Parametric study of dissipative drift modes and their dynamic stabilization in a weakly ionized plasma

1979 ◽  
Vol 57 (5) ◽  
pp. 739-744 ◽  
Author(s):  
C. Boucher ◽  
S. Q. Mah ◽  
H. W. H. Van Andel ◽  
J. Teichmann

A detailed experimental study is made of dissipative drift modes in a weakly ionized plasma. The appearance of various modes as the plasma parameters are changed is compared with theory. A detailed study of the m = 3 mode in cylindrical geometry shows good agreement between experiment and a locally applied theoretical model. A method of dynamic stabilization using oscillating azimuthal magnetic field is studied and theory and experiment are compared for the m = 3 mode.

1979 ◽  
Vol 57 (11) ◽  
pp. 1890-1895
Author(s):  
S. Q. Mah ◽  
H. W. H. Van Andel

The mechanism of anomalous plasma transport associated with dissipative drift instabilities in a weakly ionized plasma is investigated experimentally. Detailed measurements of the phase difference between electron density and potential fluctuations are presented. The results show good agreement between predicted anomalous losses associated with this phase difference and measured reductions in the plasma density. It is shown experimentally that dynamic stabilization using an oscillating azimuthal magnetic field effectively reduces the plasma losses due to the fluctuations.


2018 ◽  
Vol 145 ◽  
pp. 03003
Author(s):  
Polya Dobreva ◽  
Monio Kartalev ◽  
Olga Nitcheva ◽  
Natalia Borodkova ◽  
Georgy Zastenker

We investigate the behaviour of the plasma parameters in the magnetosheath in a case when Interball-1 satellite stayed in the magnetosheath, crossing the tail magnetopause. In our analysis we apply the numerical magnetosheath-magnetosphere model as a theoretical tool. The bow shock and the magnetopause are self-consistently determined in the process of the solution. The flow in the magnetosheath is governed by the Euler equations of compressible ideal gas. The magnetic field in the magnetosphere is calculated by a variant of the Tsyganenko model, modified to account for an asymmetric magnetopause. Also, the magnetopause currents in Tsyganenko model are replaced by numericaly calulated ones. Measurements from WIND spacecraft are used as a solar wind monitor. The results demonstrate a good agreement between the model-calculated and measured values of the parameters under investigation.


1979 ◽  
Vol 46 (1) ◽  
pp. 151-155 ◽  
Author(s):  
F. C. Moon

Experimental evidence and a theoretical model are presented for the magnetoelastic buckling of a rigid superconducting ring in a steady circumferential (toroidal)magnetic field. The theoretical model predicts a coupled translation and pitch displacement of the coil in the buckled mode. A discussion is given of both the linear and nonlinear magnetic perturbation forces. The experiments were conducted in liquid helium (4.2°K). The lowest natural frequency of the rigid coil on elastic springs was observed to decrease near the buckling current. Agreement between theory and experiment is fair. These results may have design implications for poloidal field coils in magnetic fusion Tokamak reactors.


1989 ◽  
Vol 111 (3) ◽  
pp. 670-674 ◽  
Author(s):  
J. Seyed-Yagoobi ◽  
J. C. Chato ◽  
J. M. Crowley ◽  
P. T. Krein

An induction electrohydrodynamic (EHD) pump in axisymmetric, vertical configuration was designed and built. The flow rates were measured for various temperature profiles and several values of frequency, voltage, wavelength, and electric conductivity. The experimental data are generally in good agreement with the theoretical model presented in Part 1. With the present apparatus at relatively low voltages, velocities four times higher than natural circulation velocity are easily obtained. The external pressure load and entrance temperature profile play important roles on the operation of the pump and must be considered carefully in the design.


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