SciTech Connect

    Ono, Masayuki

    1993-05-01

    Electrostatic waves in the ion cyclotron range of frequencies (ICRF) were studied in the Princeton L-4 and ACT-1 devices for approximately ten years, from 1975 to 1985. The investigation began in the L-4 linear device, looking for the parametric excitation of electrostatic ion cyclotron waves in multi-ion-species plasmas. In addition, this investigation verified multi-ion-species effects on the electrostatic ion cyclotron wave dispersion religion including the ion-ion hybrid resonance. Finite-Larmor-radius modification of the wave dispersion relation was also observed, even for ion temperatures of T{sub i} {approx} 1/40 eV. Taking advantage of the relatively high field and long device length of L-4, the existence of the cold electrostatic ion cyclotron wave (CES ICW) was verified. With the arrival of the ACT-1 toroidal device, finite-Larmor-radius (FLR) waves were studied in a relatively collisionless warm-ion hydrogen plasma. Detailed investigations of ion Bernstein waves (IBW) included the verification of mode-transformation in their launching, their wave propagation characteristics, their absorption, and the resulting ion heating. This basic physics activity played a crucial role in developing a new reactor heating concept termed ion Bernstein wave heating. Experimental research in the lower hybrid frequency range confirmed the existence of FLR effects near the lower hybrid resonance, predicted by Stix in 1965. In a neon plasma with a carefully placed phased wave exciter, the neutralized ion Bernstein wave was observed for the first time. Using a fastwave ICRF antenna, two parasitic excitation processes for IBW -- parametric instability and density-gradient-driven excitation -- were also discovered. In the concluding section of this paper, a possible application of externally launched electrostatic waves is suggested for helium ash removal from fusion reactor plasmas.

  10. 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.

  11. 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.

  12. Active diagnostic of the eigenmode formation in the ion-cyclotron frequency range in the GAMMA10 central cell

    SciTech Connect

    Yamaguchi, Y.; Ichimura, M.; Higaki, H.; Kakimoto, S.; Nakagome, K.; Nemoto, K.; Katano, M.; Nakajima, H.; Fukuyama, A.; Cho, T.

    2006-10-15

    A wide-band radio-frequency (rf) probe system was constructed for the active diagnostic of the eigenmode formations in the ion-cyclotron range of frequency (ICRF) in GAMMA10. An antenna was installed in the peripheral region in the central cell. The low power rf pulse with the frequency sweep is applied to the antenna. The waves excited in the plasma are detected with a magnetic probe. The excitation of eigenmodes is described by using the antenna-plasma-probe transfer function. The transfer function can be obtained from the antenna current signal and the magnetic probe signal. When the real and imaginary parts of the transfer function are plotted on the complex plane, the resultant curves are approximately circular, indicating an eigenmode formation. The results of the measurement show that several eigenmodes can be excited in the present experimental condition.

  13. Measurements of energetic helium-3 minority distributions during ion cyclotron radio-frequency heating in the Princeton Large Torus

    SciTech Connect

    Hammett, G.W.; Kaita, R.; Wilson, J.R.

    1988-03-01

    Ion cyclotron radio-frequency heating experiments were performed with a /sup 3/He minority ion species in a /sup 4/He majority plasma in the Princeton Large Torus. The energetic /sup 3/He ion ''tail'' was measured directly with a charge exchange neutral analyzer for the first time. Comparisons with bounce-averaged quasi-linear calculations suggest a modestly peaked radi-frequency power deposition profile. The double charge exchange process /sup 3/He/sup + +/ )plus) /sup 4/He/sup 0/ )plus) /sup 3/He/sup 0/ )plus) /sup 4/He/sup + +/ demonstrated in these measurements may be useful as part of an alpha particle diagnostic in a fusion reactor experiment. 18 refs., 4 figs.

  14. Monte Carlo orbit/full wave simulation of ion cyclotron resonance frequency wave damping on resonant ions in tokamaks

    SciTech Connect

    Choi, M.; Chan, V.S.; Pinsker, R.I.; Chiu, S.C.; Heidbrink, W.W.

    2005-07-15

    To investigate the experimentally observed interaction between beam ion species and fast Alfven wave (FW), a Monte Carlo code, ORBIT-RF [V. S. Chan, S. C. Chiu, and Y. A. Omelchenko, Phys. Plasmas 9, 501 (2002)], which solves the time-dependent Hamiltonian guiding center drift equations, has been upgraded to incorporate a steady-state neutral beam ion slowing-down distribution, a quasilinear high harmonic radio frequency diffusion operator and the wave fields from the two-dimensional ion cyclotron resonance frequency full wave code (TORIC4) [M. Brambilla, Plasma Phys. Controlled Fusion 41, 1 (1999)]. Comparison of ORBIT-RF simulation of power absorption with fixed amplitudes of FW fields from TORIC4 power absorption calculation, which assumes Maxwellian plasma distributions, attains agreement within a factor of two. The experimentally measured enhanced neutron rate is reproduced to within 30% from ORBIT-RF simulation using a single dominant toroidal and poloidal wave number.

  15. Plasma and cyclotron frequency effects on output power of the plasma wave-pumped free-electron lasers

    NASA Astrophysics Data System (ADS)

    Zolghadr, S. H.; Jafari, S.; Raghavi, A.

    2016-05-01

    Significant progress has been made employing plasmas in the free-electron lasers (FELs) interaction region. In this regard, we study the output power and saturation length of the plasma whistler wave-pumped FEL in a magnetized plasma channel. The small wavelength of the whistler wave (in sub-μm range) in plasma allows obtaining higher radiation frequency than conventional wiggler FELs. This configuration has a higher tunability by adjusting the plasma density relative to the conventional ones. A set of coupled nonlinear differential equations is employed which governs on the self-consistent evolution of an electromagnetic wave. The electron bunching process of the whistler-pumped FEL has been investigated numerically. The result reveals that for a long wiggler length, the bunching factor can appreciably change as the electron beam propagates through the wiggler. The effects of plasma frequency (or plasma density) and cyclotron frequency on the output power and saturation length have been studied. Simulation results indicate that with increasing the plasma frequency, the power increases and the saturation length decreases. In addition, when density of background plasma is higher than the electron beam density (i.e., for a dense plasma channel), the plasma effects are more pronounced and the FEL-power is significantly high. It is also found that with increasing the strength of the external magnetic field frequency, the power decreases and the saturation length increases, noticeably.

  16. Cyclotron resonance at microwave frequencies in two-dimensional hole system in AlGaAs/GaAs quantum wells.

    SciTech Connect

    Ong, N. P.; Bayrakci, S. P.; Lai, K. W.; Pan, Wei; Tsui, Daniel Chee; West, Ken W.; Pfeiffer, Loren N.

    2003-07-01

    Cyclotron resonance at the microwave frequency is used to measure the band edge mass (m{sub b}) in the two-dimensional hole (2DH) system, confined in 30 nm quantum wells in the Al{sub 0.1}Ga{sub 0.9}As/GaAs/Al{sub 0.1}Ga{sub 0.9}As heterostructures. We find that for 2DH density p {le} 1.0 x 10{sup 10} cm{sup -2}, m{sub b} is nearly constant, {approx}0.35m{sub e}. It increases with increasing density, to {approx}0.5m{sub e} at p = 7.4 x 10{sup 10} cm{sup -2}.

  17. 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.

  18. Novel Reactor Relevant RF Actuator Schemes for the Lower Hybrid and the Ion Cyclotron Range of Frequencies

    NASA Astrophysics Data System (ADS)

    Bonoli, Paul

    2014-10-01

    This paper presents a fresh physics perspective on the onerous problem of coupling and successfully utilizing ion cyclotron range of frequencies (ICRF) and lower hybrid range of frequencies (LHRF) actuators in the harsh environment of a nuclear fusion reactor. The ICRF and LH launchers are essentially first wall components in a fusion reactor and as such will be subjected to high heat fluxes. The high field side (HFS) of the plasma offers a region of reduced heat flux together with a quiescent scrape off layer (SOL). Placement of the ICRF and LHRF launchers on the tokamak HFS also offers distinct physics advantages: The higher toroidal magnetic field makes it possible to couple faster phase velocity LH waves that can penetrate farther into the plasma core and be absorbed by higher energy electrons, thereby increasing the current drive efficiency. In addition, re-location of the LH launcher off the mid-plane (i.e., poloidal ``steering'') allows further control of the deposition location. Also ICRF waves coupled from the HFS couple strongly to mode converted ion Bernstein waves and ion cyclotron waves waves as the minority density is increased, thus opening the possibility of using this scheme for flow drive and pressure control. Finally the quiescent nature of the HFS scrape off layer should minimize the effects of RF wave scattering from density fluctuations. Ray tracing / Fokker Planck simulations will be presented for LHRF applications in devices such as the proposed Advanced Divertor Experiment (ADX) and extending to ITER and beyond. Full-wave simulations will also be presented which demonstrate the possible combinations of electron and ion heating via ICRF mode conversion. Work supported by the US DoE under Contract Numbers DE-FC02-01ER54648 and DE-FC02-99ER54512.

  19. Synergy in Two-Frequency Fast Wave Cyclotron Harmonic Absorption in DIII-D

    SciTech Connect

    Pinsker, R. I.; Choi, M.; Heidbrink, W. W.; Zhu, Y.; Porkolab, M.; Baity, F. W.; Hosea, J. C.

    2009-11-26

    Fast waves (FWs) at 60 MHz and at 90 MHz are coupled to DIII-D discharges for central heating and current drive at net FW power up to 3.5 MW. The primary absorption mechanism is intended to be direct electron damping in the plasma core. In discharges at B = 2 T with fast deuteron populations from neutral beam injection, 4th and 6th deuterium cyclotron harmonic absorption on the fast ions competes with direct electron damping. Previous experiments have shown that the 6{omega}{sub D} absorption of the 90 MHz FWs is weaker than the 4{omega}{sub D} absorption of 60 MHz FWs, in agreement with a model that includes unspecified edge losses. Recent experiments have shown that if the fast deuterons are accelerated by absorption of 60 MHz (4{omega}{sub D}) FWs, adding 90 MHz power (6{omega}{sub D}) can increase the fusion neutron rate by a larger increment than is obtained with 90 MHz power alone. Details of this synergy between 4{omega}{sub D} and 6{omega}{sub D} absorption are presented.

  20. A detailed comparison of antenna impedance measurements on ASDEX Upgrade with the ion cyclotron range of frequencies antenna code TOPICA

    NASA Astrophysics Data System (ADS)

    Stepanov, I.; Noterdaeme, J.-M.; Bobkov, V.; Faugel, H.; Coster, D.; Milanesio, D.; Maggiora, R.; Siegl, G.; Bilato, R.; Brambilla, M.; Verdoolaege, G.; Braun, F.; Fünfgelder, H.; D'Inca, R.; Suttrop, W.; Kallenbach, A.; Schweinzer, J.; Wolfrum, E.; Fischer, R.; Mlynek, A.; Nikolaeva, V.; Guimarais, L.; the ASDEX Upgrade Team

    2015-09-01

    New antenna diagnostics on the ASDEX Upgrade, in the form of voltage and current probe pairs on the feeding lines of each ion cyclotron range of frequencies antenna, close to the input ports, have made it possible to study in detail the behavior of the ASDEX Upgrade two-strap antenna under changing loading conditions, and compare these measurements with the results of simulations using the TOPICA code. The present work extends previous studies by using the input impedance (more precisely, the complex voltage reflection coefficient Γ ) on each antenna port for comparison, instead of the more commonly used loading resistance or coupled power. The electron density profiles used for the simulation were reconstructed from the deuterium-carbon-nitrogen interferometer and lithium beam emission spectroscopy measurements, edge-localized mode-synchronized and averaged over time intervals from 10 to 200 ms depending on the case; 112 cases were compared from seven ASDEX Upgrade discharges with widely different plasma parameters and two operating frequencies (30 and 36.5 MHz). Very good agreement in \\vert Γ\\vert was found with the measurements on antenna 3 (<3% averaged over a shot), and good agreement was found with antennas 1 and 2 (<10%) the code reproduced the correct trend in loading resistance {{R}\\text{L}} in a significant majority of cases, although the discrepancies in the absolute values were rather high (up to  ˜50%) due to high reflection. Sources of discrepancy are discussed.

  1. Frequency sweep rates of rising tone electromagnetic ion cyclotron waves: Comparison between nonlinear theory and Cluster observation

    SciTech Connect

    He, Zhaoguo; Zong, Qiugang Wang, Yongfu; Liu, Siqing; Lin, Ruilin; Shi, Liqin

    2014-12-15

    Resonant pitch angle scattering by electromagnetic ion cyclotron (EMIC) waves has been suggested to account for the rapid loss of ring current ions and radiation belt electrons. For the rising tone EMIC wave (classified as triggered EMIC emission), its frequency sweep rate strongly affects the efficiency of pitch-angle scattering. Based on the Cluster observations, we analyze three typical cases of rising tone EMIC waves. Two cases locate at the nightside (22.3 and 22.6 magnetic local time (MLT)) equatorial region and one case locates at the duskside (18MLT) higher magnetic latitude (λ = –9.3°) region. For the three cases, the time-dependent wave amplitude, cold electron density, and cold ion density ratio are derived from satellite data; while the ambient magnetic field, thermal proton perpendicular temperature, and the wave spectral can be directly provided by observation. These parameters are input into the nonlinear wave growth model to simulate the time-frequency evolutions of the rising tones. The simulated results show good agreements with the observations of the rising tones, providing further support for the previous finding that the rising tone EMIC wave is excited through the nonlinear wave growth process.

  2. An algorithm for the calculation of 3-D ICRF (Ion Cyclotron Range of Frequencies) fields in tokamak geometry

    SciTech Connect

    Smithe, D.N.; Colestock, P.L.; Kashuba, R.J.; Kammash, T.

    1987-04-01

    A computational scheme is developed which permits tractable calculation of three-dimensional full-wave solutions to the Maxwell-Vlasov equations under typical Ion Cyclotron Range of Frequencies (ICRF) experimental conditions. The method is unique in that power deposition to the plasma is determined via the anti-Hermitian part of a truncated warm-plasma dielectric operator, rather than as the result of an assumed phenomenological collision frequency. The resulting computer code allows arbitrary variation of density, temperature, magnetic field, and minority concentration in the poloidal plane by performing a convolution of poloidal modes to produce a coupled system of differential equations in the radial variable. By assuming no inhomogeneity along the toroidal axis, an inverse transform over k/sub parallel/ is performed to yield the full three-dimensional field solutions. The application of the code to TFTR-like plasmas shows a mild resonance structure in antenna loading related to the changing number of wavelengths between antenna and the resonance layer. 48 figs.

  3. Measurements of ICRF (ion cyclotron range of frequencies) loading with a ridged waveguide coupler on PLT

    SciTech Connect

    Greene, G.J.; Wilson, J.R.; Colestock, P.L.; Fortgang, C.M.; Hosea, J.C.; Hwang, D.Q.; Nagy, A.

    1987-11-01

    An ICRF ridged waveguide coupler has been installed on PLT for measurements of plasma loading. The coupler was partially filled with TiO/sub 2/ dielectric in order to sufficiently lower the cutoff frequency and utilized a tapered ridge for improved matching. Vacuum field measurements indicated a single propagating mode in the coupler and emphasized the importance of considering the fringing fields at the mouth of the waveguide. Low power experiments were carried out at 72.6 and 95.0 MHz without any external impedance matching network. Plasma loading increased rapidly as the face of the coupler approached the plasma, and, at fixed position, increased with line-averaged plasma density. At the lower frequency, the reflection coefficient exhibited a minimum (<8%) at a particular coupler position. At both frequencies, measurements indicated efficient power coupling to the plasma. Magnetic probe signals showed evidence of dense eigenmodes suggesting excitation of the fast wave. 24 refs., 13 figs.

  4. High Mass Resolving Power Radio Frequency Glow Discharge Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (RFGD-FTICR/MS)

    SciTech Connect

    Nichols, L.S.

    2001-01-05

    The combination of a radio frequency glow discharge (rfGD) external ion source with a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer has resulted in the ability to perform high mass resolution elemental analysis of both conductive and nonconductive materials. Samples investigated in the present study include copper, brass, and a National Institute of Standards and Technology (NIST) glass standard, SRM 1412. Analyses of both the copper and the brass materials resulted in ultra-high mass resolving power (m/Dm > 100,000). A mass resolving power of 280,000 (FWHM) was obtained for the 63Cu+ isotope of the copper sample, the highest reported to date for rfGD studies. In addition, study of the SRM 1412 glass standard revealed mass spectral peaks related to metal oxides present in the glass matrix at concentrations of approximately 4 percent (by weight). The resulting preliminary data demonstrate the capabilities of a rfGD-FTICR instrument and its promise as a powerful tool in distinguishing between isobaric and other mass spectral interferences in insulators, as well as conducting materials.

  5. Study of toroidal flow generation by ion cyclotron range of frequency minority heating in the Alcator C-Mod plasma

    NASA Astrophysics Data System (ADS)

    Murakami, S.; Itoh, K.; Zheng, L. J.; Van Dam, J. W.; Bonoli, P.; Rice, J. E.; Fiore, C. L.; Gao, C.; Fukuyama, A.

    2016-01-01

    The averaged toroidal flow of energetic minority ions during ICRF (ion cyclotron range of frequencies) heating is investigated in the Alcator C-Mod plasma by applying the GNET code, which can solve the drift kinetic equation with complicated orbits of accelerated energetic particles. It is found that a co-directional toroidal flow of the minority ions is generated in the region outside of the resonance location, and that the toroidal velocity reaches more than 40% of the central ion thermal velocity (Vtor ˜ 300 km/s with PICRF ˜ 2 MW). When we shift the resonance location to the outside of |r /a |˜0.5 , the toroidal flow immediately inside of the resonance location is reduced to 0 or changes to the opposite direction, and the toroidal velocity shear is enhanced at r/a ˜ 0.5. A radial diffusion equation for toroidal flow is solved by assuming a torque profile for the minority ion mean flow, and good agreements with experimental radial toroidal flow profiles are obtained. This suggests that the ICRF driven minority ion flow is related to the experimentally observed toroidal rotation during ICRF heating in the Alcator C-Mod plasma.

  6. Comment on "Mode Conversion of Waves In The Ion-Cyclotron Frequency Range in Magnetospheric Plasmas"

    SciTech Connect

    Kim, Eun; Johnson, J. R.

    2014-02-01

    Recently, Kazakov and Fulop [1] studied mode conversion (MC) at the ion-ion hybrid (IIH) resonance in planetary magnetospheric plasmas by simplifying the dispersion relation of the fast wave (FW) modes to describe a cutoff-resonance (CR) pair near the IIH resonance, which can be reduced to a Budden problem. They suggested that when the IIH resonance frequency (ωS) approaches the crossover frequency (ωcr), and the parallel wavenumber (k∥) is close to the critical wavenumber k* ∥(ωS = ωcr), MC can be efficient for arbitrary heavy ion density ratios. In this Comment, we argue that (a) the FW dispersion relation cannot be simplified to the CR pair especially near ωcr because in many parameter regimes there is a cutoff-resonance-cutoff (CRC) triplet that completely changes the wave absorption; and (b) the maximum MC efficiency does not always occur near k∥ ≈ k*∥∥.

  7. Electrostatic ion cyclotron waves in a plasma with an ion beam and counterstreaming bulk electrons - Waves in the zero-frequency band

    NASA Astrophysics Data System (ADS)

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

    1985-12-01

    A common feature of the auroral plasma in the region above field-aligned (parallel) potential drops are electrostatic hydrogen cyclotron (EHC) waves. The present paper has the objective to show that wave excitation in the zero-frequency band can occur when the ion beams and the current-carrying bulk electrons counterstream. The instability mechanism involves the Landau interaction of the slow (negative energy) ion-beam-cyclotron waves with the drifting electrons and also with the target (background) ions. Only the latter resonant interaction between the beam and the target ions was considered by Okuda and Nishikawa (1984). In this study, it is shown that an electron drift makes an additional unstable contribution to the waves in the zero-frequency band, including those discussed by Okuda and Nishikawa.

  8. Electrostatic ion cyclotron waves in a plasma with an ion beam and counterstreaming bulk electrons - Waves in the zero-frequency band. [in aurora

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    A common feature of the auroral plasma in the region above field-aligned (parallel) potential drops are electrostatic hydrogen cyclotron (EHC) waves. The present paper has the objective to show that wave excitation in the zero-frequency band can occur when the ion beams and the current-carrying bulk electrons counterstream. The instability mechanism involves the Landau interaction of the slow (negative energy) ion-beam-cyclotron waves with the drifting electrons and also with the target (background) ions. Only the latter resonant interaction between the beam and the target ions was considered by Okuda and Nishikawa (1984). In this study, it is shown that an electron drift makes an additional unstable contribution to the waves in the zero-frequency band, including those discussed by Okuda and Nishikawa.

  9. Measurements of ion cyclotron range of frequencies mode converted wave intensity with phase contrast imaging in Alcator C-Mod and comparison with full-wave simulations

    NASA Astrophysics Data System (ADS)

    Tsujii, N.; Porkolab, M.; Bonoli, P. T.; Lin, Y.; Wright, J. C.; Wukitch, S. J.; Jaeger, E. F.; Green, D. L.; Harvey, R. W.

    2012-08-01

    Radio frequency waves in the ion cyclotron range of frequencies (ICRF) are widely used to heat tokamak plasmas. In ICRF heating schemes involving multiple ion species, the launched fast waves convert to ion cyclotron waves or ion Bernstein waves at the two-ion hybrid resonances. Mode converted waves are of interest as actuators to optimise plasma performance through current drive and flow drive. In order to describe these processes accurately in a realistic tokamak geometry, numerical simulations are essential, and it is important that these codes be validated against experiment. In this study, the mode converted waves were measured using a phase contrast imaging technique in D-H and D-3He plasmas. The measured mode converted wave intensity in the D-3He mode conversion regime was found to be a factor of ˜50 weaker than the full-wave predictions. The discrepancy was reduced in the hydrogen minority heating regime, where mode conversion is weaker.

  10. Effect of electron-cyclotron resonance plasma heating conditions on the low-frequency modulation of the gyrotron power at the L-2M stellarator

    SciTech Connect

    Batanov, G. M.; Borzosekov, V. D.; Kolik, L. V.; Konchekov, E. M. Malakhov, D. V.; Petelin, M. I.; Petrov, A. E.; Sarksyan, K. A.; Skvortsova, N. N.; Stepakhin, V. D.; Kharchev, N. K.

    2015-08-15

    Low-frequency modulation of the gyrotron power at the L-2M stellarator was studied at different modes of plasma confinement. The plasma was heated at the second harmonic of the electron gyrofrequency. The effect of reflection of gyrotron radiation from the region of electron-cyclotron resonance plasma heating, as well as of backscattering of gyrotron radiation from fluctuations of the plasma density, on the modulation of the gyrotron power was investigated.

  11. Spectral analysis of ICRF (Ion Cyclotron Range of Frequencies) wave field measurements in the Tara Central Cell

    SciTech Connect

    Wang, L.; Golovato, S.N.; Horne, S.F.

    1987-12-01

    A simple spectral analysis technique has been developed to analyse the digital signals from an array of magnetic probes for ICRF field measurements in the Tara Tandem Mirror central cell. The wave dispersion relations of both the applied ICRF and the Alfven Ion Cyclotron Instability have been studied and the waves have been identified as slow in cyclotron waves. The radial profiles of field amplitude and wave vectors were also generated. 9 refs., 10 figs.

  12. Observation of ICRF (ion cyclotron range of frequencies) wave-packet propagation in a tokamak plasma

    SciTech Connect

    Greene, G.J.; Gould, R.W.

    1987-11-01

    Experimental observation of ICRF wave-packet propagation in a tokamak plasma is reported. Studies were carried out in the Caltech Research Tokamak in a pure hydrogen plasma and in a regime where fast-wave damping was sufficiently small to permit multiple toroidal transits of the wave-packet. Waves were launched by exciting a small loop antenna with a short burst of rf current and were detected with shielded magnetic probes. Probe scans revealed a large increase in wave-packet amplitude at smaller minor radii, and the packet velocity was found to be independent of radial position. Measurement of the packet transit time yielded direct information about the wave group velocity. Packet velocity was investigated as a function of the fundamental excitation frequency, plasma density, and toroidal magnetic field. Results are compared with the predictions of a cold plasma model which includes a vacuum layer at the edge. 24 refs., 8 figs.

  13. Design, performance, and grounding aspects of the International Thermonuclear Experimental Reactor ion cyclotron range of frequencies antenna

    SciTech Connect

    Durodié, F. Dumortier, P.; Vrancken, M.; Messiaen, A.; Huygen, S.; Louche, F.; Van Schoor, M.; Vervier, M.; Winkler, K.

    2014-06-15

    ITER's Ion Cyclotron Range of Frequencies (ICRF) system [Lamalle et al., Fusion Eng. Des. 88, 517–520 (2013)] comprises two antenna launchers designed by CYCLE (a consortium of European associations listed in the author affiliations above) on behalf of ITER Organisation (IO), each inserted as a Port Plug (PP) into one of ITER's Vacuum Vessel (VV) ports. Each launcher is an array of 4 toroidal by 6 poloidal RF current straps specified to couple up to 20 MW in total to the plasma in the frequency range of 40 to 55 MHz but limited to a maximum system voltage of 45 kV and limits on RF electric fields depending on their location and direction with respect to, respectively, the torus vacuum and the toroidal magnetic field. A crucial aspect of coupling ICRF power to plasmas is the knowledge of the plasma density profiles in the Scrape-Off Layer (SOL) and the location of the RF current straps with respect to the SOL. The launcher layout and details were optimized and its performance estimated for a worst case SOL provided by the IO. The paper summarizes the estimated performance obtained within the operational parameter space specified by IO. Aspects of the RF grounding of the whole antenna PP to the VV port and the effect of the voids between the PP and the Blanket Shielding Modules (BSM) surrounding the antenna front are discussed. These blanket modules, whose dimensions are of the order of the ICRF wavelengths, together with the clearance gaps between them will constitute a corrugated structure which will interact with the electromagnetic waves launched by ICRF antennas. The conditions in which the grooves constituted by the clearance gaps between the blanket modules can become resonant are studied. Simple analytical models and numerical simulations show that mushroom type structures (with larger gaps at the back than at the front) can bring down the resonance frequencies, which could lead to large voltages in the gaps between the blanket modules and perturb the

  14. Design, performance, and grounding aspects of the International Thermonuclear Experimental Reactor ion cyclotron range of frequencies antenna

    NASA Astrophysics Data System (ADS)

    Durodié, F.; Dumortier, P.; Vrancken, M.; Messiaen, A.; Bamber, R.; Hancock, D.; Huygen, S.; Lockley, D.; Louche, F.; Maggiora, R.; Milanesio, D.; Nightingale, M. P. S.; Shannon, M.; Tigwell, P.; Van Schoor, M.; Vervier, M.; Wilson, D.; Winkler, K.

    2014-06-01

    ITER's Ion Cyclotron Range of Frequencies (ICRF) system [Lamalle et al., Fusion Eng. Des. 88, 517-520 (2013)] comprises two antenna launchers designed by CYCLE (a consortium of European associations listed in the author affiliations above) on behalf of ITER Organisation (IO), each inserted as a Port Plug (PP) into one of ITER's Vacuum Vessel (VV) ports. Each launcher is an array of 4 toroidal by 6 poloidal RF current straps specified to couple up to 20 MW in total to the plasma in the frequency range of 40 to 55 MHz but limited to a maximum system voltage of 45 kV and limits on RF electric fields depending on their location and direction with respect to, respectively, the torus vacuum and the toroidal magnetic field. A crucial aspect of coupling ICRF power to plasmas is the knowledge of the plasma density profiles in the Scrape-Off Layer (SOL) and the location of the RF current straps with respect to the SOL. The launcher layout and details were optimized and its performance estimated for a worst case SOL provided by the IO. The paper summarizes the estimated performance obtained within the operational parameter space specified by IO. Aspects of the RF grounding of the whole antenna PP to the VV port and the effect of the voids between the PP and the Blanket Shielding Modules (BSM) surrounding the antenna front are discussed. These blanket modules, whose dimensions are of the order of the ICRF wavelengths, together with the clearance gaps between them will constitute a corrugated structure which will interact with the electromagnetic waves launched by ICRF antennas. The conditions in which the grooves constituted by the clearance gaps between the blanket modules can become resonant are studied. Simple analytical models and numerical simulations show that mushroom type structures (with larger gaps at the back than at the front) can bring down the resonance frequencies, which could lead to large voltages in the gaps between the blanket modules and perturb the RF

  15. 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.

  16. 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

  17. Characterization and performance of a field aligned ion cyclotron range of frequency antenna in Alcator C-Moda)

    NASA Astrophysics Data System (ADS)

    Wukitch, S. J.; Garrett, M. L.; Ochoukov, R.; Terry, J. L.; Hubbard, A.; Labombard, B.; Lau, C.; Lin, Y.; Lipschultz, B.; Miller, D.; Reinke, M. L.; Whyte, D.; Alcator C-Mod Team

    2013-05-01

    Ion cyclotron range of frequency (ICRF) heating is expected to provide auxiliary heating for ITER and future fusion reactors where high Z metallic plasma facing components (PFCs) are being considered. Impurity contamination linked to ICRF antenna operation remains a major challenge particularly for devices with high Z metallic PFCs. Here, we report on an experimental investigation to test whether a field aligned (FA) antenna can reduce impurity contamination and impurity sources. We compare the modification of the scrape of layer (SOL) plasma potential of the FA antenna to a conventional, toroidally aligned (TA) antenna, in order to explore the underlying physics governing impurity contamination linked to ICRF heating. The FA antenna is a 4-strap ICRF antenna where the current straps and antenna enclosure sides are perpendicular to the total magnetic field while the Faraday screen rods are parallel to the total magnetic field. In principle, alignment with respect to the total magnetic field minimizes integrated E|| (electric field along a magnetic field line) via symmetry. A finite element method RF antenna model coupled to a cold plasma model verifies that the integrated E|| should be reduced for all antenna phases. Monopole phasing in particular is expected to have the lowest integrated E||. Consistent with expectations, we observed that the impurity contamination and impurity source at the FA antenna are reduced compared to the TA antenna. In both L and H-mode discharges, the radiated power is 20%-30% lower for a FA-antenna heated discharge than a discharge heated with the TA-antennas. However, inconsistent with expectations, we observe RF induced plasma potentials (via gas-puff imaging and emissive probes to be nearly identical for FA and TA antennas when operated in dipole phasing). Moreover, the highest levels of RF-induced plasma potentials are observed using monopole phasing with the FA antenna. Thus, while impurity contamination and sources are indeed

  18. Chord integrated neutral particle diagnostic data analysis for neutral beam injection and ion cyclotron radio frequency heated plasma in a complex Large Helical Device geometry

    SciTech Connect

    Veshchev, E. A.; Goncharov, P. R.; Ozaki, T.; Sudo, S.; Lyon, J. F.

    2006-10-15

    Energy and angle-resolved measurements of charge exchange neutral particle fluxes from the plasma provide information about T{sub i}, as well as non-Maxwellian substantially anisotropic ion distribution tails due to neutral beam injection (NBI) and ion cyclotron radio frequency (ICRF) heating. The measured chord integral neutral flux calculation scheme for the Large Helical Device magnetic surface geometry is given. Calculation results are shown for measurable atomic energy spectra corresponding to heating-induced fast ion distributions from simplified Fokker-Planck models. The behavior of calculated and experimental suprathermal particle distributions from NBI and ICRF heated plasma is discussed in the context of the experimental data interpretation.

  19. Brazing of ceramic and graphite to metal in the fabrication of ICRF (ion cyclotron range of frequencies) antenna and feedthrough components

    SciTech Connect

    Schechter, D.E.; Sluss, F.; Hoffman, D.J.

    1987-01-01

    Fabrication of some of the more critical components of ion cyclotron range of frequencies (ICRF) antenna and feedthrough assemblies has involved the brazing of alumina ceramic and graphite to various metals. Copper end pieces have been successfully brazed to alumina cylinders for use in feedthroughs for TEXTOR and in feedthroughs and capacitors for a Tokamak Fusion Test Reactor (TFTR) antenna. Copper-plated Inconel rods and tubes have been armored with graphite for construction of Faraday shields on antennas for Doublet III-D and TFTR. Details of brazing procedures and test results, including rf performance, mechanical strength, and thermal capabilities, are presented. 14 figs.

  20. Measurements of ion cyclotron range of frequencies mode converted wave intensity with phase contrast imaging in Alcator C-Mod and comparison with full-wave simulations

    SciTech Connect

    Tsujii, N.; Porkolab, M.; Bonoli, P. T.; Lin, Y.; Wright, J. C.; Wukitch, S. J.; Jaeger, E. F.; Green, D. L.; Harvey, R. W.

    2012-08-15

    Radio frequency waves in the ion cyclotron range of frequencies (ICRF) are widely used to heat tokamak plasmas. In ICRF heating schemes involving multiple ion species, the launched fast waves convert to ion cyclotron waves or ion Bernstein waves at the two-ion hybrid resonances. Mode converted waves are of interest as actuators to optimise plasma performance through current drive and flow drive. In order to describe these processes accurately in a realistic tokamak geometry, numerical simulations are essential, and it is important that these codes be validated against experiment. In this study, the mode converted waves were measured using a phase contrast imaging technique in D-H and D-{sup 3}He plasmas. The measured mode converted wave intensity in the D-{sup 3}He mode conversion regime was found to be a factor of {approx}50 weaker than the full-wave predictions. The discrepancy was reduced in the hydrogen minority heating regime, where mode conversion is weaker.

  1. Kinematics of four-wave decay of high-frequency plasma oscillations into upper hybrid and electron-cyclotron plasma waves under multiple electron gyroresonance conditions

    NASA Astrophysics Data System (ADS)

    Vas'kov, V. V.; Ryabova, N. A.

    1996-03-01

    We consider the conditions for four-wave decay of two primary plasmons with wave vectorěc k_{_0 } and frequency ω0 close to the multiple gyroresonance frequency nωBe into two secondary plasmons with frequencies ω1 > ω0 and ω2 < ω0. The secondary plasmons belong to the upper hybrid and the electron cyclotron branches. It is shown that the main features of the broad upshifted maximum (BUM) in the SEE spectrum can be explained in the context of the proposed process. The BUM feature appears in the region of frequencies having a positive shift from the high-power radio wave frequency. In particular the broad band nature of the BUM can be a result of the broad spectrum of wave number k0 of the primary plasma waves. In this case the observed cut-off frequency Δfcutoff limiting the BUM spectrum on the lower side can result from the lower bound of k0 (the increase in ω1 corresponds to decay of shorter wave plasmons). In our approach we assume that the generation of primary plasma oscillations by the high-power radio wave and the conversion of secondary plasma waves into the electromagnetic waves is due to coherent scattering of corresponding waves by small-scale magnetic-field-aligned artificial irregularities or to another nonlinear processes.

  2. Method and apparatus for ion cyclotron spectrometry

    DOEpatents

    Dahl, David A [Idaho Falls, ID; Scott, Jill R [Idaho Falls, ID; McJunkin, Timothy R [Idaho Falls, ID

    2010-08-17

    An ion cyclotron spectrometer may include a vacuum chamber that extends at least along a z-axis and means for producing a magnetic field within the vacuum chamber so that a magnetic field vector is generally parallel to the z-axis. The ion cyclotron spectrometer may also include means for producing a trapping electric field within the vacuum chamber that includes at least a first section that induces a first magnetron effect that increases a cyclotron frequency of an ion and at least a second section that induces a second magnetron effect that decreases the cyclotron frequency of an ion. The cyclotron frequency changes induced by the first and second magnetron effects substantially cancel one another so that an ion traversing the at least first and second sections will experience no net change in cyclotron frequency.

  3. An initial measurement of a fast neutral spectrum for ion cyclotron range of frequency heated plasma using two-channel compact neutral particle analyzers in KSTAR

    NASA Astrophysics Data System (ADS)

    Kim, S. H.; Wang, S. J.; Park, M.; Kim, S. K.

    2013-11-01

    The accurate measurement of fast neutral particles from high energy ion tails is very important since it is a measure of ion cyclotron range of frequency (ICRF) or neutral beam (NB) ion heating. In KSTAR, fast neutral measurements have been carried out using a compact neutral particle analyzer based on the silicon photo diode since 2010. As a result, the fast neutral spectrum was observed consistent with the ion temperature, diamagnetic energy, and neutron flux in 2011. However, there was fast neutral count beyond the injected neutral beam energy in NB-only heating. Since it is difficult to expect the count unless the temperature is high enough to diffuse the fast ions beyond the beam energy it was required to identify what it is. During the 2012 campaign, the two-channel diode detectors with and without a particle stopper were used to distinguish fast neutral counts and other counts by a hard X-ray or neutrons. As a result, it was confirmed that the high energy component beyond the beam energy originated from a hard X-ray or neutrons. Finally, it was observed that faster neutrals are generated by ICRF heating and enhanced by electron cyclotron heating compared to NB-only heating.

  4. An initial measurement of a fast neutral spectrum for ion cyclotron range of frequency heated plasma using two-channel compact neutral particle analyzers in KSTAR

    SciTech Connect

    Kim, S. H.; Park, M.; Kim, S. K.; Wang, S. J.

    2013-11-15

    The accurate measurement of fast neutral particles from high energy ion tails is very important since it is a measure of ion cyclotron range of frequency (ICRF) or neutral beam (NB) ion heating. In KSTAR, fast neutral measurements have been carried out using a compact neutral particle analyzer based on the silicon photo diode since 2010. As a result, the fast neutral spectrum was observed consistent with the ion temperature, diamagnetic energy, and neutron flux in 2011. However, there was fast neutral count beyond the injected neutral beam energy in NB-only heating. Since it is difficult to expect the count unless the temperature is high enough to diffuse the fast ions beyond the beam energy it was required to identify what it is. During the 2012 campaign, the two-channel diode detectors with and without a particle stopper were used to distinguish fast neutral counts and other counts by a hard X-ray or neutrons. As a result, it was confirmed that the high energy component beyond the beam energy originated from a hard X-ray or neutrons. Finally, it was observed that faster neutrals are generated by ICRF heating and enhanced by electron cyclotron heating compared to NB-only heating.

  5. ITER Plasma at Electron Cyclotron Frequency Domain: Tokamak Core Plasma Diagnostics Based on the Synergy of Stimulated Raman and Brillouin Scatterings

    NASA Astrophysics Data System (ADS)

    Stefan, V. Alexander

    2012-10-01

    A novel plasma diagnostic method is proposed based on the synergy of stimulated Raman and Brillouin scatterings. A nonlinear plasma mode is excited in a 4-wave coupling,footnotetextV. Alexander STEFAN, Nonlinear Electromagnetic Radiation Plasma Interactions, (S-U-Press, 2008). leading to the appearance of suprathermal electrons and accelerated ions at the plasma edgefootnotetextV. Alexander Stefan, Abstract: D1.00018 : ITER Plasma at Electron Cyclotron Frequency Domain: Stimulated Raman Scattering off Gould-Trivelpiece Modes and Generation of Suprathermal Electrons and Energetic Ions; Bulletin of the American Physical Society APS April Meeting 2011 Volume 56, Number 4. with the parameters directly dependent on the plasma parameters in the core of tokamak. Accordingly, plasma diagnostic in the core region, (ion temperature), can be performed by the diagnostics of suprathermal electrons and accelerated ions at the edge plasma.

  6. An algorithm for the analysis of inductive antennas of arbitrary cross-section for heating in the ion cyclotron range of frequencies

    SciTech Connect

    Lehrman, I.S.; Colestock, P.L.

    1986-10-01

    The application of Ion Cyclotron Range of Frequency (ICRF) heating to near ignited plasmas will require launching structures that will be capable of withstanding the harsh plasma environment. The recessed antenna configuration is expected to provide sufficient protection for the structure, but to date no analysis has been done to determine if adequate coupling can be achieved in such a configuration. In this work we present a method for determining the current distribution for the antenna in the direction transverse to current flow and predict antenna loading in the presence of plasma. Antennas of arbitrary cross section are analyzed above ground planes of arbitrary shape. Results from ANDES, the ANtenna DESign code, are presented and compared to experimental results.

  7. Parametric study of two-dimensional potential structures induced by radio-frequency sheaths coupled with transverse currents in front of the Ion Cyclotron Resonance Heating antenna

    SciTech Connect

    Faudot, E.; Heuraux, S.; Colas, L.

    2006-04-15

    For the first time, a two-dimensional (2D) fluid model and an analytical expression for the rectified potential with respect to the transverse polarization current are established and verified by a 2D PIC (particle in cell) code over the validity domain of our model. Then the model is extended to the overall ion cyclotron frequency range used in different heating and current drive scenarios. First, the models demonstrate that these transverse polarization currents add some inertia in the temporal dynamic. Due to the nonlinear behavior of the I-V sheath characteristic, the time average amplitude (dc potential) of the rectified potential structure is increased compared to the time average rf potential. Second, they induce only a slight widening of the potential structure. Such modifications are quantified using a 'test map' initially characterized by a Gaussian shape. The map is assumed to remain Gaussian near its summit. The time behavior of the peak can be estimated analytically in the presence of polarization current as a function of its width r{sub 0} and amplitude {phi}{sub 0} (normalized to local temperature and to a characteristic length for transverse transport). A potential peaking criterion has been built to determine the peaking zone of the dc potential structure induced by the rf field. Computations made for typical parameters of the edge plasma in front of the antenna of the Tokamak Tore Supra show that the dc rectified potential is up to 50% higher than the previous computations neglecting polarization current effects. The weak diffused and high dc potential structures computed can explain the hot spot formation induced by convective cells associated to high energetic ion fluxes on the corners of the Ion Cyclotron Resonance Heating ant0010en.

  8. Observation of ion cyclotron range of frequencies mode conversion plasma flow drive on Alcator C-Moda)

    NASA Astrophysics Data System (ADS)

    Lin, Y.; Rice, J. E.; Wukitch, S. J.; Greenwald, M. J.; Hubbard, A. E.; Ince-Cushman, A.; Lin, L.; Marmar, E. S.; Porkolab, M.; Reinke, M. L.; Tsujii, N.; Wright, J. C.; Alcator C-Mod Team

    2009-05-01

    At modest H3e levels (n3He/ne˜8%-12%), in relatively low density D(H3e) plasmas, n¯e≤1.3×1020 m-3, heated with 50 MHz rf power at Bt0˜5.1 T, strong (up to 90 km/s) toroidal rotation (Vϕ) in the cocurrent direction has been observed by high-resolution x-ray spectroscopy on Alcator C-Mod. The change in central Vϕ scales with the applied rf power (≤30 km s-1 MW-1), and is generally at least a factor of 2 higher than the empirically determined intrinsic plasma rotation scaling. The rotation in the inner plasma (r /a≤0.3) responds to the rf power more quickly than that of the outer region (r /a≥0.7), and the rotation profile is broadly peaked for r /a≤0.5. Localized poloidal rotation (0.3≤r/a≤0.6) in the ion diamagnetic drift direction (˜2 km/s at 3 MW) is also observed, and similarly increases with rf power. Changing the toroidal phase of the antenna does not affect the rotation direction, and it only weakly affects the rotation magnitude. The mode converted ion cyclotron wave (MC ICW) has been detected by a phase contrast imaging system and the MC process is confirmed by two-dimensional full wave TORIC simulations. The simulations also show that the MC ICW is strongly damped on H3e ions in the vicinity of the MC layer, approximately on the same flux surfaces where the rf driven flow is observed. The flow shear in our experiment is marginally sufficient for plasma confinement enhancement based on the comparison of the E ×B shearing rate and gyrokinetic linear stability analysis.

  9. Lower hybrid current drive and ion cyclotron range of frequencies heating experiments in H-mode plasmas in Experimental Advanced Superconducting Tokomak

    NASA Astrophysics Data System (ADS)

    Zhang, X. J.; Wan, B. N.; Zhao, Y. P.; Ding, B. J.; Xu, G. S.; Gong, X. Z.; Li, J. G.; Lin, Y.; Taylor, G.; Noterdaeme, J. M.; Braun, F.; Wukitch, S.; Magne, R.; Litaudon, X.; Kumazawa, R.; Kasahara, H.

    2014-06-01

    An ion cyclotron range of frequencies (ICRF) system with power up to 6.0 MW and a lower hybrid current drive (LHCD) system up to 4 MW have been applied for heating and current drive experiments in Experimental Advanced Superconducting Tokomak (EAST). Significant progress has been made with ICRF heating and LHCD for realizing the H-mode plasma operation in EAST. During 2010 and 2012 experimental campaigns, ICRF heating experiments were carried out at the fixed frequency of 27MHz, achieving effective ions and electrons heating with the H minority heating (H-MH) mode. The H-MH mode produced good plasma performance, and realized H-mode using ICRF power alone in 2012. In 2010, H-modes were generated and sustained by LHCD alone, where lithium coating and gas puffing near the mouth of the LH launcher were applied to improve the LHCD power coupling and penetration into the core plasmas of H-modes. In 2012, the combination of LHCD and ICRH power extended the H-mode duration up to over 30 s. H-modes with various types of edge localized modes (ELMs) have been achieved with HIPB98(y, 2) ranging from 0.7 to over unity. A brief overview of LHCD and ICRF Heating experiment and their application in achieving H-mode operation during these two campaigns will be presented.

