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Mode structure symmetry breaking of reversed shear Alfvén eigenmodes and its impact on the generation of parallel velocity asymmetries in energetic particle distribution

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Plasma Science and Technology 2022年第2期24卷 17-27页

作者： Guo MENG Philipp LAUBER Xin WANG Zhixin LU max-planck-institut fiir plasmaphysik D-85748 GarchingGermany

In this work,the gyrokinetic eigenvalue code LIGKA,the drift-kinetic/MHD hybrid code HMGC and the gyrokinetic full-f code TRIMEG-GKX are employed to study the mode structure details of reversed shear Alfvén eigenmodes(RSAEs).Using the parameters from an ASDEXUpgrade plasma,a benchmark with the three different physical models for RSAE without and with energetic particles(EPs)is carried *** agreement has been found for the mode frequency and the growth *** structure symmetry breaking(MSSB)is observed when EPs are included,due to the EPs’non-perturbative *** is found that the MSSB properties are featured by a finite radial wave phase velocity,and the linear mode structure can be well described by an analytical complex Gaussian expressionФ(s)=e^(-σ(s-s_(0))^(2))with complex parametersσand s_(0),where s is the normalized radial *** mode structure is distorted in opposite manners when the EP drive shifted from one side of qminto the other side,and specifically,a non-zero average radial wave number with opposite signs is *** initial EP density profiles and the corresponding mode structures have been used as the input of HAGIS code to study the EP *** parallel velocity of EPs is generated in opposite directions,due to different values of the average radial wave number,corresponding to different initial EP density profiles with EP drive shifted away from the qmin.

关键词： reversed shear Alfvén eigenmode symmetry breaking energetic particles non-perturbative effects

CREEP DEFORMATION OF INTERMETALLIC ALLOYS

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Acta Metallurgica Sinica(English Letters) 1995年第Z1期8卷 431-440页

作者： Gerhard Sauthoff(max-planck-institut fur Eisenforschung GmbH., D-40074 Dusseldorf,Germany) max-planck-institut fur Eisenforschung GmbH Dusseldorf Germany

Intermetallics for structural applications at high temperatures must show a sufficient high temperature strength which is controlled by creep processes. In the first section the creep behaviour of single-phase intermetallic alloys is overviewed with respect to stress and temperature dependence and effects of composition and microstructure. It is shown in particular that creep deformation is controlled by diffusion. The second section refers to multiphase intermetallic alloys, and both particulate and non-particulate alloys are regarded. Data are presented for single-phase and multiphase alloys based on B2 phases and lesscommon phases and the consequences of diffusion control for alloy design are discussed.

关键词： creep B2 phases NiAl particulate alloys,multiphase alloys

Deuterium retention in chemically vapor deposited tungsten carbide coatings and hot-rolled tungsten exposed to low-energy deuterium plasma

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Tungsten 2022年第1期4卷 10-19页

作者： Vladimir Kh.Alimov Joachim Roth Frumkin institute of Physical Chemistry and Electrochemistry Russian Academy of SciencesMoscow 119071Russia max-planck-institut fur plasmaphysik 85748 GarchingGermany

Samples of chemically vapor deposited(CVD)coatings of tungsten carbides W_(45)C_(55)and W_(60)C_(40)and samples of hot-rolled tungsten were exposed to deuterium(D)plasma at sample temperatures ranging from 323 to 813 K,as a result of which the samples were irradiated with D ions with an energy of about 200 eV per D particle at a flux of D particles of about1.1×10^(21)D·m^(-2)·s^(-1)to a fluence of about 2×10^(24)D·m^(-2).The concentration of deuterium in these samples was examined by the D(3 He,p)4 He nuclear *** on the measured deuterium depth profiles and assuming that these profiles are determined by diffusing D atoms,the diffusion coefficients of deuterium in the CVD tungsten carbide coatings were *** these diffusion coefficients,an estimate of the Arrhenius relation for the diffusion coefficients of deuterium in CVD tungsten carbide coatings was obtained:D=2.5×10^(-3)exp(-1.12 eV/kT)m~2·s^(-1),where T is temperature expressed in Kelvin,and k is the Boltzmann *** concentration of trapped deuterium in the bulk of CVD tungsten carbide coatings is practically independent of the stoichiometry of the *** decreases from about 5×10^(-2)to about 7×10^(-4)D/(W+C)with an increase in the deuterium plasma exposure temperature from 373 to 813 *** concentration of trapped deuterium in hot-rolled tungsten,expressed in units of the D/W atomic ratio,is more than an order of magnitude lower than the concentration of deuterium in tungsten carbides,and also decreases with increasing plasma exposure temperature.

