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  • 1
    Electronic Resource
    Electronic Resource
    Total synthesis of (+)-pseudomonic acid C (1986)
    s.l. : American Chemical Society
    The @journal of organic chemistry 51 (1986), S. 3916-3918 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00370a040
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  • 2
    Electronic Resource
    Electronic Resource
    Investigation of magnetic reconnection during a sawtooth crash in a high-temperature tokamak plasma (1994)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 1 (1994), S. 3269-3276 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this paper a laboratory investigation is made on magnetic reconnection in high-temperature Tokamak Fusion Test Reactor (TFTR) plasmas [Plasma Physics and Controlled Nuclear Fusion Research 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. 1, p. 51]. The motional Stark effect (MSE) diagnostic is employed to measure the pitch angle profile of magnetic field lines, and hence the q profile. An analytical expression that relates pitch angle to q profile is presented for a toroidal plasma with circular cross section. During the crash phase of sawtooth oscillations in plasma discharges, the ECE (electron cyclotron emission) diagnostic measures a fast flattening of the two-dimensional (2-D) electron temperature profile in a poloidal plane, an observation consistent with the Kadomtsev reconnection theory. On the other hand, the MSE measurements indicate that central q values do not relax to unity after the crash, but increase only by 5%–15%, typically from 0.7 to 0.8. The latter result is in contradiction with the 2-D models of Kadomtsev and/or Wesson. In the present study this puzzle is addressed by a simultaneous analysis of electron temperature and q profile evolutions. Based on a heuristic model for magnetic reconnection during the sawtooth crash, the small change of q, i.e., partial reconnection, is attributed to the precipitous drop of pressure gradients that drive the instability and the reconnection process, as well as flux conserving plasma dynamics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.870479
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  • 3
    Electronic Resource
    Electronic Resource
    First-order quasi-phase matched LiNbO3 waveguide periodically poled by applying an external field for efficient blue second-harmonic generation (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 435-436 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A novel method of fabricating a periodic domain structure with ideal laminar domains in LiNbO3 by applying an external field at room temperature is proposed. The method allows a high blue beam power of 20.7 mW and a high conversion efficiency of 600%/W cm2 to be obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.108925
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  • 4
    Electronic Resource
    Electronic Resource
    Asymmetric synthesis via axially dissymmetric molecules. 7. Synthetic applications of the enantioselective reduction by binaphthol-modified lithium aluminum hydride reagents (1984)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 106 (1984), S. 6717-6725 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00334a042
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  • 5
    Electronic Resource
    Electronic Resource
    Global magnetic fluctuations in spheromak plasmas and relaxation toward a minimum-energy state (1985)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 28 (1985), S. 3667-3675 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Globally coherent modes have been observed during formation in the S-1 Spheromak plasma [Plasma Physics and Controlled Nuclear Fusion 1984 (IAEA, Vienna, Austria, 1985), Vol. 2, p. 535] by analysis of magnetic field fluctuations measured from outside the plasma. The modes are of low n number (2≤n≤5), where n is defined by the functional dependence einφ of the fluctuation on toroidal angle φ. These modes are shown to be related to flux conversion and plasma relaxation toward a minimum-energy state during the spheromak formation. The modes are active while the q profile is rapidly changing, with q on axis, q0, rising to 0.7. A significant finding is the temporal progression through the n=5, 4, 3, 2; m=1 mode sequence as q rises through rational fractions m/n. During formation, peak amplitudes of the n=2, 3, 4 modes relative to the unperturbed field have been observed as high as 20%, while more typical amplitudes are below 5%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.865321
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  • 6
    Electronic Resource
    Electronic Resource
    Sawtooth stabilization by electron cyclotron heating at the q=1 surface in the WT-3 tokamak (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 2200-2204 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Sawtooth oscillations (STO) in the Ohmically heated (OH) WT-3 tokamak [Plasma Physics and Controlled Nuclear Fusion Research 1988 (IAEA, Vienna, 1989), Vol. 1, p. 563] are strongly modified or suppressed by localized electron cyclotron resonance heating (ECH) near the q=1 surface, where q refers to the safety factor. The effect of ECH is much stronger when it is applied on the high-field side, as compared to the low-field side. Complete suppression of the STO is achieved for the duration of the ECH when it is applied on the high-field side, in a low-density plasma, provided the ECH power exceeds a threshold value. This threshold decreases with the increasing safety factor at the limiter qL and the complete stabilization of STO can be obtained even when ECH is applied on the low-field side in the high-qL region. It is noticeable that these complete stabilizations can be obtained only by the localized ECH with the elliptic antenna. The STO stabilization is attributed to a modification of the current density profile by high-energy electrons generated by ECH, which reduces the shear in the q=1 region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859636
