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1.
The DT experimental campaign on JET (1997) represents a major step forward
for neutron emission spectroscopy (NES) diagnostic through the high quality
data collected by the Magnetic Proton Recoil (MPR) spectrometer. These data
for different DT plasma heating scenarios were analyzed here to determine
the underlying fuel ion populations which in turn were used to project the
2.5-MeV neutron emission spectra for deuterium plasmas. The results on
neutron spectra for DT and D plasmas in the same conditions were compared in
order to determine the plasma information that could be expected from NES
diagnosis of D plasmas and the instrumental characteristics that would be
required. Future NES experiments would make dual sight line observations
possible and the added diagnostic value is also assessed based on the
present results. 相似文献
2.
V. Milosavljević S. Djeniže 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(3):385-390
On the basis of the precisely recorded 706.52 nm He I line shape we have obtained the basic plasma parameters i.e. electron temperature (T) and electron density (N) using our new line deconvolution procedure in the case of five various plasmas created in a linear, low-pressure, pulsed
arc discharge. Plasma parameters have been also measured using independent experimental diagnostical techniques. Excellent
agreement was found among the two sets of the obtained parameters. This enables our deconvolution procedure to recommendation
for plasma diagnostical purposes, especially in astrophysics where direct measurements of the plasma parameters (T and N) are not possible. Besides, on the basis of the observed asymmetry of the Stark broadened line profile we have obtained its
ion broadening parameter (A) caused by influence of the ion microfield to the line broadening mechanism and also the influence of the ion dynamic effect
(D) to the line shape. Our A and D parameters represent the first data obtained experimentally using the line profile deconvolution procedure. We have found
stronger influence of the ion contribution to the 706.52 nm He I line profile than the existing theoretical approximations
estimate. This can be important for plasma modeling or for diagnostics.
Received 30 October 2002 Published online 15 April 2003
RID="a"
ID="a"e-mail: vladimir@ff.bg.ac.yu 相似文献
3.
4.
S. I. Masharov 《Russian Physics Journal》1996,39(9):839-842
A general expression is obtained for the thermodiffusion coefficientD
T of a film, also for its dependence on temperature, film thickness and type of concentration distribution of the interstitials,
according to its profile. In neglecting interaction of interstitials with each other in a model of a film with single-plane
boundaries with the vacuum and the substrate, it is shown thatD
T>D
T
(∞) is possible, whereD
T
(∞) is the thermodiffusion coefficient of a bulk specimen.
Ural State Technical University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 43–46, September,
1996. 相似文献
5.
P. Dalmas de Réotier J. P. Sanchez A. Yaouanc S. W. Harris O. Hartmann E. Karlsson R. Wäppling D. Gignoux B. Gorges D. Schmitt Ph. L'Héritier A. Weidinger P. C. M. Gubbens 《Hyperfine Interactions》1991,64(1-4):389-394
Zero-field μSR studies of some hexagonal intermetallic compounds are described. Our LaNI5 data provide information on the muon localisation site. This site could be one of the deuterium sites deduced from neutron
diffraction. A comparison of the temperature dependence of the exponential damping rate, λ(T), of our samples shows that λ(T) is strongly influenced by crystal field effects. The TbNi5 spectra exhibit two components forT<60 K. We discuss the possible explanations of this result. We see a μSR signal below the magnetic phase transition in GdNi5. This makes the study of the spin-lattice relaxation rate possible in the ordered magnetic state. 相似文献
6.
7.
Mutual mass diffusion and thermal diffusion has been investigated in poly(dimethylsiloxane)/ poly(ethylmethylsiloxane) (PDMS/PEMS) polymer blends of equal weight fractions. Molar masses ranged from below 1 to over 20 kg/mol. Both the mutual mass (D) and the thermal diffusion (DT) coefficient contain a thermally activated factor with an activation temperature of 1415 K. The molar mass dependence of DT is due to an end-group effect of the local friction coefficient. The thermal diffusion coefficient in the limit of long chains and infinite temperature is DT0, = - 1.69×10-7cm2(sK)-1. The Soret coefficient ST of blends far enough away from a critical point is proportional to the static structure factor S(q = 0). 相似文献
8.