关键词： Chemically vapor deposited tungsten carbides Tungsten Deuterium plasma Deuterium depth profiles Deuterium diffusion coefficients

A Coupled Model Study on the Intensification of the Asian Summer Monsoon in IPCC SRES Scenarios

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Advances in Atmospheric Sciences 2005年第6期22卷 798-806页

作者： Min WEI max-planck-institut fur Meteorologie Bundesstrasse 53 D-20146 Hamburg Germany

The Asian summer monsoon is an important part of the climate system. Investigating the response of the Asian summer monsoon to changing concentrations of greenhouse gases and aerosols will be meaningful to understand and predict climate variability and climate change not only in Asia but also globally. In order to diagnose the impacts of future anthropogenic emissions on monsoon climates, a coupled general circulation model of the atmosphere and the ocean has been used at the max-planck-institute for Meteorology. In addition to carbon dioxide, the major well mixed greenhouse gases such as methane, nitrous oxide, several chlorofluorocarbons, and CFC substitute gases are prescribed as a function of time. The sulfur cycle is simulated interactively, and both the direct aerosol effect and the indirect cloud albedo effect are considered. furthermore, changes in tropospheric ozone have been pre-calculated with a chemical transport model and prescribed as a function of time and space in the climate simulations. Concentrations of greenhouse gases and anthropogenic emissions of sulfur dioxide are prescribed according to observations （1860-1990） and projected into the future （1990-2100） according to the Scenarios A2 and B2 in Special Report on Emissions Scenarios （SRES, Nakcenovic et al., 2000） developed by the Intergovernmental Panel on Climate Change （IPCC）. It is found that the Indian summer monsoon is enhanced in the scenarios in terms of both mean precipitation and interannual variability. An increase in precipitation is simulated for northern China but a decrease for the southern part. furthermore, the simulated future increase in monsoon variability seems to be linked to enhanced ENSO variability towards the end of the scenario integrations.

关键词： asian summer monsoon climate change IPCC SRES scenarios

Relationship Between Oct agonal Quasicrystal and β-Mn Type Crystal in Cut Description

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Chinese Physics Letters 1996年第3期13卷 199-202页

作者： LI Fang-hua CHENG Yi-fan institute of Physics Chinese Academy of SciencesBeijing 1000801 max-planck-institut fur Metallforschung Institut fur Werkstoff-WeissenschaftSeestrasse 9270147 StuttgartGermany

The transformation from the octagonal lattice to a square lattice is demonstrated straightforward under the cut description by introducing a peculiar linear phason *** calculated lattice parameter of the ft-Mn structure from the edge length of squares and rhombi forming the octagonal quasilattice is in agreement with experimental results.

关键词： strain. agonal lattice

Theoretical Analysis on Effect of Adding Argon to Hydrogen Plasma

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Plasma Science and Technology 2004年第2期6卷 2204-2212页

作者：胡纯栋 E.Speth institute of Plasma Physics Chinese Academy of Sciences Hefei 230031 China max-planck-institut fiir plasmaphysik EURATOM-Association 85748 Garching Germany

An increased of H ion beam current whenever argon gas is added has been observed. The physics behind argon effect is that in the production of more H atoms, a part of H atoms will be converted to H2*(v>4) to increase H- density. Increase of nH depends on the rate of added Ar η %, primary filling pressure P, electron density neAr and recombination coefficient 7 of H atom. Adding 25% Ar is optimal, although there have been assumed various parameters. Increase of nH depends on decreased recombination coefficient 7, and increased primary filling pressure P. The increase of nH is small when the pressure P maximum Ar effect.

