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571.
We review the present theoretical and numerical understanding of magnetic field amplification in cosmic large-scale structure, on length scales of galaxy clusters and beyond. Structure formation drives compression and turbulence, which amplify tiny magnetic seed fields to the microGauss values that are observed in the intracluster medium. This process is intimately connected to the properties of turbulence and the microphysics of the intra-cluster medium. Additional roles are played by merger induced shocks that sweep through the intra-cluster medium and motions induced by sloshing cool cores. The accurate simulation of magnetic field amplification in clusters still poses a serious challenge for simulations of cosmological structure formation. We review the current literature on cosmological simulations that include magnetic fields and outline theoretical as well as numerical challenges. 相似文献
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C. Bertucci F. Duru N. Edberg M. Fraenz C. Martinecz K. Szego O. Vaisberg 《Space Science Reviews》2011,162(1-4):113-171
This article summarizes and aims at comparing the main features of the induced magnetospheres of Mars, Venus and Titan. All three objects form a well-defined induced magnetosphere (IM) and magnetotail as a consequence of the interaction of an external wind of plasma with the ionosphere and the exosphere of these objects. In all three, photoionization seems to be the most important ionization process. In all three, the IM displays a clear outer boundary characterized by an enhancement of magnetic field draping and massloading, along with a change in the plasma composition, a decrease in the plasma temperature, a deflection of the external flow, and, at least for Mars and Titan, an increase of the total density. Also, their magnetotail geometries follow the orientation of the upstream magnetic field and flow velocity under quasi-steady conditions. Exceptions to this are fossil fields observed at Titan and the near Mars regions where crustal fields dominate the magnetic topology. Magnetotails also concentrate the escaping plasma flux from these three objects and similar acceleration mechanisms are thought to be at work. In the case of Mars and Titan, global reconfiguration of the magnetic field topology (reconnection with the crustal sources and exits into Saturn??s magnetosheath, respectively) may lead to important losses of plasma. Finally, an ionospheric boundary related to local photoelectron signals may be, in the absence of other sources of pressure (crustal fields) a signature of the ultimate boundary to the external flow. 相似文献
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W.D. Apel J.C. Arteaga L. Bähren K. Bekk M. Bertaina P.L. Biermann J. Blümer H. Bozdog I.M. Brancus P. Buchholz S. Buitink E. Cantoni A. Chiavassa K. Daumiller V. de Souza F. Di Pierro P. Doll M. Ender R. Engel H. Falcke M. Finger D. Fuhrmann H. Gemmeke C. Grupen A. Haungs D. Heck J.R. Hörandel A. Horneffer D. Huber T. Huege P.G. Isar K.-H. Kampert D. Kang O. Krömer J. Kuijpers K. Link P. Łuczak M. Ludwig H.J. Mathes M. Melissas C. Morello S. Nehls J. Oehlschläger N. Palmieri T. Pierog J. Rautenberg H. Rebel M. Roth C. Rühle A. Saftoiu 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
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S.R. Sanderson J.M. Austin Z. Liang F. Pintgen J.E. Shepherd H.G. Hornung 《Progress in Aerospace Sciences》2010,46(2-3):116-131
We note the common existence of a supersonic jet structure locally embedded within a surrounding transonic flow field in the hitherto unrelated phenomena of unstable gaseous detonation and hypervelocity blunt body shock wave interaction. Extending prior results that demonstrate the consequences of reduced endothermic reaction rate for the supersonic jet fluid in the blunt body case, we provide an explanation for observations of locally reduced OH PLIF signal in images of the keystone reaction zone structure of weakly unstable detonations. Modeling these flow features as exothermically reacting jets with similarly reduced reaction rates, we demonstrate a mechanism for jetting of bulk pockets of unreacted fluid with potentially differing kinetic pathways into the region behind the primary detonation front of strongly unstable mixtures. We examine the impact of mono-atomic and diatomic diluents on transverse structure. The results yield insight into the mechanisms of transition and characteristic features of both weakly and strongly unstable mixtures. 相似文献
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A functional scheme, primary informative signals, a method of electrode system structural parameters synthesis and evaluation of a systematic error of the ion-marking sensor for aerodynamic angle and airspeed measurement are the focus of this paper. 相似文献