High-frequency electron drift instability in the cross-field configuration of Hall thrusters

2006 ◽  
Vol 13 (10) ◽  
pp. 102111 ◽  
Author(s):  
A. Ducrocq ◽  
J. C. Adam ◽  
A. Héron ◽  
G. Laval
Keyword(s):  
High Frequency ◽  
Field Configuration ◽  
Electron Drift ◽  
Hall Thrusters ◽  
The Cross ◽  
Drift Instability

Numerical studies of the ExB electron drift instability in Hall thrusters

2019 ◽  
Vol 28 (6) ◽  
pp. 064002 ◽  
Author(s):  
Francesco Taccogna ◽  
Pierpaolo Minelli ◽  
Zahra Asadi ◽  
Guillaume Bogopolsky
Keyword(s):  
Electron Drift ◽  
Hall Thrusters ◽  
Numerical Studies ◽  
Drift Instability

scholarly journals Sticky islands in stochastic webs and anomalous chaotic cross-field particle transport by E×B electron drift instability

2021 ◽  
Vol 145 ◽  
pp. 110810
Author(s):  
D. Mandal ◽  
Y. Elskens ◽  
X. Leoncini ◽  
N. Lemoine ◽  
F. Doveil
Keyword(s):  
Particle Transport ◽  
Electron Drift ◽  
Drift Instability

scholarly journals A high-frequency non-resonant elliptical vibration-assisted cutting device for diamond turning microstructured surfaces

2021 ◽  
Vol 112 (11-12) ◽  
pp. 3247-3261
Author(s):  
Zhengjian Wang ◽  
Xichun Luo ◽  
Haitao Liu ◽  
Fei Ding ◽  
Wenlong Chang ◽  
...  
Keyword(s):  
Heat Generation ◽  
High Frequency ◽  
Diamond Turning ◽  
Coupling Ratio ◽  
Modal Characteristics ◽  
Elliptical Vibration ◽  
Microstructured Surfaces ◽  
Operational Frequency ◽  
The Cross ◽  
Cross Axis

AbstractIn recent years, research has begun to focus on the development of non-resonant elliptical vibration-assisted cutting (EVC) devices, because this technique offers good flexibility in manufacturing a wide range of periodic microstructures with different wavelengths and heights. However, existing non-resonant EVC devices for diamond turning can only operate at relatively low frequencies, which limits their machining efficiencies and attainable microstructures. This paper concerns the design and performance analysis of a non-resonant EVC device to overcome the challenge of low operational frequency. The structural design of the non-resonant EVC device was proposed, adopting the leaf spring flexure hinge (LSFH) and notch hinge prismatic joint (NHPJ) to mitigate the cross-axis coupling of the reciprocating displacements of the diamond tool and to combine them into an elliptical trajectory. Finite element analysis (FEA) using the mapped meshing method was performed to assist the determination of the key dimensional parameters of the flexure hinges in achieving high operational frequency while considering the cross-axis coupling and modal characteristics. The impact of the thickness of the LSFH on the sequence of the vibrational mode shape for the non-resonant EVC device was also quantitatively revealed in this study. Moreover, a reduction in the thickness of the LSFH can reduce the natural frequency of the non-resonant EVC device, thereby influencing the upper limit of its operational frequency. It was also found that a decrease in the neck thickness of the NHPJ can reduce the coupling ratio. Experimental tests were conducted to systematically evaluate the heat generation, cross-axis coupling, modal characteristics and diamond tool’s elliptical trajectory of a prototype of the designed device. The test results showed that it could operate at a high frequency of up to 5 kHz. The cross-axis coupling ratio and heat generation of the prototype are both at an acceptable level. The machining flexibility and accuracy of the device in generating microstructures of different wavelengths and heights through tuning operational frequency and input voltage have also been demonstrated via manufacturing the micro-dimple arrays and two-tier microstructured surfaces. High-precision microstructures were obtained with 1.26% and 10.67% machining errors in wavelength and height, respectively.

Dispersion relation of high-frequency plasma oscillations in Hall thrusters

2008 ◽  
Vol 15 (3) ◽  
pp. 034502 ◽  
Author(s):  
A. Lazurenko ◽  
G. Coduti ◽  
S. Mazouffre ◽  
G. Bonhomme
Keyword(s):  
Dispersion Relation ◽  
High Frequency ◽  
Hall Thrusters ◽  
Plasma Oscillations ◽  
High Frequency Plasma ◽  
Frequency Plasma

Secondary instability of cross-flow vortices in Falkner–Skan–Cooke boundary layers

1998 ◽  
Vol 368 ◽  
pp. 339-357 ◽  
Author(s):  
MARKUS HÖGBERG ◽  
DAN HENNINGSON
Keyword(s):  
Growth Rate ◽  
Shear Layer ◽  
Boundary Layers ◽  
Growth Rates ◽  
High Frequency ◽  
Cross Flow ◽  
Low Frequency ◽  
Secondary Instability ◽  
The Cross ◽  
Flow Vortex

Linear eigenvalue calculations and spatial direct numerical simulations (DNS) of disturbance growth in Falkner–Skan–Cooke (FSC) boundary layers have been performed. The growth rates of the small-amplitude disturbances obtained from the DNS calculations show differences compared to linear local theory, i.e. non-parallel effects are present. With higher amplitude initial disturbances in the DNS calculations, saturated cross-flow vortices are obtained. In these vortices strong shear layers appear. When a small random disturbance is added to a saturated cross-flow vortex, a low-frequency mode is found located at the bottom shear layer of the cross-flow vortex and a high-frequency secondary instability is found at the upper shear layer of the cross-flow vortex. The growth rates of the secondary instabilities are found from detailed analysis of simulations of single-frequency disturbances. The low-frequency disturbance is amplified throughout the domain, but with a lower growth rate than the high-frequency disturbance, which is amplified only once the cross-flow vortices have started to saturate. The high-frequency disturbance has a growth rate that is considerably higher than the growth rates for the primary instabilities, and it is conjectured that the onset of the high-frequency instability is well correlated with the start of transition.

Multiscale Multifractal Detrended Cross-Correlation Analysis of High-Frequency Financial Time Series

2019 ◽  
Vol 18 (03) ◽  
pp. 1950014 ◽  
Author(s):  
Jingjing Huang ◽  
Danlei Gu
Keyword(s):  
Time Series ◽  
Correlation Analysis ◽  
High Frequency ◽  
Cross Correlation ◽  
Financial Time Series ◽  
Chinese Market ◽  
Change Of Scale ◽  
Cross Correlation Analysis ◽  
Cross Correlations ◽  
The Cross

In order to obtain richer information on the cross-correlation properties between two time series, we introduce a method called multiscale multifractal detrended cross-correlation analysis (MM-DCCA). This method is based on the Hurst surface and can be used to study the non-linear relationship between two time series. By sweeping through all the scale ranges of the multifractal structure of the complex system, it can present more information than the multifractal detrended cross-correlation analysis (MF-DCCA). In this paper, we use the MM-DCCA method to study the cross-correlations between two sets of artificial data and two sets of 5[Formula: see text]min high-frequency stock data from home and abroad. They are SZSE and SSEC in the Chinese market, and DJI and NASDAQ in the US market. We use Hurst surface and Hurst exponential distribution histogram to analyze the research objects and find that SSEC, SZSE and DJI, NASDAQ all show multifractal properties and long-range cross-correlations. We find that the fluctuation of the Hurst surface is related to the positive and negative of [Formula: see text], the change of scale range, the difference of national system, and the length of time series. The results show that the MM-DCCA method can give more abundant information and more detailed dynamic processes.

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