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  • 1
    Publication Date: 2023-05-12
    Keywords: Area/locality; Conductivity, average; ELEVATION; Heat flow; LATITUDE; LONGITUDE; Method comment; Number; Number of conductivity measurements; Number of temperature data; Sample, optional label/labor no; Temperature gradient
    Type: Dataset
    Format: text/tab-separated-values, 139 data points
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  • 2
    Publication Date: 2023-05-12
    Keywords: Area/locality; Conductivity, average; Depth, bottom/max; ELEVATION; Heat production, average; LATITUDE; LONGITUDE; Method comment; Number; Number of conductivity measurements; Number of temperature data; Sample, optional label/labor no; Temperature gradient
    Type: Dataset
    Format: text/tab-separated-values, 37 data points
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 197 (1963), S. 1166-1167 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] RECENT correspondence in Nature1' 2 has indicated renewed interest in the subject of glasses in ignimbrites and, by implication, immiscibility in silicate magmas. Ignimbrites containing glass of more than one composition are rare and probably analogous to rhyolite-basalt mix lavas in origin. Only ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 1646-1651 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Heavy-ion beam probing generally consists of passing a beam of 1+ ions through a plasma imbedded in a magnetic field. Secondary ions with higher ionization levels are produced by ionizing collisions with the plasma electrons. Detection of the secondary ions with a small-aperture electrostatic energy analyzer allows continuous fluctuation measurements of the plasma density and space potential with both spatial and temporal resolution. Spatial resolution is the order of 0.1 cm3 and temporal resolution is presently electronics limited to ∼1 μs. The energy of the probing beam is determined primarily by the requirement that the secondary ion must escape from the plasma. Typical beam energies extend from 10 to 500 keV. The range of plasma densities that have been investigated is 1012 cm−3〈ne〈1014 cm−3. At the higher densities, beam attenuation becomes a serious problem. Higher beam energies provide better penetration of the magnetic field, and reduced beam attenuation. Heavy-ion beam probes were first used to measure a coherent density fluctuation on a hollow cathode arc in 1969, and soon afterward to measure the space potential. Since then beam probes have been used to measure the space potential and fluctuations in both density and space potential for plasmas with varying magnetic geometries. There is continuing development work to study the feasibility of using beam probes to measure magnetic fluctuations and magnetic field structure. Sensitivity for measuring density and potential fluctuations is best demonstrated by what is the most sophisticated beam probe to date: the 500-keV system on TEXT. For broadband measurements (50–250 kHz), the TEXT beam probe has demonstrated a sensitivity to space potential fluctuations of 2 V (rms), and resolution for ñe/ne of 10−3.Recent measurements on both ISX-B and TEXT have demonstrated the capability of obtaining simultaneous ñ and cursive-phi˜ measurements at three separate locations in the plasma. For some locations the sample volumes are poloidally separated and S(kθ, w) can be estimated for both ñ and cursive-phi˜. This permits evaluation of the net electrostatic-fluctuation-induced particle flux. Some of the problems still being encountered with present beam probes are the nonideal behavior of the energy analyzer, cross talk between ñ and cursive-phi˜ for high-wave-number fluctuations, the effect of finite sample volume and sample volume spacing on the evaluation of k spectra, simultaneous measurement of two components of the k vector, probing of the complex 3-D magnetic fields, and extension of the measurements to higher-energy beam probe systems.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 1670-1672 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Neoclassical theory predicts that radial electric fields develop in plasmas confined in nonaxisymmetric tori and that they strongly influence the confinement in such devices. A heavy-ion beam probe has been planned for the ATF torsatron at Oak Ridge National Laboratory with the primary goal of providing direct measurements of the plasma potential radial profile and thus of the radial electric field. The complex ATF geometry and magnetic field structure present a diagnostic environment more challenging than that found on previous beam probe systems which have operated on tokamaks, mirrors, and bumpy tori. Particular attention has been given to system alignment and control capabilities. Since the probing ion trajectories remain essentially the same with or without the plasma, an in situ calibration scheme using suitable ionization targets is possible. Installation of the complete diagnostic system is planned for 1988.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 1673-1675 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Recent applications of heavy-ion beam probes on such devices as the TEXT tokamak have shown the importance of increasing the capabilities of both the beam injection and detection systems. To this end we have investigated a new solid-state ion detector that will substantially improve spatial resolution. The application of the diagnostic technique on substantially larger devices will also require new electrostatic energy analyzer geometries, which are also under investigation.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 57 (1986), S. 1822-1824 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A heavy ion beam probe diagnostic is planned for ATF. The most significant device characteristics affecting the implementation of such a system on this complex magnetic geometry not encountered on tokamaks are the large toroidal separation (15°) of vertical and horizontal ports and substantial magnetic return fields in the region of the ion optics and energy analyzer electric fields. Procedures have been developed to make the application of beam probing possible in this environment.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The development of an electrostatic energy analyzer to be used with the 2-MeV heavy ion beam probe on the TEXT-Upgrade tokamak has presented several very interesting voltage breakdown phenomena. In order to maintain a 400-kV potential on large surface area plates (46.2 cm×152 cm) various configurations of support dielectrics, voltage feedthrough, plate materials, and plate geometry have been evaluated. Experimental evaluation of several designs and the resulting modifications leading to a working analyzer will be presented. This work was supported by the U.S. Department of Energy.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The new heavy ion beam probe diagnostic system on TEXT is presently operational at reduced energy. Thallium and cesium ion beams with energy up to 590 keV have been obtained using a single injection beamline and an energy analyzer that can be operated with low-energy beams only (≤590 keV). At full energy (up to 2 MeV) two injection beamlines and two energy analyzers (presently under construction) will allow access to 90% of the plasma cross section. Stable 2-MeV test beams with currents up to 10 μA have been obtained but not injected into the tokamak. The capacitive liner feedback control system allowed stable operations with ripple less than 100 V. Results of initial operations and preliminary measurements of density fluctuations are presented. This work is supported by the U. S. Department of Energy.
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  • 10
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An energy analyzer based on the Proca and Green parallel-plate design is being developed for use with the 2 MeV heavy ion beam probe on TEXT. In a departure from the conventional configuration, guard ring electrodes will not be used. Instead, a shaped top plate will provide for comparable, or improved, uniformity of the analyzer electric field region. To quantify this effect, and to characterize the electrostatic field, numerical solution methods have been utilized. Simulations have included effects of top plate shape, wire screens, vacuum chamber design, and dielectric support structures. The modeling has permitted us to design an analyzer electrode structure that is an integral part of a uniquely shaped vacuum vessel. The design electric field is 20 kV/cm with less than 1% error in uniformity within the parallel plate region. To examine the electric field structure experimentally, a quarter-scale prototype analyzer has been constructed and tested. The electric field characteristics are examined by varying the path of a heavy ion beam through the analyzer and examining the resulting analyzer performance. A simulated vacuum wall can be positioned to examine the effects of different vessel configurations and to determine the sensitivity of the analyzer to this boundary condition. The experimental results show excellent agreement with the numerically predicted fields and confirm the validity of the shaped top plate electrode concept.
    Type of Medium: Electronic Resource
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