N. A. Silant’ev 《Journal of Experimental and Theoretical Physics》1997,85(4):712-723
An analysis is made of the relation between accurate formulas for the coefficients of turbulent diffusion D
T and the alpha effect α
T for a magnetic field in the Lagrange and Euler representations. It is shown that the quadratic term with respect to α
T in the diffusion coefficient derived by Moffatt and Kraichnan is incorrect and should be dropped. First, a numerical solution
of the nonlinear equation (DIA equation) for the Green function is presented, describing the transport of a magnetic field
for the case of incompressible, uniform, isotropic, steady-state turbulence possessing helicity. These solutions are used
to calculate the steady-state coefficients D
T and α
T for various values of the parameters ξ
0=u
0
σ
0/R
0, a=H
0/u
0
2
p
0, σ
0/σ
1, and R
0/R
1, where u
0, σ
0, and R
0 are the characteristic velocity, lifetime, and scale of the turbulent pulsations, and H
0, σ
1, and R
1 are similar values describing the helicity of the medium h(1,2)=〈u(1)· (∇×u(2))〉, and the parameter α characterizes the degree of helicity. The DIA values of D
T and α
T and the self-consistent values of these quantities calculated using the Green tensor in the diffusion approximation are in
qualitative agreement. It is shown that the coefficient of turbulent diffusion is always positive for all the types of turbulence
studied. Nonsteady-state values of D
T(t) and α
T(t) calculated by a self-consistent method are given.
Zh. éksp. Teor. Fiz. 112, 1312–1331 (October 1997) 相似文献
9.
A. R. Nemets V. A. Krupin L. A. Klyuchnikov K. V. Korobov M. R. Nurgaliev 《Physics of Atomic Nuclei》2016,79(7):1204-1209
The paper describes the scanning spectroscopic diagnostics designed for measurement of line integrated plasma radiation in two visible spectral ranges. This diagnostic system is aimed at measuring the bremsstrahlung absolute values and profile with high spatial resolution. The bremsstrahlung absolute values are used to determine the value and radial distribution of effective plasma ion charge Z eff(r) in T-10 discharges. The importance of Z eff measurement is due to its strong influence on plasma heating, confinement, and stability. The spatial distribution of emission for one of the chosen spectral lines is measured simultaneously with bremsstrahlung. The spatial resolution of measurements is ~1 cm, and the temporal resolution is up to 10 ms. The spectral equipment and methods for its calibration are described. Examples of line integrated brightness distribution in a “continuum window” of 5236 ± 6 Å and brightness of the lines C5+ (5291 Å), He1+ (4686 Å), and Dβ (4861 Å) are given. Flattening of the bremsstrahlung brightness profile in the central region of the plasma column in some discharges with sawtooth oscillations in the T-10 is observed. The measured effective ion charge profiles in ohmic discharges with high plasma density and low discharge currents demonstrate accumulation of light impurities at the column axis; as a consequence, quenching of sawtooth oscillations in some discharges is observed. The developed diagnostics provides necessary data for investigation of heat, particle, and current transport in the plasma of the T-10. Successful application of the obtained data on Z eff(r) for investigation of geodesic acoustic modes of plasma oscillations in the T-10 should be specially noted. 相似文献
10.
Precision measurements of the real and imaginary parts of the microwave surface impedance Z ac(T) = R ac(T) + iX ac(T) of the conducting ac layers of the k-(BEDT-TTF)2Cu[N(CN)2]Br crystals in the temperature interval of 0.5 < T < 100 K have demonstrated a series of features: (i) the temperature course of the field penetration depth is close to linear Δλac(T)∞ΔX ac(T) in the superconducting state at T T c ∼ 11.5 K; (ii) the curves R ac(T) = X ac(T) coincide at T c < T < 40 K; (iii) the X ac(T) value at T > 40 K increases in comparison with R ac(T); (iv) the dependence R ac(T) at T > 40 K is nonmonotonic in thin crystals. These features of the impedance Z ac(T) with increasing T are interpreted in terms of (i) the d-type symmetry of the superconducting order parameter, (ii) normal skin effect, (iii) manifestations of the antiferromagnetic fluctuations, and (iv) the size effect. The electrodynamic parameters of k-(BEDT-TTF)2Cu[N(CN)2]Br have been determined. 相似文献
11.