  10. Validation of full-wave simulations for mode conversion of waves in the ion cyclotron range of frequencies with phase contrast imaging in Alcator C-Mod

    SciTech Connect

    Tsujii, N.; Porkolab, M.; Bonoli, P. T.; Edlund, E. M.; Ennever, P. C.; Lin, Y.; Wright, J. C.; Wukitch, S. J.; Jaeger, E. F.; Green, D. L.; Harvey, R. W.

    2015-08-15

    Mode conversion of fast waves in the ion cyclotron range of frequencies (ICRF) is known to result in current drive and flow drive under optimised conditions, which may be utilized to control plasma profiles and improve fusion plasma performance. To describe these processes accurately in a realistic toroidal geometry, numerical simulations are essential. Quantitative comparison of these simulations and the actual experimental measurements is important to validate their predictions and to evaluate their limitations. The phase contrast imaging (PCI) diagnostic has been used to directly detect the ICRF waves in the Alcator C-Mod tokamak. The measurements have been compared with full-wave simulations through a synthetic diagnostic technique. Recently, the frequency response of the PCI detector array on Alcator C-Mod was recalibrated, which greatly improved the comparison between the measurements and the simulations. In this study, mode converted waves for D-{sup 3}He and D-H plasmas with various ion species compositions were re-analyzed with the new calibration. For the minority heating cases, self-consistent electric fields and a minority ion distribution function were simulated by iterating a full-wave code and a Fokker-Planck code. The simulated mode converted wave intensity was in quite reasonable agreement with the measurements close to the antenna, but discrepancies remain for comparison at larger distances.

  11. Lower hybrid current drive and ion cyclotron range of frequencies heating experiments in H-mode plasmas in Experimental Advanced Superconducting Tokomak

    SciTech Connect

    Zhang, X. J.; Wan, B. N. Zhao, Y. P.; Ding, B. J.; Xu, G. S.; Gong, X. Z.; Li, J. G.; Lin, Y.; Wukitch, S.; Taylor, G.; Noterdaeme, J. M.; Braun, F.; Magne, R.; Litaudon, X.; Kumazawa, R.; Kasahara, H.

    2014-06-15

    An ion cyclotron range of frequencies (ICRF) system with power up to 6.0 MW and a lower hybrid current drive (LHCD) system up to 4 MW have been applied for heating and current drive experiments in Experimental Advanced Superconducting Tokomak (EAST). Significant progress has been made with ICRF heating and LHCD for realizing the H-mode plasma operation in EAST. During 2010 and 2012 experimental campaigns, ICRF heating experiments were carried out at the fixed frequency of 27MHz, achieving effective ions and electrons heating with the H minority heating (H-MH) mode. The H-MH mode produced good plasma performance, and realized H-mode using ICRF power alone in 2012. In 2010, H-modes were generated and sustained by LHCD alone, where lithium coating and gas puffing near the mouth of the LH launcher were applied to improve the LHCD power coupling and penetration into the core plasmas of H-modes. In 2012, the combination of LHCD and ICRH power extended the H-mode duration up to over 30 s. H-modes with various types of edge localized modes (ELMs) have been achieved with H{sub IPB98}(y, 2) ranging from 0.7 to over unity. A brief overview of LHCD and ICRF Heating experiment and their application in achieving H-mode operation during these two campaigns will be presented.

  12. FEL on slow cyclotron wave

    SciTech Connect

    Silivra, A.

    1995-12-31

    A physical mechanism of interaction of fast electromagnetic wave with slow cyclotron wave of relativistic electron beam in a FEL with helical wiggler field is described. It is shown that: (1) interaction is possible for both group of steady state electron trajectories (2) positive gain is achieved within certain interval of guide field strength (3) operation wavelength for group 1 trajectories ({Omega}{sub 0}/{gamma} < k{omega}{upsilon}{parallel}) is shorter than for the conventional FEL synchronism. A nonlinear analysis shows that efficiency of slow cyclotron FEL is restricted mainly by a breakdown of a single electron synchronism due to dependence of (modified) electron cyclotron frequency on an energy of electron. Nevertheless, as numerical simulation shows, typical efficiency of 15 % order is achieved in millimeter wavelength band for the midrelativistic ({gamma}= 3 {divided_by} 4) slow cyclotron wave FEL. Tapering of magnetic field results in a substantial increase of efficiency.

  13. Iterated finite-orbit Monte Carlo simulations with full-wave fields for modeling tokamak ion cyclotron resonance frequency wave heating experiments

    SciTech Connect

    Choi, M.; Chan, V. S.; Lao, L. L.; Pinsker, R. I.; Green, D.; Berry, L. A.; Jaeger, F.; Park, J. M.; Heidbrink, W. W.; Liu, D.; Podesta, M.; Harvey, R.; Smithe, D. N.; Bonoli, P.

    2010-05-15

    The five-dimensional finite-orbit Monte Carlo code ORBIT-RF[M. Choi et al., Phys. Plasmas 12, 1 (2005)] is successfully coupled with the two-dimensional full-wave code all-orders spectral algorithm (AORSA) [E. F. Jaeger et al., Phys. Plasmas 13, 056101 (2006)] in a self-consistent way to achieve improved predictive modeling for ion cyclotron resonance frequency (ICRF) wave heating experiments in present fusion devices and future ITER [R. Aymar et al., Nucl. Fusion 41, 1301 (2001)]. The ORBIT-RF/AORSA simulations reproduce fast-ion spectra and spatial profiles qualitatively consistent with fast ion D-alpha [W. W. Heidbrink et al., Plasma Phys. Controlled Fusion 49, 1457 (2007)] spectroscopic data in both DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] and National Spherical Torus Experiment [M. Ono et al., Nucl. Fusion 41, 1435 (2001)] high harmonic ICRF heating experiments. This work verifies that both finite-orbit width effect of fast-ion due to its drift motion along the torus and iterations between fast-ion distribution and wave fields are important in modeling ICRF heating experiments.

  14. Iterated finite-orbit Monte Carlo simulations with full-wave fields for modeling tokamak ion cyclotron resonance frequency wave heating experiments

    SciTech Connect

    Choi, M.; Green, David L; Heidbrink, W. W.; Harvey, R. W.; Liu, D.; Chan, V. S.; Berry, Lee A; Jaeger, Erwin Frederick; Lao, L.L.; Pinsker, R. I.; Podesta, M.; Smithe, D. N.; Park, J. M.; Bonoli, P.

    2010-01-01

    The five-dimensional finite-orbit Monte Carlo code ORBIT-RF [M. Choi , Phys. Plasmas 12, 1 (2005)] is successfully coupled with the two-dimensional full-wave code all-orders spectral algorithm (AORSA) [E. F. Jaeger , Phys. Plasmas 13, 056101 (2006)] in a self-consistent way to achieve improved predictive modeling for ion cyclotron resonance frequency (ICRF) wave heating experiments in present fusion devices and future ITER [R. Aymar , Nucl. Fusion 41, 1301 (2001)]. The ORBIT-RF/AORSA simulations reproduce fast-ion spectra and spatial profiles qualitatively consistent with fast ion D-alpha [W. W. Heidbrink , Plasma Phys. Controlled Fusion 49, 1457 (2007)] spectroscopic data in both DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] and National Spherical Torus Experiment [M. Ono , Nucl. Fusion 41, 1435 (2001)] high harmonic ICRF heating experiments. This work verifies that both finite-orbit width effect of fast-ion due to its drift motion along the torus and iterations between fast-ion distribution and wave fields are important in modeling ICRF heating experiments. (C) 2010 American Institute of Physics. [doi:10.1063/1.3314336

  15. A new B-dot probe-based diagnostic for amplitude, polarization, and wavenumber measurements of ion cyclotron range-of frequency fields on ASDEX Upgrade.

    PubMed

    Ochoukov, R; Bobkov, V; Faugel, H; Fünfgelder, H; Noterdaeme, J-M

    2015-11-01

    A new B-dot probe-based diagnostic has been installed on an ASDEX Upgrade tokamak to characterize ion cyclotron range-of frequency (ICRF) wave generation and interaction with magnetized plasma. The diagnostic consists of a field-aligned array of B-dot probes, oriented to measure fast and slow ICRF wave fields and their field-aligned wavenumber (k(//)) spectrum on the low field side of ASDEX Upgrade. A thorough description of the diagnostic and the supporting electronics is provided. In order to compare the measured dominant wavenumber of the local ICRF fields with the expected spectrum of the launched ICRF waves, in-air near-field measurements were performed on the newly installed 3-strap ICRF antenna to reconstruct the dominant launched toroidal wavenumbers (k(tor)). Measurements during a strap current phasing scan in tokamak discharges reveal an upshift in k(//) as strap phasing is moved away from the dipole configuration. This result is the opposite of the k(tor) trend expected from in-air near-field measurements; however, the near-field based reconstruction routine does not account for the effect of induced radiofrequency (RF) currents in the passive antenna structures. The measured exponential increase in the local ICRF wave field amplitude is in agreement with the upshifted k(//), as strap phasing moves away from the dipole configuration. An examination of discharges heated with two ICRF antennas simultaneously reveals the existence of beat waves at 1 kHz, as expected from the difference of the two antennas' operating frequencies. Beats are observed on both the fast and the slow wave probes suggesting that the two waves are coupled outside the active antennas. Although the new diagnostic shows consistent trends between the amplitude and the phase measurements in response to changes applied by the ICRF antennas, the disagreement with the in-air near-field measurements remains. An electromagnetic model is currently under development to address this issue.

  16. A new B-dot probe-based diagnostic for amplitude, polarization, and wavenumber measurements of ion cyclotron range-of frequency fields on ASDEX Upgrade

    NASA Astrophysics Data System (ADS)

    Ochoukov, R.; Bobkov, V.; Faugel, H.; Fünfgelder, H.; Noterdaeme, J.-M.

    2015-11-01

    A new B-dot probe-based diagnostic has been installed on an ASDEX Upgrade tokamak to characterize ion cyclotron range-of frequency (ICRF) wave generation and interaction with magnetized plasma. The diagnostic consists of a field-aligned array of B-dot probes, oriented to measure fast and slow ICRF wave fields and their field-aligned wavenumber (k//) spectrum on the low field side of ASDEX Upgrade. A thorough description of the diagnostic and the supporting electronics is provided. In order to compare the measured dominant wavenumber of the local ICRF fields with the expected spectrum of the launched ICRF waves, in-air near-field measurements were performed on the newly installed 3-strap ICRF antenna to reconstruct the dominant launched toroidal wavenumbers (ktor). Measurements during a strap current phasing scan in tokamak discharges reveal an upshift in k// as strap phasing is moved away from the dipole configuration. This result is the opposite of the ktor trend expected from in-air near-field measurements; however, the near-field based reconstruction routine does not account for the effect of induced radiofrequency (RF) currents in the passive antenna structures. The measured exponential increase in the local ICRF wave field amplitude is in agreement with the upshifted k//, as strap phasing moves away from the dipole configuration. An examination of discharges heated with two ICRF antennas simultaneously reveals the existence of beat waves at 1 kHz, as expected from the difference of the two antennas' operating frequencies. Beats are observed on both the fast and the slow wave probes suggesting that the two waves are coupled outside the active antennas. Although the new diagnostic shows consistent trends between the amplitude and the phase measurements in response to changes applied by the ICRF antennas, the disagreement with the in-air near-field measurements remains. An electromagnetic model is currently under development to address this issue.

  17. CLOVERLEAF CYCLOTRON

    DOEpatents

    McMillan, E.M.; Judd, D.L.

    1959-02-01

    A cyclotron is presented embodying a unique magnetic field configuration, which configuration increases in intensity with radius and therefore compensates for the reltivistic mass effect, the field having further convolutions productive of axial stability in the particle beam. By reconciling the seemingly opposed requirements of mass increase compensation on one hand and anial stability on the other, the production of extremely high current particle beams in the relativistie energy range is made feasible. Certain further advantages inhere in the invention, notably an increase in the usable magnet gap, simplified and more efficient extraction of the beam from the accelerator, and ready adaptation to the use of multiply phased excitation as contrasted with the single phased systems herstofore utilized. General

  18. A new B-dot probe-based diagnostic for amplitude, polarization, and wavenumber measurements of ion cyclotron range-of frequency fields on ASDEX Upgrade

    SciTech Connect

    Ochoukov, R.; Bobkov, V.; Faugel, H.; Fünfgelder, H.; Noterdaeme, J.-M.

    2015-11-15

    A new B-dot probe-based diagnostic has been installed on an ASDEX Upgrade tokamak to characterize ion cyclotron range-of frequency (ICRF) wave generation and interaction with magnetized plasma. The diagnostic consists of a field-aligned array of B-dot probes, oriented to measure fast and slow ICRF wave fields and their field-aligned wavenumber (k{sub //}) spectrum on the low field side of ASDEX Upgrade. A thorough description of the diagnostic and the supporting electronics is provided. In order to compare the measured dominant wavenumber of the local ICRF fields with the expected spectrum of the launched ICRF waves, in-air near-field measurements were performed on the newly installed 3-strap ICRF antenna to reconstruct the dominant launched toroidal wavenumbers (k{sub tor}). Measurements during a strap current phasing scan in tokamak discharges reveal an upshift in k{sub //} as strap phasing is moved away from the dipole configuration. This result is the opposite of the k{sub tor} trend expected from in-air near-field measurements; however, the near-field based reconstruction routine does not account for the effect of induced radiofrequency (RF) currents in the passive antenna structures. The measured exponential increase in the local ICRF wave field amplitude is in agreement with the upshifted k{sub //}, as strap phasing moves away from the dipole configuration. An examination of discharges heated with two ICRF antennas simultaneously reveals the existence of beat waves at 1 kHz, as expected from the difference of the two antennas’ operating frequencies. Beats are observed on both the fast and the slow wave probes suggesting that the two waves are coupled outside the active antennas. Although the new diagnostic shows consistent trends between the amplitude and the phase measurements in response to changes applied by the ICRF antennas, the disagreement with the in-air near-field measurements remains. An electromagnetic model is currently under development to

  19. Beamline pulsing system for cyclotrons

    NASA Astrophysics Data System (ADS)

    Heikkinen, Jouko; Gustafsson, Jouni; Kivikoski, Markku; Liukkonen, Esko; Nieminen, Veikko

    A beamline pulsing system for cyclotrons is presented. The function of this system is to modify the structure of a cyclotron ion beam guided to the desired research target by a beamline. In some in-beam experiments, an adjustment of the time structure of the beam is sometimes needed. This kind of situation occurs if, for example, the life time of the target material is longer than the period corresponding to the beam frequency. In this case, the frequency of the ion pulses hitting the target is 10-21 MHz depending on the frequency of the acceleration voltage. The adjustment of the ion beam pulse frequency is carried out by a beamline deflector. Deflection is achieved by feeding a high-amplitude (10-15 kV) RF-signal between the deflection plates positioned into the beamline. This signal is generated from the cyclotron reference signal by frequency division, phase adjustment and amplification. Simulation and test results indicate that the specified deflection signal level is achieved with 1 kW of RF-power.

  20. Cyclotron axial ion-beam-buncher system

    SciTech Connect

    Hamm, R.W.; Swenson, D.A.; Wangler, T.P.

    1982-02-11

    Adiabatic ion bunching is achieved in a cyclotron axial ion injection system through the incorporation of a radio frequency quadrupole system, which receives ions from an external ion source via an accelerate-decelerate system and a focusing einzel lens system, and which adiabatically bunches and then injects the ions into the median plane of a cyclotron via an electrostatic quadrupole system and an inflection mirror.

  1. 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.

  2. Electromagnetic ion cyclotron waves at proton cyclotron harmonics

    NASA Astrophysics Data System (ADS)

    Chaston, C. C.; Bonnell, J. W.; McFadden, J. P.; Ergun, R. E.; Carlson, C. W.

    2002-11-01

    Waves with frequencies in the vicinity of the proton cyclotron frequency and its harmonics are commonly observed from the Fast Auroral Snapshot spacecraft when traversing regions of auroral particle acceleration. In areas of upward current, large-amplitude electromagnetic waves with frequencies within 5% of the local proton gyrofrequency Ωp and its harmonics are often observed where upstreaming ion beams exist. These waves have electric field (E1) and magnetic field (B1) amplitudes of up to 1 V m-1 and 2 nT with the ratio E1/B1 as small as c. The waves occur in the low-altitude portion of the primary auroral acceleration potential, where plasma densities are ≤1 cm-3. It is shown how these waves grow through inverse Landau resonance with a cold field-aligned electron beam superimposed on an accelerated and magnetically mirrored plasma sheet electron component in the absence of any significant plasma densities at energies below ˜100 eV. Significantly, the drift velocity of the cold beam (voeb) is several times larger than its thermal velocity veb, and it is this feature that allows the wave to become electromagnetic at cyclotron harmonics while simultaneously giving rise to broadband electrostatic emissions spanning the first few cyclotron harmonics as is observed.

  3. Method and apparatuses for ion cyclotron spectrometry

    DOEpatents

    Dahl, David A.; Scott, Jill R.; McJunkin, Timothy R.

    2012-03-06

    An ion cyclotron spectrometer may include a vacuum chamber that extends at least along a z-axis and means for producing a magnetic field within the vacuum chamber so that a magnetic field vector is generally parallel to the z-axis. The ion cyclotron spectrometer may also include means for producing a trapping electric field within the vacuum chamber. The trapping electric field may comprise a field potential that, when taken in cross-section along the z-axis, includes at least one section that is concave down and at least one section that is concave up so that ions traversing the field potential experience a net magnetron effect on a cyclotron frequency of the ions that is substantially equal to zero. Other apparatuses and a method for performing ion cyclotron spectrometry are also disclosed herein.

  4. Comparison of particle-in-cell simulations with experimentally observed frequency shifts between ions of the same mass-to-charge in Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Leach, Franklin E; Kharchenko, Andriy; Heeren, Ron M A; Nikolaev, Eugene; Amster, I Jonathan

    2010-02-01

    It has been previously observed that the measured frequency of ions in a Fourier transform mass spectrometry experiment depend upon the number of trapped ions, even for populations consisting exclusively of a single mass-to-charge. Since ions of the same mass-to-charge are thought not to exert a space-charge effect among themselves, the experimental observation of such frequency shifts raises questions about their origin. To determine the source of such experimentally observed frequency shifts, multiparticle ion trajectory simulations have been conducted on monoisotopic populations of Cs(+) ranging from 10(2) ions to 10(6) ions. A close match to experimental behavior is observed. By probing the effect of ion number and orbital radius on the shift in the cyclotron frequency, it is shown that for a monoisotopic population of ions, the frequency shift is caused by the interaction of ions with their image-charge. The addition of ions of a second mass-to-charge to the simulation allows the comparison of the magnitude of the frequency shift resulting from space-charge (ion-ion) effects versus ion interactions with their image charge.

  5. 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.

  6. 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.

  7. 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.

  8. Experimental results of an electron cyclotron resonance oxygen source and a low energy beam transport system for 1 MeV integral split ring radio frequency quadruple accelerator upgrade project

    SciTech Connect

    Peng, S. X.; Zhang, M.; Song, Z. Z.; Xu, R.; Zhao, J.; Yuan, Z. X.; Yu, J. X.; Chen, J.; Guo, Z. Y.

    2008-02-15

    To meet the requirements of developing separated function radio frequency quadruple (rfq) and upgrading the 1 MeV integral split ring rfq accelerator, an electron cyclotron resonance O{sup +} ion source and low energy beam transport (LEBT) system have been developed. Using two Einzel lenses to focus the beam, more than 6 mA O{sup +} peak beam current with energy of 22 keV can be easily obtained at the end of LEBT when the duty faction is at 1/6. The normalized root-mean-square emittance of 90% of the beam is about 0.12{pi} mm mrad. By changing the focusing power of lenses, the beam waist can be shifted from 80 mm before the beam diaphragm 2 to 80 mm after it. The experimental results will be presented in this article.

  9. Beam buncher for the K130-cyclotron

    NASA Astrophysics Data System (ADS)

    Saario, J.; Gustafsson, J.; Kotilainen, P.; Kaski, K.; Lassila, A.; Liukkonen, E.

    1996-02-01

    A beam buncher, developed to improve the beam efficiency in the K130 cyclotron at University of Jyväskylä, is described. The basic acceleration frequency and the second harmonic component were used to simulate a saw-tooth wave, needed for axial injection of the beam. With this method up to eight times increase in the beam intensity was achieved.

  10. Ion-cyclotron instability in magnetic mirrors

    SciTech Connect

    Pearlstein, L.D.

    1987-02-02

    This report reviews the role of ion-cyclotron frequency instability in magnetic mirrors. The modes discussed here are loss-cone or anisotropy driven. The discussion includes quasilinear theory, explosive instabilities of 3-wave interaction and non-linear Landau damping, and saturation due to non-linear orbits. (JDH)

  11. Cyclotron Institute Upgrade Project

    SciTech Connect

    Clark, Henry; Yennello, Sherry; Tribble, Robert

    2014-08-26

    The Cyclotron Institute at Texas A&M University has upgraded its accelerator facilities to extend research capabilities with both stable and radioactive beams. The upgrade is divided into three major tasks: (1) re-commission the K-150 (88”) cyclotron, couple it to existing beam lines to provide intense stable beams into the K-500 experimental areas and use it as a driver to produce radioactive beams; (2) develop light ion and heavy ion guides for stopping radioactive ions created with the K-150 beams; and (3) transport 1+ ions from the ion guides into a charge-breeding electron-cyclotron-resonance ion source (CB-ECR) to produce highly-charged radioactive ions for acceleration in the K-500 cyclotron. When completed, the upgraded facility will provide high-quality re-accelerated secondary beams in a unique energy range in the world.

  12. Cyclotron resonance cooling by strong laser field

    SciTech Connect

    Tagcuhi, Toshihiro; Mima, Kunioka

    1995-12-31

    Reduction of energy spread of electron beam is very important to increase a total output radiation power in free electron lasers. Although several cooling systems of particle beams such as a stochastic cooling are successfully operated in the accelerator physics, these cooling mechanisms are very slow and they are only applicable to high energy charged particle beams of ring accelerators. We propose here a new concept of laser cooling system by means of cyclotron resonance. Electrons being in cyclotron motion under a strong magnetic field can resonate with circular polarized electromagnetic field, and the resonance take place selectively depending on the velocity of the electrons. If cyclotron frequency of electrons is equal to the frequency of the electromagnetic field, they absorb the electromagnetic field energy strongly, but the other electrons remain unchanged. The absorbed energy will be converted to transverse kinetic energy, and the energy will be dumped into the radiation energy through bremastrahlung. To build a cooling system, we must use two laser beams, where one of them is counter-propagating and the other is co-propagating with electron beam. When the frequency of the counter-propagating laser is tuned with the cyclotron frequency of fast electrons and the co-propagating laser is tuned with the cyclotron frequency of slow electrons, the energy of two groups will approach and the cooling will be achieved. We solve relativistic motions of electrons with relativistic radiation dumping force, and estimate the cooling rate of this mechanism. We will report optimum parameters for the electron beam cooling system for free electron lasers.

  13. 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.

  14. 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

  15. 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.

  16. Electrostatic ion-cyclotron waves in a two-ion component plasma

    NASA Technical Reports Server (NTRS)

    Suszcynsky, David M.; Merlino, Robert L.; D'Angelo, Nicola

    1988-01-01

    The excitation of electrostatic ion cyclotron (EIC) waves is studied in a single-ended Q machine in a two-ion component plasma (Ca+ and K+). Over a large range of relative concentrations of Cs+ and K+ ions, two modes are excited with frequencies greater than the respective cyclotron frequencies of the ions. The results are discussed in terms of a fluid theory of electrostatic ion cyclotron waves in a two-ion component plasma.

  17. 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.

  18. Xe/+/ -induced ion-cyclotron harmonic waves

    NASA Astrophysics Data System (ADS)

    Jones, D.

    Xenon ion sources on an ejectable package separated from the main payload during the flights of Porcupine rockets F3 and F4 which were launched from Kiruna, Sweden on March 19 and 31, 1979, respectively. The effects of the xenon ion beam, detected by the LF (f less than 16 kHz) wideband electric field experiment and analyzed by using a sonograph, are discussed. Particular attention is given to the stimulation of the ion-cyclotron harmonic waves which are usually linked to the local proton gyro-frequency, but are sometimes related to half that frequency. It was found that in a plasma dominated by O(+) ions, a small amount (1-10%) of protons could cause an effect such that the O(+) cyclotron harmonic waves are set up by the hydrogen ions, the net result being the observation of harmonic emissions separated by the hydrogen ion gyro frequency.

  19. K-130 Cyclotron vacuum system

    NASA Astrophysics Data System (ADS)

    Yadav, R. C.; Bhattacharya, S.; Bhole, R. B.; Roy, Anindya; Pal, Sarbajit; Mallik, C.; Bhandari, R. K.

    2012-11-01

    The vacuum system for K-130 cyclotron has been operational since 1977. It consists of two sub-systems, main vacuum system and beam line vacuum system. The main vacuum system is designed to achieve and maintain vacuum of about 1 × 10-6 mbar inside the 23 m3 volume of acceleration chamber comprising the Resonator tank and the Dee tank. The beam line vacuum system is required for transporting the extracted beam with minimum loss. These vacuum systems consist of diffusion pumps backed by mechanical pumps like roots and rotary pumps. The large vacuum pumps and valves of the cyclotron vacuum system were operational for more than twenty five years. In recent times, problems of frequent failures and maintenance were occurring due to aging and lack of appropriate spares. Hence, modernisation of the vacuum systems was taken up in order to ensure a stable high voltage for radio frequency system and the extraction system. This is required for efficient acceleration and transportation of high intensity ion beam. The vacuum systems have been upgraded by replacing several pumps, valves, gauges and freon units. The relay based control system for main vacuum system has also been replaced by PLC based state of the art control system. The upgraded control system enables inclusion of additional operational logics and safety interlocks into the system. The paper presents the details of the vacuum system and describes the modifications carried out for improving the performance and reliability of the vacuum system.

  20. 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.

  1. Cyclotron Research and Applications

    SciTech Connect

    Mach, Rostislav

    2010-01-05

    The twenty years old cyclotron U-120M was upgraded for R and D and Production of Radiopharmaceuticals. R and D on short-lived Radiopharmaceuticals production is done at this accelerator. These Radiopharmaceuticals are eventually delivered to nearby hospitals. Development of new diagnostic radiopharmaceuticals is also pursued at the facility. your paper.

  2. Electromagnetic cyclotron waves in the solar wind: Wind observation and wave dispersion analysis

    NASA Astrophysics Data System (ADS)

    Jian, L. K.; Moya, P. S.; Viñas, A. F.; Stevens, M.

    2016-03-01

    Wind observed long-lasting electromagnetic cyclotron waves near the proton cyclotron frequency on 11 March 2005, in the descending part of a fast wind stream. Bi-Maxwellian velocity distributions are fitted for core protons, beam protons, and α-particles. Using the fitted plasma parameters we conduct kinetic linear dispersion analysis and find ion cyclotron and/or firehose instabilities grow in six of 10 wave intervals. After Doppler shift, some of the waves have frequency and polarization consistent with observation, thus may be correspondence to the cyclotron waves observed.

  3. A new ion cyclotron range of frequency scenario for bulk ion heating in deuterium-tritium plasmas: How to utilize intrinsic impurities in our favour

    SciTech Connect

    Kazakov, Ye. O.; Ongena, J.; Van Eester, D.; Lerche, E.; Messiaen, A.; Dumont, R.; Mantsinen, M.

    2015-08-15

    A fusion reactor requires plasma pre-heating before the rate of deuterium-tritium fusion reactions becomes significant. In ITER, radio frequency (RF) heating of {sup 3}He ions, additionally puffed into the plasma, is one of the main options considered for increasing bulk ion temperature during the ramp-up phase of the pulse. In this paper, we propose an alternative scenario for bulk ion heating with RF waves, which requires no extra {sup 3}He puff and profits from the presence of intrinsic Beryllium impurities in the plasma. The discussed method to heat Be impurities in D-T plasmas is shown to provide an even larger fraction of fuel ion heating.

  4. 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.

  5. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole

    SciTech Connect

    Rodrigues, G. Kanjilal, D.; Roy, A.; Becker, R.; Baskaran, R.

    2014-02-15

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged {sup 238}U{sup 40+} (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

  6. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole.

    PubMed

    Rodrigues, G; Becker, R; Hamm, R W; Baskaran, R; Kanjilal, D; Roy, A

    2014-02-01

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged (238)U(40+) (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

  7. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole

    NASA Astrophysics Data System (ADS)

    Rodrigues, G.; Becker, R.; Hamm, R. W.; Baskaran, R.; Kanjilal, D.; Roy, A.

    2014-02-01

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged 238U40+ (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

  8. Backward mode of the ion-cyclotron wave in a semi-bounded magnetized Lorentzian plasma

    SciTech Connect

    Ki, Dae-Han; Jung, Young-Dae

    2012-08-15

    The backward modes of the surface ion-cyclotron wave are investigated in a semi-bounded magnetized Lorentzian plasma. The dispersion relation of the backward mode of the surface ion-cyclotron wave is obtained using the specular reflection boundary condition with the plasma dielectric function. The result shows that the nonthermal effect suppresses the wave frequency as well as the group velocity of the surface ion-cyclotron wave. It is also found that the nonthermal effect on the surface ion-cyclotron wave increases with an increase of the wave number. In addition, it is found that the propagation domain of the surface ion-cyclotron wave increases with an increase of the ratio of the electron plasma frequency to the electron gyrofrequency. It is also found that the nonthermal effect increases the propagation domain of the surface ion-cyclotron wave in a semi-bounded magnetized Lorentzian plasma.

  9. Tandem mirror ICRF (ion cyclotron range of frequency) and SRX (Second Region Experiment) physics analyses: Progress report for period August 15, 1986-April 14, 1987

    SciTech Connect

    Not Available

    1987-04-01

    The ICRF electromagnetic fields are solved for an axisymmetric mirror plasma. For these calculations a numerical code that solves for global wave solutions of the cold plasma wave equation is used. The resulting radial ponderomotive force is evaluated and its possible impact on MHD stability is discussed. The slow wave is always found to be present and dominates the electric field structure when ..omega.. < ..cap omega../sub ci min/. The radial ponderomotive force is stabilizing when ..omega.. > ..cap omega../sub ci min/ but becomes destabilizing at higher densities and driving frequencies. So called low n 'infernal' modes which reflect a breakdown in standard ballooning theory at low shear in presence of significant pressure gradients have been codiscovered. Intermediate n infernal behavior is found to set the most stringent requirement for second region access and operation. Access to the high ..beta.., second region of MHD stability has been studied for large aspect ratio (A > 6) near circular cross section tokamak geometry. Evolving high epsilon..beta..phi equilibria generated by a 1-1/2D Transport code have been analyzed for both high and low n, internal and external mode stability. Neutral beam induced current programming is shown to modify the shear profile and to drive q on axis significantly above unity. This reduces the radial extent of the unstable zone which develops and the time required to cross it, thus reducing the demands on alternate stabilization mechanisms. These calculations show transition to the second region when epsilon..beta..phi greater than or equal to 1. An enhanced transport model, triggered locally by n = infinity unstable flux surfaces, suggests that controlled transition to the second region is possible solely with current profile programming that raises q/sub 0/ greater than or equal to 1.5 at plausible auxiliary heating power levels (approx.3.5 MW) for SRX parameters. 25 refs., 30 figs., 5 tabs.

  10. 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.

  11. Design Study Of Cyclotron Magnet With Permanent Magnet

    SciTech Connect

    Kim, Hyun Wook; Chai, Jong Seo

    2011-06-01

    Low energy cyclotrons for Positron emission tomography (PET) have been wanted for the production of radio-isotopes after 2002. In the low energy cyclotron magnet design, increase of magnetic field between the poles is needed to make a smaller size of magnet and decrease power consumption. The Permanent magnet can support this work without additional electric power consumption in the cyclotron. In this paper the study of cyclotron magnet design using permanent magnet is shown and also the comparison between normal magnet and the magnet which is designed with permanent magnet is shown. Maximum energy of proton is 8 MeV and RF frequency is 79.3 MHz. 3D CAD design was done by CATIA P3 V5 R18 and the All field calculations had been performed by OPERA-3D TOSCA. The self-made beam dynamics program OPTICY is used for making isochronous field and other calculations.

  12. Design Study Of Cyclotron Magnet With Permanent Magnet

    NASA Astrophysics Data System (ADS)

    Kim, Hyun Wook; Chai, Jong Seo

    2011-06-01

    Low energy cyclotrons for Positron emission tomography (PET) have been wanted for the production of radio-isotopes after 2002. In the low energy cyclotron magnet design, increase of magnetic field between the poles is needed to make a smaller size of magnet and decrease power consumption. The Permanent magnet can support this work without additional electric power consumption in the cyclotron. In this paper the study of cyclotron magnet design using permanent magnet is shown and also the comparison between normal magnet and the magnet which is designed with permanent magnet is shown. Maximum energy of proton is 8 MeV and RF frequency is 79.3 MHz. 3D CAD design was done by CATIA P3 V5 R18 [1] and the All field calculations had been performed by OPERA-3D TOSCA [2]. The self-made beam dynamics program OPTICY [3] is used for making isochronous field and other calculations.

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

    SciTech Connect

    England, A.C.

    1983-01-01

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

  14. Ion Cyclotron Waves at Titan

    NASA Astrophysics Data System (ADS)

    Russell, C. T.; Wei, H.; Cowee, M.; Neubauer, F. M.; Dougherty, M. K.

    2014-12-01

    The observation of ion cyclotron waves was generally expected well before Cassini arrived at Titan in 2004, because strong ion cyclotron waves were seen at Io where its atmosphere interacted with the corotating magnetospheric plasma. However, the region of the interaction of the Saturnian magnetospheric plasma with the Titan atmosphere has been quite devoid of ion cyclotron waves. Finally, on pass T63, ion cyclotron waves were seen briefly. More recently, on pass T98, a longer sequence of ion cyclotron waves also occurred. On pass T63, the pick-up ion signature is that of both H+ and H2+, while on pass T98, only H+ ion cyclotron waves are observed. We examine the strength of these waves and their region of occurrence in the light of our previous work on the expected occurrence of these waves.

  15. Relativistic electromagnetic ion cyclotron instabilities.

    PubMed

    Chen, K R; Huang, R D; Wang, J C; Chen, Y Y

    2005-03-01

    The relativistic instabilities of electromagnetic ion cyclotron waves driven by MeV ions are analytically and numerically studied. As caused by wave magnetic field and in sharp contrast to the electrostatic case, interesting characteristics such as Alfve nic behavior and instability transition are discovered and illuminated in detail. The instabilities are reactive and are raised from the coupling of slow ions' first-order resonance and fast ions' second-order resonance, that is an essential extra mechanism due to relativistic effect. Because of the wave magnetic field, the nonresonant plasma dielectric is usually negative and large, that affects the instability conditions and scaling laws. A negative harmonic cyclotron frequency mismatch between the fast and slow ions is required for driving a cubic (and a coupled quadratic) instability; the cubic (square) root scaling of the peak growth rate makes the relativistic effect more important than classical mechanism, especially for low fast ion density and Lorentz factor being close to unity. For the cubic instability, there is a threshold (ceiling) on the slow ion temperature and density (the external magnetic field and the fast ion energy); the Alfve n velocity is required to be low. This Alfve nic behavior is interesting in physics and important for its applications. The case of fast protons in thermal deuterons is numerically studied and compared with the analytical results. When the slow ion temperature or density (the external magnetic field or the fast ion energy) is increased (reduced) to about twice (half) the threshold (ceiling), the same growth rate peak transits from the cubic instability to the coupled quadratic instability and a different cubic instability branch appears. The instability transition is an interesting new phenomenon for instability. PMID:15903591

  16. A laboratory study of collisional electrostatic ion cyclotron waves

    NASA Technical Reports Server (NTRS)

    Suszcynsky, D. M.; Cartier, S. L.; Merlino, R. L.; Dangelo, N.

    1986-01-01

    The effects of neutral-particle collisions on electrostatic ion cyclotron instability are analyzed. Experiments were conducted in the Q machine of Motley (1975) with a cesium plasma in which the neutral gas pressure in the main chamber varied from about 5 microtorr-10 mtorr. The relation between electrostatic ion cyclotron wave amplitude and frequency and neutral argon pressure is examined. It is observed that over the full range of neutral pressure the frequency changes by less than 10 percent and the ion cyclotron waves continue to be excited and reach amplitudes of at least several percent at values of the neutral pressure where the ion-neutral collision frequency/ion gyrofrequency is about 0.3.

  17. Cyclotron waves in a non-neutral plasma column

    SciTech Connect

    Dubin, Daniel H. E.

    2013-04-15

    A kinetic theory of linear electrostatic plasma waves with frequencies near the cyclotron frequency {Omega}{sub c{sub s}} of a given plasma species s is developed for a multispecies non-neutral plasma column with general radial density and electric field profiles. Terms in the perturbed distribution function up to O(1/{Omega}{sub c{sub s}{sup 2}}) are kept, as are the effects of finite cyclotron radius r{sub c} up to O(r{sub c}{sup 2}). At this order, the equilibrium distribution is not Maxwellian if the plasma temperature or rotation frequency is not uniform. For r{sub c}{yields}0, the theory reproduces cold-fluid theory and predicts surface cyclotron waves propagating azimuthally. For finite r{sub c}, the wave equation predicts that the surface wave couples to radially and azimuthally propagating Bernstein waves, at locations where the wave frequency equals the local upper hybrid frequency. The equation also predicts a second set of Bernstein waves that do not couple to the surface wave, and therefore have no effect on the external potential. The wave equation is solved both numerically and analytically in the WKB approximation, and analytic dispersion relations for the waves are obtained. The theory predicts that both types of Bernstein wave are damped at resonances, which are locations where the Doppler-shifted wave frequency matches the local cyclotron frequency as seen in the rotating frame.

  18. Electrostatic ion cyclotron velocity shear instability

    NASA Technical Reports Server (NTRS)

    Lemons, D. S.; Winske, D.; Gary, S. P.

    1992-01-01

    A local electrostatic dispersion equation is derived for a shear flow perpendicular to an ambient magnetic field, which includes all kinetic effects and involves only one important parameter. The dispersion equation is cast in the form of Gordeyev integrals and is solved numerically. Numerical solutions indicate that an ion cyclotron instability is excited. The instability occurs roughly at multiples of the ion cyclotron frequency (modified by the shear), with the growth rate or the individual harmonics overlapping in the wavenumber. At large values of the shear parameter, the instability is confined to long wavelengths, but at smaller shear, a second distinct branch at shorter wavelengths also appears. The properties of the instability obtained are compared with those obtained in the nonlocal limit by Ganguli et al. (1985, 1988).

  19. 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.

  20. Electromagnetic Ion Cyclotron Waves in the Helium Branch Induced by Multiple Electromagnetic Ion Cyclotron Triggered Emissions

    NASA Astrophysics Data System (ADS)

    Shoji, M.; Omura, Y.; Grison, B.; Pickett, J. S.; Dandouras, I. S.; Engebretson, M. J.

    2011-12-01

    Electromagnetic ion cyclotron (EMIC) triggered emissions with rising tones between the H+ and He+ cyclotron frequencies were found in the inner magnetosphere by the recent Cluster observations. Another type of EMIC wave with a constant frequency is occasionally observed below the He+ cyclotron frequency after the multiple EMIC triggered emissions. We performed a self-consistent hybrid simulation with a one-dimensional cylindrical magnetic flux model approximating the dipole magnetic field of the Earth's inner magnetosphere. In the presence of energetic protons with a sufficient density and temperature anisotropy, multiple EMIC triggered emissions are reproduced due to the nonlinear wave growth mechanism of rising-tone chorus emissions, and a constant frequency wave in the He+ EMIC branch is subsequently generated. Through interaction with the multiple EMIC rising-tone emissions, the velocity distribution function of the energetic protons is strongly modified. Because of the pitch angle scattering of the protons, the gradient of the distribution in velocity phase space is enhanced along the diffusion curve of the He+ branch wave, resulting in the linear growth of the EMIC wave in the He+ branch.

  1. Ion Cyclotron Waves at Titan: Harbingers of Atmospheric Loss

    NASA Astrophysics Data System (ADS)

    Russell, C. T.; Wei, H. Y.; Cowee, M. M.; Neubauer, F.; Dougherty, M. K.

    2014-04-01

    When a flowing magnetized plasma intercepts a neutral atmosphere such as Titan's exosphere, we expect that any atoms or molecules that become ionized by photoionization impact ionization or charge exchange could lead to the acceleration and pick-up of those newly formed ions. This process creates an ion distribution function that often is highly unstable to the production of ion-cyclotron waves. Such waves have been observed in the Earth's polar cusp [1], at the Moon [2], at Mars [3], at Io [4], and at Enceladus [5]. We had expected also to observe these waves at Titan but neither the Voyager Titan passage nor the early Cassini Titan flybys produced ion-cyclotron waves. Modelling studies have suggested that the growth time is long and the waves will not grow until some distance far downstream. However, on two passes by Titan T63 and T98, ion cyclotron waves have been seen with the T98 wave field having been much more pronounced. Figure 1 below shows the transverse and compressional power as dynamic spectra versus time on the T98 inbound pass to Titan. The ion cyclotron waves clearly arise at the expected frequency just below the piston cyclotron frequency. It is remarkable that no such waves are seen outbound at T98.This is in agreement with the initial trajectories of newborn ions which lead away from the dense deeper atmosphere inbound and into the dense deeper atmosphere outbound. On the T63 pass, a short period of waves was seen near the proton and H2+ cyclotron frequencies. We discuss these rare ion cyclotron waves at Titan in the light of hybrid simulations of ion pickup under conditions in Saturn's outer magnetosphere.

  2. 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.

  3. Quantum non demolition measurement of cyclotron excitations in a Penning trap

    NASA Technical Reports Server (NTRS)

    Marzoli, Irene; Tombesi, Paolo

    1993-01-01

    The quantum non-demolition measurement of the cyclotron excitations of an electron confined in a Penning trap could be obtained by measuring the resonance frequency of the axial motion, which is coupled to the cyclotron motion through the relativistic shift of the electron mass.

  4. 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.

  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. Relativistic Cyclotron Resonance Shape in Magnetic Bottle Geonium

    NASA Astrophysics Data System (ADS)

    Dehmelt, Hans; Mittleman, Richard; Liu, Yuan

    1988-10-01

    The thermally excited axial oscillation of the electron through the weak magnetic bottle needed for the continuous Stern-Gerlach effect modulates the cyclotron frequency and produces a characteristic ≈ 12-kHz-wide vertical rise-exponential decline line shape of the cyclotron resonance. At the same time the relativistic mass shift decreases the frequency by ≈ 200 Hz per cyclotron motion quantum level n. Nevertheless, our analysis of the complex line shape shows that it should be possible to produce an abrupt rise in the cyclotron quantum number n from 0 to ≈ 20 over a small fraction of 200 Hz, when the 160-GHz microwave drive approaches the n = 0 → 1 transition, and a jump of 14 levels over a frequency increment of 200 Hz has already been observed in preliminary work. This realizes an earlier proposal to generate a very sharp cyclotron resonance feature by quasithermal excitation with a square noise band and should provide a way to detect spin flips when a weak bottle is used to reduce the broadening of the g - 2 resonance by a factor of 20.

  7. Cyclotrons and positron emitting radiopharmaceuticals

    SciTech Connect

    Wolf, A.P.; Fowler, J.S.

    1984-01-01

    The state of the art of Positron Emission Tomography (PET) technology as related to cyclotron use and radiopharmaceutical production is reviewed. The paper discusses available small cyclotrons, the positron emitters which can be produced and the yields possible, target design, and radiopharmaceutical development and application. 97 refs., 12 tabs. (ACR)

  8. Simultaneous observations of electrostatic oxygen cyclotron waves and ion conics

    NASA Technical Reports Server (NTRS)

    Kintner, P. M.; Scales, W.; Vago, J.; Arnoldy, R.; Garbe, G.; Moore, T.

    1989-01-01

    A sounding rocket launched to 927 km apogee during an auroral substorm encountered regions of large quasi-static electric fields (not greater than 400 mV/m), ion conics (up to 700 eV maximum observed energy), and fluctuating electric fields near the oxygen cyclotron frequency. Since the fluctuating electric fields frequently exhibited spectral peaks just above the local oxygen cyclotron frequency, and since the fluctuating electric fields were linearly polarized, they are positively identified as electrostatic oxygen cyclotron waves (EOCW). The maximum amplitude of the EOCW was about 5 mV/m rms. The EOCW closely correlated with the presence of ion conics. Because of the relatively low amplitude of the EOCW and their relatively low coherence, it cannot be concluded that they are solely responsible for the production of the ion conics.

  9. Ion cyclotron resonance cell

    DOEpatents

    Weller, R.R.

