scholarly journals Rotating and propagating LIB stabilized by self-induced magnetic field

1984 ◽  
Vol 2 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Hiroyuki Murakami ◽  
Takayuki Aoki ◽  
Shigeo Kawata ◽  
Keishiro Niu

Rotating motion of a propagating LIB is analyzed in order to suppress the mixed mode of the Kelvin-Helmholtz instability, the tearing instability and the sausage instability by the action of a self-induced magnetic field in the axial direction. The beams are assumed to be charge-neutralized but not current-neutralized. The steady-state solutions of a propagating LIB with rotation are first obtained numerically. Through the dispersion relation with respect to the ikonal type of perturbations, which are added to the steady-state solutions, the growth rates of instabilities appearing in an LIB are obtained. It is concluded that if the mean rotating velocity of an LIB is comparable to the propagation velocity, in other words, if the induced magnetic field intensity in the axial direction is comparable to the magnetic field intensity in the azimuthal direction, the instability disappears in the propagating ion beam.


2010 ◽  
Vol 20 (3) ◽  
pp. 744-747 ◽  
Author(s):  
Yoshinori Yanagisawa ◽  
Hideki Nakagome ◽  
Davide Uglietti ◽  
Tsukasa Kiyoshi ◽  
Ruixin Hu ◽  
...  


2011 ◽  
Vol 314-316 ◽  
pp. 1079-1082 ◽  
Author(s):  
Feng Yun Yu

Tensile tests were carried out on demagnetization 16Mn and Q235 steel samples at loading state, and the magnetic memory characteristics were analyzed. Experimental results show the mean magnetic field intensity (MMFI) of a measuring point is more effective than that of other measuring points at the same stage to study tensile magnetic memory characteristics of demagnetization 16Mn and Q235 steel samples. At the elastic deformation stage, the MMFI of the measuring points at one fracture side increases while it decreases on the other fracture side. The MMFI decreases with the distance from the fracture location, and the change rate of the MMFI is almost equal. The variation law shows changes of opposite direction. At the strengthening phase, the relation between MMFI and tensile displacement is similar with that of the plastic deformation stage, but the variation amplitude was accelerated obviously. Comparison of 16Mn and Q235 steel shows that the standard deviation variation of the magnetic field intensity with the tensile displacement increases as the tensile strength of materials increases. For the demagnetization bearing components, weak areas can be estimated according to breaking laws, so more monitoring points can be set. Pre-breaks could be found through the appearance of inflection point of the MMFI of monitoring point. The inflection point of the mean curve is the breakpoint.



2016 ◽  
Vol 21 (2) ◽  
pp. 273-283 ◽  
Author(s):  
A. Bhandari ◽  
V. Kumar

AbstractThe flow of a ferrofluid due to a rotating disk in the presence of a non-uniform magnetic field in the axial direction is studied through mathematical modeling of the problem. Contour and surface plots in the presence of10kilo-ampere/meter,100kilo-ampere/meter magnetization force are presented here for radial, tangential and axial velocity profiles, and results are also drawn for the magnetic field intensity. These results are compared with the ordinary case where magnetization force is absent.



Author(s):  
Xue Guangming ◽  
Zhang Peilin ◽  
He Zhongbo ◽  
Li Xin ◽  
Zeng Wei ◽  
...  

A theoretical magnetic field intensity model within giant magnetostrictive material was presented. This model was established just like the reluctance model, while could describe the non-uniform distribution flexibly for its integral form. This model employed magnetic circuit theorem calculating the mean of the magnetic field, while used a normalized function describing the distributing character. The distributing function was determined by Biot–Savart law and relative permeability of the material. The model was validated with the help of the experimental device. At last, the fitting degree of the model with the tested results in predicting the performance of the actuator is researched.



2008 ◽  
Vol 8 (3) ◽  
pp. 501-507 ◽  
Author(s):  
G. Prattes ◽  
K. Schwingenschuh ◽  
H. U. Eichelberger ◽  
W. Magnes ◽  
M. Boudjada ◽  
...  

Abstract. We present the results of ground-based Ultra Low Frequency (ULF) magnetic field measurements observed from June to August 2004 during the Bovec earthquake on 12 July 2004. Further we give information about the seismic activity in the local observatory region for an extended time span 2004 and 2005. ULF magnetic field data are provided by the South European Geomagnetic Array (SEGMA) where the experience and heritage from the CHInese MAGnetometer (CHIMAG) fluxgate magnetometer comes to application. The intensities of the horizontal H and vertical Z magnetic field and the polarization ratio R of the vertical and horizontal magnetic field intensity are analyzed taking into consideration three SEGMA observatories located at different close distances and directions from the earthquake epicenter. We observed a significant increase of high polarization ratios during strong seismic activity at the observatory nearest to the Bovec earthquake epicenter. Apart from indirect ionospheric effects electromagnetic noise could be emitted in the lithosphere due to tectonic effects in the earthquake focus region causing anomalies of the vertical magnetic field intensity. Assuming that the measured vertical magnetic field intensities are of lithospheric origin, we roughly estimate the amplitude of electromagnetic noise in the Earths crust considering an average electrical conductivity of <σ>=10−3 S/m and a certain distance of the observatory to the earthquake epicenter.



Author(s):  
Pushap Lata Sharma ◽  
Sumit Gupta

This paper deals with the convection of micropolar fluids heated and soluted from below in the presence of suspended particles (fine dust) and uniform vertical rotation and uniform vertical magnetic field in a porous medium. Using the Boussinesq approximation, the linearized stability theory and normal mode analysis, the exact solutions are obtained for the case of two free boundaries. It is found that the presence of the suspended particles number density, the rotation parameter, stable solute, magnetic field intensity and medium permeability bring oscillatory modes which were non–existent in their absence. It is found that the presence of coupling between thermal and micropolar effects, rotation parameter, solute parameter and suspended particles may introduce overstability in the system. Graphs have been plotted by giving numerical values to the parameters accounting for rotation parameter , magnetic field solute parameter, the dynamic microrotation viscosity and coefficient of angular viscosity to depict the stability characteristics, for both the cases of stationary convection and overstability. It is found that Rayleigh number for the case of overstability and stationary convection increases with increase in rotation parameter, as well as with magnetic field intensity, solute parameter and decreases with increase in micropolar coefficients and medium permeability, for a fixed wave number, implying thereby the stabilizing effect of rotation parameter, magnetic field intensity ,solute parameter and destabilizing effect of micropolar coefficients and medium permeability on the thermosolutal convection of micropolar fluids.



2019 ◽  
Vol 7 (13) ◽  
pp. 3740-3743 ◽  
Author(s):  
Ying Li ◽  
Yue Long ◽  
Guoqiang Yang ◽  
Chen-Ho Tung ◽  
Kai Song

The wavelength of amplified spontaneous emission based on liquid magnetically responsive photonic crystals can be tuned by simply changing the magnetic field intensity.



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