We analyze the fusion process involving two deuterium nuclei in the case of deceleration of a fast deuteron with an energy
of approximately 100 keV located in a deuterium target. We calculate the probability ω
fus(ε) of generating a neutron by a fast deuteron with an initial kinetic energy ε during its deceleration. The mean free path
of fast deuterons with respect to their relaxation is found for various deuterium targets. The data are analyzed for neutron
generation in deuterium cluster beams under laser irradiation. The method of neutron generation in the collision of two deuterium
cluster beams is suggested.
The text was submitted by the author in English. 相似文献
12.
R. J. Jiménez Riobóo M. Philipp M. A. Ramos J. K. Krüger 《The European physical journal. E, Soft matter》2009,30(1):19-26
The temperature and concentration dependence of the refractive index, n
D(x, T) , in ethanol-water mixtures agrees with previous data in the ethanol-rich concentration range. The refractive index versus concentration x determined at 20 °
C shows the expected maximum at about 41 mol% water (22 mass% water). The temperature derivative of the refractive index, dn
D
/dT, shows anomalies at lower water concentrations at about 10 mol% water but no anomaly at 41 mol% water. Both anomalies are
related to intermolecular interactions, the one in nD seems to be due to molecular segregation and cluster formation while the origin of the second one in dn
D
/dT is still not clear. 相似文献
13.
A simple and unified model, without any adjustable parameter, is established for size effect on Curie temperature of low-dimensional
ferroelectrics (thin films, nanowires and nanoparticles), T
c(D), where D denotes size of low-dimensional ferroelectrics. T
c(D) function is based on consideration on the size dependence of spontaneous polarization of low-dimensional ferroelectrics
P
s(D), which is determined by the misfit strain at the ferroelectrics/substrate interface. It is shown that P
s(D) and T
c(D) functions decrease or increase when the misfit strain is tensile or compressive. The numerically predicted results are in
agreement with the available experimental results of BaTiO3 and PbTiO3 nanoparticles and thin films. 相似文献
14.
J. D. Hey M. Korten Y. T. Lie A. Pospieszczyk D. Rusbüldt B. Schweer B. Unterberg J. Wienbeck E. Hintz 《等离子体物理论文集》1996,36(5):583-604
Profiles of the Balmer lines Da(Ha), Dβ(Hβ) and Dγ(Hγ) have been measured in the scrape-off layer and within the edge of the TEXTOR (upgrade) plasma, under Ohmic conditions and with neutral-beam injection. Each line profile shows a strong Zeeman effect in the vicinity of line centre, and a marked central dip when mainly the σ components are observed. The line core evidently originates from cold atoms in the edge plasma, excited in the course of molecular dissociation, while the broad pedestal on which the core rests is radiated by excited atoms produced through charge-exchange recombination of deuterons (protons), transported outwards from the much hotter plasma interior, and by atoms heated directly by collisions with the deuterons (protons). Core temperatures of about 0.5 eV and less are obtained from line profile analysis. 相似文献
15.
16.
H. Kojima Y. Fukuzawa T. Manabe S. Takamura T. Okada N. Ohno 《Czechoslovak Journal of Physics》2003,53(10):895-902
We achieved a potential well more than fifty times deeper than the plasma electron temperature, down to -0.3 kV with the electrode biasing, by the cross-field radial arcing current of up to 150 A which flows between the small electron-emitting electrode (LaB6) inserted to the plasma center and the stainless-steel wall of vacuum chamber. The empirical scaling of the radial resistance of plasma R
r on the radial arcing current I
b and the toroidal magnetic field B
T is found to be R
r I
b
-1.2
B
T
1.0. Structural dynamics of negative potential well formation is observed: the potential dip propagates from the plasma core to the periphery. The ion saturation current also increases, starting from the inner region. The fluctuation frequency in I
sat changes abruptly from 200 kHz to 30 kHz in a time of around 0.25 ms after negative biasing. 相似文献
17.