    1995-02-14

    An ion cyclotron resonance cell is disclosed having two adjacent sections separated by a center trapping plate. The first section is defined by the center trapping plate, a first end trapping plate, and excitation and detector electrodes. The second section includes a second end trapping plate spaced apart from the center plate, a mirror, and an analyzer. The analyzer includes a wavelength-selective light detector, such as a detector incorporating an acousto-optical device (AOD) and a photodetector. One or more ion guides, grounded plates with holes for the ion beam, are positioned within the vacuum chamber of the mass spectrometer between the ion source and the cell. After ions are trapped and analyzed by ion cyclotron resonance techniques in the first section, the ions of interest are selected according to their mass and passed into the second section for optical spectroscopic studies. The trapped ions are excited by light from a laser and caused thereby to fluoresce. The fluorescent light emitted by the excited ions is reflected by the mirror and directed onto the detector. The AOD is scanned, and the photodetector output is recorded and analyzed. The ions remain in the second section for an extended period, enabling multiple studies to be carried out on the same ensemble of ions. 5 figs.

  10. Ion cyclotron resonance cell

    DOEpatents

    Weller, Robert R.

    1995-01-01

    An ion cyclotron resonance cell having two adjacent sections separated by a center trapping plate. The first section is defined by the center trapping plate, a first end trapping plate, and excitation and detector electrodes. The second section includes a second end trapping plate spaced apart from the center plate, a mirror, and an analyzer. The analyzer includes a wavelength-selective light detector, such as a detector incorporating an acousto-optical device (AOD) and a photodetector. One or more ion guides, grounded plates with holes for the ion beam, are positioned within the vacuum chamber of the mass spectrometer between the ion source and the cell. After ions are trapped and analyzed by ion cyclotron resonance techniques in the first section, the ions of interest are selected according to their mass and passed into the second section for optical spectroscopic studies. The trapped ions are excited by light from a laser and caused thereby to fluoresce. The fluorescent light emitted by the excited ions is reflected by the mirror and directed onto the detector. The AOD is scanned, and the photodetector output is recorded and analyzed. The ions remain in the second section for an extended period, enabling multiple studies to be carried out on the same ensemble of ions.

  11. Probing the hydrogen exosphere of Mars with ion cyclotron waves

    NASA Astrophysics Data System (ADS)

    Wei, H. Y.; Cowee, M. M.; Russell, C. T.

    2013-09-01

    Ion cyclotron waves are generated during the interaction between the solar wind and the Martian exosphere. When the atmospheric neutrals are ionized in the solar wind, the fresh ions are accelerated by the electric field and gyrate around the magnetic field in the solar wind, in a process called ion pick-up. As the ions gyrate, ion cyclotron waves grow from the free energy of the highly anisotropic distribution of these fresh ions, with left-handed polarization and a wave frequency near the ion's gyro-frequency. Observations of the ion cyclotron waves enable us to study the atmospheric loss due to solar wind pick-up process. At Mars, the exospheric hydrogen is picked up by the solar wind and produces proton cyclotron waves. The Mars Global Surveyor detected proton cyclotron waves which extend from the magnetosheath of Mars to over 12 Mars radii with amplitudes that vary slowly with distance. A hybrid simulation is applied to study the wave generation and evolution due to solar wind pick-up to try to understand the relation between the wave energy and pickup rate. By comparing the wave observations and the hybrid simulation results, we hope to better understand the hydrogen exosphere configuration and the loss of water from Mars.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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).

  19. Intelligent low-level RF system by non-destructive beam monitoring device for cyclotrons

    NASA Astrophysics Data System (ADS)

    Sharifi Asadi Malafeh, M. S.; Ghergherehchi, M.; Afarideh, H.; Chai, J. S.; Yoon, Sang Kim

    2016-04-01

    The project of a 10 MeV PET cyclotron accelerator for medical diagnosis and treatment was started at Amirkabir University of Technology in 2012. The low-level RF system of the cyclotron accelerator is designed to stabilize acceleration voltage and control the resonance frequency of the cavity. In this work an Intelligent Low Level Radio Frequency Circuit or ILLRF, suitable for most AVF cyclotron accelerators, is designed using a beam monitoring device and narrow band tunable band-pass filter. In this design, the RF phase detection does not need signal processing by a microcontroller.

  20. N-bursty emission from Uranus: A cyclotron maser source?

    NASA Technical Reports Server (NTRS)

    Curran, D. B.; Menietti, J. D.

    1993-01-01

    Ray tracing studies of RX-mode emission from the north polar regions of Uranus indicate that the n-bursty radio emission may have a source along field lines with footprints near the northern magnetic pole (perhaps in the cusp), but not necessarily associated with regions of strong UV emission. This is in contrast with similar studies for the Uranus nightside smooth radio emission, which are believed to be due to the cyclotron maser instability. Source regions can be found for both hollow and filled emission cones and for frequencies well above the local gyrofreuquency implying that mechanisms other than the cyclotron maser mechanism may be operating.

  1. BEST medical radioisotope production cyclotrons

    SciTech Connect

    Sabaiduc, Vasile; Milton, Bruce; Suthanthiran, Krishnan; Johnson, Richard R.; Gelbart, W. Z.

    2013-04-19

    Best Cyclotron Systems Inc (BCSI) is currently developing 14 MeV, 25 MeV, 35MeV and 70MeV cyclotrons for radioisotope production and research applications as well as the entire spectrum of targets and nuclear synthesis modules for the production of Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT) and radiation therapy isotopes. The company is a subsidiary of Best Medical International, renowned in the field of medical instrumentation and radiation therapy. All cyclotrons have external negative hydrogen ion sources, four radial sectors with two dees in opposite valleys, cryogenic vacuum system and simultaneous beam extraction on opposite lines. The beam intensity ranges from 400 {mu}A to 1000 {mu}A, depending on the cyclotron energy and application.

  2. Cyclotron Production of Medical Radioisotopes

    SciTech Connect

    Avila-Rodriguez, M. A.; Zarate-Morales, A.; Flores-Moreno, A.

    2010-08-04

    The cyclotron production of radioisotopes for medical applications is gaining increased significance in diagnostic molecular imaging techniques such as PET and SPECT. In this regard, radioisotope production has never been easier or more convenient until de introduction of compact medical cyclotrons in the last few decades, which allowed the use of short-lived radioisotopes in in vivo nuclear medicine studies on a routine basis. This review outlines some general considerations about the production of radioisotopes using charged particle accelerators.

  3. Design study of the KIRAMS-430 superconducting cyclotron magnet

    NASA Astrophysics Data System (ADS)

    Kim, Hyun Wook; Kang, Joonsun; Hong, Bong Hwan; Jung, In Su

    2016-07-01

    Design study of superconducting cyclotron magnet for the carbon therapy was performed at the Korea Institute of Radiological and Medical Science (KIRAMS). The name of this project is The Korea Heavy Ion Medical Accelerator (KHIMA) project and a fixed frequency cyclotron with four spiral sector magnet was one of the candidate for the accelerator type. Basic parameters of the cyclotron magnet and its characteristics were studied. The isochronous magnetic field which can guide the 12C6+ ions up to 430 MeV/u was designed and used for the single particle tracking simulation. The isochronous condition of magnetic field was achieved by optimization of sector gap and width along the radius. Operating range of superconducting coil current was calculated and changing of the magnetic field caused by mechanical deformations of yokes was considered. From the result of magnetic field design, structure of the magnet yoke was planned.

  4. Cassini observations of ion cyclotron waves and ions anisotropy

    NASA Astrophysics Data System (ADS)

    Crary, F. J.; Dols, V. J.; Cassidy, T. A.; Tokar, R. L.

    2013-12-01

    In Saturn's equatorial, inner magnetosphere, the production of fresh ions in a pick-up distribution generates ion cyclotron waves. These waves are a sensitive indicator of fresh plasma production, but the quantitative relation between wave properties and ionization rates is nontrivial. We present a combined analysis of Cassini MAG and CAPS data, from a variety of equatorial orbits between 2005 and 2012. Using the MAG data, we determine the amplitude and peak frequency of ion cyclotron waves. From the CAPS data we extract the parallel and perpendicular velocity distribution of water group ions. We compare these results with hybrid simulations of the ion cyclotron instability and relate the observed wave amplitudes and ion velocity distributions to the production rate of pickup ions. The resulting relation between wave and plasma properties will allow us to infer ion production rates even at times when no direct ion measurements are available.

  5. Ion cyclotron waves around Mars: observations and simulations

    NASA Astrophysics Data System (ADS)

    Wei, H. Y.; Cowee, M. M.; Russell, C. T.

    2012-04-01

    Ion cyclotron waves are generated during the interaction between the solar wind and the Martian exosphere. When the atmospheric neutrals are ionized in the solar wind, the fresh ions are accelerated by the electric field and gyrate around the magnetic field in the solar wind, in a process called ion pick-up. In the meanwhile, ion cyclotron waves grow from the free energy of the largely anisotropic distribution of these fresh ions, with left-handed polarization and a wave frequency near the ion's gyrofrequency. Observations of the ion cyclotron waves enable us to study the atmospheric loss due to solar wind pick-up process. At Mars, the exospheric hydrogen is picked up by the solar wind and produces proton cyclotron waves. The Mars Global Surveyor detected proton cyclotron waves which extend from the magnetosheath of Mars to over 12 Mars radii with amplitudes that vary slowly with distance. A hybrid simulation is applied to study the wave generation and evolution due to solar wind pick-up to try to understand the relation between the wave energy and pickup rate. By comparing the wave observations and the hybrid simulation results, we hope better understand the hydrogen exosphere configuration and the loss of water from Mars.

  6. Multi-Species Test of Ion Cyclotron Resonance Heating at High Altitudes

    NASA Technical Reports Server (NTRS)

    Persoon, A. M.; Peterson, W. K.; Andre, M.; Chang, T.; Gurnett, D. A.; Retterer, J. M.; Crew, G. B.

    1997-01-01

    Observations of ion distributions and plasma waves obtained by the Dynamics Explorer 1 satellite in the high-altitude, nightside auroral zone are used to study ion energization for three ion species. A number of theoretical models have been proposed to account for the transverse heating of these ion populations. One of these, the ion cyclotron resonance heating (ICRH) mechanism, explains ion conic formation through ion cyclotron resonance with broadband electromagnetic wave turbulence in the vicinity of the characteristic ion cyclotron frequency. The cyclotron resonant heating of the ions by low-frequency electromagnetic waves is an important energy source for the transport of ions from the ionosphere to the magnetosphere. In this paper we test the applicability of the ICRH mechanism to three simultaneously heated and accelerated ion species by modelling the ion conic formation in terms of a resonant wave-particle interaction in which the ions extract energy from the portion of the broadband electromagnetic wave spectrum which includes the ion cyclotron frequency. Using a Monte Carlo technique we evaluate the ion heating produced by the electromagnetic turbulence at low frequencies and find that the wave amplitudes near the ion cyclotron frequencies are sufficient to explain the observed ion energies.

  7. Multi-Species Test of Ion Cyclotron Resonance Heating at High Altitudes

    NASA Technical Reports Server (NTRS)

    Persoon, A. M.; Peterson, W. K.; Andre, M.; Chang, T.; Gurnett, D. A.; Retterer, J. M.; Crew, G. B.

    1997-01-01

    Observations of ion distributions and plasma waves obtained by the Dynamics Explorer 1 satellite in the high-altitude, nightside auroral zone are used to study ion energization for three ion species. A number of theoretical models have been proposed to account for the transverse heating of these ion populations. One of these, the ion cyclotron resonance heating (ICRH) mechanism, explains ion conic formation through ion cyclotron resonance with broadband electromagnetic wave turbulence in the vicinity of the characteristic ion cyclotron frequency. The cyclotron resonant heating of the ions by low- frequency electromagnetic waves is an important energy source for the transport of ions from the ionosphere to the magnetosphere. In this paper we test the applicability of the ICRH mechanism to three simultaneously heated and accelerated ion species by modelling the ion conic formation in terms of a resonant wave-particle interaction in which the ions extract energy from the portion of the broadband electromagnetic wave spectrum which includes the ion cyclotron frequency. Using a Monte Carlo technique we evaluate the ion heating produced by the electromagnetic turbulence at low frequencies and find that the wave amplitudes near the ion cyclotron frequencies are sufficient to explain the observed ion energies.

  8. 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.

  9. Folded waveguide coupler for ion cyclotron heating

    SciTech Connect

    Owens, T.L.; Chen, G.L.

    1986-01-01

    A new type of waveguide coupler for plasma heating in the ion cyclotron range of frequencies is described. The coupler consists of a series of interleaved metallic vanes within a rectangular enclosure analogous to a wide rectangular waveguide that has been ''folded'' several times. At the mouth of the coupler, a plate is attached which contains coupling apertures in each fold or every other fold of the waveguide, depending upon the wavenumber spectrum desired. This plate serves primarily as a wave field polarizer that converts coupler fields to the polarization of the fast magnetosonic wave within the plasma. Theoretical estimates indicate that the folded waveguide is capable of high-efficiency, multimegawatt operation into a plasma. Bench tests have verified the predicted field structure within the waveguide in preparation for high-power tests on the Radio Frequency Test Facility at the Oak Ridge National Laboratory.

  10. Narrow heavy-hole cyclotron resonances split by the cubic Rashba spin-orbit interaction in strained germanium quantum wells

    NASA Astrophysics Data System (ADS)

    Failla, M.; Myronov, M.; Morrison, C.; Leadley, D. R.; Lloyd-Hughes, J.

    2015-07-01

    The spin-orbit interaction was found to split the cyclotron resonance of heavy holes confined in high-mobility, compressively strained germanium quantum wells. The interference between coherent spin-split cyclotron resonances was tracked on picosecond time scales using terahertz time-domain spectroscopy. Analysis in the time domain, or using a time-frequency decomposition based on the Gabor-Morlet wavelet, was necessary when the difference between cyclotron frequencies was comparable to the linewidth. The cubic Rashba spin-orbit coefficient β was determined via two methods: (i) the magnetic-field dependence of the cyclotron frequencies, and (ii) the spin-resolved subband densities. An enhanced β and spin polarization was created by tailoring the strain to enhance the spin-orbit interaction. The amplitude modulation of the narrow, interfering cyclotron resonances is a signature of spin coherences persisting for more than 10 ps.

  11. Evidence for proton cyclotron waves near Comet Giacobini-Zinner

    NASA Technical Reports Server (NTRS)

    Tan, L. C.; Mason, G. M.; Tsurutani, B. T.

    1993-01-01

    We have computed frequency spectra of power density and polarization parameters of magnetohydrodynamic waves from observations on board the ICE spacecraft as it flew past Comet Giacobini-Zinner on September 11, 1985. Since the spectral parameters are frequency dependent, we find that the analysis is best carried out in a 'wave' reference frame where one of the major axes is along the wave normal direction for each frequency component. The power density along the wave normal direction shows a systematic peak structure which we identify as belonging to cyclotron wave harmonics of pickup ions near the comet. The fundamental harmonics of the cyclotron waves are also consistent with the gyrofrequencies calculated from the magnetic field data.

  12. Evidence for proton cyclotron waves near Comet Giacobini-Zinner

    NASA Astrophysics Data System (ADS)

    Tan, L. C.; Mason, G. M.; Tsurutani, B. T.

    1993-02-01

    We have computed frequency spectra of power density and polarization parameters of magnetohydrodynamic waves from observations on board the ICE spacecraft as it flew past Comet Giacobini-Zinner on September 11, 1985. Since the spectral parameters are frequency dependent, we find that the analysis is best carried out in a 'wave' reference frame where one of the major axes is along the wave normal direction for each frequency component. The power density along the wave normal direction shows a systematic peak structure which we identify as belonging to cyclotron wave harmonics of pickup ions near the comet. The fundamental harmonics of the cyclotron waves are also consistent with the gyrofrequencies calculated from the magnetic field data.

  13. Use of cyclotrons in medicine

    NASA Astrophysics Data System (ADS)

    Qaim, S. M.

    2004-10-01

    Cyclotrons are versatile ion-accelerating machines which find many applications in medicine. In this short review their use in hadron therapy is briefly discussed. Proton therapy is gaining significance because of its capability to treat deep-lying tumours. A strong area of application of cyclotrons involves the production of short-lived neutron deficient radiotracers for use in emission tomography, especially positron emission tomography. This fast and quantitative in vivo diagnostic technique is being increasingly used in neurology, cardiology and oncology. Besides routine patient care, considerable interdisciplinary work on development of new positron emitters is under way. A short account of those efforts is given. The use of cyclotrons in the production of radionuclides for internal radiotherapy is also briefly described.

  14. Electron cyclotron harmonic wave acceleration

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  15. Design Features Of K = 100 Cyclotron Magnet For ISOL RIB Production

    SciTech Connect

    Park, Jin Ah; Gad, Kh. M. M.; Chai, Jong-Seo

    2011-06-01

    K = 100 Separated Sector Cyclotron was designed in conceptual for the ISOL driver. It has 4 separated sector magnets. Two SF cyclotrons will be used as the injectors for separated sector cyclotron. RF frequency is 70 MHz, 4th harmonics. We have designed sector magnet without trim and harmonic coils. Minimum radius of the magnet is 55 cm and maximum radius is 1.8 m. Designed magnets were calculated and simulated by OPERA 3D (TOSCA) code. Ion beam dynamics calculations have been done using particle studio code to prove the focusing properties of the designed magnets.

  16. Experiments on ion cyclotron damping at the deuterium fourth harmonic in DIII-D

    SciTech Connect

    Pinsker, R.I.; Petty, C.C.; Baity, F.W.; Bernabei, S.; Greenough, N.; Heidbrink, W.W.; Mau, T.K.; Porkolab, M.

    1999-05-01

    Absorption of fast Alfven waves by the energetic ions of an injected beam is evaluated in the DIII-D tokamak. Ion cyclotron resonance absorption at the fourth harmonic of the deuteron cyclotron frequency is observed with deuterium neutral beam injection (f = 60 MHz, B{sub T} = 1.9 T). Enhanced D-D neutron rates are evidence of absorption at the Doppler-shifted cyclotron resonance. Characteristics of global energy confinement provide further proof of substantial beam acceleration by the rf. In many cases, the accelerated deuterons cause temporary stabilization of the sawtooth (monster sawteeth), at relatively low rf power levels of {approximately}1 MW.

  17. Cyclotron and linac production of Ac-225.

    PubMed

    Melville, Graeme; Allen, Barry J

    2009-04-01

    Radium needles that were once implanted into tumours as a cancer treatment are now obsolete and constitute a radioactive waste problem, as their half-life is 1600 years. The reduction of radium by photonuclear transmutation by bombarding Ra-226 with high-energy photons from a medical linear accelerator (linac) has been investigated. A linac dose of 2800 Gy produced about 2.4 MBq (64 microCi) of Ra-225, which decays to Ac-225 and can then be used for 'Targeted Alpha Therapy' (TAT) of cancer. This result, while consistent with theoretical calculations, is far too low to be of practical use unless much larger quantities of radium are irradiated. The increasing application of Ac-225 for cancer therapy indicates the potential need for its increased production and availability. This paper investigates the possibility of producing of Ac-225 in commercial quantities, which could potentially reduce obsolete radioactive material and displace the need for expensive importation of Ac-225 from the USA and Russia in the years ahead. Scaled up production of Ac-225 could theoretically be achieved by the use of a high current cyclotron or linac. Production specifications are determined for a linac in terms of current, pulse length and frequency, as well as an examination of other factors such as radiation issues and radionuclei separation. Yields are compared with those calculated for the Australian National Cyclotron in Sydney.

  18. Nonlinear sub-cyclotron resonance as a formation mechanism for gaps in banded chorus

    DOE PAGESBeta

    Fu, Xiangrong; Guo, Zehua; Dong, Chuanfei; Gary, S. Peter

    2015-05-14

    An interesting characteristic of magnetospheric chorus is the presence of a frequency gap at ω ≃ 0.5Ωe, where Ωe is the electron cyclotron angular frequency. Recent chorus observations sometimes show additional gaps near 0.3Ωe and 0.6Ωe. Here we present a novel nonlinear mechanism for the formation of these gaps using Hamiltonian theory and test particle simulations in a homogeneous, magnetized, collisionless plasma. We find that an oblique whistler wave with frequency at a fraction of the electron cyclotron frequency can resonate with electrons, leading to effective energy exchange between the wave and particles.

  19. The isochronous cyclotron: principles and recent developments.

    PubMed

    Strijckmans, K

    2001-01-01

    The principals of a cyclotron are described. A magnetic field guides the ions in circular paths, while an electric field accelerates them. The main problem in any accelerator is not to accelerate ions, but to focus them. An isochronous cyclotron overrules the problems related to relativistic mass increase during acceleration. Harmonic operation and negative (vs positive) ion acceleration (and extraction) are explained, as they make dedicated PET cyclotrons a simple, reliable, and suitable tool. The characteristics of such PET cyclotrons are described, as well as their technical implementation. The IBA 18/9 PET cyclotron is given as an example.

  20. Nonlinear particle simulation of ion cyclotron waves in toroidal geometry

    SciTech Connect

    Kuley, A. Lin, Z.; Bao, J.; Wei, X. S.; Xiao, Y.

    2015-12-10

    Global particle simulation model has been developed in this work to provide a first-principles tool for studying the nonlinear interactions of radio frequency (RF) waves with plasmas in tokamak. In this model, ions are considered as fully kinetic particles using the Vlasov equation and electrons are treated as guiding centers using the drift kinetic equation with realistic electron-to-ion mass ratio. Boris push scheme for the ion motion has been developed in the toroidal geometry using magnetic coordinates and successfully verified for the ion cyclotron and ion Bernstein waves in global gyrokinetic toroidal code (GTC). The nonlinear simulation capability is applied to study the parametric decay instability of a pump wave into an ion Bernstein wave side band and a low frequency ion cyclotron quasi mode.

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  2. 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.

  3. Cyclotron resonance maser experiments in first and second harmonics

    NASA Astrophysics Data System (ADS)

    Shahadi, Avi; Drori, Rami; Jerby, Eli

    1995-09-01

    Cyclotron-resonance maser (CRM) oscillator experiments in a nondispersive (TEM-mode) waveguide are reported in this paper. The table-top CRM oscillator constructed in our laboratory operates with a low-energy (< 5 keV), low-current (< 1 A) electron beam. The electron beam is rotating in the cyclotron frequency due to an axial magnetic field produced by an external solenoid. The large electron transverse velocity, needed to obtain amplification in a TEM-CRM, is achieved by a strong kicker coil. The coplanar waveguide used in this experiment supports odd and even TEM-modes, and enables cyclotron interactions with both first and second harmonics. Microwave output power at the first cycoltron harmonic is observed in the range of 3-6 GHz, where the frequency is tuned by the axial magnetic field in this range. A considerable second harmonic emission is observed around 7 GHz frequency. This experiment may lead to the developement of a new compact high-power microwave source.

  4. Apparent electrostatic ion cyclotron waves in the diffuse aurora

    NASA Technical Reports Server (NTRS)

    Bering, E. A.

    1983-01-01

    Emissions that have properties consistent with electrostatic ion cyclotron (EIC) waves have been observed at low altitude in the diffuse aurora by a sounding rocket payload. Peaks were observed in the power spectrum of the electric field near the hydrogen and oxygen ion cyclotron frequencies. Doppler shift and polarization analyses have been performed using EIC wave parameters derived from linear theory. Both analyses indicated that these emissions had properties consistent with those expected for H(+) and O(+) EIC waves. The two analyses indicated that both emission bands were due to waves propagating eastward parallel to the poleward boundary of the diffuse aurora. The large local cold plasma density and resulting Landau damping require that the source be local. Magnetometer data indicated the presence of a downward parallel current density of 5 microamps/sq m. Sufficient free energy for the waves was available from this current, although the waves were observed frequently at altitudes where the ion-neutral collision frequency exceeded the oxygen cyclotron frequency.

  5. Design of the 1.5 MW, 30-96 MHz ultra-wideband 3 dB high power hybrid coupler for Ion Cyclotron Resonance Frequency (ICRF) heating in fusion grade reactor

    NASA Astrophysics Data System (ADS)

    Yadav, Rana Pratap; Kumar, Sunil; Kulkarni, S. V.

    2016-01-01

    Design and developmental procedure of strip-line based 1.5 MW, 30-96 MHz, ultra-wideband high power 3 dB hybrid coupler has been presented and its applicability in ion cyclotron resonance heating (ICRH) in tokamak is discussed. For the high power handling capability, spacing between conductors and ground need to very high. Hence other structural parameters like strip-width, strip thickness coupling gap, and junction also become large which can be gone upto optimum limit where various constrains like fabrication tolerance, discontinuities, and excitation of higher TE and TM modes become prominent and significantly deteriorates the desired parameters of the coupled lines system. In designed hybrid coupler, two 8.34 dB coupled lines are connected in tandem to get desired coupling of 3 dB and air is used as dielectric. The spacing between ground and conductors are taken as 0.164 m for 1.5 MW power handling capability. To have the desired spacing, each of 8.34 dB segments are designed with inner dimension of 3.6 × 1.0 × 40 cm where constraints have been significantly realized, compensated, and applied in designing of 1.5 MW hybrid coupler and presented in paper.

  6. Design of the 1.5 MW, 30-96 MHz ultra-wideband 3 dB high power hybrid coupler for Ion Cyclotron Resonance Frequency (ICRF) heating in fusion grade reactor.

    PubMed

    Yadav, Rana Pratap; Kumar, Sunil; Kulkarni, S V

    2016-01-01

    Design and developmental procedure of strip-line based 1.5 MW, 30-96 MHz, ultra-wideband high power 3 dB hybrid coupler has been presented and its applicability in ion cyclotron resonance heating (ICRH) in tokamak is discussed. For the high power handling capability, spacing between conductors and ground need to very high. Hence other structural parameters like strip-width, strip thickness coupling gap, and junction also become large which can be gone upto optimum limit where various constrains like fabrication tolerance, discontinuities, and excitation of higher TE and TM modes become prominent and significantly deteriorates the desired parameters of the coupled lines system. In designed hybrid coupler, two 8.34 dB coupled lines are connected in tandem to get desired coupling of 3 dB and air is used as dielectric. The spacing between ground and conductors are taken as 0.164 m for 1.5 MW power handling capability. To have the desired spacing, each of 8.34 dB segments are designed with inner dimension of 3.6 × 1.0 × 40 cm where constraints have been significantly realized, compensated, and applied in designing of 1.5 MW hybrid coupler and presented in paper.

  7. Cyclotron Production of Technetium-99m

    NASA Astrophysics Data System (ADS)

    Gagnon, Katherine M.

    Technetium-99m (99mTc) has emerged as the most widely used radionuclide in medicine and is currently obtained from a 99Mo/ 99mTc generator system. At present, there are only a handful of ageing reactors worldwide capable of producing large quantities of the parent isotope, 99Mo, and owing to the ever growing shutdown periods for maintenance and repair of these ageing reactors, the reliable supply 99mTc has been compromised in recent years. With an interest in alternative strategies for producing this key medical isotope, this thesis focuses on several technical challenges related to the direct cyclotron production of 99mTc via the 100Mo(p,2n)99mTc reaction. In addition to evaluating the 100Mo(p,2n)99mTc and 100Mo(p,x)99Mo reactions, this work presented the first experimental evaluation of the 100Mo(p,2n) 99gTc excitation function in the range of 8-18 MeV. Thick target calculations suggested that large quantities of cyclotron-produced 99mTc may be possible. For example, a 6 hr irradiation at 500 μA with an energy window of 18→10 MeV is expected to yield 1.15 TBq of 99mTc. The level of coproduced 99gTc contaminant was found to be on par with the current 99Mo/99mTc generator standard eluted with a 24 hr frequency. Highly enriched 100Mo was required as the target material for 99mTc production and a process for recycling of this expensive material is presented. An 87% recovery yield is reported, including metallic target preparation, irradiation, 99mTc extraction, molybdate isolation, and finally hydrogen reduction to the metal. Further improvements are expected with additional optimization experiments. A method for forming structurally stable metallic molybdenum targets has also been developed. These targets are capable of withstanding more than a kilowatt of beam power and the reliable production and extraction of Curie quantities of 99mTc has been demonstrated. With the end-goal of using the cyclotron-produced 99mTc clinically, the quality of the cyclotron

  8. Cyclotron Resonance in Accreting Pulsars

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Dipankar

    2016-07-01

    Cyclotron Resonance Absorption/Scattering features provide direct measurement of magnetic field strength in the line forming region. This has enabled the estimation of magnetic field strengths of nearly two dozen neutron stars in accreting high mass binary systems. With improved spectroscopic sensitivity, new X-ray observatories such as NuSTAR, Astrosat and Hitomi are opening the doors to studying detailed features such as the line shape and phase dependence with high significance. Such studies will help understand the nature of matter accumulation in, and outflow from, the magnetically confined accretion column on the neutron star. This talk will describe the results of MHD simulations of the matter flow in such systems, the diagnostics of such flows using cyclotron lines, and comparison with recent observations from NuSTAR and Astrosat.

  9. Commercial compact cyclotrons in the 90`s

    SciTech Connect

    Milton, B.F.

    1995-09-01

    Cyclotrons continue to be efficient accelerators for radio-isotope production. In recent years, developments in the accelerator technology have greatly increased the practical beam current in these machines while also improving the overall system reliability. These developments combined with the development of new isotopes for medicine and industry, and a retiring of older machines indicate a strong future for commercial cyclotrons. In this paper the authors will survey recent developments in the areas of cyclotron technology, as they relate to the new generation of commercial cyclotrons. Design criteria for the different types of commercial cyclotrons will be presented, with reference to those demands that differ from those in a research oriented cyclotron project. The authors also discuss the possibility of systems designed for higher energies and capable of extracted beam currents of up to 2.0 mA.

  10. Global Simulation of Electromagnetic Ion Cyclotron Waves

    NASA Technical Reports Server (NTRS)

    Khazanov, George V.; Gallagher, D. L.; Kozyra, J. U.

    2007-01-01

    It is very well known that the effects of electromagnetic ion cyclotron (EMIC) waves on ring current (RC) ion and radiation belt (RB) electron dynamics strongly depend on such particle/wave characteristics as the phase-space distribution function, frequency, wave-normal angle, wave energy, and the form of wave spectral energy density. The consequence is that accurate modeling of EMIC waves and RC particles requires robust inclusion of the interdependent dynamics of wave growth/damping, wave propagation, and particles. Such a self-consistent model is being progressively developed by Khazanov et al. This model is based on a system of coupled kinetic equations for the RC and EMIC wave power spectral density along with the ray tracing equations. We will discuss the recent progress in understanding EMIC waves formation mechanisms in the inner magnetosphere. This problem remains unsettled in spite of many years of experimental and theoretical studies. Modern satellite observations by CRRES, Polar and Cluster still do not reveal the whole picture experimentally since they do not stay long enough in the generation region to give a full account of all the spatio-temporal structure of EMIC waves. The complete self-consistent theory taking into account all factors significant for EMIC waves generation remains to be developed. Several mechanisms are discussed with respect to formation of EMIC waves, among them are nonlinear modification of the ionospheric reflection by precipitating energetic protons, modulation of ion-cyclotron instability by long-period (Pc3/4) pulsations, reflection of waves from layers of heavy-ion gyroresonances, and nonlinearities of wave generation process. We show that each of these mechanisms have their attractive features and explains certain part experimental data but any of them, if taken alone, meets some difficulties when compared to observations. We conclude that development of a refined nonlinear theory and further correlated analysis of modern

  11. Global Simulation of Electromagnetic Ion Cyclotron Waves

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.; Gamayunov, K.; Gallagher, D. L.; Kozyra, J. U.

    2007-01-01

    It is well known that the effects of electromagnetic ion cyclotron (EMIC) waves on ring current (RC) ion and radiation belt (RB) electron dynamics strongly depend on such particle/wave characteristics as the phase-space distribution function, frequency, wave-normal angle, wave energy, and the form of wave spectral energy density. The consequence is that accurate modeling of EMIC waves and RC particles requires robust inclusion of the interdependent dynamics of wave growth/damping, wave propagation, and particles. Such a self-consistent model is being progressively developed by Khazanov et al. [2002 - 2007]. This model is based on a system of coupled kinetic equations for the RC and EMIC wave power spectral density along with the ray tracing equations. We will discuss the recent progress in understanding EMIC waves formation mechanisms in the inner magnetosphere. This problem remains unsettled in spite of many years of experimental and theoretical studies. Modern satellite observations by CRRES, Polar and Cluster still do not reveal the whole picture experimentally since they do not stay long enough in the generation region to give a full account of all the spatio-temporal structure of EMIC waves. The complete self-consistent theory taking into account all factors significant for EMIC waves generation remains to be developed. Several mechanisms are discussed with respect to formation of EMIC waves, among them are nonlinear modification of the ionospheric reflection by precipitating energetic protons, modulation of ion-cyclotron instability by long-period (Pc3/4) pulsations, reflection of waves from layers of heavy-ion gyroresonances, and nonlinearities of wave generation process. We show that each of these mechanisms have their attractive features and explains certain part experimental data but any of them, if taken alone, meets some difficulties when compared to observations. We conclude that development of a refined nonlinear theory and further correlated analysis

  12. Electrostatic ion-cyclotron waves in a nonuniform magnetic field

    NASA Technical Reports Server (NTRS)

    Cartier, S. L.; Dangelo, N.; Merlino, R. L.

    1985-01-01

    The properties of electrostatic ion-cyclotron waves excited in a single-ended cesium Q machine with a nonuniform magnetic field are described. The electrostatic ion-cyclotron waves are generated in the usual manner by drawing an electron current to a small exciter disk immersed in the plasma column. The parallel and perpendicular (to B) wavelengths and phase velocities are determined by mapping out two-dimensional wave phase contours. The wave frequency f depends on the location of the exciter disk in the nonuniform magnetic field, and propagating waves are only observed in the region where f is approximately greater than fci, where fci is the local ion-cyclotron frequency. The parallel phase velocity is in the direction of the electron drift. From measurements of the plasma properties along the axis, it is inferred that the electron drift velocity is not uniform along the entire current channel. The evidence suggests that the waves begin being excited at that axial position where the critical drift velocity is first exceeded, consistent with a current-driven excitation mechanism.

  13. Electromagnetic fluctuation spectrum associated with the drift Alfven-cyclotron instability

    SciTech Connect

    Rha, Kicheol; Ryu, Chang-Mo; Yoon, Peter H.

    2012-07-15

    The present paper investigates the electromagnetic fluctuation spectrum associated with the drift Alfven-cyclotron instability by means of a two-dimensional particle-in-cell simulation, which may be plausibly associated with a current disruption event. The current disruption event shows localized high-amplitude electromagnetic fluctuations. In recent theories, these fluctuation characteristics are shown to correspond to the drift Alfven-cyclotron instability. A simulation is carried out to clarify this instability. The simulation shows that the drift Alfven-cyclotron instabilities are excited in two frequency regimes, a relatively low frequency mode propagating in a quasi-perpendicular direction while the second high-frequency branch propagating in a predominantly parallel propagation direction, consistent with observations as well as with a recent theory.

  14. Cyclotron-based of plant gravisensing

    NASA Astrophysics Data System (ADS)

    Kordyum, E.; Kalinina, Ia.; Bogatina, N.; Kondrachuk, A.

    Roots exhibit positive gravitropism they grow in the direction of a gravitational vector while shoots respond negatively and grow opposite to a gravitational vector We first demonstrated the inversion of roots gravitropism from positive to negative one under gravistimulation in the weak combined magnetic field WCMF consisted of permanent magnetic field PMF with the magnitude of order of 50 mu T and altering magnetic field AMF with the 6 mu T magnitude and a frequency of 32 Hz It was found that the effect of inversion has a resonance nature It means that in the interval of frequencies 1-45 Hz inversion of root gravitropism occurs only at frequency 32 Hz 2-3-day old cress seedlings were gravistimulated in moist chambers which are placed in mu -metal shields Inside mu -metal shields combined magnetic fields have been created The magnitude of magnetic fields was measured by a flux-gate magnetometer Experiments were performed in darkness at temperature 20 pm 1 0 C We measured the divergence angle of a growing root from its horizontal position After 1 h of gravistimulation in the WCMF we observed negative gravitropism of cress roots i e they grow in the opposite direction to a gravitational vector Frequency of 32 Hz for the magnitude of the PMF applied formally corresponds to cyclotron frequency of Ca 2 ions This indicates possible participation of calcium ions in root gravitropism There are many evidences of resonance effects of the WCMF on the biological processes that involve Ca 2 but the nature of

  15. Ion cyclotron heating experiments in magnetosphere plasma device RT-1

    SciTech Connect

    Nishiura, M. Yoshida, Z.; Yano, Y.; Kawazura, Y.; Saitoh, H.; Yamasaki, M.; Mushiake, T.; Kashyap, A.; Takahashi, N.; Nakatsuka, M.; Fukuyama, A.

    2015-12-10

    The ion cyclotron range of frequencies (ICRF) heating with 3 MHz and ∼10 kW is being prepared in RT-1. The operation regime for electron cyclotron resonance (ECR) heating is surveyed as the target plasmas. ECRH with 8.2 GHz and ∼50 kW produces the plasmas with high energy electrons in the range of a few ten keV, but the ions still remain cold at a few ten eV. Ion heating is expected to access high ion beta state and to change the aspect of plasma confinement theoretically. The ICRF heating is applied to the target plasma as an auxiliary heating. The preliminary result of ICRF heating is reported.

  16. Ion Behavior in an Electrically Compensated Ion Cyclotron Resonance Trap

    PubMed Central

    Brustkern, Adam M.; Rempel, Don L.; Gross, Michael L.

    2010-01-01

    We recently described a new electrically compensated trap in FT ion cyclotron resonance mass spectrometry and developed a means of tuning traps of this general design. Here, we describe a continuation of that research by comparing the ion transient lifetimes and the resulting mass resolving powers and signal-to-noise (S/N) ratios that are achievable in the compensated vs. uncompensated modes of this trap. Transient lifetimes are ten times longer under the same conditions of pressure, providing improved mass resolving power and S/N ratios. The mass resolving power as a function of m/z is linear (log-log plot) and nearly equal to the theoretical maximum. Importantly, the ion cyclotron frequency as a function of ion number decreases linearly in accord with theory, unlike its behavior in the uncompensated mode. This linearity should lead to better control in mass calibration and increased mass accuracy than achievable in the uncompensated mode. PMID:21499521

  17. Double-peaked electrostatic ion cyclotron harmonic waves

    NASA Technical Reports Server (NTRS)

    Boardsen, S. A.; Gurnett, D. A.; Peterson, W. K.

    1990-01-01

    Electrostatic H(+) cyclotron harmonic waves are often observed along the auroral field lines at altitudes of 1-3.5 R(E) by the Dynamics Explorer 1 satellite. A small fraction of these waves are found to have two peaks associated with each harmonic instead of one peak. The waves occur below the lower hybrid frequency and are usually relatively weak, about a factor of 4 smaller than typical electric field amplitudes of other H(+) cyclotron harmonic wave events. The double-peaked spectral signature is believed to be produced by Doppler shifts arising from the satellite velocity relative to the plasma rest frame. The waves were found to have wavelengths of the order of 300 m and phase velocities of the order of 150 km/s.

  18. Compressibility and cyclotron damping in the oblique Alfven wave

    SciTech Connect

    Harmon, J.K. )

    1989-11-01

    Compressibility, magnetic compressibility, and damping rate are calculated for the obliquely propagating Alfven shear wave in high- and low-beta Vlasov plasmas. There is an overall increase in compressibility as beta is reduced from {beta} = 1 to {beta}{much lt}1. For high obliquity {theta} and low frequency ({omega} {much lt} {Omega}{sub p}) the compressibility C follows a k{sup 2} wave number dependence; for high {theta} and low {beta} the approximation C(k) {approx} k{sub n}{sup 2} {identical to} (kV{sub A}/{Omega}{sub p}){sup 2} holds for wave numbers up to the proton cyclotron resonance, where {Omega}{sub p} is the proton cyclotron frequency and V{sub A} is the Alfven velocity. Strong proton cyclotron damping sets in at k{sub n} of the order of unity; the precise k{sub n} position of the damping cutoff increases with decreasing {beta} and increasing {theta}. Hence compressibility can exceed unity near the damping cutoff for high-{theta} waves in a low-{beta} plasma. The magnetic compressibility of the oblique Alfven wave also has a k{sup 2} dependence and can reach a maximum value of the order of 10% at high wave number. It is shown that Alfven compressibility could be the dominant contributor to the near-Sun solar wind density fluctuation spectrum for k>10{sup {minus}2} km{sup {minus}1} and hence might cause some of the flattening at high wave number seen in radio scintillation measurements. This would also be consistent with the notion that the observed density spectrum inner scale is a signature of cyclotron damping.

  19. 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.

  20. 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.

  1. 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

  2. Calculation of the spontaneous cyclotron emissivity using the complete relativistic resonance condition

    NASA Technical Reports Server (NTRS)

    Freund, H. P.; Wu, C. S.; Gaffey, J. D., Jr.

    1984-01-01

    An expression for the spectral emissivity of spontaneous synchrotron radiation for a plasma which consists of both thermal and suprathermal electron components is derived using the complete relativistic cyclotron resonance condition. The expression is valid over all angles of propagation. The result is applied to the study of the emission of radiation from an energetic population of electrons with a loss-cone distribution in a relatively low-density plasma (i.e., the electron plasma frequency is less than the cyclotron frequency).

  3. Cyclotron-based effects on plant gravitropism

    NASA Astrophysics Data System (ADS)

    Kordyum, E.; Sobol, M.; Kalinina, Ia.; Bogatina, N.; Kondrachuk, A.

    Primary roots exhibit positive gravitropism and grow in the direction of the gravitational vector, while shoots respond negatively and grow opposite to the gravitational vector. We first demonstrated that the use of a weak combined magnetic field (CMF), which is comprised of a permanent magnetic field and an alternating magnetic field with the frequency resonance of the cyclotron frequency of calcium ions, can change root gravitropism from a positive direction to negative direction. Two-day-old cress seedlings were gravistimulated in a chamber that was placed into a μ-metal shield where this CMF was created. Using this "new model" of a root gravitropic response, we have studied some of its components including the movement of amyloplasts-statoliths in root cap statocytes and the distribution of Ca 2+ ions in the distal elongation zone during gravistimulation. Unlike results from the control, amyloplasts did not sediment in the distal part of a statocyte, and more Ca 2+ accumulation was observed in the upper side of a gravistimulated root for seedlings treated with the CMF. For plants treated with the CMF, it appears that a root gravitropic reaction occurs by a normal physiological process resulting in root bending although in the opposite direction. These results support the hypothesis that both the amyloplasts in the root cap statocytes and calcium are important signaling components in plant gravitropism.

  4. Cyclotron Line Measurements with INTEGRAL

    NASA Technical Reports Server (NTRS)

    Pottschmidt, K.; Kreykenbohm, I.; Caballero, I.; Fritz, S.; Schoenherr, G.; Kretschmar, P.; Wilms, J.; McBride, V. A.; Suchy, S.; Rothschild, R. E.

    2008-01-01

    Due to its broadband energy coverage, INTEGRAL has made important contributions to observing and interpreting cyclotron lines, which are present in the 10-100 keV range of a sample of accreting pulsars. In these systems photons with energies fulfilling the resonance condition inelastically Compton scatter off electrons quantized in the accretion column above the neutron star's magnetic pole(s). This process gives rise to the broad, absorption-like lines or 'cyclotron resonant scattering features' (CRSF). The observed lines allow to directly measure the B-fields of these sources, resulting in values of a few times 1E12G. In this overview I will present recent highlights regarding CRSF observations as well as discuss current ideas and models for the physical conditions in the accretion column. Among the former are the stability of the spectrum of Vela X-1 during giant flares in 2003, the observation of three cyclotron lines during the 2004 outburst of V0332+53, the confirmation of the fundamental line at approximately 45 keV during a 2005 normal outburst of A0535-26, and the simultaneous detection of the two lines in the dipping source 4U 1907+09 (for which also a torque reversal was detected for the first time). Through these and other observations it has become increasingly apparent that two types of observations can potentially be used to constrain the accretion column geometry: the determination of energy ratios for multiple harmonic lines (only two sources with greater than 2 lines are known), was well as the evolution of the fundamental line centroid, which, for different sources, may or may not be correlated with flux. Furthermore, first steps have been taken away from the usual phenomenological description of the lines, towards a physical approach based on self-consistent CRSF modeling. Initial applications are presented.

  5. Ion cyclotron waves at Titan

    NASA Astrophysics Data System (ADS)

    Russell, C. T.; Wei, H. Y.; Cowee, M. M.; Neubauer, F. M.; Dougherty, M. K.

