ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
Collection
Keywords
Publisher
Language
Years
  • 1
    Electronic Resource
    Electronic Resource
    Electron-transfer mechanism of fluorescence quenching in polar solvents. I. Dicyanobenzene as quencher (1972)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 76 (1972), S. 469-473 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100648a002
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Survey of magnetohydrodynamic instabilities in the advanced stellarator Wendelstein 7-AS (2001)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 8 (2001), S. 931-956 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Magnetohydrodynamic (MHD) instabilities in the Wendelstein 7-AS stellarator (W7-AS) [G. Grieger et al., Phys. Fluids B 4, 2081 (1992)] are characterized experimentally in various plasma parameter regimes and heating scenarios. The observations are compared with theoretical predictions for particular cases. In the high-β range (〈β〉≤2%) no clear evidence of a stability β-limit could be found yet. In the lower β regime fast particle driven global Alfvén modes are the most important instabilities during neutral beam injection (NBI). Besides of coherent modes with almost no effect on the plasma performance additional Alfvén modes appear at higher frequencies up to 400 kHz, which show nonlinear phenomena-like bursting, frequency chirping, and MHD induced energy and fast particle losses. The activity of edge localized modes (ELMs) is investigated in NBI heated discharges. The issue of current driven instabilities and their potential stabilization by a stellarator field has been investigated with regard to the design of compact hybrid stellarator systems. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1346633
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Measurement of light impurity densities and Zeff in JET using x-ray tomography (1991)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 62 (1991), S. 1531-1538 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In the vast majority of plasmas produced in the JET tokamak the x-ray emission at energies above about 1 keV is dominated by bremsstrahlung radiation from the background deuterium ions, and both bremsstrahlung and recombination radiation from one or two light impurity species such as beryllium and carbon. Under these circumstances local values of impurity densities and concentrations, or alternatively of the effective charge Zeff of the ion mixture, are derived from tomographic measurements of the local x-ray emissivity at energies above 1–3 keV, in conjunction with measurements of electron density and temperature profiles. These calculations are performed using the intrinsic emissivities due to the impurity ions. The emissivities into the relevant energy bands, determined by the detector and filter characteristics, were calculated assuming coronal ionization equilibrium, and tabulated as a function of electron temperature. This method offers a good spatial and temporal resolution, and is successfully applied to most plasma conditions where the relative proportions of impurities are known. We also present a detailed sensitivity study to assess the effects of errors in the input data, and a comparison with established methods based on visible bremsstrahlung measurements, and charge exchange spectroscopy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142482
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Derivation of local impurity transport quantities from soft-x radiation evolution during tracer injection at W7-AS : Proceedings of the 12th topical conference on high temperature plasma diagnostics (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 603-607 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A frequently used method for determination of impurity transport coefficients is the analysis of the radial and temporal time evolution of the impurity density of injected tracer impurities. In cases when the impurity density cannot be measured directly, e.g., by active charge exchange recombination spectroscopy, the impurity density has to be reconstructed from impurity radiation as measured, e.g., by the soft-x camera. Due to the energy integrated information, assumption about the spatial ionization state distribution, e.g., coronal equilibrium, is necessary. This might not be valid in cases of large transport. Consequently, the transport quantities, derived under the preliminary assumption of radial coronal distribution, are used again in an iterative way to improve the density reconstruction in order to approach more realistic transport quantities. The procedure was applied to plasma discharges in the stellarator Wendelstein 7-AS. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149357
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Diagnostic strategy of the W7-X stellarator (1997)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 1244-1249 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The Wendelstein 7-X experiment is a concept test for properties of reactor relevant plasmas in advanced stellarators. Prominent features include a modular superconducting coil assembly, a fivefold toroidal symmetry, and a helical magnetic axis. Due to the optimization process, W7-X is characterized by a vacuum magnetic field configuration with smooth magnetic surfaces, improved equilibrium properties with a weak dependence of rotational transform and shear on the plasma pressure β, good magneto-hydrodynamic stability properties due to magnetic well stabilization, reduced neoclassical transport losses and negligible bootstrap current in the long mean-free-path regime, good collisionless α-particle confinement in an equivalent reactor, and, as a technical aspect, good feasibility of the superconducting modular coils. W7-X will be heated by continuous electron cyclotron resonance heating and pulsed neutral beam injection and ion cyclotron resonance heating. The envisaged parameters are Te≤10 keV, Ti≤6 keV central densities ≤3×1020 m−3 with an averaged 〈β〉≤5%. Despite the complicated geometrical structure, all basic diagnostics are compatible with W7-X. Generally, diagnostic methods and applications in a stellarator are not different from those in tokamaks. However, special efforts are being made to equip the experiment with those diagnostics necessary to measure the quantities directly related with the optimization of the machine: the verification of the predicted magnetic topology and characterization of the configuration throughout the entire parameter range, the identification of equilibrium and stability, and the determination of the confinement properties. The article describes the strategy developed which assures that the detailed measurement needs of the W7-X experimental program can be met. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148226
