The origin of jets emitted from black holes is not well understood, however there are two possible energy sources, the accretion disk or the rotating black hole. Magnetohydrodynamic simulations show a well-defined jet that extracts energy from a black hole. If plasma near the black hole is threaded by large-scale magnetic flux, it will rotate with respect to asymptotic infinity creating large magnetic stresses.These stresses are released as a relativistic jet at the expense of black hole rotational energy. The physics of the jet initiation in the simulations is described by the theory of black hole gravitohydromagnetics.Most quasars radiate a small fraction of their emission in the radio band (radio quiet), yet about 10% launch powerful radio jets (a highly collimated beam of energy and particles) with kinetic luminosities rivalling or sometimes exceeding the luminosity of the quasar host (radio loud).1 There is currently no clear theoretical understanding of the physics that occasionally switches on these powerful beams of energy in quasars.Powerful extragalactic radio sources tend to be associated with large elliptical galaxy host that harbour supermassive black holes (~10 9 M0). 2 The synchrotron emitting jets are clearly highly magnetized and appe ar to emanate from the environs of the central black hole, within the resolution limits of very long baseline interferometry (VLBI).Observations (see the supplementary file) indicate that jets emitted from supermassive black hole magnetospheres are likely required for any theory to be in accord with the data. 2,3,4 Previous perfect magnetohydrodynamic (MHD hereafter) simulations of entire black hole magnetospheres have shown some suggestive results. For example, the 2 simulations of [5] were the first to s how energy extraction from the black hole, but there was no outflow of plasma. Numerical models of an entire magnetosphere involve a complex set of equations that reflect the interaction of the background space-time with the plasma. In many instances, the only way to get any time evolution of the magnetosphere is to assume unphysical initial conditions. 5,6,9,10 Even so, previous simulations have not shown a black hole radiating away its potential energy into a pair of bipolar jets. 5,6,7,8,9,10 Most importantly, in previous efforts the underlying physics is masked by the complexity of the simulation. Thus, this numerical work has done little to clarify the fundamental physics that couples the jet to the black hole.We exploit the simplification that the full set of MHD equations in curved spacetime indicate that a magnetized plasma can be regarded as a fluid composed of nonlinear strings in which the strings are mathematically equivalent to thin magnetic flux tubes. 11,12 In this treatment, a flux tube is thin by definition if the pressure variations across the flux tube is negligible compared to the total external pressure (gas plus magnetic), P, that represents the effects of the enveloping magnetized plasma (the magnetosphere). By concentrating ...
[1] We study the Venus-solar wind interaction and the hemispheric asymmetries of the Venus plasma environment in the global HYB-Venus hybrid simulation. We concentrate especially on the role of the flow-aligned interplanetary magnetic field (IMF) component (i.e., the Parker spiral angle or the IMF cone angle) and analyze the dawn-dusk and E sw asymmetries between four magnetic quadrants around Venus. Using the simulation model, we study two upstream condition cases in detail: the perpendicular IMF to the solar wind flow case and the nominal Parker spiral case (dominant flow-aligned IMF component). Several differences and similarities were found in these two simulation runs. Common features of the Venus plasma environment between the two cases include asymmetric magnetic barrier and tail lobes and asymmetric planetary ion escape in the direction of the solar wind convection electric field. Further, protons of planetary origin and of solar wind origin were found to follow similar velocity patterns in the Venus plasma wake in both cases. The differences when the IMF flow-aligned component is dominating compared to the perpendicular IMF case, the so-called (magnetic) dawn-dusk asymmetries, include the parallel bow shock and the foreshock region, the asymmetric magnetic barrier, the asymmetric tail current system, and the asymmetric central tail current sheet. Further, the escaping planetary H + and O + ion fluxes are concentrated more on the hemisphere of the parallel bow shock. When interpreting in situ plasma and magnetic observations from Venus, the features of at least these two basic IMF configurations should be considered.
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