关键词： H- ion beam Ar effect neutral beam injection

Changes of crystallinity and spherulite morphology in isotactic polypropylene after rolling and heat treatment

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Journal of University of Science and Technology Beijing 2008年第4期15卷 514-520页

作者： Juan Jia Weimin Mao Dierk Raabe School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China max-planck-institut fur Eisenforschung Max-Planck-Str. 1 Düsseldorf 40237 Germany

The spherulite morphology of the rolled and subsequent heat-treated isotactic polypropylene （iPP） was observed by polarized microscopy, and the crystallinity evolution of materials was also measured by the wide angle X-ray scattering （WAXS）. Rolling led to the oblate spherulites in the deformed iPP samples. The sheared crystalline lamellae broke apart into sets of crystalline blocks during rolling. As a result, the crystallinity of the iPP samples was greatly reduced during deformation, which induced the unclear spherulites and spherulite boundaries. Subsequent heat treatment resulted in the strong reerystallization of the rolled iPP samples. But the recrystaUizatinn in this work only meant the rearrangement of the macromolecule along the unbroken crystalline lamellae and the existing small crystalline blocks in the deformed spherulites. Heat treatment did not change the shape of the spherulites formed during deformation. The recrystallization also resulted in very clear spherulites and spherulite boundaries.

关键词： isotaetic polypropylene (iPP) rolling heat treatment X-ray diffraction crystallinity spherulites

Thermodynamic and rate variational formulation of models for inhomogeneous gradient materials with microstructure and application to phase field modeling

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Acta Mechanica Sinica 2015年第2期31卷 162-172页

作者： Svyatoslav Gladkov Bob Svendsen Material Mechanics RWTH Aachen Aachen Germany Microstructure Physics and Alloy Design Max-Planck-Institut fur Eisenforschung DusseldorfGermany

In this work,thermodynamic models for the energetics and kinetics of inhomogeneous gradient materials with microstructure are formulated in the context of continuum thermodynamics and material *** simplicity,attention is restricted to isothermal *** materials of interest here are characterized by（1） first- and secondorder gradients of the deformation field and（2） a kinematic microstructure field and its gradient（e.g.,in the sense of director,micromorphic or Cosserat microstructure）.Material inhomogeneity takes the form of multiple phases and chemical constituents,modeled here with the help of corresponding phase *** requirements together with the dissipation principle result in the reduced model field and constitutive *** cases of these include the wellknown Cahn-Hilliard and Ginzburg-Landau *** the last part of the work,initial boundary value problems for this class of materials are formulated with the help of rate variational methods.

关键词： Continuum thermodynamics Material inhomogeneity Conservative Non-conservative phase fields

Tomography of a simply magnetized toroidal plasma

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Plasma Science and Technology 2018年第2期20卷 87-96页

作者： Ruggero BARNI Stefano CALDIROLA Luca FATTORINI Claudia RICCARDI Dipartimento di Fisica G.Occhialini Università degli Studi di Milano-Bicocca piazza della Scienza 3 1-20126 Milano Italy max planck institut fur plasmaphysik Boltzmann Strasse 2 D-85748 Garching Germany

Optical emission spectroscopy is a passive diagnostic technique,which does not perturb the plasma *** particular,in a hydrogen plasma,Balmer-alpha（Hα） emission can be easily measured in the visible range along a line of sight from outside the plasma *** emission lines in the visible spectral range from hydrogen atoms and molecules can be exploited too,in order to gather complementary pieces of information on the plasma *** allows us to capture bi-dimensional *** propose to adopt an emission spectroscopy tomography for studying the transverse profiles of magnetized plasmas when Abel inversion is not *** experimental campaign was carried out at the Thorello device,a simple magnetized *** characteristics of the profile extraction method,which we implemented for this purpose are discussed,together with a few results concerning the plasma profiles in a simply magnetized torus configuration.

关键词： optical emission spectroscopy magnetized plasma simply magnetized torus plasma diagnostics