    2016-03-01

    During the interaction of Titan's thick atmosphere with the ambient plasma, it was expected that ion cyclotron waves would be generated by the free energy of the highly anisotropic velocity distribution of the freshly ionized atmospheric particles created in the interaction. However, ion cyclotron waves are rarely observed near Titan, due to the long growth times of waves associated with the major ion species from Titan's ionosphere, such as CH4+ and N2+. In the over 100 Titan flybys obtained by Cassini to date, there are only two wave events, for just a few minutes during T63 flyby and for tens of minutes during T98 flyby. These waves occur near the gyrofrequencies of proton and singly ionized molecular hydrogen. They are left-handed, elliptically polarized, and propagate nearly parallel to the field lines. Hybrid simulations are performed to understand the wave growth under various conditions in the Titan environment. The simulations using the plasma and field conditions during T63 show that pickup protons with densities ranging from 0.01 cm-3 to 0.02 cm-3 and singly ionized molecular hydrogens with densities ranging from 0.015 cm-3 to 0.25 cm-3 can drive ion cyclotron waves with amplitudes of ~0.02 nT and of ~0.04 nT within appropriate growth times at Titan, respectively. Since the T98 waves were seen farther upstream than the T63 waves, it is possible that the instability was stronger and grew faster on T98 than T63.

  6. Lawrence's Legacy : Seaborg's Cyclotron - The 88-Inch Cyclotron turns 40

    NASA Astrophysics Data System (ADS)

    McMahan, Margaret; Clark, David

    2003-04-01

    In 1958, Sputnik had recently been launched by the Russians, leading to worry in Congress and increased funding for science and technology. Ernest Lawrence was director of the "Rad Lab" at Berkeley. Another Nobel Prize winner, Glenn Seaborg, was Associate Laboratory Director and Director of the Nuclear Chemistry Division. In this atmosphere, Lawrence was phoned by commissioners of the Atomic Energy Commission and asked what they could do for Seaborg, "because he did such a fine job of setting up the chemistry for extracting plutonium from spent reactor fuel" [1]. In this informal way, the 90-Inch (eventually 88-Inch) Cyclotron became a line item in the federal budget at a cost of 3M (later increased to 5M). The 88-Inch Cyclotron achieved first internal beam on Dec. 12, 1961 and first external beam in May 1962. Forty years later it is still going strong. Pieced together from interviews with the retirees who built it, Rad Lab reports and archives from the Seaborg and Lawrence collections, the story of its design and construction - on-time and under-budget - provides a glimpse into the early days of big science. [1] remarks made by Elmer Kelly, "Physicist-in-charge' of the project on the occasion of the 40th anniversary celebration.

  7. Superconducting cyclotrons at Michigan State University

    NASA Astrophysics Data System (ADS)

    Blosser, H. G.

    1987-04-01

    This paper describes the status of the three superconducting cyclotrons which are in operation or under construction at the National Superconducting Cyclotron Laboratory. The oldest of these, the K500, has been in operation since September 1982 supporting a national user program in heavy ion nuclear physics. A second large research cyclotron, the K800, is now nearing completion. This cyclotron will accelerate lighter heavy ions to 200 MeV/nuc and heavier particles up to energies given by 1200 Q2/ A MeV/nucleon. The magnet for this cyclotron came into operation in May 1984 and has performed smoothly and reliably in three extended operating periods. At present, K800 construction activity centers on fabrication and installation of the rf system, the extraction system, and the ECR injection line. The third NSCL superconducting cyclotron is a smaller 50 MeV deuteron cyclotron to be used for neutron therapy in the radiation oncology center of a major Detroit hospital (Harper Hospital). Design features of this small, application oriented, cyclotron are described in some detail.

  8. The cyclotron development activities at CIAE

    NASA Astrophysics Data System (ADS)

    Zhang, Tianjue; Li, Zhenguo; An, Shizhong; Yin, Zhiguo; Yang, Jianjun; Yang, Fang

    2011-12-01

    The cyclotron has an obvious advantage in offering high average current and beam power. Cyclotron development for various applications, e.g. radioactive ion-beam (RIB) generation, clean nuclear energy systems, medical diagnostics and isotope production, were performed at China Institute of Atomic Energy (CIAE) for over 50 years. At the moment two cyclotrons are being built at CIAE, the 100 MeV, CYCIAE-100, and a 14 MeV, the CYCIAE-14. Meanwhile, we are designing and proposing to build a number of cyclotrons with different energies, among them are the CYCIAE-70, the CYCIAE-800, and the upgrading of CYCIAE-CRM, which is going to increase its beam current to mA level. The contribution will present an overall introduction to the cyclotron development activities conducted at CIAE, with different emphasis to each project in order to demonstrate the design and construction highlights.

  9. 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.

  10. Effect of dust charge fluctuations on current-driven electrostatic ion-cyclotron instability in a collisional magnetized plasma

    SciTech Connect

    Sharma, Suresh C.; Sharma, Kavita; Gahlot, Ajay

    2013-05-15

    Current-driven electrostatic ion-cyclotron (EIC) instability is studied in a collisional magnetized dusty plasma. The growth rate and unstable mode frequencies were evaluated based on existing physical parameters relevant to ion cyclotron waves in dusty plasmas. It is found that the unstable mode frequency and growth rate of current-driven EIC instability increase with δ (ion-to-electron density ratio). Moreover, the increase in electron neutral collisional frequency (ν{sub e}) has no effect on the unstable mode frequency while the normalized growth rate has linear dependence on ν{sub e}.

  11. Linear and nonlinear physics of the magnetoacoustic cyclotron instability of fusion-born ions in relation to ion cyclotron emission

    SciTech Connect

    Carbajal, L. Cook, J. W. S.; Dendy, R. O.; Chapman, S. C.

    2014-01-15

    The magnetoacoustic cyclotron instability (MCI) probably underlies observations of ion cyclotron emission (ICE) from energetic ion populations in tokamak plasmas, including fusion-born alpha-particles in JET and TFTR [Dendy et al., Nucl. Fusion 35, 1733 (1995)]. ICE is a potential diagnostic for lost alpha-particles in ITER; furthermore, the MCI is representative of a class of collective instabilities, which may result in the partial channelling of the free energy of energetic ions into radiation, and away from collisional heating of the plasma. Deep understanding of the MCI is thus of substantial practical interest for fusion, and the hybrid approximation for the plasma, where ions are treated as particles and electrons as a neutralising massless fluid, offers an attractive way forward. The hybrid simulations presented here access MCI physics that arises on timescales longer than can be addressed by fully kinetic particle-in-cell simulations and by analytical linear theory, which the present simulations largely corroborate. Our results go further than previous studies by entering into the nonlinear stage of the MCI, which shows novel features. These include stronger drive at low cyclotron harmonics, the re-energisation of the alpha-particle population, self-modulation of the phase shift between the electrostatic and electromagnetic components, and coupling between low and high frequency modes of the excited electromagnetic field.

  12. FREQUENCY CONTROL OF RF HEATING OF GASEOUS PLASMA

    DOEpatents

    Herold, E.W.

    1962-09-01

    This invention relates to the heating of gaseous plasma by radiofrequency ion-cyclotron resonance heating. The cyclotron resonance frequencies are varied and this invention provides means for automatically controlling the frequency of the radiofrequency to maximize the rate of heating. To this end, a servo-loop is provided to sense the direction of plasma heating with frequency and a control signal is derived to set the center frequency of the radiofrequency energy employed to heat the plasma. (AEC)

  13. Low-frequency electrostatic waves in the solar wind

    NASA Astrophysics Data System (ADS)

    Sreeraj, T.; Singh, Satyavir; Singh Lakhina, Gurbax

    2016-07-01

    Electrostatic ion cyclotron waves are one of the ubiquitous features in space and laboratory plasmas. Here we present a linear study of electrostatic ion cyclotron waves in the solar wind. We model the solar wind by three-component magnetised plasma consisting of hot electrons with kappa distribution and fluid cold protons and doubly charged Helium ions. A numerical analysis of the linear electrostatic dispersion relation has been carried out for slow solar wind parameters and for -oblique wave propagation. The system supports four different modes i.e., fast and slow acoustic modes, and proton and Helium cyclotron modes. It has to be emphasised that for parallel propagation, physically acceptable solution to the dispersion relation are those of fast and slow acoustic modes. For oblique propagation, the coupling between various modes can be seen. Moreover, when the angle of propagation is increased the separation between acoustic modes and cyclotron modes increases and at perpendicular propagation, only proton and Helium-cyclotron modes can exist. The effect of various parameters like number density and temperature of Helium ions and kappa index on the dispersive properties has also been investigated. As the number density of helium ions increases, frequency of proton cyclotron mode decreases and frequency of Helium cyclotron mode increases at a fixed wave number. When the value of kappa increases, the frequency of the proton cyclotron mode increases but it does not have significant effect on the frequency of the Helium cyclotron mode. Likewise, when the temperature of Helium ions increases, the frequency of Helium cyclotron mode increases, however, the frequency of proton cyclotron mode remains more or less unchanged.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Electronuclear ion fusion in an ion cyclotron resonance reactor

    SciTech Connect

    Cowgill, Donald F.

    1996-12-01

    A method and apparatus for generating nuclear fusion by ion cyclotron resonance in an ion trap reactor. The reactor includes a cylindrical housing having an axial axis, an internal surface, and first and second ends. First and second end plates that are charged are respectively located at the first and second ends of the cylindrical housing. A gas layer is adsorbed on the internal surface of the cylindrical housing. Ions are desorbed from the gas layer, forming a plasma layer adjacent to the cylindrical housing that includes first ions that have a same charge sign as the first and second end plates. A uniform magnetic field is oriented along the axial axis of the cylindrical housing. Second ions, that are unlike the first ions, but have the same charge sign, are injected into the cylindrical housing along the axial axis of the cylindrical housing. A radio frequency field resonantly accelerates the injected second ions at the cyclotron resonance frequency of the second ions. The second ions circulate in increasing helical orbits and react with the first ions, at the optimum energy for nuclear fusion. The amplitude of the radio frequency field is adjusted to accelerate the second ions at a rate equal to the rate of tangential energy loss of the second ions by nuclear scattering in the first ions, causing the ions to continually interact until fusion occurs.

  19. 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.

  20. All-magnetic extraction for cyclotron beam reacceleration

    DOEpatents

    Hudson, E.D.; Mallory, M.L.

    1975-07-22

    An isochronous cyclotron can be modified to provide an initial electron stripping stage, a complete acceleration of the stripped ions through the cyclotron to a first energy state, means for returning the ions to an intermediate cyclotron orbit through a second stripping stage, further acceleration of the now higher energy stripped ions through the cyclotron to their final energy, and final extraction of the ions from the cyclotron. (auth)

  1. 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.

  2. 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.

  3. Cyclotron resonance of figure-of-eight orbits in a type-II Weyl semimetal

    NASA Astrophysics Data System (ADS)

    Koshino, Mikito

    2016-07-01

    We study the cyclotron resonance in the electron-hole joint Fermi surface of a type-II Weyl semimetal. In magnetic field, the electron and hole pockets touching at the Weyl node are hybridized to form quantized Landau levels corresponding to semiclassical 8-shaped orbits. We calculate the dynamical conductivities for the electric fields oscillating in x and y directions and find that the resonant frequencies in x and y differ by a factor of two, reflecting the figure-of-eight electron motion in real space. The peculiar anisotropy in the cyclotron resonance serves as a unique characteristic of the dumbbell-like Fermi surface.

  4. 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

  5. Cyclotron-Cherenkov and Cherenkov instabilities

    SciTech Connect

    Kho, T.H.; Lin, A.T. . Dept. of Physics)

    1990-06-01

    The effect of the conventional Cherenkov instability on the cyclotron-Cherenkov maser is investigated for the case of a relativistic electron beam propagating along a background magnetic field in a dielectric using particle simulations. Both Cherenkov and cyclotron-Cherenkov instabilities are excited when the phase velocity of light in the dielectric is less than the beam velocity. It is demonstrated in the high-power regime, where the cyclotron-Cherenkov mode has the higher growth rate, that the Cherenkov mode has little effect on the nonlinear efficiency of the cyclotron-Cherenkov mode. High efficiency is possible, affirming previous predictions based on single mode calculations. The effect of beam momentum spread is studied.

  6. Low energy cyclotron for radiocarbon dating

    SciTech Connect

    Welch, J.J.

    1985-01-01

    The author built and tested a low energy cyclotron for radiocarbon dating similar to a conventional mass spectrometer. These tests clearly show that with the addition of a conventional ion source, the low energy cyclotron can perform the extremely high sensitivity /sup 14/C measurements that are now done at accelerator facilities. The author found that no significant background is present when the cyclotron is tuned to accelerate /sup 14/C negative ions and the transmission efficiency is adequate to perform radiocarbon dating on milligram samples of carbon. The internal ion source used did not produce sufficient current to detect /sup 14/C directly at modern concentrations. The author shows how a conventional carbon negative ion source located outside the cyclotron magnet, would produce sufficient beam and provide for quick sample changing to make radiocarbon dating milligram samples with a modest laboratory instrument feasible.

  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. Building 211 cyclotron characterization survey report

    SciTech Connect

    1998-03-30

    The Building 211 Cyclotron Characterization Survey includes an assessment of the radioactive and chemical inventory of materials stored within the facility; an evaluation of the relative distribution of accelerator-produced activation products within various cyclotron components and adjacent structures; measurement of the radiation fields throughout the facility; measurement and assessment of internal and external radioactive surface contamination on various equipment, facility structures, and air-handling systems; and an assessment of lead (Pb) paint and asbestos hazards within the facility.

  9. Rotatable superconducting cyclotron adapted for medical use

    DOEpatents

    Blosser, Henry G.; Johnson, David A.; Riedel, Jack; Burleigh, Richard J.

    1985-01-01

    A superconducting cyclotron (10) rotatable on a support structure (11) in an arc of about 180.degree. around a pivot axis (A--A) and particularly adapted for medical use is described. The rotatable support structure (13, 15) is balanced by being counterweighted (14) so as to allow rotation of the cyclotron and a beam (12), such as a subparticle (neutron) or atomic particle beam, from the cyclotron in the arc around a patient. Flexible hose (25) is moveably attached to the support structure for providing a liquified gas which is supercooled to near 0.degree. K. to an inlet means (122) to a chamber (105) around superconducting coils (101, 102). The liquid (34) level in the cyclotron is maintained approximately half full so that rotation of the support structure and cyclotron through the 180.degree. can be accomplished without spilling the liquid from the cyclotron. With the coils vertically oriented, each turn of the winding is approximately half immersed in liquid (34) and half exposed to cold gas and adequate cooling to maintain superconducting temperatures in the section of coil above the liquid level is provided by the combination of cold gas/vapor and by the conductive flow of heat along each turn of the winding from the half above the liquid to the half below.

  10. Note: Control of liquid helium supply to cryopanels of Kolkata superconducting cyclotron

    SciTech Connect

    Bhattacharyya, T. K. Pal, G.

    2015-02-15

    The Kolkata superconducting cyclotron utilises liquid helium to cool the main magnet niobium-titanium (NbTi) coil and the cryopanels. Three liquid helium cooled cryopanels, placed inside the dees of the radio-frequency system, maintain the high vacuum in the acceleration region of the superconducting cyclotron. The small cryostat placed inside the cryogenic distribution manifold located at the basement of the superconducting cyclotron building supplies liquid helium in parallel branches to three cold heads, used for cooling their associated cryopanels. The level in the cryostat has to be maintained at an optimum value to ensure uninterrupted flow of liquid helium to these three cold heads. This paper describes the transfer function of the overall system, its tuning parameters, and discusses the actual control of cryostat level by using these parameters.

  11. Multi-ion, multi-event test of ion cyclotron resonance heating

    NASA Technical Reports Server (NTRS)

    Persoon, Ann M.

    1993-01-01

    The multi-ion, multi-event study of ion cyclotron resonance heating has been funded to study ion energization through ion cyclotron resonance with low frequency broadband electromagnetic turbulence. The modeling algorithm for the ion cyclotron resonance heating (ICRH) of oxygen ions was presented in Crew et al. (1990). Crew and his co-authors developed a two-parameter representation of selected oxygen conic distributions and modelled the conic formation in terms of resonance heating. The first year of this study seeks to extend the work of Crew and his co-authors by testing the applicability of the ICRH mechanism to helium ion conic distributions, using data obtained from the Energetic Ion Composition Spectrometer and the Plasma Wave Instrument on Dynamics Explorer 1.

  12. The multi-ion, multi-event test of ion cyclotron resonance heating

    NASA Technical Reports Server (NTRS)

    Persoon, Ann M.

    1993-01-01

    The multi-ion, multi-event study of ion cyclotron resonance heating was funded to study ion energization through ion cyclotron resonance with low frequency broadband electromagnetic turbulence. The initial work on the ion cyclotron resonance heating (ICRH) of oxygen ions was presented in Crew et al. Crew and his co-authors developed a two-parameter representation of selected oxygen conic distributions and modeled the conic formation in terms of resonance heating. The first year seeks to extend the work of Crew and his co-authors by testing the applicability of the ICRH mechanism to helium ion conic distributions, using data obtained from the Energetic Ion Composition Spectrometer and the Plasma Wave Instrument on Dynamics Explorer 1.

  13. Analysis of Cyclotron Resonance Spectroscopy in a Landau-quantized 2DEG using Characteristic Matrix Methods

    NASA Astrophysics Data System (ADS)

    Hilton, David

    2013-03-01

    We develop a new characteristic matrix-based method to analyze cyclotron resonance experiments in high mobility (μe = 3 . 7 ×106cm2V-1s-1) two-dimensional electron gas samples where direct interference between primary and satellite reflections has previously limited the frequency resolution. We use terahertz time-domain spectroscopy to measure the cyclotron resonance and extract the dephasing lifetime where multiple pulses from the substrate with a separation of ~ 15 ps directly interfere in the time-domain. We find a cyclotron dephasing lifetime of 15 . 1 +/- 0 . 5 ps at 1.5 K and 5 . 0 +/- 0 . 5 ps at 75 K. This work is supported by the National Science Foundation under Grant No. DMR-1056827. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by NSF Cooperative Agreement No. DMR-0654118

  14. Note: control of liquid helium supply to cryopanels of Kolkata superconducting cyclotron.

    PubMed

    Bhattacharyya, T K; Pal, G

    2015-02-01

    The Kolkata superconducting cyclotron utilises liquid helium to cool the main magnet niobium-titanium (NbTi) coil and the cryopanels. Three liquid helium cooled cryopanels, placed inside the dees of the radio-frequency system, maintain the high vacuum in the acceleration region of the superconducting cyclotron. The small cryostat placed inside the cryogenic distribution manifold located at the basement of the superconducting cyclotron building supplies liquid helium in parallel branches to three cold heads, used for cooling their associated cryopanels. The level in the cryostat has to be maintained at an optimum value to ensure uninterrupted flow of liquid helium to these three cold heads. This paper describes the transfer function of the overall system, its tuning parameters, and discusses the actual control of cryostat level by using these parameters. PMID:25725894

  15. Note: control of liquid helium supply to cryopanels of Kolkata superconducting cyclotron.

    PubMed

    Bhattacharyya, T K; Pal, G

    2015-02-01

    The Kolkata superconducting cyclotron utilises liquid helium to cool the main magnet niobium-titanium (NbTi) coil and the cryopanels. Three liquid helium cooled cryopanels, placed inside the dees of the radio-frequency system, maintain the high vacuum in the acceleration region of the superconducting cyclotron. The small cryostat placed inside the cryogenic distribution manifold located at the basement of the superconducting cyclotron building supplies liquid helium in parallel branches to three cold heads, used for cooling their associated cryopanels. The level in the cryostat has to be maintained at an optimum value to ensure uninterrupted flow of liquid helium to these three cold heads. This paper describes the transfer function of the overall system, its tuning parameters, and discusses the actual control of cryostat level by using these parameters.

  16. Experiments on ion cyclotron damping at the deuterium fourth harmonic in DIII-D

    SciTech Connect

    Pinsker, R. I.; Baity, F. W.; Bernabei, S.; Greenough, N.; Heidbrink, W. W.; Mau, T. K.; Petty, C. C.; Porkolab, M.

    1999-09-20

    Absorption of fast Alfven waves by the energetic ions of an injected beam is evaluated in the DIII-D tokamak. Ion cyclotron resonance absorption at the fourth harmonic of the deuteron cyclotron frequency is observed with deuterium neutral beam injection (f=60 MHz, B{sub T}=1.9 T). Enhanced D-D neutron rates are evidence of absorption at the Doppler-shifted cyclotron resonance. Characteristics of global energy confinement provide further proof of substantial beam acceleration by the rf. In many cases, the accelerated deuterons cause temporary stabilization of the sawtooth (''monster sawteeth''), at relatively low rf power levels of {approx}1 MW. (c) 1999 American Institute of Physics.

  17. On the excitation of cyclotron harmonic waves by newborn heavy ions

    NASA Technical Reports Server (NTRS)

    Brinca, Armando L.; Tsurutani, Bruce T.

    1989-01-01

    Wave measurements in planetary foreshocks and cometary environments show the sporadic occurrence of magnetic spectra with harmonic structure related to ion-cyclotron frequencies. Dilute populations of anisotropic and/or drifting charged particles can excite obliquely propagating modes with spacecraft frequencies close to the observed harmonics. Previous analyses of this generation mechanism are extended to drifting and nondrifting loss-cone-type distributions of heavy ions in a dense hydrogen magnetoplasma, characterizing the complex (real frequency and growth rate) dispersion, polarization, and compressibility of the unstable cyclotron harmonic waves. Solution of the full kinetic dispersion equation shows that it is possible to attain harmonic excitation, both in the drifting and nondrifting regimes. However, the bandwidth inherent to frequency Doppler shifts of obliquely propagating waves might preclude the observation of spectral structure in the spacecraft frame. The Giotto observations in the upstream region of comet Halley provide a reference to discuss the results.

  18. Nonlinear sub-cyclotron resonance as a formation mechanism for gaps in banded chorus

    SciTech Connect

    Fu, Xiangrong; Guo, Zehua; Dong, Chuanfei; Gary, S. Peter

    2015-05-14

    An interesting characteristic of magnetospheric chorus is the presence of a frequency gap at ω ≃ 0.5Ωe, where Ωe is the electron cyclotron angular frequency. Recent chorus observations sometimes show additional gaps near 0.3Ωe and 0.6Ωe. Here we present a novel nonlinear mechanism for the formation of these gaps using Hamiltonian theory and test particle simulations in a homogeneous, magnetized, collisionless plasma. We find that an oblique whistler wave with frequency at a fraction of the electron cyclotron frequency can resonate with electrons, leading to effective energy exchange between the wave and particles.

  19. Proton Heating by Cyclotron Waves in the Presence of a Finite Source and a Sink

    NASA Astrophysics Data System (ADS)

    Kim, S.; Yoon, P. H.; Choe, G.

    2012-12-01

    One of the outstanding problems in the study of solar wind is the acceleration of protons and heavy ions. The preferential heating of these ions in the direction perpendicular to the ambient magnetic field is interpreted as the resonant heating by cyclotron waves. The present paper investigates the resonant cyclotron heating of the solar wind ions by quasilinear theoretical formalism. The major focus is on the role of source and sink terms associated with the Alfven-cyclotron waves. If one considers low-frequency Alfvenic waves as the wave source, then the resulting cyclotron heating is extremely small [Yoon & Fang 2009, Rha et al., 2011, Moya et al., 2011]. However, with a finite source term an appreciable heating can result [Yoon & Fang 2009]. The purpose of the present paper is to investigate the problem of Alfvenic turbulent heating by cyclotron resonance with a continuous source of Alfvenic turbulence as well as a sink term. We also discuss the role of nonlinear mode coupling as well as the effects of spatial inhomogeneity.

  20. An energy spread minimization system for microbeam generation in the JAERI AVF cyclotron

    NASA Astrophysics Data System (ADS)

    Fukuda, Mitsuhiro; Kurashima, Satoshi; Miyawaki, Nobumasa; Okumura, Susumu; Kamiya, Tomihiro; Oikawa, Masakazu; Nakamura, Yoshiteru; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Yoshida, Kenichi; Yokota, Watalu; Arakawa, Kazuo; Kumata, Yukio; Fukumoto, Yasushi; Saito, Katsuhiko

    2003-09-01

    A heavy-ion microbeam with energy of hundreds of MeV is a significantly useful probe for research in biology and biotechnology. A single-ion hit technique using the heavy-ion microbeam is being developed at the JAERI AVF cyclotron facility for elucidation of biofunctions. For production of a microbeam with a spot size of one micro-meter in diameter, the energy spread in the beam is required to be reduced to 0.02% to minimize the effect of chromatic aberrations in the focusing lenses. The energy spread in the cyclotron beam depends on a waveform of the acceleration voltage and beam phase acceptance of the cyclotron. The typical energy spread of the cyclotron beam is around 0.1% in the ordinary acceleration mode using a sinusoidal voltage waveform. The energy spread can be reduced by superimposing a fifth-harmonic voltage waveform on the fundamental one to generate a flat-top waveform for uniform energy gain. The flat-top acceleration system has been designed for the variable-energy multi-particle AVF cyclotron with acceleration harmonic mode of 1, 2 and 3. An additional coaxial cavity has been installed to generate the fifth-harmonic voltage, coupled to the main resonator. The frequency range of the fifth harmonics, 55-110 MHz, was fully covered by the flat-top acceleration system.

  1. 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.

  2. 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.

  3. Ray tracing of lower hybrid and ion cyclotron waves

    NASA Astrophysics Data System (ADS)

    Brambilla, Marco

    1986-08-01

    We review the use of ray tracing codes for the investigation of wave propagation and plasma heating in toroidal axisymmetric geometry, with particular emphasis to the lower hybrid and ion cyclotron frequency ranges. After a summary of the approximations involved, we point out that, at these low frequencies, a full-wave treatment of the launching structure on the one hand, and of singular layers (wave and particle resonances) on the other hand, are an essential part of any ray tracing code. The spectral approach to ray tracing, which makes explicit use of the decomposition of the hf fields in toroidal modes allowed by axisymmetry, is instrumental to cope with electrically short antennas whose radiation pattern is dominated by diffraction, and to allow a plausible evaluation of Landau and cyclotron damping, and of wave behaviour near conversion layers. Numerical methods and structure of ray tracing briefly discussed, and a few examples are presented, obtained with the RAYLH and RAYIC codes developed by the author. The rapidly growing number of applications of ray tracing in the literature is also briefly summarised; it is the best proof that this approximate method, if its possibilities and limits are properly understood, can give precious insight into the physics of hf heating of tokamak plasmas.

  4. Acceleration of suprathermal ions by lightning-generated ion cyclotron waves.

    NASA Astrophysics Data System (ADS)

    Kuzichev, Ilya; Shklyar, David

    Lightning-induced emissions play important role in ion dynamics in the low-altitude magnetosphere. In particular, resonant interaction of ions with lower hybrid waves excited by lightning discharges leads to efficient ion heating; and the interaction with ion cyclotron waves is considered as a preheating mechanism. Such resonant wave-particle interaction is usually considered in two limiting cases: in the framework of quasi-linear theory, when the interaction with small amplitude wide spectrum waves is assumed, and in the case of monochromatic waves. In this report, we discuss resonant interaction of ions with special ion cyclotron wave packets which do not correspond to any of these cases. Some of wave packets formed of ion cyclotron waves generated by lightning strokes have a peculiar type of trajectories: they get stuck in the region where wave frequency becomes close to the local ion cyclotron frequency. These wave packets are characterized by wave frequency and wave vector which vary in space and time and, thus, along particle trajectory. What is more, the wave vector increases linearly with time. We derive the equations describing resonant interaction of ions with such ion cyclotron wave packets and obtain the resonance conditions. For suprathermal ions under consideration, the first cyclotron resonance gives the main contribution to resonant interaction. We show that the resonance condition for this resonance is defined by the detuning of the wave frequency from the local ion cyclotron frequency. The equations of motion have been solved numerically for test particles. Numerical results and analytical estimates demonstrate the essential difference between the interaction under consideration and the case of wide spectrum waves described by quasi-linear theory. Whereas the latter leads to particle diffusion in the phase space, the interaction we study leads to preferential ion acceleration. Hence, the ion energization has a non-diffusive character. The results

  5. Cyclotron resonance effects in a fluorescent lamp plasma

    NASA Astrophysics Data System (ADS)

    Orr, Julie; Wolfson, Richard

    1990-10-01

    A plasma physics experiment is described, which is suitable for undergraduate courses in electromagnetism as well as for independent projects. Using the plasma of a fluorescent lamp inside a conducting cavity that is immersed in a magnetic field, the experiment shows the effect of electron cyclotron motion of plasma electrons on the resonant modes of the cavity. An added benefit of the magnetic field is the ability to measure the plasma density through a frequency shift technique, but without having to know the mode frequencies in the absence of plasma. Density measurements made using this technique are consistent with those described in an earlier article on the unmagnetized fluorescent lamp plasma, and with the literature on fluorescent lamps and gas discharges. Understanding the experiment described here will give the advanced undergraduate experience in the theory of electromagnetic wave propagation in magnetized plasma, in the theory of resonant cavities, and in microwave and instrumentation techniques.

  6. 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.

  7. Low energy cyclotron for radiocarbon dating

    SciTech Connect

    Welch, J.J.

    1984-12-01

    The measurement of naturally occurring radioisotopes whose half lives are less than a few hundred million years but more than a few years provides information about the temporal behavior of geologic and climatic processes, the temporal history of meteoritic bodies as well as the production mechanisms of these radioisotopes. A new extremely sensitive technique for measuring these radioisotopes at tandem Van de Graaff and cyclotron facilities has been very successful though the high cost and limited availability have been discouraging. We have built and tested a low energy cyclotron for radiocarbon dating similar in size to a conventional mass spectrometer. These tests clearly show that with the addition of a conventional ion source, the low energy cyclotron can perform the extremely high sensitivity /sup 14/C measurements that are now done at accelerator facilities. We found that no significant background is present when the cyclotron is tuned to accelerate /sup 14/C negative ions and the transmission efficiency is adequate to perform radiocarbon dating on milligram samples of carbon. The internal ion source used did not produce sufficient current to detect /sup 14/C directly at modern concentrations. We show how a conventional carbon negative ion source, located outside the cyclotron magnet, would produce sufficient beam and provide for quick sampling to make radiocarbon dating milligram samples with a modest laboratory instrument feasible.

  8. Van Allen Probes observations of oxygen cyclotron harmonic waves in the inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Usanova, M. E.; Malaspina, D. M.; Jaynes, A. N.; Bruder, R. J.; Mann, I. R.; Wygant, J. R.; Ergun, R. E.

    2016-09-01

    Waves with frequencies in the vicinity of the oxygen cyclotron frequency and its harmonics have been regularly observed on the Van Allen Probes satellites during geomagnetic storms. We focus on properties of these waves and present events from the main phase of two storms on 1 November 2012 and 17 March 2013 and associated dropouts of a few MeV electron fluxes. They are electromagnetic, in the frequency range ~0.5 to several Hz, and amplitude ~0.1 to a few nT in magnetic and ~0.1 to a few mV/m in electric field, with both the wave velocity and the Poynting vector directed almost parallel to the background magnetic field. These properties are very similar to those of electromagnetic ion cyclotron waves, which are believed to contribute to loss of ring current ions and radiation belt electrons and therefore can be also important for inner magnetosphere dynamics.

  9. 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.

  10. Improving cancer treatment with cyclotron produced radionuclides

    SciTech Connect

    Larson, S.M. Finn, R.D.

    1992-08-04

    This report describes the author's continuing long term goal of promoting nuclear medicine applications by improving the scientific basis for tumor diagnosis treatment and treatment follow-up based on the use of cyclotron produced radiotracers in oncology. The program has 3 interactive components: Radiochemistry /Cyclotron; Pharmacology; and Immunology. An essential strategy is as follows: novel radionuclides and radiotracers developed in the Radiochemistry/Cyclotron section under the DOE grant during the 1989--1992 grant period, will be employed in the Pharmacology and Immunology sections of the DOE grant during the 1992--1995 grant period. The development of novel radionuclides and tracers is of course useful in and of itself, but their utility is greatly enhanced by the interaction with the immunology and pharmacology components of the program.

  11. 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).

  12. RF physics of ICWC discharge at high cyclotron harmonics

    SciTech Connect

    Lyssoivan, A.; Van Eester, D.; Wauters, T.; Vervier, M.; Van Schoor, M.; Bobkov, V.; Rohde, V.; Schneider, P.; Douai, D.; Kogut, D.; Kreter, A.; Möller, S.; Philipps, V.; Sergienko, G.; Moiseenko, V.; Noterdaeme, J.-M.; Collaboration: TEXTOR Team; ASDEX Upgrade Team

    2014-02-12

    Recent experiments on Ion Cyclotron Wall Conditioning (ICWC) performed in tokamaks TEXTOR and ASDEX Upgrade with standard ICRF antennas operated at fixed frequencies but variable toroidal magnetic field demonstrated rather contrasting parameters of ICWC discharge in scenarios with on-axis fundamental ion cyclotron resonance (ICR) for protons,ω=ω{sub H+}, and with its high cyclotron harmonics (HCH), ω=10ω{sub cH+}⋅ HCH scenario: very high antenna coupling to low density RF plasmas (P{sub pl}≈0.9P{sub RF-G}) and low energy Maxwellian distribution of CX hydrogen atoms with temperature T{sub H}≈350 eV. Fundamental ICR: lower antenna-plasma coupling efficiency (by factor of about 1.5 times) and generation of high energy non-Maxwellian CX hydrogen atoms (with local energy E{sub ⊥H} ≥1.0 keV). In the present paper, we analyze the obtained experimental results numerically using (i) newly developed 0-D transport code describing the process of plasma production with electron and ion collisional ionization in helium-hydrogen gas mixture and (ii) earlier developed 1-D Dispersion Relation Solver accounting for finite temperature effects and collision absorption mechanisms for all plasma species in addition to conventionally examined Landau/TTPM damping for electrons and cyclotron absorption for ions. The numerical study of plasma production in helium with minor hydrogen content in low and high toroidal magnetic fields is presented. The investigation of the excitation, conversion and absorption of plasma waves as function of B{sub T}-field suggests that only fast waves (FW) may give a crucial impact on antenna coupling and characteristics of the ICWC discharge using standard poloidally polarized ICRF antennas designed to couple RF power mainly to FW. The collisional (non-resonant) absorption by electrons and ions and IC absorption by resonant ions of minor concentration in low T{sub e} plasmas is studied at fundamental ICR and its high harmonics.

  13. Surface cyclotron resonance on InSb in Voigt configuration

    NASA Astrophysics Data System (ADS)

    Merkt, U.

    1985-11-01

    Magnetic fields parallel to space-charge layers on semiconductors define a crossed-field configuration with strong electric fields. Analytical expressions for the resulting hybrid electric-magnetic surface band structure and its optical transitions are derived in the triangular-well approximation of the electrostatic potential. The results of the one-band effective-mass approximation are extended to a two-level model that accounts for the nonparabolicity of narrow-band-gap semiconductors such as InSb. In the hybrid surface band structure, electrons with bulklike wave functions exist, allowing the experimental study of conduction-band cyclotron resonance in crossed fields. This is done in a wide range of frequencies, magnetic fields, and inversion electron densities, i.e., electric field strengths. The experimental results are discussed within the proposed models and are compared with experiments on other semiconductors. Specifically, the destruction of the Landau quantization in crossed electric and magnetic fields is investigated, both theoretically and experimentally; polarons are also studied. This is possible because of the absence of coupled plasma cyclotron-LO-phonon modes in the present degenerate electron system.

  14. 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.

  15. Parametric coupling of lower hybrid wave with gyrating ion beam driven ion cyclotron instability in a plasma

    NASA Astrophysics Data System (ADS)

    Singh, Rohtash; Tripathi, V. K.

    2013-07-01

    A lower hybrid wave, launched into a tokamak for supplementary heating in the presence of neutral beam turned gyrating ion beam, is seen to excite some prominent channels of parametric decay. The beam driven deuterium cyclotron mode is further destabilized by the lower hybrid pump through the nonlinear 4-wave coupling, involving higher and lower frequency lower hybrid sidebands, when ω0/k0zv0z=(1-ωLH2/ω02) , where ωLH is the lower hybrid frequency, ω0 and k0z are the frequency and parallel wave number of the pump wave, and v0z is the velocity of ion beam parallel to the magnetic field. The growth rate increases with parallel wave number of the ion-cyclotron mode. The pump is also susceptible to parametric upconversion into an upper sideband shifted by the frequency of the negative energy deuterium cyclotron mode. For typical parameters, the growth rate of this channel is around one fiftieth of deuterium cyclotron frequency and falls off with the transverse wave number of the mode.

  16. Parametric coupling of lower hybrid wave with gyrating ion beam driven ion cyclotron instability in a plasma

    SciTech Connect

    Singh, Rohtash; Tripathi, V. K.

    2013-07-15

    A lower hybrid wave, launched into a tokamak for supplementary heating in the presence of neutral beam turned gyrating ion beam, is seen to excite some prominent channels of parametric decay. The beam driven deuterium cyclotron mode is further destabilized by the lower hybrid pump through the nonlinear 4-wave coupling, involving higher and lower frequency lower hybrid sidebands, when ω{sub 0}/k{sub 0z}v{sub 0z}=(1−ω{sub LH}{sup 2}/ω{sub 0}{sup 2}) , where ω{sub LH} is the lower hybrid frequency, ω{sub 0} and k{sub 0z} are the frequency and parallel wave number of the pump wave, and v{sub 0z} is the velocity of ion beam parallel to the magnetic field. The growth rate increases with parallel wave number of the ion-cyclotron mode. The pump is also susceptible to parametric upconversion into an upper sideband shifted by the frequency of the negative energy deuterium cyclotron mode. For typical parameters, the growth rate of this channel is around one fiftieth of deuterium cyclotron frequency and falls off with the transverse wave number of the mode.

  17. 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.

  18. Comparative study of ion cyclotron waves at Mars, Venus and Earth

    NASA Astrophysics Data System (ADS)

    Wei, H. Y.; Russell, C. T.; Zhang, T. L.; Blanco-Cano, X.

    2011-08-01

    Ion cyclotron waves are generated in the solar wind when it picks up freshly ionized planetary exospheric ions. These waves grow from the free energy of the highly anisotropic distribution of fresh pickup ions, and are observed in the spacecraft frame with left-handed polarization and a wave frequency near the ion's gyrofrequency. At Mars and Venus and in the Earth's polar cusp, the solar wind directly interacts with the planetary exospheres. Ion cyclotron waves with many similar properties are observed in these diverse plasma environments. The ion cyclotron waves at Mars indicate its hydrogen exosphere to be extensive and asymmetric in the direction of the interplanetary electric field. The production of fast neutrals plays an important role in forming an extended exosphere in the shape and size observed. At Venus, the region of exospheric proton cyclotron wave production may be restricted to the magnetosheath. The waves observed in the solar wind at Venus appear to be largely produced by the solar-wind-Venus interaction, with some waves at higher frequencies formed near the Sun and carried outward by the solar wind to Venus. These waves have some similarity to the expected properties of exospherically produced proton pickup waves but are characterized by magnetic connection to the bow shock or by a lack of correlation with local solar wind properties respectively. Any confusion of solar derived waves with exospherically derived ion pickup waves is not an issue at Mars because the solar-produced waves are generally at much higher frequencies than the local pickup waves and the solar waves should be mostly absorbed when convected to Mars distance as the proton cyclotron frequency in the plasma frame approaches the frequency of the solar-produced waves. In the Earth's polar cusp, the wave properties of ion cyclotron waves are quite variable. Spatial gradients in the magnetic field may cause this variation as the background field changes between the regions in which

  19. Bi-directional Alfvén cyclotron instabilities in the mega-amp spherical tokamak

    SciTech Connect

    Sharapov, S. E. Akers, R.; Ayed, N. Ben; Cunningham, G.; Lilley, M. K.; Cecconello, M.; Cook, J. W. C.; Verwichte, E.

    2014-08-15

    Alfvén cyclotron instabilities excited by velocity gradients of energetic beam ions were investigated in MAST experiments with super-Alfvénic neutral beam injection over a wide range of toroidal magnetic fields from ∼0.34 T to ∼0.585 T. In MAST discharges with high magnetic field, a discrete spectrum of modes in the sub-cyclotron frequency range is excited toroidally propagating counter to the beam and plasma current (toroidal mode numbers n < 0). At lower magnetic field ≤0.45 T, a discrete spectrum of Compressional Alfvén Eigenmodes (CAEs) with n > 0 arises, in addition to the modes with n < 0. At lowest magnetic fields, the CAEs with n > 0 become dominant, they are observed in frequency range from ∼250 kHz for n=1 to ∼3.5 MHz for n=15, well above the on-axis ion cyclotron frequency (∼2.5 MHz). The data is interpreted in terms of normal and anomalous Doppler resonances modified by magnetic drift terms due to inhomogeneity and curvature of the magnetic field. A Hall MHD model is applied for computing the eigenfrequencies and the spatial mode structure of CAEs and a good agreement with the experimental frequencies is found.

  20. Cyclotron-based neutron source for BNCT

    NASA Astrophysics Data System (ADS)

    Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K.; Tanaka, H.; Sakurai, Y.; Maruhashi, A.

    2013-04-01

    Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation & treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8×109 neutrons/cm2/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with 10B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

  1. 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.

  2. Cyclotron-based neutron source for BNCT

    SciTech Connect

    Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K.; Tanaka, H.; Sakurai, Y.; Maruhashi, A.

    2013-04-19

    Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation and treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8 Multiplication-Sign 109 neutrons/cm{sup 2}/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with {sup 10}B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

  3. 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.

  4. Physics of Cyclotron Resonance Scattering Features

    NASA Astrophysics Data System (ADS)

    Sschoenherr, Gabriele; Schwarm, Fritz-Walter; Falkner, Sebastian; Dauser, Thomas; Pottschmidt, Katja; Kretschmar, Peter; Klochkov, Dmitry; Ferrigno, Carlo; Britton Hemphill, Paul; Wilms, Joern

    2016-04-01

    Cyclotron resonant scattering features (short: cyclotron lines) are sensitive tracers of the physics of the accretion columns and mounds of X-ray pulsars. They form by interaction of X-ray photons with magnetically quantized electrons in the accreted plasma close to the neutron star. Such lines have been observed as absorption-like features for about 20 X-ray pulsars. Their energies provide a direct measure of the magnetic field strength in the line-forming region. By detailed modelling of the lines and of their parameter dependencies we can further decipher the physical conditions in the accretion column. For instance the fact that the complex scattering cross sections have a strong angle-dependence relates the phase-resolved cyclotron line shapes to parameters that constrain the systems’ still poorly understood geometry. Modelling the physics of cyclotron lines to a degree that allows for detailed and solid comparison to data therefore provides a unique access also to a better understanding of the overall picture of magnetically accreting neutron star systems.

  5. Dispersion relation of electrostatic ion cyclotron waves in multi-component magneto-plasma

    SciTech Connect

    Khaira, Vibhooti Ahirwar, G.

    2015-07-31

    Electrostatic ion cyclotron waves in multi component plasma composed of electrons (denoted by e{sup −}), hydrogen ions (denoted by H{sup +}), helium ions (denoted by He{sup +}) and positively charged oxygen ions (denoted by O{sup +})in magnetized cold plasma. The wave is assumed to propagate perpendicular to the static magnetic field. It is found that the addition of heavy ions in the plasma dispersion modified the lower hybrid mode and also allowed an ion-ion mode. The frequencies of the lower hybrid and ion- ion hybrid modes are derived using cold plasma theory. It is observed that the effect of multi-ionfor different plasma densities on electrostatic ion cyclotron waves is to enhance the wave frequencies. The results are interpreted for the magnetosphere has been applied parameters by auroral acceleration region.

  6. MM-wave cyclotron auto-resonance maser for plasma heating

    NASA Astrophysics Data System (ADS)

    Ceccuzzi, S.; Dattoli, G.; Di Palma, E.; Doria, A.; Gallerano, G. P.; Giovenale, E.; Mirizzi, F.; Spassovsky, I.; Ravera, G. L.; Surrenti, V.; Tuccillo, A. A.

    2014-02-01

    Heating and Current Drive systems are of outstanding relevance in fusion plasmas, magnetically confined in tokamak devices, as they provide the tools to reach, sustain and control burning conditions. Heating systems based on the electron cyclotron resonance (ECRH) have been extensively exploited on past and present machines DEMO, and the future reactor will require high frequencies. Therefore, high power (≥1MW) RF sources with output frequency in the 200 - 300 GHz range would be necessary. A promising source is the so called Cyclotron Auto-Resonance Maser (CARM). Preliminary results of the conceptual design of a CARM device for plasma heating, carried out at ENEA-Frascati will be presented together with the planned R&D development.

  7. MM-wave cyclotron auto-resonance maser for plasma heating

    SciTech Connect

    Ceccuzzi, S.; Ravera, G. L.; Tuccillo, A. A.; Dattoli, G.; Di Palma, E.; Doria, A.; Gallerano, G. P.; Giovenale, E.; Spassovsky, I.; Surrenti, V.; Mirizzi, F.

    2014-02-12

    Heating and Current Drive systems are of outstanding relevance in fusion plasmas, magnetically confined in tokamak devices, as they provide the tools to reach, sustain and control burning conditions. Heating systems based on the electron cyclotron resonance (ECRH) have been extensively exploited on past and present machines DEMO, and the future reactor will require high frequencies. Therefore, high power (≥1MW) RF sources with output frequency in the 200 - 300 GHz range would be necessary. A promising source is the so called Cyclotron Auto-Resonance Maser (CARM). Preliminary results of the conceptual design of a CARM device for plasma heating, carried out at ENEA-Frascati will be presented together with the planned R and D development.

