scholarly journals Modelling of parallel dynamics of a pellet-produced plasmoid

2021 ◽  
Vol 87 (4) ◽  
Author(s):  
A. Runov ◽  
P. Aleynikov ◽  
A.M. Arnold ◽  
B.N. Breizman ◽  
P. Helander

The parallel expansion of a dense, pellet-produced plasmoid is modelled with parameters relevant to pellet fuelling experiments in the Wendelstein7-X stellarator. Good agreement is found between the analytical theory and more detailed modelling. In particular, much of the energy deposited in the pellet by the ambient plasma is transferred to the pellet ions by the ambipolar electric field during the expansion. The validity of the hydrodynamic treatment of the plasmoid and the ambient plasma is discussed.

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1622
Author(s):  
Wipawee Tepnatim ◽  
Witchuda Daud ◽  
Pitiya Kamonpatana

The microwave oven has become a standard appliance to reheat or cook meals in households and convenience stores. However, the main problem of microwave heating is the non-uniform temperature distribution, which may affect food quality and health safety. A three-dimensional mathematical model was developed to simulate the temperature distribution of four ready-to-eat sausages in a plastic package in a stationary versus a rotating microwave oven, and the model was validated experimentally. COMSOL software was applied to predict sausage temperatures at different orientations for the stationary microwave model, whereas COMSOL and COMSOL in combination with MATLAB software were used for a rotating microwave model. A sausage orientation at 135° with the waveguide was similar to that using the rotating microwave model regarding uniform thermal and electric field distributions. Both rotating models provided good agreement between the predicted and actual values and had greater precision than the stationary model. In addition, the computational time using COMSOL in combination with MATLAB was reduced by 60% compared to COMSOL alone. Consequently, the models could assist food producers and associations in designing packaging materials to prevent leakage of the packaging compound, developing new products and applications to improve product heating uniformity, and reducing the cost and time of the research and development stage.


2021 ◽  
Author(s):  
Konrad Steinvall ◽  
Yuri Khotyaintsev ◽  
Giulia Cozzani ◽  
Andris Vaivads ◽  
Christopher Owen ◽  
...  

<p>Solar wind current sheets have been extensively studied at 1 AU. The recent advent of Parker Solar Probe and Solar Orbiter (SolO) has enabled us to study these structures at a range of heliocentric distances.</p><p>We present SolO observations of current sheets in the solar wind at heliocentric distances between 0.55 and 0.85 AU, some of which show signatures of ongoing magnetic reconnection. We develop a method to find the deHoffman-Teller frame which minimizes the Y-component (the component tangential to the spacecraft orbit) of the electric field. Using the electric field measurements from RPW and magnetic field measurements from MAG, we use our method to determine the deHoffman-Teller frame of solar wind current sheets. The same method can also be used on the Alfvénic turbulence and structures found in the solar wind to obtain a measure of the solar wind velocity.</p><p>Our preliminary results show a good agreement between our modified deHoffmann-Teller analysis based on the single component E-field, and the conventional deHoffman-Teller analysis based on 3D plasma velocity measurements from PAS. This opens up the possibility to use the RPW and MAG data to obtain an estimate of the solar wind velocity when particle data is unavailable.</p>


1996 ◽  
Vol 10 (29) ◽  
pp. 1471-1476
Author(s):  
MIRCEA ANDRECUT

The temperature dependence of the second-order crystalline electric field (CEF) parameters of rare earth intermetallic compound CeZn 2 was deduced from the least-squares nonlinear fit to the reciprocal paramagnetic susceptibility along principal crystalline axes. The results of the calculation are in good agreement with the experimental values.


1992 ◽  
Vol 47 (1-2) ◽  
pp. 45-48
Author(s):  
M. J. Ponnambalam

AbstractThe electric field gradients (EFG) in aluminium due to a monovacancy and the interstitial muon are evaluated. The valence effect EFG qv is calculated using perturbed electron density δn(r)values obtained from density functional theory in an analytic expression which is valid at all distances from the impurity. The size effect EFG qs is evaluated using a new oscillatory form for the near neighbour (nn) displacements. The numerical values of qs are computed using fractional nn displacements available in the literature. For the total EFG good agreement with experiment is obtained without the use of any parameter.


2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
A. Paffi ◽  
F. Apollonio ◽  
R. Pinto ◽  
M. Liberti

Previous studies identified the train compartment as the place where people can experience the highest exposure levels (still below the international guideline limits) to electromagnetic fields in the radiofrequency range. Here a possible scenario of a train compartment has been reproduced and characterized, both numerically and experimentally. A good agreement between the simulated electric field distributions and measurements has been found. Results indicate that the higher values of exposure in specific positions inside the train compartment depend on the number of active cell phones, the bad coverage condition, the cell orientation, and the presence of metallic walls. This study shows that the proposed approach, based on the scenarios characterization, may efficiently support the assessment of the individual electromagnetic exposure.