H. Kachkachi D.A. Garanin 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,22(3):291-300
Analytical calculations based on finite-size spin-wave theory and Monte Carlo (MC) simulations are performed to investigate
the validity of the well-known relation m(H, T) = M(H, T)B
D[M(H, T)
H/T] between the induced magnetization m of the magnetic particle and its intrinsic magnetization M for the Ising and isotropic classical models (B
D(x) is the Langevin function, D is the number of spin components, is the number of atoms in the particle). It follows from general arguments and from our analytical results for the Heisenberg
model at T≪T
c that this relation is not exact for any finite D and nonzero temperature. Nevertheless, corrections to this formula remain very small practically in the whole range T < T
c if ≫ 1, as confirmed by our Monte Carlo calculations. At T
T
c/4 there is a good agreement between the MC and finite-size spin-wave calculations for the field dependence of m and M for the Heisenberg model with free boundary conditions.
Received 1st December 2000 相似文献
18.
S. V. Grigor’ev S. A. Klimko S. V. Maleev A. I. Okorokov V. V. Runov D. Yu. Chernyshov 《Journal of Experimental and Theoretical Physics》1997,85(6):1168-1179
A magnetic phase transition in carbon-doped (0.1 and 0.7 at. %) Fe70Ni30 Invar alloys was investigated by the method of depolarization of a transmitted neutron beam and by small-angle scattering
of polarized neutrons. It is shown that for both alloys, two characteristic length scales of magnetic correlations coexist
above T
c. Small-angle scattering by critical correlations with radius R
c is described well by the Ornstein-Zernike (OZ) expression. The longer-scale (second) correlations, whose size can be estimated
from depolarization data, are not described by the OZ expression, and hypothetically can be modeled by a squared OZ expression,
which in coordinate space corresponds to the relation 〈M(r)M(0)〉∝exp(−r/R
d), where R
d is the correlation length of the second scale. The temperature dependence of the correlation radius R
c was obtained: R
c ∝ ((T−T
c)/Tc)−ν
, where ν≈2/3 is the critical exponent for ferromagnets, over a wide temperature range up to T
c
exp
, at which the correlation radius becomes constant and equals its maximum value R
c(T
c)=R
c
max
. The maximum correlation radius established (R
c
max
=140 Å and 230 Å for the first and second alloys, respectively) characterizes the length-scale of the fluctuation for which
the appearance of critical correlations first results in the formation of a ferromagnetic phase, and the phenomenon itself
exhibits a “disruption” of the second-order phase transition at T=T
c
exp
, as a result of which a first-order transition arises. Temperature hysteresis was also detected in the measured polarization
of the transmitted beam and intensity of small-angle neutron scattering in the alloy above T
c, confirming the character of this magnetic transition as a first-order transition close to a second-order transition.
Zh. éksp. Teor. Fiz. 112, 2134–2155 (December 1997) 相似文献
19.
Expressions for power reflection (R), transmission (T) and absorption (A) coefficients for p-polarized wave for a warm, collisional, magnetized and moving plasma slab (with sharp boundaries and thickness d0) are investigated. The effects of plasma slab velocity (β=v/c), electron density (ωp/ω)2 and plasma temperature (KBT) on reflection (R), transmission (T) and absorption (A) coefficients are discussed numerically. It is observed that for the value β=?0.6, reflection coefficient (R) becomes more than unity, whereas absorption coefficient (A) becomes quite negligible while transmission coefficient (T) shows oscillatory behaviour. The variation with plasma frequency (ωp/ω)2 shows that at lower plasma frequency (ωp/ω)2=0.2 transmission (T) and absorption (A) coefficients are minimum while reflection coefficient (R) is maximum. 相似文献
20.
I. A. Buryakov 《Technical Physics》2004,49(8):967-972
A method for determining the kinetic coefficients of ion transfer in gases, viz., mobility K and longitudinal (D
L) and transverse (D
T) diffusion coefficients, as functions of the electric field E and gas temperature T is described. The method is based on the measurement of the increments to the ion mobility coefficients as functions of the
electric field at a parametrically specified temperature. The kinetic transport coefficients K(E, T) and D
L, T(E, T) are determined for positive ions of aniline, pyridine, benzene, orthotoluidine, dimethyl methyl phosphonate, N-methyl aniline,
N,N-dimethyl aniline, N,N-diethyl aniline, and diphenyl amine (DPA) formed as a result of β-ionization in air. 相似文献