  8. Development of an Accelerator Mass Spectrometer based on a Cyclotron

    SciTech Connect

    Kim, Dogyun; Bhang, Hyeongchan; Kim, Jongwon

    2011-12-13

    An accelerator mass spectrometer based on a cyclotron has been developed, and a prototype of the injection beam line has been constructed. Mass resolution of the cyclotron is designed to be over 4000. A sawtooth RF buncher in the beam line and a flat-topping RF system for the cyclotron were utilized to enhance beam transmission efficiency, which is a primary factor for improvement compared to previous cyclotron mass spectrometers. The injection beam line comprises an ion source, Einzel lens, RF buncher, 90 deg. dipole magnet and a slit box containing beam diagnostic devices. A carbon beam was measured at the location of the slit box, and beam phase spaces will be measured. The design of a cyclotron magnet was done, and orbit tracking was carried out using cyclotron optics codes. A scheme of radial injection was chosen to place a beam on the equilibrium orbit of the cyclotron. The injection scheme will be optimized after the beam measurements are completed.

  9. 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.

  10. 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.

  11. 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.

  12. Low current performance of the Bern medical cyclotron down to the pA range

    NASA Astrophysics Data System (ADS)

    Auger, M.; Braccini, S.; Ereditato, A.; Nesteruk, K. P.; Scampoli, P.

    2015-09-01

    A medical cyclotron accelerating H- ions to 18 MeV is in operation at the Bern University Hospital (Inselspital). It is the commercial IBA 18/18 cyclotron equipped with a specifically conceived 6 m long external beam line ending in a separate bunker. This feature is unique for a hospital-based facility and makes it possible to conduct routine radioisotope production for PET diagnostics in parallel with multidisciplinary research activities, among which are novel particle detectors, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. Several of these activities, such as radiobiology experiments for example, require low current beams down to the pA range, while medical cyclotrons are designed for high current operation above 10 μA. In this paper, we present the first results on the low current performance of a PET medical cyclotron obtained by ion source, radio-frequency and main coil tuning. With this method, stable beam currents down to (1.5+/- 0.5 ) pA were obtained and measured with a high-sensitivity Faraday cup located at the end of the beam transport line.

  13. Simulations of heavy ion heating by electromagnetic ion cyclotron waves driven by proton temperature anisotropies

    NASA Technical Reports Server (NTRS)

    Tanaka, M.

    1985-01-01

    Heating of heavy ions by the electromagnetic ion cyclotron (EMIC) waves, which are driven by proton temperature anisotropies, is studied by means of hybrid particle simulations. Initially, relaxation of the temperature anisotropies in the proton distribution and isotropic heating of the heavy ions are observed (phase I), followed by substantial perpendicular heating of the heavy ions (phase II). The heavy ions are distinctly gyrophase modulated by the EMIC waves. The isotropic heating in phase I is due to magnetic trapping by the excited proton cyclotron waves. The perpendicular heating in phase II is attributed to cyclotron resonance with the EMIC waves, which becomes possible by means of the preceding heating in phase I. Saturation of the EMIC instability is instead attributed to magnetic trapping of the majority ions: protons. When the proton anisotropy is very large, frequency shift (decrease) of the proton cyclotron waves to less than 1/2 Ohm(p) is observed. The present mechanism is not only relevant to He(+) heating in the dayside equator of the magnetosphere, but it also predicts hot He2(+) ions behind the earth's bow shock.

  14. Optimized magnet for a 250 MeV proton radiotherapy cyclotron

    NASA Astrophysics Data System (ADS)

    Kim, J.; Blosser, H.

    2001-12-01

    The NSCL accelerator group in 1993 carried out an extensive design study [1] for a K250 superconducting cyclotron for advanced cancer therapy. A private company ACCEL now offers cyclotrons based on this study on a commercial basis, and actual construction of a first such cyclotron is likely in the near future. In view of this, further optimization of the design of the superconducting magnet is currently underway. The configuration of the cyclotron has many similarities with previous NSCL-built superconducting cyclotrons—notable differences are the peak average field of 3 T (required by the focusing limit for protons) vs the 5 tesla of other MSU designs, and the use of four sectors rather than three to avoid the νr=3/2 stopband. The further optimization of the magnetic design described here keys on using the true 3D magnetic field program to more precisely match the design to an optimized orbital frequency configuration and to explore reducing the amount of spiral in the hills which then shortens the linear length of the rf elements and therefore reduces capacity and power consumption.

  15. Resonance of relativistic electrons with electromagnetic ion cyclotron waves

    DOE PAGESBeta

    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

  16. Nonresonant interaction of heavy ions with electromagnetic ion cyclotron waves

    NASA Technical Reports Server (NTRS)

    Berchem, J.; Gendrin, R.

    1985-01-01

    The motion of a heavy ion in the presence of an intense ultralow-frequency electromagnetic wave propagating along the dc magnetic field is analyzed. Starting from the basic equations of motion and from their associated two invariants, the heavy ion velocity-space trajectories are drawn. It is shown that after a certain time, particles whose initial phase angles are randomly distributed tend to bunch together, provided that the wave intensity b-sub-1 is sufficiently large. The importance of these results for the interpretation of the recently observed acceleration of singly charged He ions in conjunction with the occurrence of large-amplitude ion cyclotron waves in the equatorial magnetosphere is discussed.

  17. 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.

  18. 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 \

  19. 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.

  20. Stimulated scattering of a whistler wave off ion-cyclotron and ion-acoustic modes in a dusty plasma

    SciTech Connect

    Annou, R.; Tripathi, V.K.

    1998-01-01

    A whistler wave propagating through a magnetized dusty plasma undergoes stimulated Brillioun scattering off ion-cyclotron and ion-acoustic modes. The dust has little effect on nonlinear coupling. However, it reduces the growth rate by introducing linear damping on the low-frequency modes. {copyright} {ital 1998 American Institute of Physics.}

  1. Temperature effects on the pickup process of water group and hydrogen ions - Extensions of 'A theory for low-frequency waves observed at Comet Giacobini-Zinner' by M. L. Goldstein and H. K. Wong

    NASA Technical Reports Server (NTRS)

    Brinca, Armando L.; Tsurutani, Bruce T.

    1988-01-01

    Cometary heavy ions can resonantly excite hydromagnetic wave activity with spacecraft frequency spectra strongly deviating from the ion cyclotron frequency. The influence of the newborn particle temperature on this effect is assessed, its relevance to the interpretation of the observations is discussed, and an alternative, more efficient mechanism to generate spacecraft frequencies of the order of the proton cyclotron frequency is suggested.

  2. 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.

  3. 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.

  4. Diatom response to extremely low-frequency magnetic fields

    SciTech Connect

    Parkinson, W.C.; Sulik, G.L. )

    1992-06-01

    Reports that extremely low-frequency magnetic fields can interfere with normal biological cell function continue to stimulate experimental activity as well as investigations into the possible mechanism of the interaction. The cyclotron resonance' model of Liboff has been tested by Smith et al. using as the biological test system the diatom Amphora coffeiformis. They report enhanced motility of the diatom in response to a low-frequency electromagnetic field tuned to the cyclotron resonance condition for calcium ions. We report here an attempt to reproduce their results. Following their protocol diatoms were seeded onto agar plates containing varying amounts of calcium and exposed to colinear DC and AC magnetic fields tuned to the cyclotron resonant condition for frequencies of 16, 30, and 60 Hz. The fractional motility was compared with that of control plates seeded at the same time from the same culture. We find no evidence of a cyclotron resonance effect.

  5. Toward a System-Based Approach to Electromagnetic Ion Cyclotron Waves in Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Gamayunov, K. V.; Engebretson, M. J.; Rassoul, H.

    2015-12-01

    We consider a nonlinear wave energy cascade from the low frequency range into the higher frequency domain of electromagnetic ion cyclotron (EMIC) wave generation as a possible source of seed fluctuations for EMIC wave growth due to the ion cyclotron instability in Earth's magnetosphere. The theoretical analysis shows that energy cascade from the Pc 4-5 frequency range (2-22 mHz) into the range of Pc 1-2 pulsations (0.1-5 Hz) is able to supply the level of seed fluctuations that guarantees growth of EMIC waves up to an observable level during one pass through the near equatorial region where the ion cyclotron instability takes place. We also analyze magnetic field data from the Polar and Van Allen Probes spacecraft to test this nonlinear mechanism. We restrict our analysis to magnetic spectra only. We do not analyze the third-order moment for total energy of the magnetic and velocity fluctuations, but judge whether a nonlinear energy cascade is present or whether it is not by only analyzing the appearance of power-law distributions in the low frequency part of the magnetic field spectra. While the power-law spectrum alone does not guarantee that a nonlinear cascade is present, the power-law distribution is a strong indication of the possible development of a nonlinear cascade. Our data analysis shows that a nonlinear energy cascade is indeed observed in both the outer and inner magnetosphere, and EMIC waves are growing from this nonthermal background. All the analyzed data are in good agreement with the theoretical model presented in this study. Overall, the results of this study support a nonlinear energy cascade in Earth's magnetosphere as a mechanism which is responsible for supplying seed fluctuating energy in the higher frequency domain where EMIC waves grow due to the ion cyclotron instability. Keywords: nonlinear energy cascade, ultra low frequency waves, electromagnetic ion cyclotron waves, seed fluctuationsAcknowledgments: This paper is based upon work

  6. Extending the feasibility boundary of the isochronous cyclotron

    NASA Astrophysics Data System (ADS)

    Schubert, Jeffrey R.

    A number of recent design innovations have made the isochronous cyclotron a design option for applications that were previously considered best served by other types of accelerators. Several such proposed and existing applications of cyclotron technology are described. To provide a basis for these reviews the general characteristics of the isochronous cyclotron are summarized, including investigations of improved methods of computer simulations of cyclotron features. The possibility of reducing cyclotron size and cost by raising the maximum magnetic field from 5 to 8 tesla has been studied; the magnetic and electric fields for such an ultra compact cyclotron have been simulated and beam quality satisfactory for applications in nuclear physics is indicated. The feasibility of a cyclotron based accelerator mass spectrometry (AMS) program at the National superconducting Cyclotron Laboratory (NSCL) has also being studied; a feasibility example of an inexpensive high resolution AMS cyclotron is developed based on the use of an existing magnet and scaling from the handful of existing designs. A review of the central region of the first commercial 235 MeV proton cyclotron for cancer therapy is presented; orbit studies are summarized and an improved central region is discussed.

  7. Observation of increased ion cyclotron resonance signal duration through electric field perturbations.

    PubMed

    Kaiser, Nathan K; Bruce, James E

    2005-09-15

    Ion motion in Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) is complex and the subject of ongoing theoretical and experimental studies. Two predominant pathways for the loss of ICR signals are thought to include damping of cyclotron motion, in which ions lose kinetic energy and radially damp toward the center of the ICR cell, and dephasing of ion coherence, in which ions of like cyclotron frequency become distributed out of phase at similar cyclotron radii. Both mechanisms result in the loss of induced ion image current in FTICR-MS measurements and are normally inseparable during time-domain signal analysis. For conventional ICR measurements which take advantage of ion ensembles, maximization of the ion population size and density can produce the desired effect of increasing phase coherence of ions during cyclotron motion. However, this approach also presents the risk of coalescence of ion packets of similar frequencies. In general, ICR researchers in the past have lacked the tools necessary to distinguish or independently control dephasing and damping mechanisms for ICR signal loss. Nonetheless, the ability to impart greater phase coherence of ions in ICR measurements will allow significant advances in FTICR-MS research by improving the current understanding of ICR signal loss contributions of dephasing and damping of ion ensembles, increasing overall time-domain signal length, and possibly, resulting in more routine ultrahigh resolution measurements. The results presented here demonstrate the ability to employ a high density electron beam to perturb electric fields within the ICR cell during detection of cyclotron motion, in an approach we call electron-promoted ion coherence (EPIC). As such, EPIC reduces ICR signal degradation through loss of phase coherence, and much longer time-domain signals can be obtained. Our results demonstrate that time-domain signals can be extended by more than a factor of 4 with the implementation of EPIC, as

  8. Laboratory Modeling of Spike-like Operation of Magnetospheric Cyclotron Masers

    NASA Astrophysics Data System (ADS)

    Golubev, S. V.; Razin, S. V.; Zorin, V. G.; Vodopyanov, A. V.; Mansfeld, D. A.; Demekhov, A. G.; Trakhtengerts, V. Y.

    We present a study of pulsating regimes of whistler cyclotron instability in a labora- tory magnetic mirror trap. This study is aimed at searching common and specific fea- tures of spike-like regimes of magnetospheric and laboratory cyclotron masers. The plasma with hot-electron population is produced in the trap by the ECR discharge. The energetic electrons with anisotropic velocity distribution have energies of about 5 to 100 keV. Quasi-periodic spikes of precipitated energetic electrons are detected by the current pulses produced by these electrons hitting semiconductor detectors (pin-diodes) at the ends of the trap. Associated with these spikes is the electromagnetic emission propagating quasi-parallel to the magnetic field. The emission spectrum is bounded from above by the frequency which is below the electron gyrofrequency in the central cross-section of the trap. Precipitation of energetic electrons is found to be quasi- uniform across the trap. These and other features allow us to identify the electron precipitation mechanism as the turbulent diffusion at whistler-mode waves generated by the cyclotron instability of the energetic electrons. We study the dynamics of pulsating regime as dependent on the ambient gas pres- sure, power of the heating pulse, mirror ratio, and the position of the gyroresonance level for the heating radiation with respect to the trap center. Several mechanisms of spike formation are considered. In particular, we discuss the role of wave reflection at the ends of the plasma column, the heating of the background plasma by the excited radiation, and nonlinear modification of the hot-electron distribution function. We found that the spike-like regimes of precipitation observed in the laboratory trap are generally consistent with the theory of cyclotron masers and can have much in common with similar regimes in space cyclotron masers, in particular, in magneto- spheric radiation belts and solar flare loops.

  9. New magnet pole shape for isochronous cyclotrons

    SciTech Connect

    Thorn, C.E.; Chasman, C.; Baltz, A.J.

    1981-01-01

    A new design has been developed for shaping pole tips to produce the radially increasing fields required for isochronous cyclotrons. The conventional solid hill poles are replaced by poles mounted over a small secondary gap which tapers radially from maximum at the magnet edge to zero near the center. Field measurements with a model magnet and calculations with the code TRIM show an increase in field at the edge of the magnet without the usual corresponding large increase in fringing, and a radial field shape more nearly field independent than for conventional hills. The flying hills have several advantages for variable energy multiparticle cyclotrons: (1) a large reduction in the power dissipated by isochronizing trim coils; (2) a more constant shape and magnitude flutter factor, eliminating flutter coils and increasing the operating range; and (3) a sharper fall-off of the fringe field, simplifying beam extraction.

  10. The Jyvaskyla (Finland) K130 cyclotron project

    NASA Astrophysics Data System (ADS)

    Liukkonen, Esko

    Tests and delivery dates of the components and cyclotron building and installation are given. A vacuum level of 0.00002 Pa was obtained after 200 hours pumping of the vacuum chamber. After venting with nitrogen the vacuum level of 0.0001 Pa was achieved. The specified level of 0.00001 Pa could not be achieved. It is possible that first experiments can be run just before the end of the year 1992.

  11. Experimental observation of acoustic emissions generated by a pulsed proton beam from a hospital-based clinical cyclotron

    SciTech Connect

    Jones, Kevin C.; Solberg, Timothy D.; Avery, Stephen; Vander Stappen, François; Janssens, Guillaume; Prieels, Damien; Bawiec, Christopher R.; Lewin, Peter A.; Sehgal, Chandra M.

    2015-12-15

    Purpose: To measure the acoustic signal generated by a pulsed proton spill from a hospital-based clinical cyclotron. Methods: An electronic function generator modulated the IBA C230 isochronous cyclotron to create a pulsed proton beam. The acoustic emissions generated by the proton beam were measured in water using a hydrophone. The acoustic measurements were repeated with increasing proton current and increasing distance between detector and beam. Results: The cyclotron generated proton spills with rise times of 18 μs and a maximum measured instantaneous proton current of 790 nA. Acoustic emissions generated by the proton energy deposition were measured to be on the order of mPa. The origin of the acoustic wave was identified as the proton beam based on the correlation between acoustic emission arrival time and distance between the hydrophone and proton beam. The acoustic frequency spectrum peaked at 10 kHz, and the acoustic pressure amplitude increased monotonically with increasing proton current. Conclusions: The authors report the first observation of acoustic emissions generated by a proton beam from a hospital-based clinical cyclotron. When modulated by an electronic function generator, the cyclotron is capable of creating proton spills with fast rise times (18 μs) and high instantaneous currents (790 nA). Measurements of the proton-generated acoustic emissions in a clinical setting may provide a method for in vivo proton range verification and patient monitoring.

  12. Cyclotron Requirements for Multi-disciplinary Programs

    SciTech Connect

    Armbruster, John M.

    2009-03-10

    As time has passed, the various Cyclotron programs have changed over the years. In the ''early'' times of Cyclotron operations, the emphasis was on a more single sided approach such as Clinical or Research or Production. However, as time passed, the disciplines became more interconnected until today, it is unusual to have a Cyclotron and only have a single program unless it is pure production. More and more, especially in public areas such as Universities or Health Centers, you are seeing programs that do all three types of disciplines: Production; Clinical or Patient Diagnostics and/or Treatment; and Research, either in the development and manufacture of new Radio-Isotopes, new Diagnostic or Therapeutic Compound Development, or Clinical Research involving subject testing. While all three of these disciplines have some common requirements, they also have some very different requirements that may be completely counterproductive to other requirements. For a program where all three disciplines are required to be successful, it is necessary come up with some sort of compromise that meets all the various requirements. During this talk, we will try to identify some of these different requirements for the various disciplines and how these could impact the other disciplines. We will also discuss ideas for some possible compromises that might reduce the conflict between the various disciplines.

  13. Improving cancer treatment with cyclotron produced radionuclides

    SciTech Connect

    Larson, S.M.; Finn, R.D.

    1992-08-04

    Our goal is to improve the scientific basis for tumor diagnosis, treatment and treatment follow-up based on the use of cyclotron produced radiotracers in oncology. The grant includes 3 interactive components: Radiochemistry/Cyclotron; Pharmacology; and Immunology. The radiochemistry group seeks to develop innovative cyclotron targetry, radiopharmaceuticals, and radiolabeled antibodies, which are then used to assess important unanswered questions in tumor pharmacology and immunology. Examples include selected positron emitting radionuclides, such as Iodine-124, and Ga-66; I-124, I-123, I-131 labeled iododeoxyuridine, C-11 colchicine, and antimetabolites, like C-11 methotrexate; and radiolabeled antibodies, 3F8, M195, A33, and MRK16 for application in the pharmacology and immunology projects. The pharmacology program studies tumor resistance to chemotherapy, particularly the phenomenon of multidrug resistance and the relationship between tumor uptake and retention and the tumor response for anti-metabolite drugs. The immunology program studies the physiology of antibody localization at the tissue level as the basis for novel approaches to improving tumor localization such as through the use of an artificial lymphatic system which mechanically reduces intratumoral pressures in tumors in vivo. Quantitative imaging approaches based on PET and SPECT in radioimmunotherapy are studied to give greater insight into the physiology of tumor localization and dosimetry.

  14. Experimental Studies of Multi-Species Pure Ion Plasmas: Cyclotron Modes, Long-Range Collisional Drag, and Non-Linear Langmuir Waves

    NASA Astrophysics Data System (ADS)

    Affolter, Matthew

    Cyclotron modes are studied on rigid rotor, multi-species ion plasmas confined in a Penning-Malmberg trap. Collective effects and radial electric fields shift the cyclotron mode frequencies away from the ''bare'' cyclotron frequencies for each species s. These frequency shifts are measured on the distinct cyclotron modes (m = 0, 1, and 2) with sinusoidal azimuthal dependence. We find that the frequency shifts corroborate a simple theory expression in which collective effects enter only through the ExB rotation frequency and the species fraction, when the plasma is radially uniform. At ultra-low temperatures, these plasmas exhibit centrifugal separation by mass, and additional frequency shifts are observed in agreement with a more general theory. Additionally, quantitative measurements of the plasma heating from short resonant cyclotron bursts are found to be proportional to the species fraction. These cyclotron modes are used as a diagnostic tool to estimate the plasma composition, in order to investigate the damping of Langmuir waves due to inter-species collisions. Experiments and theory of this collisional inter-species drag damping are presented. This also provides the first experimental confirmation of recent theory predicting enhanced collisional slowing due to long-range collisions. Drag damping theory, proportional to the collisional slowing rate, is in quantitative agreement with the experimental results only when these long-range collisions are included, exceeding classical collision calculations by as much as an order of magnitude. At large wave amplitudes, Langmuir waves exhibit harmonic generation, non-linear frequency shifts, and a parametric decay instability, which are experimentally investigated. The parametric wave-wave coupling rates are in agreement with three-wave instability theory in the dispersion dominated oscillatory coupling regime, and in the phase-locked exponential decay regime. However, significant variations are observed near the

  15. 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.

  16. Ion-cyclotron waves at Jupiter - Possibility of detection by Ulysses

    NASA Technical Reports Server (NTRS)

    Mei, YI; Thorne, Richard M.; Horne, Richard B.

    1992-01-01

    Recent thermal plasma data and a computer code by Horne (1989) are employed to evaluate the linear-path-integrated gain of waves propagating through the Io to predict the Jovian plasma-wave environment. Estimates of the nonlinear saturation amplitudes are utilized with the thermal plasma data from two frequency bands to study the convective growth of the ion-cyclotron (IC) waves. Strong cyclotron resonant damping is theorized to prevent wave propagation to the lower latitudes, and the thermal plasma and cyclotron resonant energetic ions are expected to further confine the IC waves. L-mode waves below the O(+) gyrofrequency in the equatorial region of the torus are shown to inhabit an unstable region. The IC waves probably achieve nonlinear amplitudes regardless of plasma properties due to the rapid amplification in this region. It is suggested that the Ulysses data complicate the identification of the waves because the magnetometer is not adequately sensitive and because of the low frequency of the plasma-wave detector.

  17. Ion cyclotron and spin-flip emissions from fusion products in tokamaks

    SciTech Connect

    Arunasalam, V.; Greene, G.J.; Young, K.M.

    1993-02-01

    Power emission by fusion products of tokamak plasmas in their ion cyclotron range of frequencies (ICRF) and at their spin-flip resonance frequency is calculated for some specific model fusion product velocity-space distribution functions. The background plasma of say deuterium (D) is assumed to be in equilibrium with a Maxwellian distribution both for the electrons and ions. The fusion product velocity distributions analyzed here are: (1) A monoenergetic velocity space ring distribution. (2) A monoenergetic velocity space spherical shell distribution. (3) An anisotropic Maxwellian distribution with T {perpendicular} {ne} T{parallel}and with appreciable drift velocity along the confining magnetic field. Single ``dressed`` test particle spontaneous emission calculations are presented first and the radiation temperature for ion cyclotron emission (ICE) is analyzed both for black-body emission and nonequilibrium conditions. Thresholds for instability and overstability conditions are then examined and quasilinear and nonlinear theories of the electromagnetic ion cyclotron modes are discussed. Distinctions between ``kinetic or causal instabilities`` and ``hydrodynamic instabilities`` are drawn and some numerical estimates are presented for typical tokamak parameters. Semiquantitative remarks are offered on wave accessibility, mode conversion, and parametric decay instabilities as possible for spatially localized ICE. Calculations are carried out both for k{parallel} = 0 for k{parallel} {ne} 0. The effects of the temperature anisotropy and large drift velocities in the parallel direction are also examined. Finally, proton spin-flip resonance emission and absorption calculations are also presented both for thermal equilibrium conditions and for an ``inverted`` population of states.

  18. Ion cyclotron and spin-flip emissions from fusion products in tokamaks

    SciTech Connect

    Arunasalam, V.; Greene, G.J.; Young, K.M.

    1993-02-01

    Power emission by fusion products of tokamak plasmas in their ion cyclotron range of frequencies (ICRF) and at their spin-flip resonance frequency is calculated for some specific model fusion product velocity-space distribution functions. The background plasma of say deuterium (D) is assumed to be in equilibrium with a Maxwellian distribution both for the electrons and ions. The fusion product velocity distributions analyzed here are: (1) A monoenergetic velocity space ring distribution. (2) A monoenergetic velocity space spherical shell distribution. (3) An anisotropic Maxwellian distribution with T [perpendicular] [ne] T[parallel]and with appreciable drift velocity along the confining magnetic field. Single dressed'' test particle spontaneous emission calculations are presented first and the radiation temperature for ion cyclotron emission (ICE) is analyzed both for black-body emission and nonequilibrium conditions. Thresholds for instability and overstability conditions are then examined and quasilinear and nonlinear theories of the electromagnetic ion cyclotron modes are discussed. Distinctions between kinetic or causal instabilities'' and hydrodynamic instabilities'' are drawn and some numerical estimates are presented for typical tokamak parameters. Semiquantitative remarks are offered on wave accessibility, mode conversion, and parametric decay instabilities as possible for spatially localized ICE. Calculations are carried out both for k[parallel] = 0 for k[parallel] [ne] 0. The effects of the temperature anisotropy and large drift velocities in the parallel direction are also examined. Finally, proton spin-flip resonance emission and absorption calculations are also presented both for thermal equilibrium conditions and for an inverted'' population of states.

  19. Energy transfer between energetic ring current H(+) and O(+) by electromagnetic ion cyclotron waves

    NASA Technical Reports Server (NTRS)

    Thorne, Richard M.; Horne, Richard B.

    1994-01-01

    Electromagnetic ion cyclotron (EMIC) waves in the frequency range below the helium gyrofrequency can be excited in the equatorial region of the outer magnetosphere by cyclotron resonant instability with anisotropic ring current H(+) ions. As the unducted waves propagate to higher latitudes, the wave normal should become highly inclined to the ambient magnetic field. Under such conditions, wave energy can be absorbed by cyclotron resonant interactions with ambient O(+), leading to ion heating perpendicular to the ambient magnetic field. Resonant wave absorption peaks in the vicinity of the bi-ion frequency and the second harmonic of the O(+) gyrofrequrency. This absorption should mainly occur at latitudes between 10 deg and 30 deg along auroral field lines (L is greater than or equal to 7) in the postnoon sector. The concomitant ion heating perpendicular to the ambient magnetic field can contribute to the isotropization and geomagnetic trapping of collapsed O(+) ion conics (or beams) that originate from a low-altitude ionospheric source region. During geomagnetic storms when the O(+) content of the magnetosphere is significantly enhanced, the absorption of EMIC waves should become more efficient, and it may contribute to the observed acceleration of O(+) ions of ionospheric origin up to ring current energies.

  20. The Flux Control of Cyclotron Ions Incident upon the Substrate by Employing the Ponderomotive Potential

    NASA Astrophysics Data System (ADS)

    Sato, Naoyuki; Nakamori, Hidetaka; Ikehata, Takashi; Mase, Hiroshi

    2000-10-01

    The plasma-assisted deposition is desirable processing technique to grow the epitaxial film such as oxide-metal compound semiconductor on the lower temperature substrate. To control its stoichiometry ratio and orientation more precisely, handling the flux of oxygen and metallic ions incident upon the substrate is required. Here, we propose to employ the ponderomotive potential acting independently on each species of cyclotron ions in order to govern a new method for the flux control of ions selected before the substrate. Our idea is to form the potential structure decelerating the ions before the substrate, resulting in the enhancement of the ponderomotive force on their ions. The preliminary experiment is carried out using the magnetized plasma column terminated by the floating substrate where the localized rotating electrostatic field yielding the ponderomotive potential is impressed. It is found that the ion flux decreases when rf frequency approaches to the cyclotron frequency of helium ion. However, Q-value is small because the ions would not make the cyclotron motion many times until arriving at the substrate. In order to decelerate ions, we try to form the potential hump and/or to reconstruct the ion sheath to the effective electron sheath by the ponderomotive potential.

  1. The Michigan State University Cyclotron Laboratory: Its Early Years

    NASA Astrophysics Data System (ADS)

    Austin, Sam M.

    2016-01-01

    The Michigan State University Cyclotron Laboratory was founded in 1958 and over the years grew in stature, becoming the highest-ranked university-based program in nuclear science. Its K50 cyclotron had unmatched capability as a light-ion accelerator and helped to define what a modern cyclotron could do to advance our understanding of nuclei. This paper describes the first twenty years of the Cyclotron Laboratory's evolution and gives some insight into the cultural characteristics of the laboratory, and of its early members, that led it to thrive.

  2. Cyclotron resonance in plasma flow

    SciTech Connect

    Artemyev, A. V.; Agapitov, O. V.; Krasnoselskikh, V. V.

    2013-12-15

    This paper is devoted to the mechanism of particle acceleration via resonant interaction with the electromagnetic circular wave propagating along the inhomogeneous background magnetic field in the presence of a plasma flow. We consider the system where the plasma flow velocity is large enough to change the direction of wave propagation in the rest frame. This system mimics a magnetic field configuration typical for inner structure of a quasi-parallel shock wave. We consider conditions of gyroresonant interaction when the force corresponding to an inhomogeneity of the background magnetic field is compensated by the Lorentz force of the wave-magnetic field. The wave-amplitude is assumed to be about 10% of the background magnetic field. We show that particles can gain energy if kv{sub sw}>ω>kv{sub sw}−Ω{sub c} where k is the wave number, v{sub sw} is a plasma flow velocity, and ω and Ω{sub c} are the wave frequency and the particle gyrofrequency, respectively. This mechanism of acceleration resembles the gyrosurfing mechanism, but the effect of the electrostatic field is replaced by the effect of the magnetic field inhomogeneity.

  3. Ohm's law at strong coupling: S duality and the cyclotron resonance

    SciTech Connect

    Hartnoll, Sean A.; Herzog, Christopher P.

    2007-11-15

    We calculate the electrical and thermal conductivities and the thermoelectric coefficient of a class of strongly interacting 2+1-dimensional conformal field theories with anti-de Sitter space duals. We obtain these transport coefficients as a function of charge density, background magnetic field, temperature, and frequency. We show that the thermal conductivity and thermoelectric coefficient are determined by the electrical conductivity alone. At small frequency, in the hydrodynamic limit, we are able to provide a number of analytic formulas for the electrical conductivity. A dominant feature of the conductivity is the presence of a cyclotron pole. We show how bulk electromagnetic duality acts on the transport coefficients.

  4. The Spontaneous Loss of Coherence Catastrophe in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    PubMed Central

    Aizikov, Konstantin; Mathur, Raman; O’Connor, Peter B.

    2009-01-01

    The spontaneous loss of coherence catastrophe (SLCC) is a frequently observed, yet poorly studied, space-charge related effect in Fourier-transform ion cyclotron resonance mass spectrometry (FTICR-MS). This manuscript presents an application of the filter diagonalization method (FDM) in the analysis of this phenomenon. The temporal frequency behavior reproduced by frequency shift analysis using the FDM shows the complex nature of the SLCC, which can be explained by a combination of factors occurring concurrently, governed by electrostatics and ion packet trajectories inside the ICR cell. PMID:19013078

  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. Cyclotron instability in the afterglow mode of minimum-B ECRIS.

    PubMed

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

    2016-02-01

    It was shown recently that cyclotron instability in non-equilibrium plasma of a minimum-B electron cyclotron resonance ion source (ECRIS) causes perturbation of the extracted ion current and generation of strong bursts of bremsstrahlung emission, which limit the performance of the ion source. The present work is devoted to the dynamic regimes of plasma instability in ECRIS operated in pulsed mode. Instability develops in decaying plasma shortly after heating microwaves are switched off and manifests itself in the form of powerful pulses of electromagnetic emission associated with precipitation of high energy electrons. Time-resolved measurements of microwave emission bursts are presented. It was found that even in various gases (helium and oxygen were studied) and at different values of magnetic field and heating power, the dynamic spectra demonstrate common features: decreasing frequency within a single burst as well as from one burst to another. PMID:26931947

  7. Optically detected cyclotron resonance in heavily boron-doped silicon nanostructures on n-Si (100)

    SciTech Connect

    Bagraev, N. T. Kuzmin, R. V.; Gurin, A. S.; Klyachkin, L. E.; Malyarenko, A. M.; Mashkov, V. A.

    2014-12-15

    Electron and hole cyclotron resonance at a frequency of 94 GHz is detected by a change in the intensity of photoluminescence lines whose positions are identical to those of dislocation luminescence lines D1 and D2 in single-crystal silicon and in heavily boron-doped silicon nanostructures on the Si (100) surface. The angular dependence of the spectrum of the optically detected cyclotron resonance corresponds to the tensor of the electron and hole effective mass in single-crystal silicon, and the resonance-line width indicates long carrier free-path times close to 100 ps. The results obtained are discussed within the framework of the interrelation of the electron-vibration coupling to charge and spin correlations in quasi-one-dimensional chains of dangling bonds in silicon.

  8. Development of steady-state operation using ion cyclotron heating in the Large Helical Device

    NASA Astrophysics Data System (ADS)

    Kasahara, H.; Seki, T.; Saito, K.; Seki, R.; Kumazawa, R.; Yoshimura, Y.; Kubo, S.; Shimozuma, T.; Igami, H.; Takahashi, H.; Nagasaki, K.; Ueda, Y.; Tokitani, M.; Ashikawa, N.; Shoji, M.; Wakatsuki, T.; Kamio, S.; Tsuchiya, H.; Yoshimura, S.; Tamura, N.; Suzuki, C.; Yamada, H.; Mutoh, T.

    2014-06-01

    Using a handshake shape (HAS) antenna phasing dipole for ion cyclotron heating (ICH), the heating efficiency was higher than that using a previous poloidal array antenna in the Large Helical Device. In order to sustain the dipole operation, real-time feedback for impedance matching and maintaining the same phase and power was adopted during long-pulse discharge. The HAS antenna was designed to reduce parasitic losses associated with energetic particle and radio-frequency (RF) sheath effects by field-aligned current concentration on the midplane. Local hot spots and the inhomogeneity of the diverter heat profile in the toroidal direction were reduced. The long-pulse discharge with an electron density (ne0) of 1 × 1019 m-3, center electron temperature (Te0) of 2.5 keV, a plasma duration time (td) of 19 min, and RF heating power (PRF) of 1 MW was achieved by ICH and electron cyclotron heating.

  9. 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.

  10. 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.

  11. Stability of drift-cyclotron loss-cone waves in H-mode plasmas

    DOE PAGESBeta

    Farmer, W. A.; Morales, G. J.

    2016-05-24

    The drift-cyclotron loss-cone mode was first studied in mirror machines. In such devices, particles with small pitch angles are not confined, creating a hole in the velocity distribution function that is a source of free energy and leads to micro-instabilities in the cyclotron-range of frequencies. In the edge region of tokamak devices operating under H-mode conditions, ion loss also occurs. In this case, gradient drift carries ions moving opposite to the plasma current preferentially into the divertor, creating a one-sided loss cone. A simple analysis shows that for the quiescent H-mode plasmas in DIII-D the critical gradient for instability ismore » exceeded within 2 cm of the separatrix, and the maximum growth rate at the separatrix is 3×107 s-1.« less

  12. Stability of drift-cyclotron loss-cone waves in H-mode plasmas

    NASA Astrophysics Data System (ADS)

    Farmer, W. A.; Morales, G. J.

    2016-06-01

    The drift-cyclotron loss-cone mode was first studied in mirror machines. In such devices, particles with small pitch angles are not confined, creating a hole in the velocity distribution function that is a source of free energy and leads to micro-instabilities in the cyclotron-range of frequencies. In the edge region of tokamak devices operating under H-mode conditions, ion loss also occurs. In this case, gradient drift carries ions moving opposite to the plasma current preferentially into the divertor, creating a one-sided loss cone. A simple analysis shows that for the quiescent H-mode plasmas in DIII-D the critical gradient for instability is exceeded within 2 cm of the separatrix, and the maximum growth rate at the separatrix is 3  ×  107 s‑1.

  13. 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.

  14. 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

  15. Ion cyclotron resonance as a tool in regenerative medicine.

    PubMed

    Lisi, Antonella; Ledda, Mario; de Carlo, Flavia; Pozzi, Deleana; Messina, Elisa; Gaetani, Roberto; Chimenti, Isotta; Barile, Lucio; Giacomello, Alessandro; D'Emilia, Enrico; Giuliani, Livio; Foletti, Alberto; Patti, Annamaria; Vulcano, Antonella; Grimaldi, Settimio

    2008-01-01

    The identification of suitable stem cell cultures and differentiating conditions that are free of xenogenic growth supplements is an important step in finding the clinical applicability of cell therapy in two important fields of human medicine: heart failure and bone remodeling, growth and repair. We recently demonstrated the possibility of obtaining cardiac stem cells (CSCs) from human endomyocardial biopsy specimens. CSCs self-assemble into multi-cellular clusters known as cardiospheres (CSps) that engraft and partially regenerate infarcted myocardium. CSps and cardiosphere-derived-cells (CDCs) were exposed for five days in an incubator regulated for temperature, humidity, and CO(2) inside a solenoid system. This system was placed in a magnetically shielded room. The cells were exposed simultaneously to a static magnetic field (MF) and a parallel low-alternating frequency MF, close to the cyclotron frequency corresponding to the charge/mass ratio of the Ca(++) ion. In this exposure condition, CSps and CDCs modulate their differentiation turning on cardiogenesis and turning off vasculogenesis. Cardiac markers such as troponin I (TnI) and myosin heavy chain (MHC) were up-regulated. Conversely, angiogenic markers such as vascular endothelial growth factor (VEGF) and kinase domain receptor (KDR) were down-regulated as evidenced by immunocytochemistry. Exposure to the 7 Hz calcium ion cyclotron resonance (ICR) frequency can modulate the cardiogenic vs. angiogenic differentiation process of ex vivo expanded CSCs. This may pave the way for novel approaches in tissue engineering and cell therapy. With regard to bone remodeling, it has been suggested that bone marrow-derived mesenchymal stem cells (MSC) may be considered as a potential therapeutic tool. Using the Ca(++)-dependent specific differentiation potential of the ELF-MF 7 Hz ICR, we show here that exposure of human MSC to these same MF conditions enhanced the expression of osteoblast differentiation markers such

  16. Measurements of ion cyclotron parametric decay of lower hybrid waves at the high-field side of Alcator C-Mod

    NASA Astrophysics Data System (ADS)

    Baek, S. G.; Parker, R. R.; Shiraiwa, S.; Wallace, G. M.; Bonoli, P. T.; Brunner, D.; Faust, I. C.; Hubbard, A. E.; LaBombard, B.; Porkolab, M.

    2013-05-01

    Ion cyclotron parametric decay instability (PDI) of lower hybrid (LH) waves is surveyed using edge Langmuir probes on the Alcator C-Mod tokamak. The measurement is carried out simultaneously at the high-field side (HFS) and low-field side (LFS) mid-plane of the tokamak, as well as in the outer divertor region. Different LH spectra are observed depending on the location of the probes and magnetic configuration in L-mode plasmas, with \\overrightarrow{B}\\times\\bigtriangledown B drift direction downward. In lower single null (LSN) plasmas, strong ion cyclotron PDI occurring at the HFS is observed for the first time. This instability is characterized by a frequency separation in sidebands corresponding to the ion cyclotron frequency (ωci) near the HFS scrape-off layer and develops with threshold-like behavior as density increases. In inner wall limited (IWL) plasmas, this HFS instability shows a higher density threshold compared with that in LSN plasmas. The pump width becomes broadened even in the absence of the sidebands. In upper single null plasmas with similar plasma parameters, ion cyclotron PDI sidebands have a frequency separation corresponding to ωci near the LFS and are weaker than those observed in the LSN and IWL plasmas. Correlation between the onset of ion cyclotron PDI and the observed loss of lower hybrid current drive efficiency (Wallace et al 2012 Phys. Plasmas 19 062505) is discussed.

  17. 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).

  18. Method of enhancing cyclotron beam intensity

    DOEpatents

    Hudson, Ed D.; Mallory, Merrit L.

    1977-01-01

    When an easily ionized support gas such as xenon is added to the cold cathode in sources of the Oak Ridge Isochronous Cyclotron, large beam enhancements are produced. For example, .sup.20 Ne.sup.7+ is increased from 0.05 enA to 27 enA, and .sup.16 O.sup.5+ intensities in excess of 35 e.mu.A have been extracted for periods up to 30 minutes. Approximately 0.15 cc/min of the easily ionized support gas is supplied to the ion source through a separate gas feed line and the primary gas flow is reduced by about 30%.

  19. 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.

  20. 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.

  1. A new generation of medical cyclotrons for the 90`s

    SciTech Connect

    Milton, B.F.

    1995-08-01

    Cyclotrons continue to be efficient accelerators for use in radio-isotope production. In recent years, developments in accelerator technology have greatly increased the practical beam current in these machines while also improving the overall system reliability. These developments combined with the development of new isotopes for medicine and industry, and a retiring of older machines indicates a strong future for commercial cyclotrons. In this paper the authors will survey recent developments in the areas of cyclotron technology as they relate to the new generation of commercial cyclotrons. Existing and potential markets for these cyclotrons will be presented. They will also discuss the possibility of systems capable of extracted energies up to 150 MeV and extracted beam currents of up to 2.0 mA.

  2. Cyclotron resonance effects on stochastic acceleration of light ionospheric ions

    NASA Astrophysics Data System (ADS)

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

    1982-09-01

    The production of energetic ions with conical pitch angle distributions along the auroral field lines is a subject of considerable current interest. There are several theoretical treatments showing the acceleration (heating) of the ions by ion cyclotron waves. The quasi-linear theory predicts no acceleration when the ions are nonresonant. In the present investigation, it is demonstrated that the cyclotron resonances are not crucial for the transverse acceleration of ions by ion cyclotron waves. It is found that transverse energization of ionospheric ions, such as He(+), He(++), O(++), and O(+), is possible by an Electrostatic Hydrogen Cyclotron (EHC) wave even in the absence of cyclotron resonance. The mechanism of acceleration is the nonresonant stochastic heating. However, when there are resonant ions both the total energy gain and the number of accelerated ions increase with increasing parallel wave number.

  3. Cyclotron resonance effects on stochastic acceleration of light ionospheric ions

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    The production of energetic ions with conical pitch angle distributions along the auroral field lines is a subject of considerable current interest. There are several theoretical treatments showing the acceleration (heating) of the ions by ion cyclotron waves. The quasi-linear theory predicts no acceleration when the ions are nonresonant. In the present investigation, it is demonstrated that the cyclotron resonances are not crucial for the transverse acceleration of ions by ion cyclotron waves. It is found that transverse energization of ionospheric ions, such as He(+), He(++), O(++), and O(+), is possible by an Electrostatic Hydrogen Cyclotron (EHC) wave even in the absence of cyclotron resonance. The mechanism of acceleration is the nonresonant stochastic heating. However, when there are resonant ions both the total energy gain and the number of accelerated ions increase with increasing parallel wave number.

  4. Development of accelerator mass spectrometer based on a compact cyclotron

    NASA Astrophysics Data System (ADS)

    Kim, J.-W.; Kim, D.-G.

    2011-07-01

    A small cyclotron has been designed for accelerator mass spectrometry, and the injection beam line is constructed as part of prototyping. Mass resolution of the cyclotron is estimated to be around 4000. The design of the cyclotron was performed with orbit-tracking computations using 3D magnetic and electric fields, and beam optics of the injection line was calculated using the codes such as IGUN and TRANSPORT. The radial injection scheme is chosen to place a beam on equilibrium orbit of the cyclotron. The injection line includes an ion source, Einzel lens, rf buncher, 90° dipole magnet, and quadrupole triplet magnet. A carbon beam was extracted from the front part of the injection line. An rf cavity system for the cyclotron was built and tested. A multi channel plates (MCP) detector to measure low-current ion beams was also tested. Design considerations are given to analyzing a few different radioisotopes in form of positive ions as well as negative ions.

  5. Coherent cyclotron motion beyond Kohn's theorem

    NASA Astrophysics Data System (ADS)

    Maag, T.; Bayer, A.; Baierl, S.; Hohenleutner, M.; Korn, T.; Schüller, C.; Schuh, D.; Bougeard, D.; Lange, C.; Huber, R.; Mootz, M.; Sipe, J. E.; Koch, S. W.; Kira, M.

    2016-02-01

    In solids, the high density of charged particles makes many-body interactions a pervasive principle governing optics and electronics. However, Walter Kohn found in 1961 that the cyclotron resonance of Landau-quantized electrons is independent of the seemingly inescapable Coulomb interaction between electrons. Although this surprising theorem has been exploited in sophisticated quantum phenomena, such as ultrastrong light-matter coupling, superradiance and coherent control, the complete absence of nonlinearities excludes many intriguing possibilities, such as quantum-logic protocols. Here, we use intense terahertz pulses to drive the cyclotron response of a two-dimensional electron gas beyond the protective limits of Kohn's theorem. Anharmonic Landau ladder climbing and distinct terahertz four- and six-wave mixing signatures occur, which our theory links to dynamic Coulomb effects between electrons and the positively charged ion background. This new context for Kohn's theorem unveils previously inaccessible internal degrees of freedom of Landau electrons, opening up new realms of ultrafast quantum control for electrons.

