Low-frequency oscillation in magnetized plasmas with radial electron density and temperature gradients in opposite directions

1994 ◽  
Vol 36 (1) ◽  
pp. 131-142 ◽  
Author(s):  
M Beckmann ◽  
P Frank ◽  
G Himmel
Keyword(s):  
Electron Density ◽  
Low Frequency ◽  
Temperature Gradients ◽  
Magnetized Plasmas ◽  
Frequency Oscillation ◽  
Low Frequency Oscillation ◽  
Electron Density And Temperature

Analytical description of low-frequency electron density and temperature oscillations

1996 ◽  
Vol 55 (1) ◽  
pp. 25-34 ◽  
Author(s):  
P. Frank ◽  
M. Beckmann ◽  
G. Himmel
Keyword(s):  
Electron Density ◽  
Fluid Model ◽  
Low Frequency ◽  
Analytical Description ◽  
Frequency Instability ◽  
Temperature Gradients ◽  
Temperature Oscillations ◽  
Electron Density And Temperature ◽  
Two Fluid Model ◽  
The Magnetic Field

Low-frequency density and temperature oscillations (ω « νj, ωcj, where νj is the collision frequency with neutrals and ωcj is the cyclotron frequency; j = i, e) observed in magnetized radiofrequency-produced plasmas with electron density and temperature gradients across the magnetic field are analysed using a local two-fluid model. This model incorporates the electron energy equation. The resulting dispersion relation permits study of the parameter dependence of the complex angular wave frequency. Instability is found in the case where the election density and temperature gradients have opposite signs. This instability is classified as a low-frequency drift wave, and the criteria for its onset are obtained.

Low-frequency-oscillation characteristics of ionization distribution in Hall thruster channels

Vacuum ◽  
2021 ◽  
pp. 110320
Author(s):  
Tianyuan Ji ◽  
Liqiu Wei ◽  
Haifeng Lu ◽  
Shangmin Wang ◽  
Ning Guo ◽  
...  
Keyword(s):  
Low Frequency ◽  
Hall Thruster ◽  
Frequency Oscillation ◽  
Low Frequency Oscillation ◽  
Oscillation Characteristics

A Parametric Study of Low-Frequency Damping of Mooring System

2014 ◽  
Author(s):  
Minglu Chen ◽  
Shan Huang ◽  
Nigel Baltrop ◽  
Ji Chunyan ◽  
Liangbi Li
Keyword(s):  
Low Frequency ◽  
Structure Design ◽  
The Body ◽  
Body Motion ◽  
Mooring Line ◽  
Offshore Structure ◽  
Frequency Oscillation ◽  
Low Frequency Oscillation ◽  
Line System ◽  
Irregular Wave

Mooring line damping plays an important role to the body motion of moored floating platforms. Meanwhile, it can also make contributions to optimize the mooring line system. Accurate assessment of mooring line damping is thus an essential issue for offshore structure design. However, it is difficult to determine the mooring line damping based on theoretical methods. This study considers the parameters which have impact on mooring-induced damping. In the paper, applying Morison formula to calculate the drag and initial force on the mooring line, its dynamic response is computed in the time domain. The energy dissipation of the mooring line due to the viscosity was used to calculate mooring-induced damping. A mooring line is performed with low-frequency oscillation only, the low-frequency oscillation superimposed with regular and irregular wave-frequency motions. In addition, the influences of current velocity, mooring line pretension and different water depths are taken into account.

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