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    X-ray diagnostics on WENDELSTEIN 7-AS : Proceedings of the 12th topical conference on high temperature plasma diagnostics (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 484-488 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The spatially and temporally resolved x-ray emission in the W7-AS stellarator is analyzed by three diagnostic systems. The first consists of two cameras using arrays of surface barrier diodes. A variety of absorber-foils can be used to change the spectral response of the system. This flexibility allows one to analyze impurities and magnetohydrodynamic (MHD) activity. The measurements are also used for the reconstruction of equilibrium parameters (e.g., Shafranov shift) and of the topology of MHD modes. The second system serves to monitor the electron temperature profile by using the two-foil method. Pairs of large ion-implanted Si diodes in combination with different foil combinations are used. In addition, the measurements provide routine informations about Zeff, plasma position and profile width. Finally, a compact camera system (ten cameras with planar pin-diode arrays and curved Be-foils, 320 viewing chords) inside the vacuum vessel allows one to obtain proper two-dimensional tomograms of the equilibrium flux surfaces and of mode structures without prior information. In addition to the camera systems spectral information is obtained from x-ray pulse height measurements with two Si(Li) detectors. These data are correlated with the x-ray profile measurements by an impurity radiation code. The contribution of x-ray measurements to the investigation of various physics issues is illustrated by selected examples. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149282
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Fast ion losses in the W7-AS stellarator : Papers from the thirteenth topical conference on high temperature plasma diagnostics (2001)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 72 (2001), S. 780-783 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new probe for the detection of fast escaping ions has been installed and operated at the W7-AS stellarator. Fast ions generated from neutral beam injection or ion cyclotron heating were used to study the fast ion confinement properties of the partially drift-optimized magnetic field structure as well as losses induced by magnetohydrodynamic perturbations. The design of the probe is based on the α-particle detectors of the Tokamak Fusion Test Reactor using scintillator plates and allows the detection of co-and countergoing ions simultaneously in a wide range of gyroradii and pitch angles. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1319357
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    JET soft x-ray diode array diagnostic (1986)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 57 (1986), S. 2142-2144 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The arrays of silicon diodes recently installed on the Joint European Torus (JET) measure the plasma soft x-ray emission with high temporal and spatial resolution, allowing magnetohydrodynamic (MHD) effects to be investigated. The diagnostic consists of two "pinhole'' cameras which view the same poloidal cross section in orthogonal directions. A data-acquisition system based upon three cascaded digital filters can convert the 200-kHz detector signal analog-to-digital converter (ADC) output to lower sampling rates of 10, 1, and 0.1 kHz. Initially, studies have concentrated on the sawtooth collapse. By means of a trigger system data on the sawtooth crash have regularly been recorded at a sampling frequency of 200 kHz. Using tomographic reconstruction techniques, the soft x-ray emissivity cross section during the crash has been reconstructed. First results during ion cyclotron radio frequency (ICRF) heating show no precursor activity prior to the sawtooth collapse, while during the crash, the hot central plasma is displaced off axis by about 30 cm on a time scale of 50–200 μs, after which a hollow soft x-ray profile forms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1139200
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Diagnostic strategy of the W7-X stellarator (abstract) : Proceedings of the eleventh topical conference on high temperature plasma diagnostics (1997)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 888-888 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The Wendelstein 7-X experiment is a concept test for properties of reactor relevant plasmas in advanced stellarators. Prominent features include a modular superconducting coil assembly, a five-fold toroidal symmetry, and a helical magnetic axis. Due to the optimization process, W7-X is characterized by a vacuum magnetic field configuration with smooth magnetic surfaces, improved magnetic field configuration with smooth magnetic surfaces, improved equilibrium properties with a weak dependence of rotational transform and shear on the plasma pressure β, good magneto-hydrodynamic stability properties due to magnetic well stabilization, reduced neoclassical transport losses and negligible bootstrap current in the long mean-free-path regime, good collisionless α-particle confinement in an equivalent reactor, and, as a technical aspect, good feasibility of the superconducting modular coils. W7-X will be heated by continuous electron cyclotron resonance heating and pulsed neutral beam injection and ion cyclotron resonance heating. The envisaged parameters are Te≤10 keV, Ti≤6 keV central densities ≤3×1020 m−3 with an averaged 〈β〉≤5%. Despite the complicated geometrical structure, all basic diagnostics are compatible with W7-X. Generally, diagnostic methods and applications in a stellarator are not different from those in tokamaks. However, special efforts are being made to equip the experiment with those diagnostics necessary to measure the quantities directly related with the optimization of the machine: the verification of the predicted magnetic topology and characterization of the configuration throughout the entire parameter range, the identification of equilibrium and stability, and the determination of the confinement properties. The article describes the strategy developed which assures that the detailed measurement needs of the W7-X experimental program can be met. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1147918
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    JET x-ray pulse-height analysis system (1988)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 693-699 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The pulse-height-analysis (PHA) system installed on the Joint European Torus (JET) measures the plasma soft x-ray emission (2–30 keV) with an energy resolution of 450 eV and a time resolution of 200 ms. This diagnostic includes three Si(Li) detectors, equipped with sets of remotely controlled apertures and filters, which view the plasma in the midhorizontal plane of the torus along a single tangential line of sight. Automatic analysis of the spectra yields the central electron temperature, the central concentrations of chlorine, chromium, and nickel, and Zeff. Simulations of the measured spectra using a radiation code provides the basis to construct a consistent picture of the soft x-ray emission in the central region of JET plasmas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1139812
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...