  6. Ion cyclotron emission studies: Retrospects and prospects

    NASA Astrophysics Data System (ADS)

    Gorelenkov, N. N.

    2016-05-01

    Ion cyclotron emission (ICE) studies emerged in part from the papers by A.B. Mikhailovskii published in the 1970s. Among the discussed subjects were electromagnetic compressional Alfvénic cyclotron instabilities with the linear growth rate √ {n_α /n_e } driven by fusion products, -particles which draw a lot of attention to energetic particle physics. The theory of ICE excited by energetic particles was significantly advanced at the end of the 20th century motivated by first DT experiments on TFTR and subsequent JET experimental studies which we highlight. More recently ICE theory was advanced by detailed theoretical and experimental studies on spherical torus (ST) fusion devices where the instability signals previously indistinguishable in high aspect ratio tokamaks due to high toroidal magnetic field became the subjects of experiments. We discuss further prospects of ICE theory applications for future burning plasma (BP) experiments such as those to be conducted in ITER device in France, where neutron and gamma rays escaping the plasma create extremely challenging conditions fusion alpha particle diagnostics.

  7. Acceleration of tritons with a compact cyclotron

    NASA Astrophysics Data System (ADS)

    Wegmann, H.; Huenges, E.; Muthig, H.; Morinaga, H.

    1981-01-01

    With the compact cyclotron at the Faculty of the Technical University of Munich, tritons have been accelerated to an energy of 7 MeV. A safe and reliable operation of the gas supply for the ion source was obtained by a new tritium storage system. A quantity of 1500 Ci tritium is stored by two special Zr-Al getter pumps in a non-gaseous phase. The tritium can be released in well-defined amounts by heating the getter material. During triton acceleration the pressure in the cyclotron vacuum chamber is maintained only by a large titanium sputter-ion pump, thus forming a closed vacuum system without any exhaust of tritium contaminated gas. Any tritium contaminations in the air can be detected by an extremely sensitive tritium monitoring system. The triton beam with a maximum intensity of 30 μA has been used so far to produce neutron-rich radioisotopes such as 28Mg, 43K or 72Zn, which are successfully applied in tracer techniques in the studies of biological systems.

  8. Ion cyclotron emission studies: Retrospects and prospects

    DOE PAGESBeta

    Gorelenkov, N. N.

    2016-06-05

    Ion cyclotron emission (ICE) studies emerged in part from the papers by A.B. Mikhailovskii published in the 1970s. Among the discussed subjects were electromagnetic compressional Alfv,nic cyclotron instabilities with the linear growth rate similar ~ √(nα/ne) driven by fusion products, -particles which draw a lot of attention to energetic particle physics. The theory of ICE excited by energetic particles was significantly advanced at the end of the 20th century motivated by first DT experiments on TFTR and subsequent JET experimental studies which we highlight. Recently ICE theory was advanced by detailed theoretical and experimental studies on spherical torus (ST) fusionmore » devices where the instability signals previously indistinguishable in high aspect ratio tokamaks due to high toroidal magnetic field became the subjects of experiments. Finally, we discuss prospects of ICE theory applications for future burning plasma (BP) experiments such as those to be conducted in ITER device in France, where neutron and gamma rays escaping the plasma create extremely challenging conditions fusion alpha particle diagnostics.« less

  9. Phase Resolved Cyclotron Spectroscopy of Polars

    NASA Astrophysics Data System (ADS)

    Dealaman, Shannon J.

    2010-01-01

    This research was conducted through the REU program at Cerro Tololo Interamerican Observatory in La Serena, Chile. For this research we reduced and modeled phase-resolved cyclotron spectroscopy of four AM Her stars: MN Hya, HU Aqu, VV Pup, and QS Tel. Two of the four spectra show good cyclotron harmonics while the other two were taken during a high state with too much noise in the spectra. Using a Constant-Lambda code (Schwope et al., 1990) we modeled the two good spectra and further modeled the harmonic motion of HU Aqr. The models produced for MN Hya gave parameters with a magnetic field strength between 44 MG and 43.4 MG, a plasma temperature between 4.1 keV and 5.6 keV, a log Λ of 4.2 ± 0.3, and a viewing angle set between 83.0 degrees and 70.0 degrees and HU Aqr a magnetic field between 36.0 MG and 37.6 MG, a plasma temperature between 15.0 keV and 15.5 keV, a log Λ of 4.0 ± 0.3, and a viewing angle between 89.5 degrees and 70.5 degrees. This was the first attempt to model MN Hya with a constant lambda code and the first harmonic motion model of HU Aqr.

  10. Evidence of Landau and Cyclotron Resonance between Protons and Kinetic Waves in Solar Wind Turbulence

    NASA Astrophysics Data System (ADS)

    He, Jiansen; Wang, Linghua; Tu, Chuanyi; Marsch, Eckart; Zong, Qiugang

    2015-02-01

    The wave-particle interaction processes occurring in the solar wind provide crucial information to understand the wave dissipation and simultaneous particle heating in plasma turbulence. One requires observations of both wave fluctuations and particle kinetics near the dissipation range, which have, however, not yet been analyzed simultaneously. Here we show new evidence of wave-particle interactions by combining the diagnosis of wave modes with the analysis of particle kinetics on the basis of measurements from the WIND spacecraft with a high cadence of about 3 s. Solar wind protons appear to be highly dynamic in their velocity distribution consisting of varying anisotropic core and beam components. The basic scenario of solar wind proton heating through wave-particle interaction is suggested to be the following. Left-handed cyclotron resonance occurs continuously, and is evident from the observed proton core velocity distribution and the concurrent quasi-parallel left-handed Alfvén cyclotron waves. Landau and right-handed cyclotron resonances are persistent and indicated by the observed drifting anisotropic beam and the simultaneous quasi-perpendicular right-handed kinetic Alfvén waves in a general sense. The persistence of non-gyrotropic proton distributions may cast new light on the nature of the interaction between particles and waves near and beyond the proton gyro-frequency.

  11. Ion cyclotron waves at Io: Implications for torus composition and variations of Io atmosphere

    NASA Astrophysics Data System (ADS)

    Blanco-Cano, X.; Russell, C. T.; Strangeway, R. J.

    2003-04-01

    When the flowing torus plasma encounters the upper atmosphere of Io, newly created ions are accelerated by the motional electric field. Many of these ions are reneutralized and form a spray of fast neutrals that travel far away from Io before being reionized and picked up into the torus. These ions have ring distributions able to provide free energy for wave growth via cyclotron resonance. Galileo data showed the existence of ion cyclotron waves in the Io torus, with frequencies near the gyrofrequencies of SO2+, SO+, and S+ ions. Wave characteristics change along each flyby, and from one orbit to another. The observed wave variability indicates that the Io torus is not uniform, and that ion pickup composition changes with time and space. As pickup ions originate from Io atmosphere, the wave variation suggests that the moon´s atmosphere is changing spatially as well as temporarily. We use kinetic dispersion analysis to estimate the densities in the torus for the three ring distributions that are needed to have either SO2+ (orbits I0 and I32) or SO+ (orbits I24, I25, and I27) waves as the dominant component, and S+ ion cyclotron instability above threshold. We infer from wave properties that the atmosphere of Io varies temporally throughout the mission but that it also has a spatial variation in composition at any instant of time.

  12. 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.

  13. EVIDENCE OF LANDAU AND CYCLOTRON RESONANCE BETWEEN PROTONS AND KINETIC WAVES IN SOLAR WIND TURBULENCE

    SciTech Connect

    He, Jiansen; Wang, Linghua; Tu, Chuanyi; Zong, Qiugang; Marsch, Eckart

    2015-02-20

    The wave–particle interaction processes occurring in the solar wind provide crucial information to understand the wave dissipation and simultaneous particle heating in plasma turbulence. One requires observations of both wave fluctuations and particle kinetics near the dissipation range, which have, however, not yet been analyzed simultaneously. Here we show new evidence of wave–particle interactions by combining the diagnosis of wave modes with the analysis of particle kinetics on the basis of measurements from the WIND spacecraft with a high cadence of about 3 s. Solar wind protons appear to be highly dynamic in their velocity distribution consisting of varying anisotropic core and beam components. The basic scenario of solar wind proton heating through wave–particle interaction is suggested to be the following. Left-handed cyclotron resonance occurs continuously, and is evident from the observed proton core velocity distribution and the concurrent quasi-parallel left-handed Alfvén cyclotron waves. Landau and right-handed cyclotron resonances are persistent and indicated by the observed drifting anisotropic beam and the simultaneous quasi-perpendicular right-handed kinetic Alfvén waves in a general sense. The persistence of non-gyrotropic proton distributions may cast new light on the nature of the interaction between particles and waves near and beyond the proton gyro-frequency.

  14. Nonlinear analysis of a large-orbit coaxial-waveguide cyclotron autoresonance maser amplifier

    SciTech Connect

    Ouyang Zhengbiao; Zhang Shichang

    2007-10-01

    Nonlinear simulations are presented to analyze the influences of the electron beam and the magnetic field parameters on the output power of a large-orbit coaxial-waveguide cyclotron autoresonance maser (CARM) amplifier. It is found that the guiding-center spread of the relativistic electrons has negligible impact on the output power due to the small field change felt by the large-orbit electrons. The electron-beam velocity spread and energy spread substantially decrease the output power, because these spreads directly affect the beam-wave interaction through the Doppler term and the relativistic cyclotron frequency term in the cyclotron resonance condition. However, this adverse effect may be offset by properly tapering the operating magnetic field. The output power is sensitive to both the slope and the amplitude of the tapered magnetic field. Nonlinear simulation demonstrates the feasibility that a large-orbit coaxial-waveguide CARM amplifier can be expected to provide output power with several megawatts, ultrahigh gain, and good bandwidth in the millimeter and submillimeter wavelength ranges.

  15. Spectral features of lightning-induced ion cyclotron waves at low latitudes: DEMETER observations and simulation

    NASA Astrophysics Data System (ADS)

    Shklyar, D. R.; Storey, L. R. O.; Chum, J.; JiříčEk, F.; NěMec, F.; Parrot, M.; Santolik, O.; Titova, E. E.

    2012-12-01

    We use a comprehensive analysis of 6-component ELF wave data from the DEMETER satellite to study proton whistlers, placing emphasis on low-latitude events originating from lightning strokes in the hemisphere opposite to the hemisphere of observation. In this case, the formation of proton whistlers does not involve mode conversion caused by a strong mode coupling at a crossover frequency, although a polarization reversal remains an important element in formation of the phenomenon. DEMETER measurements of the six electromagnetic field components in the frequency band below 1000 Hz make it possible to determine not only the dynamic spectrum, but also the wave polarization, the wave normal angle, and the normalized parallel component of the Poynting vector. This permits us to address fine features of proton whistlers, in particular, we show that the deviation of the upper cutoff frequency from the equatorial cyclotron frequency is related to the Doppler shift. Experimental study of proton whistlers is supplemented by an investigation of ion cyclotron wave propagation in a multicomponent magnetoplasma and by numerical modeling of spectrograms, both in the frame of geometrical optics.

  16. Scalings of Alfvén-cyclotron and ion Bernstein instabilities on temperature anisotropy of a ring-like velocity distribution in the inner magnetosphere

    DOE PAGESBeta

    Min, Kyungguk; Liu, Kaijun; Gary, S. Peter

    2016-03-18

    Here, a ring-like proton velocity distribution with ∂fp(v⊥)/∂v⊥>0 and which is sufficiently anisotropic can excite two distinct types of growing modes in the inner magnetosphere: ion Bernstein instabilities with multiple ion cyclotron harmonics and quasi-perpendicular propagation and an Alfvén-cyclotron instability at frequencies below the proton cyclotron frequency and quasi-parallel propagation. Recent particle-in-cell simulations have demonstrated that even if the maximum linear growth rate of the latter instability is smaller than the corresponding growth of the former instability, the saturation levels of the fluctuating magnetic fields can be greater for the Alfvén-cyclotron instability than for the ion Bernstein instabilities. In thismore » study, linear dispersion theory and two-dimensional particle-in-cell simulations are used to examine scalings of the linear growth rate and saturation level of the two types of growing modes as functions of the temperature anisotropy T⊥/T|| for a general ring-like proton distribution with a fixed ring speed of 2vA, where vA is the Alfvén speed. For the proton distribution parameters chosen, the maximum linear theory growth rate of the Alfvén-cyclotron waves is smaller than that of the fastest-growing Bernstein mode for the wide range of anisotropies (1≤T⊥/T||≤7) considered here. Yet the corresponding particle-in-cell simulations yield a higher saturation level of the fluctuating magnetic fields for the Alfvén-cyclotron instability than for the Bernstein modes as long as inline image. Since fast magnetosonic waves with ion Bernstein instability properties observed in the magnetosphere are often not accompanied by electromagnetic ion cyclotron waves, the results of the present study indicate that the ring-like proton distributions responsible for the excitation of these fast magnetosonic waves should not be very anisotropic.« less

  17. STEREO and Wind Observations of Intense Cyclotron Harmonic Waves at the Earth's Bow Shock and Inside the Magnetosheath

    NASA Technical Reports Server (NTRS)

    Breneman, A. W.; Cattell, C.

    2013-01-01

    We present the first observations of electron cyclotron harmonic waves at the Earth's bow shock from STEREO and Wind burst waveform captures. These waves are observed at magnetic field gradients at a variety of shock geometries ranging from quasi-parallel to nearly perpendicular along with whistler mode waves, ion acoustic waves, and electrostatic solitary waves. Large amplitude cyclotron harmonic waveforms are also observed in the magnetosheath in association with magnetic field gradients convected past the bow shock. Amplitudes of the cyclotron harmonic waves range from a few tens to more than 500 millivolts/meter peak-peak. A comparison between the short (15 meters) and long (100 meters) Wind spin plane antennas shows a similar response at low harmonics and a stronger response on the short antenna at higher harmonics. This indicates that wavelengths are not significantly larger than 100 meters, consistent with the electron cyclotron radius. Waveforms are broadband and polarizations are distinctively comma-shaped with significant power both perpendicular and parallel to the magnetic field. Harmonics tend to be more prominent in the perpendicular directions. These observations indicate that the waves consist of a combination of perpendicular Bernstein waves and field-aligned waves without harmonics. A likely source is the electron cyclotron drift instability which is a coupling between Bernstein and ion acoustic waves. These waves are the most common type of high-frequency wave seen by STEREO during bow shock crossings and magnetosheath traversals and our observations suggest that they are an important component of the high-frequency turbulent spectrum in these regions.

  18. Compact superconducting cyclotron C400 for hadron therapy

    NASA Astrophysics Data System (ADS)

    Jongen, Y.; Abs, M.; Blondin, A.; Kleeven, W.; Zaremba, S.; Vandeplassche, D.; Aleksandrov, V.; Gursky, S.; Karamyshev, O.; Karamysheva, G.; Kazarinov, N.; Kostromin, S.; Morozov, N.; Samsonov, E.; Shirkov, G.; Shevtsov, V.; Syresin, E.; Tuzikov, A.

    2010-12-01

    The compact superconducting isochronous cyclotron C400 has been designed by the IBA-JINR collaboration. It will be the first cyclotron in the world capable of delivering protons, carbon and helium ions for cancer treatment. The cyclotron construction is started this year within the framework of the Archade project (Caen, France). 12C 6+ and 4He 2+ ions will be accelerated to 400 MeV/uu energy and extracted by the electrostatic deflector, H2+ ions will be accelerated to the energy of 265 MeV/uu and extracted by stripping. The magnet yoke has a diameter of 6.6 m, the total weight of the magnet is about 700 t. The designed magnetic field corresponds to 4.5 T in the hills and 2.45 T in the valleys. Superconducting coils will be enclosed in a cryostat; all other parts of the cyclotron will be warm. Three external ion sources will be mounted on the switching magnet on the injection line located below the cyclotron. The main parameters of the cyclotron, its design, the current status of the development work on the cyclotron systems are presented.

  19. Fourier transform ion cyclotron resonance mass spectrometry: a primer.

    PubMed

    Marshall, A G; Hendrickson, C L; Jackson, G S

    1998-01-01

    This review offers an introduction to the principles and generic applications of FT-ICR mass spectrometry, directed to readers with no prior experience with the technique. We are able to explain the fundamental FT-ICR phenomena from a simplified theoretical treatment of ion behavior in idealized magnetic and electric fields. The effects of trapping voltage, trap size and shape, and other nonidealities are manifested mainly as perturbations that preserve the idealized ion behavior modified by appropriate numerical correction factors. Topics include: effect of ion mass, charge, magnetic field, and trapping voltage on ion cyclotron frequency; excitation and detection of ICR signals; mass calibration; mass resolving power and mass accuracy; upper mass limit(s); dynamic range; detection limit, strategies for mass and energy selection for MSn; ion axialization, cooling, and remeasurement; and means for guiding externally formed ions into the ion trap. The relation of FT-ICR MS to other types of Fourier transform spectroscopy and to the Paul (quadrupole) ion trap is described. The article concludes with selected applications, an appendix listing accurate fundamental constants needed for ultrahigh-precision analysis, and an annotated list of selected reviews and primary source publications that describe in further detail various FT-ICR MS techniques and applications.

  20. Cyclotron resonance maser experiments in a bifilar helical waveguide

    NASA Astrophysics Data System (ADS)

    Aharony, Alon; Drori, Rami; Jerby, Eli

    2000-11-01

    Oscillator and amplifier cyclotron-resonance-maser (CRM) experiments in a spiral bifilar waveguide are presented in this paper. The slow-wave CRM device employs a low-energy low-current electron beam (2-12 keV, ~0.5 A). The pitch angle of the helical waveguide is relatively small; hence, the phase velocity in this waveguide, Vph≅0.8c (where c is the speed of light), is much faster than the axial velocity of the electrons, Vez<=0.2c. Thus traveling-wave-tube-type interactions are eliminated in this device. According to the CRM theory, the dominant effect in this operating regime, Vezfrequency is tuned continuously in the range 2.5-8.4 GHz by varying the axial magnetic field. A fine-tuning is possible by the electron accelerating voltage. In the amplifier mode, this CRM experiment demonstrates an amplification up to 16 dB at 5 GHz. The immediate gain bandwidth is wider than 0.1 GHz (>2%). The wide tunable range of this CRM device due to the nondispersive bifilar helix is discussed.

  1. Parallel Spectral Acquisition with an Ion Cyclotron Resonance Cell Array.

    PubMed

    Park, Sung-Gun; Anderson, Gordon A; Navare, Arti T; Bruce, James E

    2016-01-19

    Mass measurement accuracy is a critical analytical figure-of-merit in most areas of mass spectrometry application. However, the time required for acquisition of high-resolution, high mass accuracy data limits many applications and is an aspect under continual pressure for development. Current efforts target implementation of higher electrostatic and magnetic fields because ion oscillatory frequencies increase linearly with field strength. As such, the time required for spectral acquisition of a given resolving power and mass accuracy decreases linearly with increasing fields. Mass spectrometer developments to include multiple high-resolution detectors that can be operated in parallel could further decrease the acquisition time by a factor of n, the number of detectors. Efforts described here resulted in development of an instrument with a set of Fourier transform ion cyclotron resonance (ICR) cells as detectors that constitute the first MS array capable of parallel high-resolution spectral acquisition. ICR cell array systems consisting of three or five cells were constructed with printed circuit boards and installed within a single superconducting magnet and vacuum system. Independent ion populations were injected and trapped within each cell in the array. Upon filling the array, all ions in all cells were simultaneously excited and ICR signals from each cell were independently amplified and recorded in parallel. Presented here are the initial results of successful parallel spectral acquisition, parallel mass spectrometry (MS) and MS/MS measurements, and parallel high-resolution acquisition with the MS array system.

  2. Parallel Spectral Acquisition with an Ion Cyclotron Resonance Cell Array.

    PubMed

    Park, Sung-Gun; Anderson, Gordon A; Navare, Arti T; Bruce, James E

    2016-01-19

    Mass measurement accuracy is a critical analytical figure-of-merit in most areas of mass spectrometry application. However, the time required for acquisition of high-resolution, high mass accuracy data limits many applications and is an aspect under continual pressure for development. Current efforts target implementation of higher electrostatic and magnetic fields because ion oscillatory frequencies increase linearly with field strength. As such, the time required for spectral acquisition of a given resolving power and mass accuracy decreases linearly with increasing fields. Mass spectrometer developments to include multiple high-resolution detectors that can be operated in parallel could further decrease the acquisition time by a factor of n, the number of detectors. Efforts described here resulted in development of an instrument with a set of Fourier transform ion cyclotron resonance (ICR) cells as detectors that constitute the first MS array capable of parallel high-resolution spectral acquisition. ICR cell array systems consisting of three or five cells were constructed with printed circuit boards and installed within a single superconducting magnet and vacuum system. Independent ion populations were injected and trapped within each cell in the array. Upon filling the array, all ions in all cells were simultaneously excited and ICR signals from each cell were independently amplified and recorded in parallel. Presented here are the initial results of successful parallel spectral acquisition, parallel mass spectrometry (MS) and MS/MS measurements, and parallel high-resolution acquisition with the MS array system. PMID:26669509

  3. Cyclotron resonance maser experiments in a bifilar helical waveguide

    PubMed

    Aharony; Drori; Jerby

    2000-11-01

    Oscillator and amplifier cyclotron-resonance-maser (CRM) experiments in a spiral bifilar waveguide are presented in this paper. The slow-wave CRM device employs a low-energy low-current electron beam (2-12 keV, approximately 0.5 A). The pitch angle of the helical waveguide is relatively small; hence, the phase velocity in this waveguide, V(ph) congruent with0.8c (where c is the speed of light), is much faster than the axial velocity of the electrons, V(ez)frequency is tuned continuously in the range 2.5-8.4 GHz by varying the axial magnetic field. A fine-tuning is possible by the electron accelerating voltage. In the amplifier mode, this CRM experiment demonstrates an amplification up to 16 dB at 5 GHz. The immediate gain bandwidth is wider than 0.1 GHz (>2%). The wide tunable range of this CRM device due to the nondispersive bifilar helix is discussed.

  4. 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.

  5. 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.

  6. 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.

  7. Direct injection into the IsoDAR Cyclotron using a RFQ

    NASA Astrophysics Data System (ADS)

    Axani, Spencer; IsoDAR Collaboration

    2015-04-01

    Beginning in the 1970s, the use of Radio Frequency Quadrupoles (RFQs) has been pervasive in linear accelerators in order to accelerate, bunch, and separate ion species. Current research suggests this may be an ideal way to inject a low energy H2+ beam axially into a cyclotron. The IsoDAR (Isotope Decay At Rest) experiment aims to implement this injection system in order to achieve higher Low Energy Beam Transport (LEBT) efficiencies and ultimately construct a novel compact neutrino factory to test the hypothesis of sterile neutrinos. This talk will focus on the research and development needed to implement a RFQ into the IsoDAR experiment.

  8. 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.

  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. 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.

  11. Improving cancer treatment with cyclotron produced radionuclides. Progress report

    SciTech Connect

    Larson, S.M.; Finn, R.D.

    1993-11-01

    This report describes our continuing long term goal of promoting nuclear medicine applications by improving the scientific basis for tumor diagnosis, treatment and treatment follow-up based on the use of cyclotron produced radiotracers in oncology. The program includes 3 interactive components: Radiochemistry/Cyclotron; Pharmacology; and Immunology. An essential strategy is as follows: novel radionuclides and radiotracers developed in the Radiochemistry/Cyclotron section will be employed in the Pharmacology and Immunology sections during the next year. The development of novel radionuclides and tracers is of course useful in and of itself, but their utility is greatly enhanced by the interaction with the immunology and pharmacology components of the program.

  12. 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

  13. 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.

  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

    2015-01-01

    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

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. Observation of fast-ion Doppler-shifted cyclotron resonance with shear Alfven waves

    SciTech Connect

    Zhang Yang; Heidbrink, W. W.; Boehmer, H.; McWilliams, R.; Vincena, S.; Carter, T. A.; Gekelman, W.; Leneman, D.; Pribyl, P.

    2008-10-15

    The Doppler-shifted cyclotron resonance ({omega}-k{sub z}v{sub z}={omega}{sub f}) between fast ions and shear Alfven waves is experimentally investigated ({omega}, wave frequency; k{sub z}, axial wavenumber; v{sub z}, fast-ion axial speed; {omega}{sub f}, fast-ion cyclotron frequency). A test particle beam of fast ions is launched by a Li{sup +} source in the helium plasma of the LArge Plasma Device (LAPD) [W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991)], with shear Alfven waves (SAW) (amplitude {delta} B/B up to 1%) launched by a loop antenna. A collimated fast-ion energy analyzer measures the nonclassical spreading of the beam, which is proportional to the resonance with the wave. A resonance spectrum is observed by launching SAWs at 0.3-0.8{omega}{sub ci}. Both the magnitude and frequency dependence of the beam-spreading are in agreement with the theoretical prediction using a Monte Carlo Lorentz code that launches fast ions with an initial spread in real/velocity space and random phases relative to the wave. Measured wave magnetic field data are used in the simulation.

  20. The NSCL cyclotron gas stopper - Entering commissioning

    NASA Astrophysics Data System (ADS)

    Schwarz, S.; Bollen, G.; Chouhan, S.; Das, J. J.; Green, M.; Magsig, C.; Morrissey, D. J.; Ottarson, J.; Sumithrarachchi, C.; Villari, A. C. C.; Zeller, A.

    2016-06-01

    Linear gas stopping cells have been used successfully at NSCL to slow down ions produced by projectile fragmentation from the 100 MeV/u to the keV energy range. These 'stopped beams' have first been used for low-energy high precision experiments and more recently for NSCLs re-accelerator ReA. A gas-filled reverse cyclotron is currently under construction by the NSCL to complement the existing stopping cells: Due to its extended stopping length, efficient stopping and fast extraction is expected even for light and medium-mass ions, which are difficult to thermalize in linear gas cells. The device is based on a 2.6 T maximum-field cyclotron-type magnet to confine the injected beam while it is slowed down in ≈100 mbar of LN2-temperature helium gas. Once thermalized, the beam will be transported to the center of the device by a traveling-wave RF-carpet system, extracted along the symmetry axis with an ion conveyor and miniature RF-carpets, and accelerated to a few tens of keV of energy for delivery to the users. The superconducting magnet has been constructed on a 60 kV platform and energized to its nominal field strength. The magnet's two cryostats use 3 cryo-refrigerators each and liquid-nitrogen cooled thermal shields to cool the coil pair to superconductivity. This concept, chosen not to have to rely on external liquid helium, has been working well. Measurements of axial and radial field profiles confirm the field calculations. The individual RF-ion guiding components for low-energy ion transport through the device have been tested successfully. The beam stopping chamber with its 0.9 m-diameter RF carpet system and the ion extraction system are being prepared for installation inside the magnet for low-energy ion transport tests.

  1. 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.

  2. 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.

  3. Heavy-ion injection from tandems into an isochronous cyclotron

    SciTech Connect

    LeVine, M.J.; Chasman, C.

    1981-01-01

    A design has been realized for the injection of heavy ion beams generated by the BNL 3-stage tandem facility into a proposed isochronous cyclotron. The tandem beams are bunched into +- 1/sup 0/ R.F. phase (less than or equal to 0.5 nsec) in two stages. The beam is then injected into the cyclotron through a valley, past a hill, and into the next valley on to a stripper foil. Only a single steerer is required to make trajectory corrections for the different beams. Two achromats are used to regulate the tandem potential and to provide phase control. A final section of the injection optics provides matching of transverse phase space to the acceptance of the cyclotron. The calculations use realistic tandem emittances and magnetic fields for the cyclotron based on measurements with a model magnet.

  4. Undergraduate Education with the Rutgers 12-Inch Cyclotron

    NASA Astrophysics Data System (ADS)

    Koeth, Timothy W.

    The Rutgers 12-Inch Cyclotron is a research grade accelerator dedicated to undergraduate education. From its inception, it has been intended for instruction and has been designed to demonstrate classic beam physics phenomena and provides students hands on experience with accelerator technology. The cyclotron is easily reconfigured, allowing experiments to be designed and performed within one academic semester. Our cyclotron offers students the opportunity to operate an accelerator and directly observe many fundamental beam physics concepts, including axial and radial betatron motion, destructive resonances, weak and azimuthally varying field (AVF) focusing schemes, RF and DEE voltage effects, diagnostic techniques, and perform low energy nuclear reactions. This paper emphasizes the unique beam physics measurements and beam manipulations capable at the Rutgers 12-Inch Cyclotron.

  5. Cyclotrons for clinical and biomedical research with PET

    SciTech Connect

    Wolf, A.P.

    1987-01-01

    The purpose of this commentary is to present some background material on cyclotrons and other particle accelerators particularly with a view toward the considerations behind acquiring and installing such a machine for purely clinical and/or biomedical research use.

  6. Transverse-longitudinal coupling by space charge in cyclotrons

    NASA Astrophysics Data System (ADS)

    Baumgarten, C.

    2011-11-01

    A method is presented that enables one to compute the parameters of matched beams with space charge in cyclotrons with emphasis on the effect of the transverse-longitudinal coupling. Equations describing the transverse-longitudinal coupling and corresponding tune shifts in first order are derived for the model of an azimuthally symmetric cyclotron. The eigenellipsoid of the beam is calculated and the transfer matrix is transformed into block-diagonal form. The influence of the slope of the phase curve on the transverse-longitudinal coupling is accounted for. The results are generalized and numerical procedures for the case of an azimuthally varying field cyclotron are presented. The algorithm is applied to the PSI injector II and ring cyclotron and the results are compared to TRANSPORT.

  7. Low-frequency magnetic fluctuation spectra in the magnetosheath and plasma depletion layer

    NASA Technical Reports Server (NTRS)

    Denton, Richard E.; Gary, S. Peter; Anderson, Brian J.; Fuselier, Stephen A.; Hudson, Mary K.

    1994-01-01

    Recent observations have delineated several different kinds of enhanced magnetic fluctuation spectra below the proton cyclotron frequency in the terrestrial magnetosheath. A model is presented that represents the variation of plasma parameters across the plasma depletion layer and into the magnetosheath proper. Using this model, we find that many of the properties of the observed spectra follow directly from the predictions of linear Vlasov instability theory. The observed progression of spectral features is a natural progression from mirror mode to merged (in frequency range) proton and He(2+) cyclotron modes to bifurcated (in frequency range) cyclotron modes as plasma convects earthward in the magnetosheath. The necessary change in dispersion surface topology from separated proton and He(2+) cyclotron surfaces at low beta to merged surfaces at high beta is described.

  8. PET computer programs for use with the 88-inch cyclotron

    SciTech Connect

    Gough, R.A.; Chlosta, L.

    1981-06-01

    This report describes in detail several offline programs written for the PET computer which provide an efficient data management system to assist with the operation of the 88-Inch Cyclotron. This function includes the capability to predict settings for all cyclotron and beam line parameters for all beams within the present operating domain of the facility. The establishment of a data base for operational records is also described from which various aspects of the operating history can be projected.

  9. POSSIBLE EVIDENCE OF ALFVEN-CYCLOTRON WAVES IN THE ANGLE DISTRIBUTION OF MAGNETIC HELICITY OF SOLAR WIND TURBULENCE

    SciTech Connect

    He Jiansen; Tu Chuanyi; Yao Shuo; Tian Hui; Marsch, Eckart

    2011-04-20

    The fluctuating magnetic helicity is considered an important parameter in diagnosing the characteristic modes of solar wind turbulence. Among them is the Alfven-cyclotron wave, which is probably responsible for the solar wind plasma heating, but has not yet been identified from the magnetic helicity of solar wind turbulence. Here, we present the possible signatures of Alfven-cyclotron waves in the distribution of magnetic helicity as a function of {theta}{sub VB}, which is the angle between the solar wind velocity and local mean magnetic field. We use magnetic field data from the STEREO spacecraft to calculate the {theta}{sub VB} distribution of the normalized reduced fluctuating magnetic helicity {sigma}{sub m}. We find a dominant negative {sigma}{sub m} for 1 s < p < 4 s (p is time period) and for {theta}{sub VB} < 30 deg. in the solar wind outward magnetic sector, and a dominant positive {sigma}{sub m} for 0.4 s < p < 4 s and for {theta}{sub VB}>150 deg. in the solar wind inward magnetic sector. These features of {sigma}{sub m} appearing around the Doppler-shifted ion-cyclotron frequencies may be consistent with the existence of Alfven-cyclotron waves among the outward propagating fluctuations. Moreover, right-handed polarized waves at larger propagation angles, which might be kinetic Alfven waves or whistler waves, have also been identified on the basis of the {sigma}{sub m} features in the angular range 40 deg. < {theta}{sub VB} < 140 deg. Our findings suggest that Alfven-cyclotron waves (together with other wave modes) play a prominent role in turbulence cascading and plasma heating of the solar wind.

  10. Ion source and injection line for high intensity medical cyclotron

    SciTech Connect

    Jia, XianLu Guan, Fengping; Yao, Hongjuan; Zhang, TianJue; Yang, Jianjun; Song, Guofang; Ge, Tao; Qin, Jiuchang

    2014-02-15

    A 14 MeV high intensity compact cyclotron, CYCIAE-14, was built at China Institute of Atomic Energy (CIAE). An injection system based on the external H− ion source was used on CYCIAE-14 so as to provide high intensity beam, while most positron emission tomography cyclotrons adopt internal ion source. A beam intensity of 100 μA/14 MeV was extracted from the cyclotron with a small multi-cusp H− ion source (CIAE-CH-I type) and a short injection line, which the H− ion source of 3 mA/25 keV H− beam with emittance of 0.3π mm mrad and the injection line of with only 1.2 m from the extraction of ion source to the medial plane of the cyclotron. To increase the extracted beam intensity of the cyclotron, a new ion source (CIAE-CH-II type) of 9.1 mA was used, with maximum of 500 μA was achieved from the cyclotron. The design and test results of the ion source and injection line optimized for high intensity acceleration will be given in this paper.

  11. Ion source and injection line for high intensity medical cyclotron

    NASA Astrophysics Data System (ADS)

    Jia, XianLu; Guan, Fengping; Yao, Hongjuan; Zhang, TianJue; Yang, Jianjun; Song, Guofang; Ge, Tao; Qin, Jiuchang

    2014-02-01

    A 14 MeV high intensity compact cyclotron, CYCIAE-14, was built at China Institute of Atomic Energy (CIAE). An injection system based on the external H- ion source was used on CYCIAE-14 so as to provide high intensity beam, while most positron emission tomography cyclotrons adopt internal ion source. A beam intensity of 100 μA/14 MeV was extracted from the cyclotron with a small multi-cusp H- ion source (CIAE-CH-I type) and a short injection line, which the H- ion source of 3 mA/25 keV H- beam with emittance of 0.3π mm mrad and the injection line of with only 1.2 m from the extraction of ion source to the medial plane of the cyclotron. To increase the extracted beam intensity of the cyclotron, a new ion source (CIAE-CH-II type) of 9.1 mA was used, with maximum of 500 μA was achieved from the cyclotron. The design and test results of the ion source and injection line optimized for high intensity acceleration will be given in this paper.

  12. Terahertz Dynamics of a Topologically Protected State: Quantum Hall Effect Plateaus near the Cyclotron Resonance of a Two-Dimensional Electron Gas.

    PubMed

    Stier, A V; Ellis, C T; Kwon, J; Xing, H; Zhang, H; Eason, D; Strasser, G; Morimoto, T; Aoki, H; Zeng, H; McCombe, B D; Cerne, J

    2015-12-11

    We measure the Hall conductivity of a two-dimensional electron gas formed at a GaAs/AlGaAs heterojunction in the terahertz regime close to the cyclotron resonance frequency using highly sensitive Faraday rotation measurements. The sample is electrically gated, allowing the electron density to be changed continuously by more than a factor of 3. We observe clear plateaulike and steplike features in the Faraday rotation angle vs electron density and magnetic field (Landau-level filling factor) even at fields or frequencies very close to cyclotron resonance absorption. These features are the high frequency manifestation of quantum Hall plateaus-a signature of topologically protected edge states. We observe both odd and even filling factor plateaus and explore the temperature dependence of these plateaus. Although dynamical scaling theory begins to break down in the frequency region of our measurements, we find good agreement with theory. PMID:26705653

  13. Terahertz Dynamics of a Topologically Protected State: Quantum Hall Effect Plateaus near the Cyclotron Resonance of a Two-Dimensional Electron Gas.

    PubMed

    Stier, A V; Ellis, C T; Kwon, J; Xing, H; Zhang, H; Eason, D; Strasser, G; Morimoto, T; Aoki, H; Zeng, H; McCombe, B D; Cerne, J

    2015-12-11

    We measure the Hall conductivity of a two-dimensional electron gas formed at a GaAs/AlGaAs heterojunction in the terahertz regime close to the cyclotron resonance frequency using highly sensitive Faraday rotation measurements. The sample is electrically gated, allowing the electron density to be changed continuously by more than a factor of 3. We observe clear plateaulike and steplike features in the Faraday rotation angle vs electron density and magnetic field (Landau-level filling factor) even at fields or frequencies very close to cyclotron resonance absorption. These features are the high frequency manifestation of quantum Hall plateaus-a signature of topologically protected edge states. We observe both odd and even filling factor plateaus and explore the temperature dependence of these plateaus. Although dynamical scaling theory begins to break down in the frequency region of our measurements, we find good agreement with theory.

  14. Theory and observations of electromagnetic ion cyclotron waves in Saturn's inner magnetosphere

    NASA Technical Reports Server (NTRS)

    Barbosa, D. D.

    1993-01-01

    High-resolution Voyager 1 magnetic field observations of Saturn's inner magnetosphere are examined for the presence of ULF waves. Quasi-circular left-hand polarized transverse oscillations are found in the near-equatorial region of 5-7 Rs with a wave period about 10 s and peak amplitude of about 2 nT. The wave is identified as the electromagnetic oxygen cyclotron mode occurring at a frequency just below the O(+) ion cyclotron frequency. A theoretical model of wave excitation based on gyroresonant coupling through a temperature anisotropy of O(+) pickup ions is developed which accounts for the principal features of the wave spectrum. It is hypothesized that wave-particle interactions provide a level of scattering commensurate with the weak pitch angle diffusion regime but nonetheless one that regulates and maintains a constant thermal anisotropy of ions along the magnetic field. Arguments are also presented that O(+) was the dominant thermal ion of the Dione-Tethys plasma torus at the time of the Pioneer 11 encounter the year previous to the Voyager 1 measurements.

  15. Theory and observations of electromagnetic ion cyclotron waves in Saturn's inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Barbosa, D. D.

    1993-06-01

    High-resolution Voyager 1 magnetic field observations of Saturn's inner magnetosphere are examined for the presence of ULF waves. Quasi-circular left-hand polarized transverse oscillations are found in the near-equatorial region of 5-7 Rs with a wave period about 10 s and peak amplitude of about 2 nT. The wave is identified as the electromagnetic oxygen cyclotron mode occurring at a frequency just below the O(+) ion cyclotron frequency. A theoretical model of wave excitation based on gyroresonant coupling through a temperature anisotropy of O(+) pickup ions is developed which accounts for the principal features of the wave spectrum. It is hypothesized that wave-particle interactions provide a level of scattering commensurate with the weak pitch angle diffusion regime but nonetheless one that regulates and maintains a constant thermal anisotropy of ions along the magnetic field. Arguments are also presented that O(+) was the dominant thermal ion of the Dione-Tethys plasma torus at the time of the Pioneer 11 encounter the year previous to the Voyager 1 measurements.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Cyclotron autoresonance maser in the millimeter region

    NASA Astrophysics Data System (ADS)

    Nikolov, N. A.; Spasovski, I. P.; Kostov, K. G.; Velichkov, J. N.; Spasov, V. A.

    1990-06-01

    This paper investigates the optimal experimental conditions for a cyclotron autoresonance maser (CARM) regime realized by a nonadiabatic magnetic beam pumping in the millimeter wavelength region. In the experiment, a Blumline-type accelerator with a voltage up to 650 kV and maximal current up to 10 kA is used to generate a hollow beam with a pulse duration of 30 ns. The electron beam, emitted from a graphite cathode with a 10-mm diameter, propagates in a cylindrical drift tube of 56 mm diam and a length of 500 mm. The external magnetic field B, provided by a solenoidal magnet, is homogeneous along the drift tube up to a distance of 300 mm from the cathode. The experiment demonstrated the generation of microwave radiation in the time interval from 0.0016 to 0.0023 sec after the switch-on of the external magnetic field. Two maxima of the output microwave power (8 and 10 MW) at a wavelength of 5 and 5.5 mm, respectively, were observed.

  1. The Oak Ridge Isochronous Cyclotron Refurbishment Project

    SciTech Connect

    Mendez, II, Anthony J; Ball, James B; Dowling, Darryl T; Mosko, Sigmund W; Tatum, B Alan

    2011-01-01

    The Oak Ridge Isochronous Cyclotron (ORIC) has been in operation for nearly fifty years at the Oak Ridge National Laboratory (ORNL). Presently, it serves as the driver accelerator for the ORNL Holifield Radioactive Ion Beam Facility (HRIBF), where radioactive ion beams are produced using the Isotope Separation Online (ISOL) technique for post-acceleration by the 25URC tandem electrostatic accelerator. Operability and reliability of ORIC are critical issues for the success of HRIBF and have presented increasingly difficult operational challenges for the facility in recent years. In February 2010, a trim coil failure rendered ORIC inoperable for several months. This presented HRIBF with the opportunity to undertake various repairs and maintenance upgrades aimed at restoring the full functionality of ORIC and improving the reliability to a level better than what had been typical over the previous decade. In this paper, we present details of these efforts, including the replacement of the entire trim coil set and measurements of their radial field profile. Comparison of measurements and operating tune parameters with setup code predictions will also be presented.

  2. Modelling of Ion Cyclotron Wall Conditioning plasmas

    NASA Astrophysics Data System (ADS)

    Douai, D.; Wauters, T.; Lyssoivan, A.; Marchuk, O.; Wünderlich, D.; Brémond, S.; Lombard, G.; Mollard, P.; Pegourié, B.; Van Oost, G.

    2011-12-01

    Ion Cyclotron Wall Conditioning (ICWC) is envisioned in ITER to clean the wall from impurities, to control the wall isotopic ratio and the hydrogen recycling in the presence of the toroidal magnetic field. Various experiments and modelling are advancing to consolidate this technique. In this contribution the modeling of ICWC is presented, which can be divided in two parts: plasma description and plasma wall interaction. Firstly a 0D plasma model, based on a set of energy and particle balance equations for Maxwellian Hydrogen and Helium species, is presented. The model takes into account elementary collision processes, coupled RF power, particle confinement, wall recycling, and active gas injection and pumping. The RF plasma production process is based mainly on electron collisional ionization. The dependency of the plasma parameters, the Hydrogen and Helium partial pressures and neutral or ionic fluxes on pressure and RF power are quantitatively in good agreement with those obtained experimentally on TORE SUPRA. Secondly an extension of the 0D model including the description of the wall interaction is presented and compared to TORE SUPRA multi-pulse ICWC discharges.

  3. The Effects of Weak Combined Magnetic Field on Cell Wall Regeneration and Frequency of Plant Protoplasts Fusion

    NASA Astrophysics Data System (ADS)

    Nedukha, Olena

    The major purpose of these experiments was to investigate plant protoplast fusion frequency and regeneration of a cell wall by protoplasts at weak combined magnetic field (CMF) with the frequency resonance to the cyclotron frequency of Mg2+, Ca2+ and K+ ions. The protoplasts were isolated from Nicotiana lumbaginifolia and N. silvestris leaf mesophyll and from callus tissues (Nicotiana tabacum and Glycine max). The special extra apparatus with ferromagnetic shield was used for estimate of CMF with the frequency resonance to the cyclotron frequency of Mg2+, Ca2+ and K+ ions. The fusion of protoplasts is realized by using of parent protoplasts isolated from one plant species, as well as from various plant species. Control samples were situated near the apparatus with CMF. The laser confocal microscopy was used for study of cell wall regeneration by single and fused protoplasts. The cytochemical methods with DAPI and calcofluor dye were also applied as the detectors for protoplast fusion and regeneration of cell wall. We have been established that CMF with frequency adjusted to the cyclotron frequency Mg2+ ions have shown the most positive influence on regeneration of cell wall by protoplasts. CMF adjusted to the cyclotron frequency of K+ ions very weakly affected on the frequency of protoplast fusion. Largest frequency of protoplasts fusion is noted in the CMF adjusted to the cyclotron frequency of Ca2+ in comparison with the control samples.

  4. A small low energy cyclotron for radioisotope measurements

    SciTech Connect

    Bertsche, K.J.