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  • 7
    Electronic Resource
    Electronic Resource
    Experimental investigation of three-dimensional magnetic reconnection by use of two colliding spheromaks (1993)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 5 (1993), S. 3691-3701 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Experimental investigation of three-dimensional (3-D) effects of magnetic reconnection dynamics has been extended by use of axially colliding spheromaks [M. Yamada et al., Phys. Fluids B 3, 2379 (1991)]. The two toroidal shape spheromak plasmas with major radii of 15–20 cm and with parallel toroidal currents of up to 30 kA collide to merge in an external equilibrium field. It is important to note that the present experimental setup allows one to investigate magnetic reconnection comprehensively from both local and global points of view. Reconnection angle θ between the merging field lines is varied by changing the polarity of the internal toroidal field and the magnitude of an external toroidal field. It is observed that the speed of counterhelicity merging with θ∼180° is about three times faster than that of cohelicity merging with θ∼90°. This suggests the significance of a 3-D effect on the reconnection process. This difference is attributed to the property of the neutral current sheets with and without the magnetic field component parallel to the reconnection (X) line. In the counterhelicity merging, the neutral current sheet is compressed in much shorter time than in the cohelicity merging, resulting in much higher current density and subsequent faster decay of the current sheet. This induces a faster magnetic reconnection. The reconnection speed increases proportionally with the initial approaching speed of the spheromaks, suggesting that a compressible driven reconnection model is consistent with the present reconnection experimental results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.860840
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  • 8
    Electronic Resource
    Electronic Resource
    Experimental study of a transformer-driven spheromak plasma (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 2591-2600 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An axial transformer was installed in the Proto S-1/C spheromak device [Yamada et al., Phys. Rev. Lett. 46, 188 (1981)] in order to study physics issues pertaining to sustained spheromak operation. An increase in both the toroidal plasma current and the toroidal flux was observed when the transformer current was pulsed. The ratio of these two quantities remained constant (within experimental error) indicating that the equilibrium spheromak magnetic field was maintained through a relaxation mechanism. At transformer currents of 10 kA, the toroidal current increased from 37 to 51 kA and the toroidal flux increased from 3.7×105 to 4.4×105 G cm2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859971
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  • 9
    Electronic Resource
    Electronic Resource
    Initial results from investigation of three-dimensional magnetic reconnection in a laboratory plasma (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 2379-2386 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A comprehensive laboratory experiment has been proposed to investigate the fundamental 3-D physics of magnetic reconnection regions and their associated hydromagnetic flows. Two toroidal plasma rings, with equal or opposite magnetic helicity, are formed and then brought together, contacting along a toroidally symmetric line. This research addresses three important questions: (1) How does magnetic helicity affect reconnection? (2) Will three-dimensional processes arise spontaneously and modify the usual Sweet–Parker or Petschek picture of two-dimensional reconnection where the global configuration is that of an axisymmetric X-point line? (3) How does the reconnection rate respond to global forcing? In a preliminary experiment carried out at the University of Tokyo [Phys. Rev. Lett. 65, 721 (1990)], the direction of the toroidal field plays an important role in the merging process. It is found that plasmas of opposite helicity merge appreciably faster than those of similar helicity. It is also found that the reconnection rate is proportional to the external force suggesting that magnetic reconnection, in the present experiment, is a forced phenomenon. A comparison of the present experimental data with 2-D computer simulation results is made.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.859607
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  • 10
    Electronic Resource
    Electronic Resource
    Experimental control of the spheromak tilting instability (1985)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 28 (1985), S. 1525-1527 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The magnetohydrodynamic (MHD) tilting instability of the spheromak configuration has been experimentally investigated by recording the time evolution of the magnetic field with small magnetic probes. Passive coil systems such as the figure-eight and saddle coils have been proven experimentally effective against this instability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.864986
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