1996 ◽  
Vol 421 ◽  
Author(s):  
J. S. Hwang ◽  
W. Y. Chou ◽  
S. L. Tyan ◽  
Y. C. Wang ◽  
H. Shen

AbstractThe built-in electric fields in a MBE grown δ-doped GaAs homojunction have been investigated by the techniques of photoreflectance and phase suppression. Two Franz-Keldysh oscillation features originating from two different fields in the structure superimpose with each other in the photoreflectance spectrum. By properly selecting the reference phase of the lock-in amplifier, one of the features can be suppressed, thus enabling us to determine the electric fields from two different regions. We have demonstrated that only two PR spectra, in-phase and outphase components, are needed to find the phase angle which suppresses one of the features. The electric field in the top layer is 3.5 ± 0.2 × 105 V/cm, which is in good agreement with theoretical calculation. The electric field in the buffer layer is 1.2 ± 0.1 × 104 V/cm, which suggests the existence of interface states at the buffer/substrate interface.


1987 ◽  
Vol 42 (4) ◽  
pp. 395-405 ◽  
Author(s):  
N. Detzer ◽  
W. Baumann ◽  
B. Schwager ◽  
J.-C. Fröhling ◽  
C. Brittinger

The synthesis of several compounds related to ADMA are described in detail. These compounds are characterized by their mass, NMR, and IR-spectra. In addition, the solvent dependent shift of the fluorescence as well as the effect of an electric field on the fluorescence have been measured. The results are in agreement with a two-state model assuming the simultaneous fluorescence from a weakly polar and a highly polar state with dipole moment μ. μ2/a3 (a is Onsager’s radius) has been determined from both effects. The results are in good agreement with an excited state dipole moment of about 60 • 10-30Cm, in the polar state.


1995 ◽  
Vol 05 (03) ◽  
pp. 797-807 ◽  
Author(s):  
J. MOSQUERA ◽  
M. GÓMEZ-GESTEIRA ◽  
V. PÉREZ-MUÑUZURI ◽  
A.P. MUÑUZURI ◽  
V. PÉREZ-VILLAR

The electric field influence on pattern formation and traveling wave propagation is investigated in the framework of the Oregonator model. When an electric field is applied to a system that can suffer spatial instabilities, Turing and Turing-like patterns (traveling fronts that become stationary patterns when reaching a zero-flux boundary) are observed. On the other hand, when an electric field is applied to a system that cannot become unstable by spatial terms and where wavefronts are propagating in the absence of electric fields, the velocity of these wavefronts is modified and can even be reversed. This is in good agreement with previous experimental results.


2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Luis Zamora-Peredo ◽  
Leandro García-González ◽  
Julián Hernández-Torres ◽  
Irving E. Cortes-Mestizo ◽  
Víctor H. Méndez-García ◽  
...  

Photoreflectance (PR) and Raman are two very useful spectroscopy techniques that usually are used to know the surface electronic states in GaAs-based semiconductor devices. However, although they are exceptional tools there are few reports where both techniques were used in these kinds of devices. In this work, the surface electronic states on AlGaAs/GaAs heterostructures were studied in order to identify the effect of factors like laser penetration depth, cap layer thickness, and surface passivation over PR and Raman spectra. PR measurements were performed alternately with two lasers (532 nm and 375 nm wavelength) as the modulation sources in order to identify internal and surface features. The surface electric field calculated by PR analysis decreased whereas the GaAs cap layer thickness increased, in good agreement with a similar behavior observed in Raman measurements (IL-/ILOratio). When the heterostructures were treated by Si-flux, these techniques showed contrary behaviors. PR analysis revealed a diminution in the surface electric field due to a passivation process whereas theIL-/ILOratio did not present the same behavior because it was dominated by the depletion layers width (cap layer thickness) and the laser penetration depth.


2020 ◽  
Vol 31 (3) ◽  
pp. 126
Author(s):  
Fatima Mohammad Hadi ◽  
Rafid Abbas Ali ◽  
Ahamed A. Al-Rubaiee

In this work, theoretical calculations and simulated data were presented to investigate the effect of the Ar: Hg mixture on electronic plasma coefficients, in addition to study the influence of the electric field and focus on electronic coefficients. The low electric field was chosen in the range (1-1000) Td, and concentrations in a limited range (0.01-0.09) mol. The results showed a clear effect of the electric field on electronic transactions, especially at low levels. These parameters values are higher for high concentrations due to the effect of the electric field on the excitation and ionization energy. In compare to elastic and inelastic collision, and cross-section collision of gas discharges. The results showed good agreement between the original data (using BOLSIG +) and the estimated data in the current work.


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