    1989-11-01

    Direct detection of {sup 14}C by accelerator mass spectrometry has proved to be a much more sensitive method for radiocarbon dating than the decay counting method invented earlier by Libby. A small cyclotron (the cyclotrino'') was proposed for direct detection of radiocarbon in 1980. This combined the suppression of background through the use of negative ions, which had been used effectively in tandem accelerators, with the high intrinsic mass resolution of a cyclotron. Development of a small electrostatically-focused cyclotron for use as a mass spectrometer was previously reported but the sensitivity needed for detection of {sup 14}C at natural abundance was not achieved. The major contributions of this work are the integration of a high current external ion source with a small flat-field, electrostatically-focused cyclotron to comprise a system capable of measuring {sup 14}C at natural levels, and the analysis of ion motion in such a cyclotron, including a detailed analysis of phase bunching and its effect on mass resolution. A high current cesium sputter negative ion source generates a beam of carbon ions which is pre-separated with a Wien filter and is transported to the cyclotron via a series of electrostatic lenses. Beam is injected radially into the cyclotron using electrostatic deflectors and an electrostatic mirror. Axial focusing is entirely electrostatic. A microchannel plate detector is used with a phase-grated output. In its present form the system is capable of improving the sensitivity of detecting {sup 14}C in some biomedical experiments by a factor of 10{sup 4}. Modifications are discussed which could bring about an additional factor of 100 in sensitivity, which is important for archaeological and geological applications. Possibilities for measurements of other isotopes, such as {sup 3}H, and {sup 10}Be, and {sup 26}Al, are discussed. 70 refs.

  5. Observations of compound sawteeth in ion cyclotron resonant heating plasma using ECE imaging on experimental advanced superconducting tokamak

    NASA Astrophysics Data System (ADS)

    Hussain, Azam; Zhao, Zhenling; Xie, Jinlin; Zhu, Ping; Liu, Wandong; Ti, Ang

    2016-04-01

    The spatial and temporal evolutions of compound sawteeth were directly observed using 2D electron cyclotron emission imaging on experimental advanced superconducting tokamak. The compound sawtooth consists of partial and full collapses. After partial collapse, the hot core survives as only a small amount of heat disperses outwards, whereas in the following full collapse a large amount of heat is released and the hot core dissipates. The presence of two q = 1 surfaces was not observed. Instead, the compound sawtooth occurs mainly at the beginning of an ion cyclotron resonant frequency heating pulse and during the L-H transition phase, which may be related to heat transport suppression caused by a decrease in electron heat diffusivity.

  6. Effects of end cell ion cyclotron fluctuations on central-cell ion confinement in the tandem mirror experiment (TMX)

    SciTech Connect

    Grubb, D.P.; Casper, T.A.; Clauser, J.F.

    1980-04-07

    The tandem mirror device (TMX) exhibits gross stability to both MHD and microinstability modes. The end-cell plasmas provide the tandem with average minimum-B stability, while the efflux of plasma from the central cell maintains the end cells (plugs) at marginal stability to loss cone modes. For some operating conditions, a residual level of plug ion cyclotron fluctuations is detected. These oscillations dominate the fluctuation frequency spectra in both the plugs and the central cell. The presence of plug ion cyclotron fluctuations in the central cell leads to resonance heating of some of the central cell ions. This heating degrades the confinement of the central cell ions; thereby increasing the amount of warm plasma stream flowing through the plugs.

  7. Ring Current-Electromagnetic Ion Cyclotron Waves Coupling

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.

    2005-01-01

    The effect of Electromagnetic Ion Cyclotron (EMIC) waves, generated by ion temperature anisotropy in Earth s ring current (RC), is the best known example of wave- particle interaction in the magnetosphere. Also, there is much controversy over the importance of EMIC waves on RC depletion. Under certain conditions, relativistic electrons, with energies 21 MeV, can be removed from the outer radiation belt (RB) by EMIC wave scattering during a magnetic storm. That is why the calculation of EMIC waves must be a very critical part of the space weather studies. The new RC model that we have developed and present for the first time has several new features that we have combine together in a one single model: (a) several lower frequency cold plasma wave modes are taken into account; (b) wave tracing of these wave has been incorporated in the energy EMIC wave equation; (c) no assumptions regarding wave shape spectra have been made; (d) no assumptions regarding the shape of particle distribution have been made to calculate the growth rate; (e) pitch-angle, energy, and mix diffusions are taken into account together for the first time; (f) the exact loss-cone RC analytical solution has been found and coupled with bounce-averaged numerical solution of kinetic equation; (g) the EMIC waves saturation due to their modulation instability and LHW generation are included as an additional factor that contributes to this process; and (h) the hot ions were included in the real part of dielectric permittivity tensor. We compare our theoretical results with the different EMIC waves models as well as RC experimental data.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Particle and fluid simulations of resistive current-driven electrostatic ion cyclotron waves

    NASA Technical Reports Server (NTRS)

    Seyler, Charles E.; Providakes, Jason

    1987-01-01

    The results from 1-D numerical simulations of electrostatic ion cyclotron waves (EIC) are presented for a model in which the electrons are a resistive (collisional) fluid. Simulations of both the kinetic and fluid descriptions are performed and compared in order to assess the fundamental limitations of fluid theory for EIC waves. The effect of ion-neutral collisions is also included using a simple Monte Carlo technique. It is found that a small ion-neutral collision frequency destroys the frequency harmonic coupling of kinetic EIC waves and tends to validate the fluid description. The saturation amplitude of the current-driven EIC instability is in agreement with recent laboratory experiments. The coherent nature (extremely narrow spectral width) and phase velocity agree with ground based (coherent backscatter radars) and in situ observations of current-driven EIC waves in the high latitude ionosphere.

  14. 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.

  15. 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.

  16. Cyclotron targets and production technologies used for radiopharmaceuticals in NPI

    NASA Astrophysics Data System (ADS)

    Fišer, M.; Kopička, K.; Hradilek, P.; Hanč, P.; Lebeda, O.; Pánek, J.; Vognar, M.

    2003-01-01

    This paper deals with some technical aspects of the development and production of cyclotronmade radiopharmaceuticals (excluding PET). In this field, nuclear chemistry and pharmacy are in a close contact; therefore, requirements of the both should be taken into account. The principles of cyclotron targetry, separation/recovery of materials and synthesis of active substances are given, as well as issues connected with formulation of pharmaceutical forms. As the radiopharmaceuticals should fulfil the requirements on in vivo preparations, there exist a variety of demands pertaining to Good Manufacturing Practice (GMP) concept, which is also briefly discussed. A typical production chain is presented and practical examples of real technologies based on cyclotron-made radionuclides are given as they have been used in Nuclear Physics Institute of CAS (NPI). Special attention is devoted to the technology of enriched cyclotron targets. Frequently used medicinal products employing cyclotron-produced active substances are characterised (Rb/Kr generators, 123I-labelled MIBG, OIH and MAB's). The cyclotron produced radioactive implants for transluminal coronary angioplasty (radioactive stents) are introduced as an example of a medical device developed for therapeutic application.

  17. Electromagnetic ion cyclotron waves suggesting minor ion existence in the inner magnetosphere observed by the Akebono satellite

    NASA Astrophysics Data System (ADS)

    Matsuda, S.; Kasahara, Y.; Goto, Y.

    2014-06-01

    It is well known that electromagnetic ion cyclotron (EMIC) waves exhibit characteristic frequencies on the basis of dispersion relations in multiple-component plasma. We present a case of EMIC waves exhibiting a sudden decrease in intensity (characteristic lower cutoff) to just above half of the proton cyclotron frequency observed in the vicinity of the geomagnetic equator by the Akebono satellite along its trajectory during a magnetic storm in April 1989. It was found that the waves propagate with a large wave normal angle with respect to the geomagnetic field line and that they had a crossover frequency above the characteristic lower cutoff. Because of stormy conditions, ion constituents were expected to fluctuate, suggesting that the characteristic frequencies of EMIC waves should have been fluctuating as well. However, the characteristic frequencies of each event did not vary despite disturbances in the inner magnetosphere, represented by a sudden decrease in the Dst index and electron density fluctuation. In addition, the waves were repeatedly observed within a half day after sudden decreases in Dst; however, they disappeared when the recovery of the Dst index became moderate. Wave generation appears to be closely correlated to fresh energetic particle injection. We study the dispersion relations of EMIC waves under the condition of multiple ion species and suggest the existence of a few percent of alpha particles (He++) or deuterons (D+), which can explain the lower cutoff of EMIC waves in the inner magnetosphere.

  18. 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.

  19. Issues in the analysis and interpretation of cyclotron lines in gamma ray bursts

    NASA Technical Reports Server (NTRS)

    Lamb, D. Q.

    1992-01-01

    The Bayesian approach is discussed to establishing the existence of lines, the importance of observing multiple cyclotron harmonics in determining physical parameters from the lines, and evidence from cyclotron lines of neutron star rotation.

  20. Conversion of compressional Alfven waves into ion-cyclotron waves in inhomogeneous magnetic fields

    SciTech Connect

    Amagishi, Y.; Tsushima, A.; Inutake, M.

    1982-04-26

    Axisymmetric compressional Alfven (fast) waves, which propagate into a region of an increasing magnetic field in a cylindrical plasma, are observed to be converted into ion-cyclotron (slow) waves via ion-cyclotron resonances.

  1. Development of a fast scintillator based beam phase measurement system for compact superconducting cyclotrons

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, Tanushyam; Kanti Dey, Malay; Dhara, Partha; Roy, Suvodeep; Debnath, Jayanta; Balakrishna Bhole, Rajendra; Dutta, Atanu; Pradhan, Jedidiah; Pal, Sarbajit; Pal, Gautam; Roy, Amitava; Chakrabarti, Alok

    2013-05-01

    In an isochronous cyclotron, measurements of central phase of the ion beam with respect to rf and the phase width provide a way to tune the cyclotron for maximum energy gain per turn and efficient extraction. We report here the development of a phase measurement system and the measurements carried out at the Variable Energy Cyclotron Centre's (VECC's) K = 500 superconducting cyclotron. The technique comprises detecting prompt γ-rays resulting from the interaction of cyclotron ion beam with an aluminium target mounted on a radial probe in coincidence with cyclotron rf. An assembly comprising a fast scintillator and a liquid light-guide inserted inside the cyclotron was used to detect the γ-rays and to transfer the light signal outside the cyclotron where a matching photo-multiplier tube was used for light to electrical signal conversion. The typical beam intensity for this measurement was a few times 1011 pps.

  2. Cyclotron development program at Jyväskylä

    NASA Astrophysics Data System (ADS)

    Heikkinen, P.; Liukkonen, E.

    2001-12-01

    The Jyväskylä K130 cyclotron has been modified to allow also negative ion acceleration with stripping extraction. A multi-cusp ion source for negative ions (H- and d-) was built [1]. The source gives over 5 mA at a voltage of 5.9 kV, which is used for 30 MeV protons. The extracted 30 MeV proton beam of 60 μA from the cyclotron has been reached. Due to very good extraction efficiency the dose rate in the cyclotron vault has decreased by a factor of 10-20 with 30 MeV protons compared to positive ion extraction. Also the inflector change was automated in order to reduce the dose for personnel.

  3. Energization of ionospheric ions by electrostatic hydrogen cyclotron waves

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    Interactions between ionospheric ions and electrostatic hydrogen cyclotron waves are studied numerically in an investigation of a possible mechanism for the energization of the low-energy ionospheric ions flowing along geomagnetic field lines to high altitudes. Ion equations of motion are solved numerically for a given number of O(+), He(+) and He(2+) ions initially in a Maxwellian distribution. All the ions considered are found capable of undergoing stochastic acceleration by a coherent electrostatic hydrogen cyclotron wave with parameters typical of the auroral plasma above 1 earth radius. The fraction of the initial ion population undergoing heating depends strongly on the mass, charge and initial temperature of the ion species, with O(+) ions only heated when their initial temperature is approximately greater than the hydrogen temperature and the lighter ions able to be heated even when cold, due to cyclotron resonant stochastic heating.

  4. Radiation effects testing at the 88-inch cyclotron at LBNL

    SciTech Connect

    McMahan, Margaret A.; Koga, Rokotura

    2001-10-09

    The effects of ionizing particles on sensitive microelectronics is an important component of the design of systems as diverse as satellites and space probes, detectors for high energy physics experiments and even internet server farms. Understanding the effects of radiation on human cells is an equally important endeavor directed towards future manned missions in space and towards cancer therapy. At the 88-Inch Cyclotron at the Berkeley Laboratory, facilities are available for radiation effects testing (RET) with heavy ions and with protons. The techniques for doing these measurements and the advantages of using a cyclotron will be discussed, and the Cyclotron facilities will be compared with other facilities worldwide. RET of the same part at several facilities of varying beam energy can provide tests of the simple models used in this field and elucidate the relative importance of atomic and nuclear effects. The results and implications of such measurements will be discussed.

  5. Distribution of thermal neutron flux around a PET cyclotron.

    PubMed

    Ogata, Yoshimune; Ishigure, Nobuhito; Mochizuki, Shingo; Ito, Kengo; Hatano, Kentaro; Abe, Junichiro; Miyahara, Hiroshi; Masumoto, Kazuyoshi; Nakamura, Hajime

    2011-05-01

    The number of positron emission tomography (PET) examinations has greatly increased world-wide. Since positron emission nuclides for the PET examinations have short half-lives, they are mainly produced using on-site cyclotrons. During the production of the nuclides, significant quantities of neutrons are generated from the cyclotrons. Neutrons have potential to activate the materials around the cyclotrons and cause exposure to the staff. To investigate quantities and distribution of the thermal neutrons, thermal neutron fluxes were measured around a PET cyclotron in a laboratory associating with a hospital. The cyclotron accelerates protons up to 18 MeV, and the mean particle current is 20 μA. The neutron fluxes were measured during both 18F production and C production. Gold foils and thermoluminescent dosimeter (TLD) badges were used to measure the neutron fluxes. The neutron fluxes in the target box averaged 9.3 × 10(6) cm(-2) s(-1) and 1.7 × 10(6) cm(-2) s(-1) during 18F and 11C production, respectively. Those in the cyclotron room averaged 4.1 × 10(5) cm(-2) s(-1) and 1.2 × 10(5) cm(-2) s(-1), respectively. Those outside the concrete wall shielding were estimated as being equal to or less than ∼3 cm s, which corresponded to 0.1 μSv h(-1) in effective dose. The neutron fluxes outside the concrete shielding were confirmed to be quite low compared to the legal limit.

  6. 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.

  7. Purification of cyclotron-produced 203Pb for labeling Herceptin.

    PubMed

    Garmestani, Kayhan; Milenic, Diane E; Brady, Erik D; Plascjak, Paul S; Brechbiel, Martin W

    2005-04-01

    A simple and rapid procedure was developed for the purification of cyclotron-produced 203Pb via the 203Tl(d,2n) 203Pb reaction. A Pb(II) selective ion-exchange resin, with commercial name Pb Resin from Eichrom Technologies, Inc., was used to purify 203Pb from the cyclotron-irradiated Tl target with excellent recovery of the enriched Tl target material. The purified 203Pb was used to radiolabel the monoclonal antibody Herceptin. The in vitro and in vivo properties of the 203Pb radioimmunoconjugate were evaluated.

  8. Residual radioactivity in a cyclotron and its surroundings.

    PubMed

    Phillips, A B; Prull, D E; Ristinen, R A; Kraushaar, J J

    1986-09-01

    Neutron-induced gamma-ray-emitting radionuclides in components and surroundings of the University of Colorado 1.3-m sector-focusing cyclotron have been measured with Ge(Li) and HPGe detectors. These measurements were made before decommissioning of the cyclotron and before approving release of the accelerator components and building space for other uses. In addition to the activities expected from previous published work, 13.3-y 152Eu and 8.6-y 154Eu were found in the concrete shielding with specific activities of tens of becquerels per kilogram (a few nanocuries per kilogram).

  9. Backward wave cyclotron-maser emission in the auroral magnetosphere.

    PubMed

    Speirs, D C; Bingham, R; Cairns, R A; Vorgul, I; Kellett, B J; Phelps, A D R; Ronald, K

    2014-10-10

    In this Letter, we present theory and particle-in-cell simulations describing cyclotron radio emission from Earth's auroral region and similar phenomena in other astrophysical environments. In particular, we find that the radiation, generated by a down-going electron horseshoe distribution is due to a backward-wave cyclotron-maser emission process. The backward wave nature of the radiation contributes to upward refraction of the radiation that is also enhanced by a density inhomogeneity. We also show that the radiation is preferentially amplified along the auroral oval rather than transversely. The results are in agreement with recent Cluster observations. PMID:25375713

  10. Backward wave cyclotron-maser emission in the auroral magnetosphere.

    PubMed

    Speirs, D C; Bingham, R; Cairns, R A; Vorgul, I; Kellett, B J; Phelps, A D R; Ronald, K

    2014-10-10

    In this Letter, we present theory and particle-in-cell simulations describing cyclotron radio emission from Earth's auroral region and similar phenomena in other astrophysical environments. In particular, we find that the radiation, generated by a down-going electron horseshoe distribution is due to a backward-wave cyclotron-maser emission process. The backward wave nature of the radiation contributes to upward refraction of the radiation that is also enhanced by a density inhomogeneity. We also show that the radiation is preferentially amplified along the auroral oval rather than transversely. The results are in agreement with recent Cluster observations.

  11. Vacuum measurements of the K500 cyclotron accelerator chamber

    SciTech Connect

    Mallory, M.L.; Miller, P.S.; Kuchar, J.; Hudson, E.D.

    1986-01-01

    To evaluate the effectiveness of the unique internal cryopumping system, the pressure in the K500 superconducting cyclotron was measured as a function of radius for various gas flow rates emanating from the internal PIG source. For the test, a nude ion gauge with vertical dimension less than 2.3 cm was built and mounted on the internal beam probe. The effect of magnetic field on the ion gauge reading was determined and a method of degaussing the cyclotron was devised. Data from the normal shielded ion gauge located approximately 6 m away from the median plane was correlated with the internal vacuum measurements.

  12. 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).

  13. The design and construction of a pulsed beam generation system based on high intensity cyclotron

    NASA Astrophysics Data System (ADS)

    An, ShiZhong; Yin, ZhiGuo; Li, PengZhan; Song, GuoFang; Wu, LongCheng; Guan, FengPing; Xie, HuaiDong; Jia, XianLu; Lu, YinLong; Zhang, TianJue

    2011-12-01

    In order to perform the studies on a pulsed beam generation system based on a high intensity cyclotron, a test beam line with a pulsed beam generation for a 10 MeV compact cyclotron (CYCIAE-10) has been designed and constructed at China Institute of Atomic Energy (CIAE). A 70 MHz continuous H-beam can be pulsed to the pulse length of less than 10 ns with a repetition rate of 4.4 MHz. The sine waveform with a frequency of 2.2 MHz is adopted for the chopper and a mesh structure with single drift and dual gaps is used for the 70 MHz buncher. A helical resonator is designed and constructed based on simulations and experiments on the RF matching for the chopper. A helical inductance loop that is exceptionally large of its kind and equipped with water cooling for the resonator has been successfully wound and a 500 W solid RF amplifier has been manufactured. A special measuring device has been designed, which can be used to measure both the DC beam and the pulsed beam. The required pulsed beam was obtained after pulsed beam tuning.

  14. 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

  15. 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.

  16. Beam tracking simulation in the central region of a 13 MeV PET cyclotron

    NASA Astrophysics Data System (ADS)

    Anggraita, Pramudita; Santosa, Budi; Taufik, Mulyani, Emy; Diah, Frida Iswinning

    2012-06-01

    This paper reports the trajectories simulation of proton beam in the central region of a 13 MeV PET cyclotron, operating with negative proton beam (for easier beam extraction using a stripper foil), 40 kV peak accelerating dee voltage at fourth harmonic frequency of 77.88 MHz, and average magnetic field of 1.275 T. The central region covers fields of 240mm × 240mm × 30mm size at 1mm resolution. The calculation was also done at finer 0.25mm resolution covering fields of 30mm × 30mm × 4mm size to see the effects of 0.55mm horizontal width of the ion source window and the halted trajectories of positive proton beam. The simulations show up to 7 turns of orbital trajectories, reaching about 1 MeV of beam energy. The distribution of accelerating electric fields and magnetic fields inside the cyclotron were calculated in 3 dimension using Opera3D code and Tosca modules for static magnetic and electric fields. The trajectory simulation was carried out using Scilab 5.3.3 code.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Method for calibrating a Fourier transform ion cyclotron resonance mass spectrometer

    DOEpatents

    Smith, Richard D.; Masselon, Christophe D.; Tolmachev, Aleksey

    2003-08-19

    A method for improving the calibration of a Fourier transform ion cyclotron resonance mass spectrometer wherein the frequency spectrum of a sample has been measured and the frequency (f) and intensity (I) of at least three species having known mass to charge (m/z) ratios and one specie having an unknown (m/z) ratio have been identified. The method uses the known (m/z) ratios, frequencies, and intensities at least three species to calculate coefficients A, B, and C, wherein the mass to charge ratio of a least one of the three species (m/z).sub.i is equal to ##EQU1## wherein f.sub.i is the detected frequency of the specie, G(I.sub.i) is a predetermined function of the intensity of the species, and Q is a predetermined exponent. Using the calculated values for A, B, and C, the mass to charge ratio of the unknown specie (m/z).sub.ii is calculated as the sum of ##EQU2## wherein f.sub.ii is the measured frequency of the unknown specie, and (I.sub.ii) is the measured intensity of the unknown specie.

  2. Performance of the beam chamber vacuum system of K = 500 cyclotron at Variable Energy Cyclotron Centre Kolkata

    SciTech Connect

    Pal, Gautam DuttaGupta, Anjan; Chakrabarti, Alok

    2014-07-15

    The beam chamber of Variable Energy Cyclotron Centre, Kolkata's K = 500 superconducting cyclotron is pumped by liquid helium cooled cryopanel with liquid nitrogen cooled radiation shield. Performance of the vacuum system was evaluated by cooling the cryopanel assembly with liquid nitrogen and liquid helium. Direct measurement of beam chamber pressure is quite difficult because of space restrictions and the presence of high magnetic field. Pressure gauges were placed away from the beam chamber. The beam chamber pressure was evaluated using a Monte Carlo simulation software for vacuum system and compared with measurements. The details of the vacuum system, measurements, and estimation of pressure of the beam chamber are described in this paper.

  3. 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.

  4. 150 MeV proton medical cyclotron design study.

    PubMed

    Burleigh, R J; Clark, D J; Flood, W S

    1975-01-01

    A brief design study has been done for a 150 MeV proton sector cyclotron. The object was to minimize cost but maintain good reliability and easy maintenance. The use of the proton beam would be for therapy, radiography and isotope production.

  5. 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)

  6. High intensity ion beam injection into the 88-inch cyclotron

    SciTech Connect

    Wutte, Daniela; Clark, Dave J.; Laune, Bernard; Leitner,Matthaeus A.; Lyneis, Claude M.

    2000-05-31

    Low cross section experiments to produce super-heavyelements have increased the demand for high intensity heavy ion beams atenergies of about 5 MeV/nucleon at the 88-Inch Cyclotron at the LawrenceBerkeley National Laboratory. Therefore, efforts are underway to increasethe overall ion beam transmission through the axial injection line andthe cyclotron. The ion beam emittance has been measured for various ionmasses and charge states. Beam transport simulations including spacecharge effects were performed for both of the injection line and the ionsource extraction. The relatively low nominal injection voltage of 10 kVwas found to be the main factor for ion beam losses, because of beam blowup due to space charge forces at higher intensities. Consequently,experiments and simulations have been performed at higherinjectionenergies, and it was demonstrated that the ion beams could still becentered in the cyclotron at these energies. Therefore, the new injectorion source VENUS and its ion beam transport system (currently underconstruction at the 88-Inch Cyclotron) are designed for extractionvoltages up to 30 kV.

  7. Silicon meets cyclotron: muon spin resonance of organosilicon radicals.

    PubMed

    West, Robert; Samedov, Kerim; Percival, Paul W

    2014-07-21

    Muons, generated at a high-powered cyclotron, can capture electrons to form muonium atoms. Muon spin resonance spectra can be recorded for organosilyl radicals obtained by addition of muonium atoms to silylenes and silenes. We present a brief summary of progress in this new area since the first such experiments were reported in 2008.

  8. Digital control in LLRF system for CYCIAE-100 cyclotron

    NASA Astrophysics Data System (ADS)

    Yin, Zhiguo; Fu, Xiaoliang; Ji, Bin; Zhang, Tianjue; Wang, Chuan

    2016-05-01

    As a driven accelerator, the CYCIAE-100 cyclotron is designed by China Institute of Atomic Energy for the Beijing Radio Ion-beam Facility project. The cyclotron RF system is designed to use two RF power sources of 100 kW to drive two half-wavelength cavities respectively. Two Dee accelerating electrodes are kept separately from each other inside the cyclotron, while their accelerating voltages are maintained in phase by the efforts of LLRF control. An analog-digital hybrid LLRF system has been developed to achieve cavity tuning control, dee voltage amplitude and phase stabilization etc. The analog subsystems designs are focused on RF signal up/down conversion, tuning control, and dee voltage regulation. The digital system provides an RF signal source, aligns the cavity phases and maintains a Finite State Machine. The digital parts combine with the analog functions to provide the LLRF control. A brief system hardware introduction will be given in this paper, followed by the review of several major characteristics of the digital control in the 100 MeV cyclotron LLRF system. The commissioning is also introduced, and most of the optimization during the process was done by changing the digital parts.

  9. 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.

  10. 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.

  11. Effect of imperfections of the radial component of a magnetic field on beam dynamics in medical cyclotron C235-V3

    NASA Astrophysics Data System (ADS)

    Karamysheva, G. A.; Kostromin, S. A.; Morozov, N. A.; Samsonov, E. V.; Syresin, E. M.

    2014-11-01

    This paper presents numerical simulations and experimental results related to the effect of imperfections of the radial component of a magnetic field on the beam dynamics in the medical cyclotron C235-V3 of the Dimitrovgrad Proton Therapy Center. These imperfections in the region of the minimal axial betatron frequency lead to a transformation of coherent motion of the center of gravity of the beam to the incoherent motion of separate particles. The radial component increases the axial size of the beam by a factor of 2 at a radius of 20 cm, which produces additional losses of protons. To reduce undesirable actions of the radial component on the axial motion, the magnetic system in the central region has been optimized using two procedures: the positioning of shim correctors on sectors and selecting a special asymmetric arrangement of the upper and lower central plugs. This led to a twofold reduction in the axial size of the beam and a decrease in proton losses. Eventually, the beam transmission in C235-V3 has been increased to 72% without a limiting aperture diaphragm, which is commonly used in cyclotrons of this type. This makes it possible to reduce the irradiation dose of machine elements and increase the beam current at a deflector entrance of the cyclotron C235-V3 by a factor of 1.5 when compared to a serial C235 cyclotron.

  12. Low-background-rate detector for ions in the 5- to 50-keV energy range to be used for radioisotope dating with a small cyclotron

    SciTech Connect

    Friedman, P.G.

    1986-01-01

    Accelerator mass spectrometry in tandem Van de Graaff accelerators has proven successful for radioisotope dating small samples. Small, inexpensive cyclotrons serving this purpose would make the technique accessible to more researchers and inexpensive enough to compare many small samples. To this end, VC Berkeley is developing a 20-cm-diameter, 30- to 40-keV cyclotron dedicated to high-sensitivity radioisotope dating, initially for /sup 14/C. At this energy, range and dE/dx methods of particle identification are impossible. Thus arises the difficult problem of reliably detecting 30- to 40-keV /sup 14/C at 10/sup -1/ counts/sec in the high-background environment of the cyclotron, where lower energy ions, electrons, and photons bombard the detector at much higher rates. To meet this challenge, an inexpensive, generally useful ion detector was developed that allows dark-count rates below 10/sup -4/ counts/sec and excellent background suppression. With the cyclotron tuned near the /sup 13/CH background peak, to the frequency for /sup 14/C, the detector suppresses the background to 6 x 10/sup -4/ counts/sec. For each /sup 14/C ion, the detector's grazing-incidence Al/sub 2/O/sub 3/ conversion dynode emits about 20 secondary electrons, which are independently multiplied in separate pores of a microchannel plate. The output signal is proportional to the number of secondary electrons, allowing pulse-height discrimination of background.

  13. 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.

  14. A theory of electron cyclotron waves generated along auroral field lines observed by ground facilities

    NASA Technical Reports Server (NTRS)

    Wu, C. S.; Yoon, Peter H.; Freund, H. P.

    1989-01-01

    A generation mechanism for radio waves in the frequency range 150 - 700 kHz observed by ground facilities is suggested in terms of an electromagnetic electron cyclotron instability driven by auroral electrons. The excited waves can propagate downward along the ambient magnetic field lines and are thus observable with ground facilities. The trapped auroral electrons are supposed to play an important role in the generation process, because they give rise to a thermal anisotropy which consequently leads to the instability. The present work is a natural extension of the theory proposed earlier by Wu et al. (1983) which was discussed in a different context but may be used to explain the observed waves originated at low altitudes. This paper presents a possible wave generation mechanism valid in the entire auroral field-line region of interest.

  15. 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. Calcium ion cyclotron resonance (ICR) transfers information to living systems: effects on human epithelial cell differentiation.

    PubMed

    Lisi, Antonella; Ledda, Mario; De Carlo, Flavia; Foletti, Alberto; Giuliani, Livio; D'Emilia, Enrico; Grimaldi, Settimio

    2008-01-01

    The specific aim of the present work concerns the effectiveness of low-frequency electromagnetic fields treatment to modify biochemical properties of human keratinocytes (HaCaT). Cells exposed to a 7 Hz electromagnetic field, tuned to calcium ion cyclotron resonance (ICR), showed modifications in the cytoskeleton. These modifications were related to different actin distributions as revealed by phalloidin fluorescence analysis. Indirect immunofluorescence with fluorescent antibodies against involucrin and beta catenin, both differentiation and adhesion markers, revealed an increase in involucrin and beta-catenin expression, indicating that exposure to electromagnetic field carries keratinocytes to an upper differentiation level. This study confirms our previous observation and supports the hypothesis that a 7 Hz calcium ICR electromagnetic field may modify cell biochemistry and interfere in the differentiation and cellular adhesion of normal keratinocytes, suggesting the possibility to use ICR electromagnetic therapy for the treatment of undifferentiated diseases.

  17. 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.

  18. 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.

  19. Observation of the Guiding Center Negative Mass Instability in the Drift Orbit Cyclotron

    NASA Astrophysics Data System (ADS)

    Burke, John Michael

    The guiding center negative mass instability has been observed in the Drift Orbit Cyclotron, which is an axisymmetric mirror machine with the magnetic field radial profile tailored so that the(, )(DEL)B drift frequency is independent of radius. Electrons are continuously injected in the radial direction to form a magnetically confined, azimuthally (DEL)B(, )drifting annulus with radius 23 cm, thickness 0.65 cm and height 7.85 cm. As the density of the annulus is increased the negative mass instability causes the radial boundries of the annulus to deform. The temporal and spacial character of the deformation of the annulus is studied experimentally near the threshold density for instability. A linear theory is used to describe the threshold density for instability and a theoretical model is presented to explain the saturation of the instability near the instability threshold.

  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. The plasma wave environment of an auroral arc - Electrostatic ion cyclotron waves in the diffuse aurora

    NASA Technical Reports Server (NTRS)

    Bering, E. A.

    1984-01-01

    Electric field plasma wave observations were made with a sounding rocket payload in and near a quiet auroral arc. This payload was launched on March 9, 1978 from Poker Flat, Alaska. The payload trajectory was close to the magnetic meridian and passed over a 40 kR auroral arc. The present investigation is concerned with ac electric field observations in the ELF and lower VLF covering a frequency range from 2.5 Hz to 8 kHz. Attention is given to aspects of instrumentation, the general situation, a data analysis, and the obtained results. Waves were observed at low altitude in a region of downward parallel current and diffuse aurora. These waves had properties consistent with those expected for hydrogen and oxygen electrostatic ion cyclotron (EIC) waves.

  3. Modelling third harmonic ion cyclotron acceleration of deuterium beams for JET fusion product studies experiments

    NASA Astrophysics Data System (ADS)

    Schneider, M.; Johnson, T.; Dumont, R.; Eriksson, J.; Eriksson, L.-G.; Giacomelli, L.; Girardo, J.-B.; Hellsten, T.; Khilkevitch, E.; Kiptily, V. G.; Koskela, T.; Mantsinen, M.; Nocente, M.; Salewski, M.; Sharapov, S. E.; Shevelev, A. E.; Contributors, JET

    2016-11-01

    Recent JET experiments have been dedicated to the studies of fusion reactions between deuterium (D) and Helium-3 (3He) ions using neutral beam injection (NBI) in synergy with third harmonic ion cyclotron radio-frequency heating (ICRH) of the beam. This scenario generates a fast ion deuterium tail enhancing DD and D3He fusion reactions. Modelling and measuring the fast deuterium tail accurately is essential for quantifying the fusion products. This paper presents the modelling of the D distribution function resulting from the NBI+ICRF heating scheme, reinforced by a comparison with dedicated JET fast ion diagnostics, showing an overall good agreement. Finally, a sawtooth activity for these experiments has been observed and interpreted using SPOT/RFOF simulations in the framework of Porcelli’s theoretical model, where NBI+ICRH accelerated ions are found to have a strong stabilizing effect, leading to monster sawteeth.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. A method for suppression of spurious fundamental-harmonic waves in gyrotrons operating at the second cyclotron harmonic

    NASA Astrophysics Data System (ADS)

    Kalynov, Yu. K.; Osharin, I. V.; Savilov, A. V.

    2016-05-01

    A typical problem of gyrotrons operating at high harmonics of the electron cyclotron frequency is the suppression of parasitic near-cutoff waves excited at lower harmonics. In this paper, a method for a significant improvement of the selectivity of the second-harmonic gyrotrons is proposed. This method is based on the use of quasi-regular cavities with short irregularities, which provide different effects on the process of excitation of the operating second-harmonic wave and the spurious fundamental-harmonic wave by the electron beam.

  10. Electromagnetic Ion Cyclotron Waves near the Plasmapause: A CLUSTER Case Study

    NASA Astrophysics Data System (ADS)

    Fraser, B. J.; Liu, Y.; Menk, F. W.

    2011-12-01

    Electromagnetic ion cyclotron (EMIC) waves in the Pc1 ultra-low frequency wave band (0.2-5Hz) observed in the plasmasphere and magnetosphere are generated by micro-scale instabilities associated with keV energetic protons of ring current origin. This case study presents a typical EMIC wave event with frequency 1.8-3.5 Hz observed by the four Cluster spacecraft when passing through perigee (L ~ 4:2) and moving northward on 2 November 2001 around 08 MLT. The event occurred around the magnetic equatorial plane within magnetic latitude range ±18 degrees with a short duration of 50 minutes. The associated cold electron density data show the wave power was confined within the narrow shell of the plasmapause where the electron density gradient decreased from 30-80 cm-3 to 20 cm-3. The radial scale size of the wave region is estimated at ~ 0:77 Re. The wave polarization was dominantly left-handed around the equatorial region and inner side of source region, but appeared right-handed close to the outer edge of the plasmapause and at higher latitudes. The Poynting flux and minimum variance analysis indicate that the wave energy was mainly transported towards high latitudes though oblique propagation was seen around the equatorial region. Enhanced H+, He+ and O+ particle energy fluxes were seen during the wave event over energy range ~25eV-40keV. Unfortunately the lower energy cold plasma composition data were not available. These observations suggest the waves originated around the equatorial region in the high density outer plasmasphere-plasmapause which overlaps the ring current; ideal conditions for wave generation by the ion cyclotron instability.

  11. Characteristics of electron cyclotron harmonic waves observed in an active two-point propagation experiment in the ionosphere

    NASA Astrophysics Data System (ADS)

    James, H. G.; Wallis, D. D.

    2008-07-01

    Electrostatic electron cyclotron waves (ECWs), also-called electron Bernstein waves, observed at harmonics nfc of the electron cyclotron frequency fc were transmitted over field-aligned emitter-receiver separations of hundreds of meters in the active rocket experiment OEDIPUS-C. Although the 300-μs rectangular current pulses into the emitting antenna were smoothly maintained during the experiment, the resulting ECW pulses at the receiver exhibited considerable variety in both the time and frequency domains. A full hot-plasma dispersion relation has been applied to ray-tracing investigations to identify the rays that could connect the emitter and receiver in a smoothly varying model of the auroral ionospheric magnetoplasma. Theoretical connecting rays were limited to frequencies extending from 1 to a few kilohertz above 2fc, which was about 2.6 MHz. But the observed pulse spectra extended over a much broader bandwidth, from several kilohertz below nfc to several kilohertz above, for n = 2, 3, and 4. The broadening is interpreted as a consequence of Doppler effect caused by payload motion and backscatter of the ECWs. Field-aligned density irregularities typical of the auroral topside ionosphere or waves nonlinearly induced by the intense near fields of the HEX antenna may act as the scatterers.

  12. High-Frequency Electrostatic Wave Generation and Transverse Ion Acceleration by Low Alfvenic Wave Components of BBELF Turbulence

    NASA Technical Reports Server (NTRS)

    Singh, Nagendra; Khazanov, George; Mukhter, Ali

    2006-01-01

    Satellite observations in the auroral plasma have revealed that extremely low frequency (ELF) waves play a dominant role in the acceleration of electrons and ions in the auroral plasma. The electromagnetic components of the ELF (EMELF) waves are the electromagnetic ion cyclotron (EMIC) waves below the cyclotron frequency of the lightest ion species in a multi-ion plasma. Shear Alfv6n waves (SAWS) constitute the lowest frequency components of the ELF waves below the ion cyclotron frequency of the heaviest ion. The -2 mechanism for the transfer of energy from such EMELF waves to ions affecting transverse ion heating still remains a matter of debate. A very ubiquitous fe8ture of ELF waves now observed in several rocket and satellite experiments is that they occur in conjunction with high-frequency electrostatic waves. The frequency spectrum of the composite wave turbulence extends from the low frequency of the Alfvenic waves to the high frequency of proton plasma frequency and/or the lower hybrid frequency. The spectrum does not show any feature organized by the ion cyclotron frequencies and their harmonics. Such broadband waves consisting of both the EM and ES waves are now popularly referred as BBELF waves. We present results here from 2.5-D particle-in-cell simulations showing that the ES components are directly generated by cross- field plasma instabilities driven by the drifts of the ions and electrons in the EM component of the BBELF waves.

  13. A SCENARIO FOR THE FINE STRUCTURES OF SOLAR TYPE IIIb RADIO BURSTS BASED ON ELECTRON CYCLOTRON MASER EMISSION

    SciTech Connect

    Wang, C. B.

    2015-06-10

    A scenario based on electron cyclotron maser (ECM) emission is proposed for the fine structures of solar radio emission. It is suggested that under certain conditions modulation of the ratio between the plasma frequency and electron gyro frequency by ultra-low-frequency waves, which is a key parameter for excitation of ECM instability, may lead to the intermittent emission of radio waves. As an example, the explanation for the observed fine-structure components in the solar Type IIIb bursts is discussed in detail. Three primary issues of Type IIIb bursts are addressed: (1) the physical mechanism that results in intermittent emission elements that form a chain in the dynamic spectrum of Type IIIb bursts, (2) the cause of split pairs (or double stria) and triple stria, and (3) why only IIIb–III bursts are observed in the events of fundamental harmonic pair emission whereas IIIb–IIIb or III–IIIb bursts are very rarely observed.

  14. 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.

  15. A Scenario for the Fine Structures of Solar Type IIIb Radio Bursts Based on Electron Cyclotron Maser Emission

    NASA Astrophysics Data System (ADS)

    Wang, C. B.

    2015-06-01

    A scenario based on electron cyclotron maser (ECM) emission is proposed for the fine structures of solar radio emission. It is suggested that under certain conditions modulation of the ratio between the plasma frequency and electron gyro frequency by ultra-low-frequency waves, which is a key parameter for excitation of ECM instability, may lead to the intermittent emission of radio waves. As an example, the explanation for the observed fine-structure components in the solar Type IIIb bursts is discussed in detail. Three primary issues of Type IIIb bursts are addressed: (1) the physical mechanism that results in intermittent emission elements that form a chain in the dynamic spectrum of Type IIIb bursts, (2) the cause of split pairs (or double stria) and triple stria, and (3) why only IIIb-III bursts are observed in the events of fundamental harmonic pair emission whereas IIIb-IIIb or III-IIIb bursts are very rarely observed.

  16. Electron cyclotron resonance deposition and plasma diagnostics of a-Si:H and a-C:H films

    NASA Technical Reports Server (NTRS)

    Shing, Y. H.

    1989-01-01

    Amorphous silicon (a-Si:H) and amorphous carbon (a-C:H) films deposited by electron cyclotron resonance (ECR) microwave plasma-enhanced chemical vapor deposition are discussed. It is shown that the ECR microwave plasma deposition technique can produce a-Si:H films with material qualities similar to and with a deposition rate one order of magnitude higher than for films deposited by radio-frequency glow discharge. The ECR-deposited a-C:H films are characterized by fluorescence, IR, and Raman spectroscopy. In situ optical emission spectroscopy plasma diagnostics indicates that ECR plasmas have a strong emission at 434 nm, which indicates a higher chemical reactivity than radio-frequency glow discharge plasmas. The radio frequency bias to the substrate is found to play a critical role in determining the film structure and the carbon bonding configuration of ECR-deposited a-C:H films.

  17. Cyclotron Harmonic Effects on Stimulated Electromagnetic Emission in the Ionosphere: a Theoretical Study

    NASA Astrophysics Data System (ADS)

    Huang, Joe

    The dissertation studies parametric instabilities and nonlinear scattering processes that explain the electron cyclotron harmonic effects on the spectral features of stimulated electromagnetic emission (SEE) spectrum observed in ionospheric modification experiments. Four topics are explored. A thermal oscillating two stream instability as the generation mechanism of electron Bernstein/upper hybrid waves by the o-mode HF heater wave is first investigated. Analysis shows that the instability zone of upper hybrid waves below the upper hybrid resonance layer becomes small when the heater frequency f_0 is operated near 3f_ c, where f_ c is the local electron cyclotron frequency. This result is used to explain the quenching of downshifted maximum (DM). Parametric decay of an upper hybrid/electron Bernstein pump wave into an upper hybrid/electron Bernstein sideband wave and a lower hybrid decay wave is next examined. When appropriate nonlinear scattering processes are taken into account, this instability process along with its cascading is proposed as a generation mechanism for the observed DM, 2DM, 3DM ... etc. as well as upshifted maximum (UM). A modulational instability of the electron Bernstein wave is also studied. This process involves the decay of a pump electron Bernstein wave into both Stokes and anti-Stokes electron Bernstein sidebands together with a lower hybrid decay mode. It is proposed that scattering of the anti-Stokes and Stokes sidebands of this modulational instability off field-aligned density irregularities produces the frequency upshifted and downshifted sidebands constituting the broad symmetric structure (BSS). The last instability studied is a second order, four wave interaction process involving two pump photons, an upper hybrid plasmon and an electron Bernstein plasmon along with driven lower hybrid fluctuations. It is suggested that (1) frequency upshifted upper hybrid waves excited by this process scatter off field-aligned density

  18. High Power Cyclotrons for Accelerator Driven System (ADS)

    NASA Astrophysics Data System (ADS)

    Calabretta, Luciano

    2012-03-01

    We present an accelerator module based on a injector cyclotron and a Superconducting Ring Cyclotron (SRC) able to accelerate H2+ molecules. H2+ molecules are extracted from the SRC stripping the binding electron by a thin carbon foil. The SRC will be able to deliver proton beam with maximum energy of 800 MeV and a maximum power of 8 MW. This module is forecasted for the DAEdALUS (Decay At rest Experiment for δcp At Laboratory for Underground Science) experiment, which is a neutrino experiment proposed by groups of MIT and Columbia University. Extensive beam dynamics studies have been carrying out in the last two years and proved the feasibility of the design. The use of H2+ molecules beam has three main advantages: 1) it reduces the space charge effects, 2) because of stripping extraction, it simplifies the extraction process w.r.t. single turn extraction and 3) we can extract more than one beam out of one SRC. A suitable upgraded version of the cyclotron module able to deliver up to 10MW beam is proposed to drive ADS. The accelerator system which is presented, consists of having three accelerators modules. Each SRC is equipped with two extraction systems delivering two beams each one with a power up to 5 MW. Each accelerator module, feeds both the two reactors at the same time. The three accelerators modules assure to maintain continuity in functioning of the two reactors. In normal operation, all the three accelerators module will deliver 6.6 MW each one, just in case one of the three accelerator module will be off, due to a fault or maintenance, the other two modules are pushed at maximum power of 10 MW. The superconducting magnetic sector of the SRC, as well as the normal conducting sector of the injector cyclotron, is calculated with the TOSCA module of OPERA3D. Here the main features of the injector cyclotron, of the SRC and the beam dynamic along the cyclotrons are presented.

  19. Large-amplitude, circularly polarized, compressive, obliquely propagating electromagnetic proton cyclotron waves throughout the Earth's magnetosheath: low plasma β conditions

    SciTech Connect

    Remya, B.; Reddy, R. V.; Lakhina, G. S.; Tsurutani, B. T.; Falkowski, B. J.; Echer, E.; Glassmeier, K.-H.

