scholarly journals Realistic MHD numerical simulations of solar convection and oscillations in inclined magnetic field regions

2009 ◽  
Vol 5 (H15) ◽  
pp. 348-348
Author(s):  
Irina N. Kitiashvili ◽  
Alexander G. Kosovichev ◽  
Alan A. Wray ◽  
Nagi N. Mansour
Keyword(s):  
Magnetic Field ◽  
Numerical Simulations ◽  
High Speed ◽  
Turbulent Convection ◽  
Inclined Magnetic Field ◽  
Filamentary Structure ◽  
Solar Convection ◽  
Wave Properties ◽  
Sunspot Penumbra ◽  
High Speed Flows

It is known that physical properties of solar turbulent convection and oscillations strongly depend on magnetic field. In particular, recent observations from SOHO/MDI revealed significant changes of the wave properties in inclined magnetic field regions of sunspots, which affect helioseismic inferences. We use realistic 3D radiative MHD numerical simulations to investigate solar convection and oscillations and their relationship in the presence of inclined magnetic field. In the case of highly inclined and strong 1-1.5 kG field the solar convection develops filamentary structure and high-speed flows (Fig. 1a), which provide an explanation to the Evershed effect in sunspot penumbra (Kitiashvili, et al. 2009).

Numerical simulations of high-speed flows in an axisymmetric ramjet

1988 ◽  
Author(s):  
K. KAILASANATH ◽  
J. GARDNER ◽  
E. ORAN ◽  
J. BORIS
Keyword(s):  
Numerical Simulations ◽  
High Speed ◽  
High Speed Flows

THE INFLUENCE OF SELECTED PARAMETERS ON MAGNETIC FLUID SEAL TIGHTNESS AND MOTION RESISTANCE

Tribologia ◽  
2017 ◽  
pp. 71-76 ◽  
Author(s):  
Marcin SZCZĘCH ◽  
Wojciech HORAK ◽  
Józef SALWIŃSKI
Keyword(s):  
Magnetic Field ◽  
Numerical Simulations ◽  
Field Distribution ◽  
Magnetic Fluid ◽  
High Speed ◽  
Critical Pressure ◽  
Motion Resistance ◽  
Seal Tightness ◽  
Vacuum Systems ◽  
The Magnetic Field

Magnetic fluid seals belong to the class of non-contact seals. They are used as protective seals for vacuum systems, high speed shafts, precision mechanics, and electromechanical devices. The proper functioning of the magnetic fluid seal is related to creating and maintaining the continuity of the fluid ring on the sealing stage. This is achieved by appropriately shaped magnetic field distribution in the region of the sealing stage. Consequently, one of the main issues with the construction of such seals is to determine the distribution of the magnetic field in this region. This paper presents the results of analytical calculations and numerical simulations, based on which the influence of selected geometric parameters on the critical pressure and motion resistance was determined.

scholarly journals 21. On the magnetic fields in interstellar space and in nebulae

1958 ◽  
Vol 6 ◽  
pp. 182-192
Author(s):  
G. A. Shajn
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
High Speed ◽  
Interstellar Space ◽  
Galactic Rotation ◽  
High Electrical Conductivity ◽  
Considerable Decrease ◽  
Electrically Conductive ◽  
Filamentary Structure ◽  
The Magnetic Field

Some aspects of the problem of magnetic fields in the interstellar space and in the nebulae are discussed in this paper. Our observational basis are the numerous photographs of the nebulae in Hα and other rays, taken with high-speed 450 and 640 mm cameras.The greatly elongated shape of many emission nebulae is interpreted as a result of three factors, the effect of the magnetic field, the macroscopic motions in these nebulae (including the tendency to expand) and the high electrical conductivity of matter. The expansion of nebulae is to be generally accompanied by the considerable decrease in brightness (roughly about d–5), but if the expansion is only in one direction, owing to the presence of a regular magnetic field, the brightness decreases much more slowly (roughly about d–2) and the nebulae remain visible for a longer time. The filamentary structure, which is very often inherent to the elongated nebulae, is, probably, an additional factor of a longer visibility of the nebulae under consideration. The great lengthening of nebulae may be reached in the period of the order of 106 years.In the dark nebulae the matter seems to be electrically conductive and the macroscopic motions of the order of 1–2 km/sec are present there, so that there are reasons to suggest that the magnetic field is also responsible for the elongated shape of many dark nebulae. One may prove that the observed elongated shape of dark and emission nebulae could not be caused by differential galactic rotation.

Effect of Magnetic Field on the Structure of High-Speed Flows

1998 ◽  
Vol 35 (5) ◽  
pp. 639-646 ◽  
Author(s):  
Justin Augustinus ◽  
Klaus A. Hoffmann ◽  
Shigeki Harada
Keyword(s):  
Magnetic Field ◽  
High Speed ◽  
High Speed Flows

Computational aspects of high-speed flows with applied magnetic field

2006 ◽  
Vol 42 (3) ◽  
pp. 389-397 ◽  
Author(s):  
O.U. Khan ◽  
K.A. Hoffmann ◽  
J.-F. Dietiker
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
High Speed ◽  
Computational Aspects ◽  
High Speed Flows

scholarly journals Supermagnetosonic subsolar magnetosheath jets and their effects: from the solar wind to the ionospheric convection

2012 ◽  
Vol 30 (1) ◽  
pp. 33-48 ◽  
Author(s):  
H. Hietala ◽  
N. Partamies ◽  
T. V. Laitinen ◽  
L. B. N. Clausen ◽  
G. Facskó ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Interplanetary Magnetic Field ◽  
High Speed ◽  
Dynamic Pressure ◽  
Bow Shock ◽  
Ionospheric Convection ◽  
Scale Size ◽  
High Dynamic ◽  
High Speed Flows

Abstract. It has recently been proposed that ripples inherent to the bow shock during radial interplanetary magnetic field (IMF) may produce local high speed flows in the magnetosheath. These jets can have a dynamic pressure much larger than the dynamic pressure of the solar wind. On 17 March 2007, several jets of this type were observed by the Cluster spacecraft. We study in detail these jets and their effects on the magnetopause, the magnetosphere, and the ionospheric convection. We find that (1) the jets could have a scale size of up to a few RE but less than ~6 RE transverse to the XGSE axis; (2) the jets caused significant local magnetopause perturbations due to their high dynamic pressure; (3) during the period when the jets were observed, irregular pulsations at the geostationary orbit and localised flow enhancements in the ionosphere were detected. We suggest that these inner magnetospheric phenomena were caused by the magnetosheath jets.

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