    2014-09-20

    During 1999 August 18, both Cassini and WIND were in the Earth's magnetosheath and detected transverse electromagnetic waves instead of the more typical mirror-mode emissions. The Cassini wave amplitudes were as large as ∼14 nT (peak to peak) in a ∼55 nT ambient magnetic field B {sub 0}. A new method of analysis is applied to study these waves. The general wave characteristics found were as follows. They were left-hand polarized and had frequencies in the spacecraft frame (f {sub scf}) below the proton cyclotron frequency (f{sub p} ). Waves that were either right-hand polarized or had f {sub scf} > f{sub p} are shown to be consistent with Doppler-shifted left-hand waves with frequencies in the plasma frame f{sub pf} < f{sub p} . Thus, almost all waves studied are consistent with their being electromagnetic proton cyclotron waves. Most of the waves (∼55%) were found to be propagating along B {sub 0} (θ{sub kB{sub 0}}<30{sup ∘}), as expected from theory. However, a significant fraction of the waves were found to be propagating oblique to B {sub 0}. These waves were also circularly polarized. This feature and the compressive ([B {sub max} – B {sub min}]/B {sub max}, where B {sub max} and B {sub min} are the maximum and minimum field magnitudes) nature (ranging from 0.27 to 1.0) of the waves are noted but not well understood at this time. The proton cyclotron waves were shown to be quasi-coherent, theoretically allowing for rapid pitch-angle transport of resonant protons. Because Cassini traversed the entire subsolar magnetosheath and WIND was in the dusk-side flank of the magnetosheath, it is surmised that the entire region was filled with these waves. In agreement with past theory, it was the exceptionally low plasma β (0.35) that led to the dominance of the proton cyclotron wave generation during this interval. A high-speed solar wind stream ((V{sub sw} ) = 598 km s{sup –1}) was the source of this low-β plasma.

  20. Fast particle-driven ion cyclotron emission (ICE) in tokamak plasmas and the case for an ICE diagnostic in ITER

    NASA Astrophysics Data System (ADS)

    McClements, K. G.; D'Inca, R.; Dendy, R. O.; Carbajal, L.; Chapman, S. C.; Cook, J. W. S.; Harvey, R. W.; Heidbrink, W. W.; Pinches, S. D.

    2015-04-01

    The detection of fast particle-driven waves in the ion cyclotron frequency range (ion cyclotron emission or ICE) could provide a passive, non-invasive diagnostic of confined and escaping fast particles (fusion α-particles and beam ions) in ITER, and would be compatible with the high radiation environment of deuterium-tritium plasmas in that device. Recent experimental results from ASDEX Upgrade and DIII-D demonstrate the efficacy of ICE as a diagnostic of different fast ion species and of fast ion losses, while recent particle-in-cell (PIC) and hybrid simulations provide a more exact comparison with measured ICE spectra and open the prospect of exploiting ICE more fully as a fast ion diagnostic in future experiments. In particular the PIC/hybrid approach should soon make it possible to simulate the nonlinear physics of ICE in full toroidal geometry. Emission has been observed previously at a wide range of poloidal angles, so there is flexibility in the location of ICE detectors. Such a detector could be implemented in ITER by installing a small toroidally orientated loop near the plasma edge or by adding a detection capability to the ion cyclotron resonance heating (ICRH) antennae. In the latter case, the antenna could be used simultaneously to heat the plasma and detect ICE, provided that frequencies close to those of the ICRH source are strongly attenuated in the detection system using a suitable filter. Wavenumber information, providing additional constraints on the fast ion distribution exciting the emission, could be obtained by measuring ICE using a toroidally distributed array of detectors or different straps of the ICRH antenna.

  1. Business models for academic medical center cyclotron operations.

    PubMed

    LeGarde, Caroline; Bledsoe, Martin L; Wahl, Richard L

    2005-06-01

    A cyclotron facility may provide a significant strategic advantage for an academic medical center that desires to build a strong research program in nuclear medicine. Such a facility may provide an advantage in obtaining support from the National Institutes of Health. A nuclear medicine research program often requires the production of short-lived radioisotopes for clinical patients. Combining the research program with a commercial production and distribution program can increase the synergies and efficiencies of an organization. This article describes various business models that combine research, clinical, and commercial operations to align an academic medical center's cyclotron program operation to its goals and resources. By coordinating these three functions, an academic medical center may be able to support extensive research capabilities that would otherwise be unattainable.

  2. Neutron spectra due (13)N production in a PET cyclotron.

    PubMed

    Benavente, J A; Vega-Carrillo, H R; Lacerda, M A S; Fonseca, T C F; Faria, F P; da Silva, T A

    2015-05-01

    Monte Carlo and experimental methods have been used to characterize the neutron radiation field around PET (Positron Emission Tomography) cyclotrons. In this work, the Monte Carlo code MCNPX was used to estimate the neutron spectra, the neutron fluence rates and the ambient dose equivalent (H*(10)) in seven locations around a PET cyclotron during (13)N production. In order to validate these calculations, H*(10) was measured in three sites and were compared with the calculated doses. All the spectra have two peaks, one above 0.1MeV due to the evaporation neutrons and another in the thermal region due to the room-return effects. Despite the relatively large difference between the measured and calculated H*(10) for one point, the agreement was considered good, compared with that obtained for (18)F production in a previous work.

  3. Sawtooth control in ITER using ion cyclotron resonance heating

    SciTech Connect

    Chapman, I. T.; Graves, J P; Johnson, T.; Asunta, O.; Bonoli, P.; Choi, M.; Jaeger, E. F.; Jucker, M.; Sauter, O.

    2011-01-01

    Numerical modeling of the effects of ion cyclotron resonance heating (ICRH) on the stability of the internal kink mode suggests that ICRH should be considered as an essential sawtooth control tool in ITER. Sawtooth control using ICRH is achieved by directly affecting the energy of the internal kink mode rather than through modification of the magnetic shear by driving localized currents. Consequently, ICRH can be seen as complementary to the planned electron cyclotron current drive actuator, and indeed will improve the efficacy of current drive schemes. Simulations of the ICRH distribution using independent RF codes give confidence in numerical predictions that the stabilizing influence of the fusion-born alphas can be negated by appropriately tailored minority (3)He ICRH heating in ITER. Finally, the effectiveness of all sawtooth actuators is shown to increase as the q = 1 surface moves towards the manetic axis, whilst the passive stabilization arising from the alpha and NBI particles decreases.

  4. H- source development for Jyväskylä cyclotron

    NASA Astrophysics Data System (ADS)

    Kuo, T.; Baartman, R.; Dutto, G.; Hahto, S.; ńrje, J.; Liukkonen, E.

    2001-12-01

    A new H- ion source terminal has been constructed since 2000 for the Jyväskylä cyclotron "H- acceleration Project." The source-extraction system design is based on the development work performed at TRIUMF. The source generates more than 5 mA of H- at 5.8 keV with an un-normalized emittance within 100π-mm-mr. Special devices for H- injection, extraction and beam merging have been completed by the Jyväskylä cyclotron group. 60 μA of proton beam at 30 MeV has been successfully extracted for physics experiments and will be used for IGISOL program and isotope production. Efforts in improving the source emittance and the injection line to bring the target current up to 100 μA are in progress.

  5. Ernest Orlando Lawrence (1901-1958), Cyclotron and Medicine

    SciTech Connect

    Chu, William T.

    2005-09-01

    On August 8, 2001, Lawrence Berkeley National Laboratory celebrated the centennial of the birth of its founder (and namesake), Ernest Orlando Lawrence. For the occasion, many speeches were given and old speeches were remembered. We recall the words of the late Luis Alvarez, a Nobel Laureate and one of the Lawrence's closest colleagues: ''Lawrence will always be remembered as the inventor of the cyclotron, but more importantly, he should be remembered as the inventor of the modern way of doing science''. J. L. Heilbron and R. W. Seidel, in the introduction of their book, ''Lawrence and His Laboratory'' stated, ''The motives and mechanisms that shaped the growth of the Laboratory helped to force deep changes in the scientific estate and in the wider society. In the entrepreneurship of its founder, Ernest Orlando Lawrence, these motives, mechanisms, and changes came together in a tight focus. He mobilized great and small philanthropists, state and local governments, corporations, and plutocrats, volunteers and virtuosos. The work they supported, from astrophysics and atomic bombs, from radiochemistry to nuclear medicine, shaped the way we observe, control, and manipulate our environment.'' Indeed, all over the civilized world, the ways we do science changed forever after Lawrence built his famed Radiation Laboratory. In this editorial, we epitomize his legacy of changing the way we do medicine, thereby affecting the health and well being of all humanity. This year marks the 75th anniversary of the invention of the cyclotron by Ernest Orlando Lawrence at the University of California at Berkeley. Lawrence conceived the idea of the cyclotron early in 1929 after reading an article by Rolf Wideroe on high-energy accelerators. In the spring of 1930 one of his students, Nels Edlefsen, constructed two crude models of a cyclotron. Later in the fall of the same year, another student, M. Stanley Livingston, constructed a 13-cm diameter model that had all the features of early

  6. Examination of the plasma located in PSI Ring Cyclotron

    NASA Astrophysics Data System (ADS)

    Pogue, N. J.; Adelmann, A.; Schneider, M.; Stingelin, L.

    2016-06-01

    A plasma has been observed inside the vacuum chamber of the PSI Ring Cyclotron. This ionized gas cloud may be a substantial contributor to several interior components having reduced lifetimes. The plasma's generation has been directly linked to the voltage that is applied to the Flat Top cavity through visual confirmation using CCD cameras. A spectrometer was used to correlate the plasma's intensity and ignition to the Flat Top cavity voltage as well as to determine the composition of the plasma. This paper reports on the analysis of the plasma using spectroscopy. The spectrometer data was analyzed to determine the composition of the plasma and that the plasma intensity (luminosity) directly corresponds to the Flat Top voltage. The results show that the plasma is comprised of elements consistent with the cyclotrons vacuum interior.

  7. Electrostatic ion-cyclotron waves in magnetospheric plasmas Nonlocal aspects

    NASA Technical Reports Server (NTRS)

    Ganguli, G.; Bakshi, P.; Palmadesso, P.

    1984-01-01

    The importance of the effect of the magnetic shear and the finite size of current channel on the electrostatic ion-cyclotron instability for the space plasmas is illustrated. A non-local treatment is used. When the channel width Lc, is larger than the shear length Ls, there is a large reduction in the growth rate along with a noteworthy reduction of the band of the unstable perpendicular wavelengths. For Lc less than or = Ls/10 the growth rate is not much altered from its local value, however for Lc/pi i less than or = 10 to the second power the growth rate starts falling below the local value and vanishes for Lc pi i. The non-local effects lead to enhanced coherence in the ion cyclotron waves. Previously announced in STAR as N84-14917

  8. Sawtooth control in ITER using ion cyclotron resonance heating

    NASA Astrophysics Data System (ADS)

    Chapman, I. T.; Graves, J. P.; Johnson, T.; Asunta, O.; Bonoli, P.; Choi, M.; Jaeger, E. F.; Jucker, M.; Sauter, O.

    2011-12-01

    Numerical modelling of the effects of ion cyclotron resonance heating (ICRH) on the stability of the internal kink mode suggests that ICRH should be considered as an essential sawtooth control tool in ITER. Sawtooth control using ICRH is achieved by directly affecting the energy of the internal kink mode rather than through modification of the magnetic shear by driving localized currents. Consequently, ICRH can be seen as complementary to the planned electron cyclotron current drive actuator, and indeed will improve the efficacy of current drive schemes. Simulations of the ICRH distribution using independent RF codes give confidence in numerical predictions that the stabilizing influence of the fusion-born alphas can be negated by appropriately tailored minority 3He ICRH heating in ITER. Finally, the effectiveness of all sawtooth actuators is shown to increase as the q = 1 surface moves towards the manetic axis, whilst the passive stabilization arising from the alpha and NBI particles decreases.

  9. PHYSICS OF ELCTRON CYCLOTRON CURRENT DRIVE ON DIII-D

    SciTech Connect

    PETTY,CC; PRATER,R; LUCE,TC; ELLIS,RA; HARVEY,RW; KINSEY,JE; LAO,LL; LOHR,J; MAKOWSKI,MA

    2002-09-01

    OAK A271 PHYSICS OF ELCTRON CYCLOTRON CURRENT DRIVE ON DIII-D. Recent experiments on the DIII-D tokamak have focused on determining the effect of trapped particles on the electron cyclotron current drive (ECCD) efficiency. The measured ECCD efficiency increases as the deposition location is moved towards the inboard midplane or towards smaller minor radius for both co and counter injection. The measured ECCD efficiency also increases with increasing electron density and/or temperature. The experimental ECCD is compared to both the linear theory (Toray-GA) as well as a quasilinear Fokker-Planck model (CQL3D). The experimental ECCD is found to be in better agreement with the more complete Fokker-Planck calculation, especially for cases of high rf power density and/or loop voltage. The narrow width of the measured ECCD profile is consistent with only low levels of radial transport for the current carrying electrons.

  10. Radiation protection aspects of the operation in a cyclotron facility

    NASA Astrophysics Data System (ADS)

    Silva, P. P. N.; Carneiro, J. C. G. G.

    2014-02-01

    The activated accelerator cyclotron components and the radioisotope production may impact on the personnel radiation exposure of the workers during the routine maintenance and emergency repair procedures and any modification of the equipment. Since the adherence of the principle of ALARA (as low as reasonable achievable) constitutes a major objective of the cyclotron management, it has become imperative to investigate the radiation levels at the workplace and the probable health effects to the worker caused by radiation exposure. The data analysis in this study was based on the individual monitoring records during the period from 2007 to 2011. Monitoring of the workplace was also performed using gamma and neutron detectors to determine the dose rate in various predetermined spots. The results of occupational radiation exposures were analysed and compared with the values established in national standards and international recommendations. Important guidelines have been developed to reduce the individual dose.

  11. 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.

  12. 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).

  13. Triggering Process of Electromagnetic Ion Cyclotron Rising Tone Emissions in the Inner Magnetosphere

    NASA Astrophysics Data System (ADS)

    Shoji, M.; Omura, Y.

    2013-12-01

    Spacecraft observations and simulations show generation of coherent electromagnetic ion cyclotron (EMIC) triggered emissions with rising-tone frequencies. In the inner magnetosphere, the spontaneously triggered EMIC waves are generated by the energetic protons with large temperature anisotropy. We reproduced EMIC triggered emissions in the Earth's magnetosphere by real scale hybrid simulations with cylindrical magnetic geometry. We obtained spontaneously triggered nonlinear EMIC waves with rising frequencies in the H+ band of the EMIC dispersion relation. The proton holes in the phase space are formed. We have also derived the theoretical optimum wave amplitude for triggering process of the EMIC nonlinear wave growth. The optimum wave amplitude and the nonlinear transition time show a good agreement with the present simulation result. The nonlinear wave growth over a limited time forms a sub-packet structure of a rising tone emission. The formation process of a sub-packet is repeated because of a new triggering wave generated by the phase-organized protons, which are released from the previous sub-packet. Then the EMIC triggered emission is formed as a train of sub-packets generated at different rising frequencies.

  14. Triggering process of electromagnetic ion cyclotron rising tone emissions in the inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Shoji, Masafumi; Omura, Yoshiharu

    2013-09-01

    Spacecraft observations and simulations show generation of coherent electromagnetic ion cyclotron (EMIC) triggered emissions with rising tone frequencies. In the inner magnetosphere, the spontaneously triggered EMIC waves are generated by the energetic protons with large temperature anisotropy. We reproduced EMIC triggered emissions in the Earth's magnetosphere by real scale hybrid simulations with cylindrical magnetic geometry. We obtained spontaneously triggered nonlinear EMIC waves with rising frequencies in the H+band of the EMIC dispersion relation. The proton holes in the phase space are formed. We have also derived the theoretical optimum wave amplitude for triggering process of the EMIC nonlinear wave growth. The optimum wave amplitude and the nonlinear transition time show a good agreement with the present simulation result. The nonlinear wave growth over a limited time forms a subpacket structure of a rising tone emission. The formation process of a subpacket is repeated because of a new triggering wave generated by the phase-organized protons, which are released from the previous subpacket. Then, the EMIC triggered emission is formed as a train of subpackets generated at different rising frequencies.

  15. Generation of auroral kilometric and Z mode radiation by the cyclotron maser mechanism

    NASA Technical Reports Server (NTRS)

    Omidi, N.; Gurnett, D. A.; Wu, C. S.

    1984-01-01

    The relativistic Doppler-shifted cyclotron resonance condition for EM wave interactions with a plasma defines an ellipse in velocity space when the product of the index of refraction and cosine of the wave normal angle is less than or equal to unity, and defines a partial ellipse when the product is greater than unity. It is also noted that waves with frequencies greater than the gyrofrequency can only resonate with particles moving in the same direction along the magnetic field, while waves with lower frequencies than these resonate with particles moving in both directions along the magnetic field. It is found, in the case of auroral kilometric radiation, that both the upgoing and the downgoing electrons are unstable and can give rise to this radiation's growth. The magnitudes of the growth rates for both the upgoing and downgoing auroral kilometric radiation are comparable, and indicate that the path lengths needed to account for the observed intensities of this radiation are of the order of a few hundred km, which is probably too large. Growth rate calculations for the Z mode radiation show that, for wave frequencies just below the gyrofrequency and wave normal angles at or near 90 deg, the electron distribution is unstable and the growth rates are large enough to account for the observed intensities.

  16. 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.

  17. 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.

  18. Study and design of the ion cyclotron resonance heating system for the stellarator Wendelstein 7-X

    SciTech Connect

    Ongena, J.; Messiaen, A.; Van Eester, D.; Schweer, B.; Dumortier, P.; Durodie, F.; Kazakov, Ye. O.; Louche, F.; Vervier, M.; Koch, R.; Krivska, A.; Lyssoivan, A.; Van Schoor, M.; Wauters, T.; Borsuk, V.; Neubauer, O.; Schmitz, O.; Altenburg, Y.; Baylard, C.; and others

    2014-06-15

    The current status of the mechanical and electromagnetic design for the ICRF antenna system for W7-X is presented. Two antenna plugins are discussed: one consisting of a pair of straps with pre-matching to cover the first frequency band, 25–38 MHz, and a second one consisting of two short strap triplets to cover a frequency band around 76 MHz. This paper focusses on the two strap antenna for the lower frequency band. Power coupling of the antenna to a reference plasma profile is studied with the help of the codes TOPICA and Microwave Studio that deliver the scattering matrix needed for the optimization of the geometric parameters of the straps and antenna box. Radiation power spectra for different phasings of the two straps are obtained using the code ANTITER II and different heating scenario are discussed. The potential for heating, fast particle generation, and current drive is discussed. The problem of RF coupling through the plasma edge and of edge power deposition is summarized. Important elements of the complete ion cyclotron resonance heating system are discussed: a resonator circuit with tap feed to limit the maximum voltage in the system, and a decoupler to counterbalance the large mutual coupling between the 2 straps. The mechanical design highlights the challenges encountered with this antenna: adaptation to a large variety of plasma configurations, the limited space within the port to accommodate the necessary matching components and the watercooling needed for long pulse operation.

  19. Nature and effects of ion-cyclotron fluctuations in TMX

    SciTech Connect

    Casper, T.A.; Poulsen, P.; Smith, G.R.

    1982-02-19

    In the tandem mirror experiment (TMX), coherent oscillations have been identified as resulting from the Alfven ion-cyclotron instability. Although the drive for this instability is localized in the end cell, the waves generated propagate out of the unstable region and interact with the central-cell ions. This interaction leads to an experimentally observed scaling of the stored end-cell energy with axial ion end-loss current.

  20. Positron-emitting isotopes produced on biomedical cyclotrons.

    PubMed

    McQuade, Paul; Rowland, Douglas J; Lewis, Jason S; Welch, Michael J

    2005-01-01

    This review will discuss the production and applications of positron-emitting radionuclides for use in Positron Emission Tomography (PET), with emphasis on radionuclides that can be produced onsite with a biomedical cyclotron. In PET the traditional radionuclides of choice are (11)C, (113)N, (15)O and (18)F and although they will be briefly discussed in this article, the emphasis of this review will be on 'non-standard' PET radionuclides that are generating increased interest by the medical research community.

  1. Pencil Beam Scanning System Based On A Cyclotron

    SciTech Connect

    Tachikawa, Toshiki; Nonaka, Hideki; Kumata, Yukio; Nishio, Teiji; Ogino, Takashi

    2011-06-01

    Sumitomo Heavy Industries, Ltd. (SHI) has developed a new pencil beam scanning system (PBS) for proton therapy in collaboration with National Cancer Center Hospital East (NCCHE). Taking advantage of the continuous beam from the cyclotron P235, the line scanning method is employed in order to realize continuous irradiation with high dose rate. 3D uniform and sphere field was irradiated and compared with the simulation.

  2. Design options for an ITER ion cyclotron system

    NASA Astrophysics Data System (ADS)

    Swain, D. W.; Baity, F. W.; Bigelow, T. S.; Ryan, P. M.; Goulding, R. H.; Carter, M. D.; Stallings, D. C.; Batchelor, D. B.; Hoffman, D. J.

    1996-02-01

    Recent changes have occurred in the design requirements for the ITER ion cyclotron system, requiring in-port launchers in four main horizontal ports to deliver 50 MW of power to the plasma. The design is complicated by the comparatively large antenna-separatrix distance of 10-20 cm. Designs of a conventional strap launcher and a folded waveguide launcher that can meet the new requirements are presented.

  3. Converting an AEG Cyclotron to H- Acceleration and Extraction

    NASA Astrophysics Data System (ADS)

    Ramsey, Fred; Carroll, Lewis; Rathmann, Tom; Huenges, Ernst; Bechtold, Matthias Mentler Volker

    2009-03-01

    Clinical Trials are under way to evaluate agents labeled with the nuclide 225Ac and its decay product 213Bi, in targeted alpha-immuno-therapy [1]. 225Ac can be produced on a medium-energy cyclotron via the nuclear reaction 226Ra(p,n)225Ac. To demonstrate proof-of-principle, a vintage AEG cyclotron, Model E33 [2], with an internal target, had been employed in a pilot production program at the Technical University of Munich (TUM). To enhance production capability and further support the clinical studies, the TUM facility has recently been refurbished and upgraded, adding a new external beam-line, automated target irradiation and transport systems, new laboratories, hot cells, etc. [3]. An improved high-power rotating target has been built and installed [4]. The AEG cyclotron itself has also been modified and upgraded to accelerate and extract H- ions. We have designed, built, and tested a new axial Penning-type ion source which is optimized for the production of H- ions. The ion source has continued to evolve through experiment and experience. Steady improvements in materials and mechanics have led to enhanced source stability, life-time, and H- production. We have also designed and built a precision H- charge-exchange beam-extraction system which is equipped with a vacuum lock. To fit within the tight mechanical constraint imposed by the narrow magnet gap, the system incorporates a novel chain-drive foil holder and foil-changer mechanism. The reconfigured cyclotron system has now been in operation for more than 1 year. Three long-duration target irradiations have been conducted. The most recent bombardment ran 160 continuous hours at a beam on target of ˜80 microamperes for a total yield of ˜70 milli-curies of 225Ac.

  4. Linear analysis of ion cyclotron interaction in a multicomponent plasma

    NASA Technical Reports Server (NTRS)

    Gendrin, R.; Ashour-Abdalla, M.; Omura, Y.; Quest, K.

    1984-01-01

    The mechanism by which hot anisotropic protons generate electromagnetic ion cyclotron waves in a plasma containing cold H(+) and He(+) ions is quantitatively studied. Linear growth rates (both temporal and spatial) are computed for different plasma parameters: concentration, temperature,and anisotropy of cold He(+) ions and of hot protons. It is shown that: (1) for parameters typical of the geostationary altitude the maximum growth rates are not drastically changed when a small proportion (about 1 to 20 percent) of cold He(+) ions is present; (2) because of the important cyclotron absorption by thermal He(+) ions in the vicinity of the He(+) gyrofrequency, waves which could resonate with the bulk of the He(+) distribution cannot be generated. Therefore quasi-linear effects, in a homogeneous medium at least, cannot be responsible for the heating of He(+) ions which is often observed in conjunction with ion cyclotron waves. The variation of growth rate versus wave number is also studied for its importance in selecting suitable parameters in numerical simulation experiments.

  5. Modern compact accelerators of cyclotron type for medical applications

    NASA Astrophysics Data System (ADS)

    Smirnov, V.; Vorozhtsov, S.

    2016-09-01

    Ion beam therapy and hadron therapy are types of external beam radiotherapy. Recently, the vast majority of patients have been treated with protons and carbon ions. Typically, the types of accelerators used for therapy were cyclotrons and synchrocyclotrons. It is intuitively clear that a compact facility fits best to a hospital environment intended for particle therapy and medical diagnostics. Another criterion for selection of accelerators to be mentioned in this article is application of superconducting technology to the magnetic system design of the facility. Compact isochronous cyclotrons, which accelerate protons in the energy range 9-30 MeV, have been widely used for production of radionuclides. Energy of 230 MeV has become canonical for all proton therapy accelerators. Similar application of a carbon beam requires ion energy of 430 MeV/u. Due to application of superconducting coils the magnetic field in these machines can reach 4-5 T and even 9 T in some cases. Medical cyclotrons with an ironless or nearly ironless magnetic system that have a number of advantages over the classical accelerators are in the development stage. In this work an attempt is made to describe some conceptual and technical features of modern accelerators under consideration. The emphasis is placed on the magnetic and acceleration systems along with the beam extraction unit, which are very important from the point of view of the facility compactness and compliance with the strict medical requirements.

  6. The cyclotron laboratory and the RFQ accelerator in Bern

    SciTech Connect

    Braccini, S.; Ereditato, A.; Kreslo, I.; Nirkko, M.; Weber, M.; Scampoli, P.; Bremen, K. von

    2013-07-18

    Two proton accelerators have been recently put in operation in Bern: an 18 MeV cyclotron and a 2 MeV RFQ linac. The commercial IBA 18/18 cyclotron, equipped with a specifically conceived 6 m long external beam line ending in a separate bunker, will provide beams for routine 18-F and other PET radioisotope production as well as for novel detector, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. The accelerator is embedded into a complex building hosting two physics laboratories and four Good Manufacturing Practice (GMP) laboratories. This project is the result of a successful collaboration between the Inselspital, the University of Bern and private investors, aiming at the constitution of a combined medical and research centre able to provide the most cutting-edge technologies in medical imaging and cancer radiation therapy. The cyclotron is complemented by the RFQ with the primary goals of elemental analysis via Particle Induced Gamma Emission (PIGE), and the detection of potentially dangerous materials with high nitrogen content using the Gamma-Resonant Nuclear Absorption (GRNA) technique. In this context, beam instrumentation devices have been developed, in particular an innovative beam profile monitor based on doped silica fibres and a setup for emittance measurements using the pepper-pot technique. On this basis, the establishment of a proton therapy centre on the campus of the Inselspital is in the phase of advanced study.

  7. RF control hardware design for CYCIAE-100 cyclotron

    NASA Astrophysics Data System (ADS)

    Yin, Zhiguo; Fu, Xiaoliang; Ji, Bin; Zhao, Zhenlu; Zhang, Tianjue; Li, Pengzhan; Wei, Junyi; Xing, Jiansheng; Wang, Chuan

    2015-11-01

    The Beijing Radioactive Ion-beam Facility project is being constructed by BRIF division of China Institute of Atomic Energy. In this project, a 100 MeV high intensity compact proton cyclotron is built for multiple applications. The first successful beam extraction of CYCIAE-100 cyclotron was done in the middle of 2014. The extracted proton beam energy is 100 MeV and the beam current is more than 20 μA. The RF system of the CYCIAE-100 cyclotron includes two half-wavelength cavities, two 100 kW tetrode amplifiers and power transmission line systems (all above are independent from each other) and two sets of Low Level RF control crates. Each set of LLRF control includes an amplitude control unit, a tuning control unit, a phase control unit, a local Digital Signal Process control unit and an Advanced RISC Machines based EPICS IOC unit. These two identical LLRF control crates share one common reference clock and take advantages of modern digital technologies (e.g. DSP and Direct Digital Synthesizer) to achieve closed loop voltage and phase regulations of the dee-voltage. In the beam commission, the measured dee-voltage stability of RF system is better than 0.1% and phase stability is better than 0.03°. The hardware design of the LLRF system will be reviewed in this paper.

  8. A Suzaku View of Cyclotron Line Sources and Candidates

    NASA Technical Reports Server (NTRS)

    Pottschmidt, K.; Suchy, S.; Rivers, E.; Rothschild, R. E.; Marcu, D. M.; Barragan, L.; Kuehnel, M.; Fuerst, F.; Schwarm, F.; Kreykenbohm, I.; Wilms, J.; Schoenherr, G.; Caballero, I.; Camero-Arranz, A.; Bodaghee, A.; Doroshenko, V.; Klochkov, D.; Santangelo, A.; Staubert, R.; Kretschmar, P.; Wilson-Hodge, C.; Finger, M. H.; Terada, Y.

    2012-01-01

    Seventeen accreting neutron star pulsars, mostly high mass X-ray binaries with half of them Be-type transients, are known to exhibit Cyclotron Resonance Scattering Features (CRSFs) in their X-ray spectra, with characteristic line energies from 10 to 60 keY. To date about two thirds of them, plus a few similar systems without known CRSFs, have been observed with Suzaku. We present an overview of results from these observations, including the discovery of a CRSF in the transient IA1118-61 and pulse phase resolved spectroscopy of OX 301-2. These observations allow for the determination of cyclotron line parameters to an unprecedented degree of accuracy within a moderate amount of observing time. This is important since these parameters vary - e.g., with orbital phase, pulse phase, or luminosity - depending on the geometry of the magnetic field of the pulsar and the properties of the accretion column at the magnetic poles. We briefly introduce a spectral model for CRSFs that is currently being developed and that for the first time is based on these physical properties. In addition to cyclotron line measurements, selected highlights from the Suzaku analyses include dip and flare studies, e.g., of 4U 1907+09 and Vela X-I, which show clumpy wind effects (like partial absorption and/or a decrease in the mass accretion rate supplied by the wind) and may also display magnetospheric gating effects.

  9. Electromagnetic ion beam instabilities - Growth at cyclotron harmonic wave numbers

    NASA Technical Reports Server (NTRS)

    Smith, Charles W.; Gary, S. Peter

    1987-01-01

    The linear theory of electromagnetic ion beam instabilities for arbitrary angles of propagation is studied, with an emphasis on the conditions necessary to generate unstable modes at low harmonics of the ion cyclotron resonance condition. The present results extend the analysis of Smith et al. (1985). That paper considered only the plasma parameters at a time during which harmonic wave modes were observed in the earth's foreshock. The parameters of that paper are used as the basis of parametric variations here to establish the range of beam properties which may give rise to observable harmonic spectra. It is shown that the growth rates of both left-hand and right-hand cyclotron harmonic instabilities are enhanced by an increase in the beam temperature anisotropy and/or the beam speed. Decreases in the beam density and/or the core-ion beta reduce the overall growth of the cyclotron harmonic instabilities but favor the growth of these modes over the growth of the nonresonant instability and thereby enhance the observability of the harmonics.

  10. Improving cancer treatment with cyclotron produced radionuclides. Progress report

    SciTech Connect

    Larson, S.M.; Finn, R.D.

    1992-08-04

    Our goal is to improve the scientific basis for tumor diagnosis, treatment and treatment follow-up based on the use of cyclotron produced radiotracers in oncology. The grant includes 3 interactive components: Radiochemistry/Cyclotron; Pharmacology; and Immunology. The radiochemistry group seeks to develop innovative cyclotron targetry, radiopharmaceuticals, and radiolabeled antibodies, which are then used to assess important unanswered questions in tumor pharmacology and immunology. Examples include selected positron emitting radionuclides, such as Iodine-124, and Ga-66; I-124, I-123, I-131 labeled iododeoxyuridine, C-11 colchicine, and antimetabolites, like C-11 methotrexate; and radiolabeled antibodies, 3F8, M195, A33, and MRK16 for application in the pharmacology and immunology projects. The pharmacology program studies tumor resistance to chemotherapy, particularly the phenomenon of multidrug resistance and the relationship between tumor uptake and retention and the tumor response for anti-metabolite drugs. The immunology program studies the physiology of antibody localization at the tissue level as the basis for novel approaches to improving tumor localization such as through the use of an artificial lymphatic system which mechanically reduces intratumoral pressures in tumors in vivo. Quantitative imaging approaches based on PET and SPECT in radioimmunotherapy are studied to give greater insight into the physiology of tumor localization and dosimetry.

  11. The cyclotron laboratory and the RFQ accelerator in Bern

    NASA Astrophysics Data System (ADS)

    Braccini, S.; Ereditato, A.; Kreslo, I.; Nirkko, M.; Scampoli, P.; von Bremen, K.; Weber, M.

    2013-07-01

    Two proton accelerators have been recently put in operation in Bern: an 18 MeV cyclotron and a 2 MeV RFQ linac. The commercial IBA 18/18 cyclotron, equipped with a specifically conceived 6 m long external beam line ending in a separate bunker, will provide beams for routine 18-F and other PET radioisotope production as well as for novel detector, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. The accelerator is embedded into a complex building hosting two physics laboratories and four Good Manufacturing Practice (GMP) laboratories. This project is the result of a successful collaboration between the Inselspital, the University of Bern and private investors, aiming at the constitution of a combined medical and research centre able to provide the most cutting-edge technologies in medical imaging and cancer radiation therapy. The cyclotron is complemented by the RFQ with the primary goals of elemental analysis via Particle Induced Gamma Emission (PIGE), and the detection of potentially dangerous materials with high nitrogen content using the Gamma-Resonant Nuclear Absorption (GRNA) technique. In this context, beam instrumentation devices have been developed, in particular an innovative beam profile monitor based on doped silica fibres and a setup for emittance measurements using the pepper-pot technique. On this basis, the establishment of a proton therapy centre on the campus of the Inselspital is in the phase of advanced study.

  12. Considerations, measurements and logistics associated with low-energy cyclotron decommissioning

    NASA Astrophysics Data System (ADS)

    Sunderland, J. J.; Erdahl, C. E.; Bender, B. R.; Sensoy, L.; Watkins, G. L.

    2012-12-01

    The University of Iowa's 20-year-old 17 MeV Scanditronix cyclotron underwent decommissioning in the summer of 2011. To satisfy local, state and federal regulations defining removal, transportation and long-term safe and environmentally secure disposal of the 22 ton activated cyclotron, a series of nuclear spectroscopic measurements were performed to characterize the nature and extent of proton and neutron activation of the 22-ton cyclotron, its associated targets, and the concrete wall that was demolished to remove the old cyclotron. Neutron activation of the concrete wall was minimal and below exempt concentrations resulting in standard landfill disposal. The cyclotron assessment revealed the expected array of short and medium-lived radionuclides. Subsequent calculations suggest that meaningful levels residual activity will have decayed virtually to background after 15 years, with the total residual activity of the entire cyclotron dropping below 37 MBq (1 mCi).

  13. 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.

  14. Considerations, measurements and logistics associated with low-energy cyclotron decommissioning

    SciTech Connect

    Sunderland, J. J.; Erdahl, C. E.; Bender, B. R.; Sensoy, L.; Watkins, G. L.

    2012-12-19

    The University of Iowa's 20-year-old 17 MeV Scanditronix cyclotron underwent decommissioning in the summer of 2011. To satisfy local, state and federal regulations defining removal, transportation and long-term safe and environmentally secure disposal of the 22 ton activated cyclotron, a series of nuclear spectroscopic measurements were performed to characterize the nature and extent of proton and neutron activation of the 22-ton cyclotron, its associated targets, and the concrete wall that was demolished to remove the old cyclotron. Neutron activation of the concrete wall was minimal and below exempt concentrations resulting in standard landfill disposal. The cyclotron assessment revealed the expected array of short and medium-lived radionuclides. Subsequent calculations suggest that meaningful levels residual activity will have decayed virtually to background after 15 years, with the total residual activity of the entire cyclotron dropping below 37 MBq (1 mCi).

  15. Compton Gamma Ray Observatory/BATSE observations of energetic electrons scattered by cyclotron resonance with waves from powerful VLF transmitters

    NASA Technical Reports Server (NTRS)

    Datlowe, Dayton W.; Imhof, William L.

    1994-01-01

    To obtain a better understanding of the wave-particle mechanisms responsible for the loss of electrons from the radiation belts, energetic electron data from the Burst and Transient Source Experiment (BATSE) on the NASA's Compton Gamma Ray Observatory (GRO) was studied. Powerful ground-based VLF transmitters resonantly scatter electrons from the inner radiation belt onto trajectories from which they precipitate into the atmosphere as they drift eastward. 563 instances in which the satellite traversed a cloud of energetic electrons which had been scattered into quasi-trapped trajectories were identified. From the longitude distribution, it was concluded that waves from the VLF transmitter NWC at 114 deg E are the origin of 257 of the events, and waves from UMSat 44 deg E related to 45 more. In another 177 cases the electrons had drifted from the longitude of these transmitters to a location in the western hemisphere. The previously reported seasonal variation in the frequency of occurrence of cyclotron resonance interaction is confirmed with the continuous coverage provided by GRO. The frequency of occurrence of the cyclotron resonance interactions is largest before sunrise, which we attribute to the diurnal variations in the transmission VLF waves through the ionosphere. For the first time, unique very narrow sheets of electrons occurring in the aftermath of a large geomagnetic storm are reported.

  16. Self-consistent full-wave and Fokker-Planck calculations for ion cyclotron heating in non-Maxwellian plasmasa)

    NASA Astrophysics Data System (ADS)

    Jaeger, E. F.; Berry, L. A.; Ahern, S. D.; Barrett, R. F.; Batchelor, D. B.; Carter, M. D.; D'Azevedo, E. F.; Moore, R. D.; Harvey, R. W.; Myra, J. R.; D'Ippolito, D. A.; Dumont, R. J.; Phillips, C. K.; Okuda, H.; Smithe, D. N.; Bonoli, P. T.; Wright, J. C.; Choi, M.

    2006-05-01

    Magnetically confined plasmas can contain significant concentrations of nonthermal plasma particles arising from fusion reactions, neutral beam injection, and wave-driven diffusion in velocity space. Initial studies in one-dimensional and experimental results show that nonthermal energetic ions can significantly affect wave propagation and heating in the ion cyclotron range of frequencies. In addition, these ions can absorb power at high harmonics of the cyclotron frequency where conventional two-dimensional global-wave models are not valid. In this work, the all-orders global-wave solver AORSA [E. F. Jaeger et al., Phys. Rev. Lett. 90, 195001 (2003)] is generalized to treat non-Maxwellian velocity distributions. Quasilinear diffusion coefficients are derived directly from the wave fields and used to calculate energetic ion velocity distributions with the CQL3D Fokker-Planck code [R. W. Harvey and M. G. McCoy, Proceedings of the IAEA Technical Committee Meeting on Simulation and Modeling of Thermonuclear Plasmas, Montreal, Canada, 1992 (USDOC NTIS Document No. DE93002962)]. For comparison, the quasilinear coefficients can be calculated numerically by integrating the Lorentz force equations along particle orbits. Self-consistency between the wave electric field and resonant ion distribution function is achieved by iterating between the global-wave and Fokker-Planck solutions.

  17. Observation of a high-confinement regime in a tokamak plasma with ion cyclotron resonance heating

    NASA Astrophysics Data System (ADS)

    Steinmetz, K.; Noterdaeme, J.-M.; Wagner, F.; Wesner, F.; Bäumler, J.; Becker, G.; Bosch, H. S.; Brambilla, M.; Braun, F.; Brocken, H.; Eberhagen, A.; Fritsch, R.; Fussmann, G.; Gehre, O.; Gernhardt, J.; v. Gierke, G.; Glock, E.; Gruber, O.; Haas, G.; Hofmann, J.; Hofmeister, F.; Izvozchikov, A.; Janeschitz, G.; Karger, F.; Keilhacker, M.; Klüber, O.; Kornherr, M.; Lackner, K.; Lisitano, G.; van Mark, E.; Mast, F.; Mayer, H. M.; McCormick, K.; Meisel, D.; Mertens, V.; Müller, E. R.; Murmann, H.; Niedermeyer, H.; Poschenrieder, W.; Puri, S.; Rapp, H.; Röhr, H.; Ryter, F.; Schmitter, K.-H.; Schneider, F.; Setzensack, C.; Siller, G.; Smeulders, P.; Söldner, F.; Speth, E.; Steuer, K.-H.; Vollmer, O.; Wedler, H.; Zasche, D.

    1987-01-01

    The H mode in ion cyclotron-resonance-heated plasmas has been investigated with and without additional neutral beam injection. Ion cyclotron-resonance heating can cause the transition into a high-confinement regime (H mode) in combination with beam heating. The H mode, however, has also been realized-for the first time-with ion cyclotron-resonance heating alone in the D (H)-hydrogen minority scheme at an absorbed rf power of 1.1 MW.

  18. The cyclotron maser theory of AKR and Z-mode radiation. [Auroral Kilometric Radiation

    NASA Technical Reports Server (NTRS)

    Wu, C. S.

    1985-01-01

    The cyclotron maser mechanism which may be responsible for the generation of auroral kilometric radiation and Z-mode radiation is discussed. Emphasis is placed on the basic concepts of the cyclotron maser theory, particularly the relativistic effect of the cyclotron resonance condition. Recent development of the theory is reviewed. Finally, the results of a computer simulation study which helps to understand the nonlinear saturation of the maser instability are reported.

  19. Study of selective heating at ion cyclotron resonance for the plasma separation process

    NASA Astrophysics Data System (ADS)

    Compant La Fontaine, A.; Pashkovsky, V. G.

    1995-12-01

    The plasma separation process by ion cyclotron resonance heating (ICRH) is studied both theoretically and experimentally on two devices: the first one called ERIC (Ion Cyclotron Resonance Experiment) at Saclay (France) [P. Louvet, Proceedings of the 2nd Workshop on Separation Phenomena in Liquids and Gases, Versailles, France, 1989, edited by P. Louvet, P. Noe, and Soubbaramayer (Centre d'Etudes Nucléaires de Saclay and Cité Scientifique Parcs et Technopoles, Ile de France Sud, France, 1989), Vol. 1, p. 5] and the other one named SIRENA at the Kurchatov Institute, Moscow, Russia [A. I. Karchevskii et al., Plasma Phys. Rep. 19, 214 (1993)]. The radio frequency (RF) transversal magnetic field is measured by a magnetic probe both in plasma and vacuum and its Fourier spectrum versus the axial wave number kz is obtained. These results are in agreement with the electromagnetic (EM) field calculation model based on resolution of Maxwell equations by a time-harmonic scheme studied here. Various axial boundary conditions models used to compute the EM field are considered. The RF magnetic field is weakly influenced by the plasma while the electric field components are strongly disturbed due to space-charge effects. In the plasma the transversal electric field is enhanced and the kz spectrum is narrower than in vacuum. The calculation of the resonant isotope heating is made by the Runge-Kutta method. The influence of ion-ion collisions, inhomogeneity of the static magnetic field B0, and the RF transversal magnetic field component on the ion acceleration is examined. These results are successfully compared with experiments of a minor isotope 44Ca heating measurements, made with an energy analyzer.

  20. Study of selective heating at ion cyclotron resonance for the plasma separation process

    SciTech Connect

    Compant La Fontaine, A.

    1995-12-01

    The plasma separation process by ion cyclotron resonance heating (ICRH) is studied both theoretically and experimentally on two devices: the first one called ERIC (Ion Cyclotron Resonance Experiment) at Saclay (France) [P. Louvet, {ital Proceedings} {ital of} {ital the} 2{ital nd} {ital Workshop} {ital on} {ital Separation} {ital Phenomena} {ital in} {ital Liquids} {ital and} {ital Gases}, Versailles, France, 1989, edited by P. Louvet, P. Noe, and Soubbaramayer (Centre d`Etudes Nucleaires de Saclay and Cite Scientifique Parcs et Technopoles, Ile de France Sud, France, 1989), Vol. 1, p. 5] and the other one named SIRENA at the Kurchatov Institute, Moscow, Russia [A. I. Karchevskii {ital et} {ital al}., Plasma Phys. Rep. {bold 19}, 214 (1993)]. The radio frequency (RF) transversal magnetic field is measured by a magnetic probe both in plasma and vacuum and its Fourier spectrum versus the axial wave number {ital k}{sub {ital z}} is obtained. These results are in agreement with the electromagnetic (EM) field calculation model based on resolution of Maxwell equations by a time-harmonic scheme studied here. Various axial boundary conditions models used to compute the EM field are considered. The RF magnetic field is weakly influenced by the plasma while the electric field components are strongly disturbed due to space-charge effects. In the plasma the transversal electric field is enhanced and the {ital k}{sub {ital z}} spectrum is narrower than in vacuum. The calculation of the resonant isotope heating is made by the Runge--Kutta method. The influence of ion--ion collisions, inhomogeneity of the static magnetic field {ital B}{sub 0}, and the RF transversal magnetic field component on the ion acceleration is examined. These results are successfully compared with experiments of a minor isotope {sup 44}Ca heating measurements, made with an energy analyzer. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.