1,472 research outputs found

    Can prominences form in current sheets

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    Two-dimensional numerical simulations of the formation of cold condensations in a vertical current sheet have been performed using the radiative, resistive MHD equations with line-tied boundary conditions at one end of the sheet. Prominence-like condensations are observed to appear above and below an X-line produced by the onset of the tearing-mode instability. Cooling in the sheet is initiated by Ohmic decay, with the densest condensations occurring in the region downstream of a fast-mode shock. This shock, which is due to the line-tied boundary conditions, terminates one of the two supermagnetosonic reconnection jets that develop when the tearing is fully developed. The condensation properties of shock waves, which may trigger or considerably enhance the conditions for thermal condensation are emphasized

    On the thermal durability of solar prominences, or how to evaporate a prominence

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    The thermal disappearance of solar prominences under strong perturbations due to wave heating, Ohmic heating, viscous heating or conduction was investigated. Specifically, how large a thermal perturbation is needed to destroy a stable thermal equilibrium was calculated. It was found that the prominence plasma appears to be thermally very rugged. Its cold equilibrium may most likely be destroyed by either strong magnetic heating or conduction in a range of parameters which is relevant to flares

    Relation between trees of fragmenting granules and supergranulation evolution

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    Context: The determination of the underlying mechanisms of the magnetic elements diffusion over the solar surface is still a challenge. Understanding the formation and evolution of the solar network (NE) is a challenge, because it provides a magnetic flux over the solar surface comparable to the flux of active regions at solar maximum. Aims: We investigate the structure and evolution of interior cells of solar supergranulation. From Hinode observations, we explore the motions on solar surface at high spatial and temporal resolution. We derive the main organization of the flows inside supergranules and their effect on the magnetic elements. Method: To probe the superganule interior cell, we used the Trees of Fragmenting Granules (TFG) evolution and their relations to horizontal Results: Evolution of TFG and their mutual interactions result in cumulative effects able to build horizontal coherent flows with longer lifetime than granulation (1 to 2 hours) over a scale up to 12\arcsec. These flows clearly act on the diffusion of the intranetwork (IN) magnetic elements and also on the location and shape of the network. Conclusions: From our analysis during 24 hours, TFG appear as one of the major elements of the supergranules which diffuse and advect the magnetic field on the Sun's surface. The strongest supergranules contribute the most to magnetic flux diffusion in the solar photosphere.Comment: 13 pages, 17 figures, accepted in Astronomy and Astrophysics movie : http://www.lesia.obspm.fr/perso/jean-marie-malherbe/Hinode2007/hinode2007.htm

    DU Explorer et Comprendre l'Univers: introduction Ă  la physique du Soleil

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    LicenceCe cours de niveau L1 donne les principales clefs pour comprendre les questions qui se posent en physique du Soleil

    An Introduction: The Task and Method of Exegesis

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    Malherbe, Abraham J. (1961) An Introduction: The Task and Method of Exegesis, Restoration Quarterly: Vol. 5 : No. 4. This repository hosts selected Restoration Quarterly articles in downloadable PDF format. For the benefit of users who would like to browse the contents of RQ, we have included all issue covers even when full-text articles from that issue are unavailable. All Restoration Quarterly articles are available in full text in the ATLA Religion Database, available through most university and theological libraries or through your local library’s inter-library loan service

    Christology in Luke - Acts

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    Malherbe, Abraham J. (1958) Christology in Luke - Acts, Restoration Quarterly: Vol. 2 : No. 2. This repository hosts selected Restoration Quarterly articles in downloadable PDF format. For the benefit of users who would like to browse the contents of RQ, we have included all issue covers even when full-text articles from that issue are unavailable. All Restoration Quarterly articles are available in full text in the ATLA Religion Database, available through most university and theological libraries or through your local library’s inter-library loan service

    Gnosis and Primitive Christianity: A Survey (1)

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    Paulus Senex

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    Malherbe, Abraham J. (1994) Paulus Senex, Restoration Quarterly: Vol. 36 : No. 4. This repository hosts selected Restoration Quarterly articles in downloadable PDF format. For the benefit of users who would like to browse the contents of RQ, we have included all issue covers even when full-text articles from that issue are unavailable. All Restoration Quarterly articles are available in full text in the ATLA Religion Database, available through most university and theological libraries or through your local library’s inter-library loan service

    Controlling the composition of a confined fluid by an electric field

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    Starting from a generic model of a pore/bulk mixture equilibrium, we propose a novel method for modulating the composition of the confined fluid without having to modify the bulk state. To achieve this, two basic mechanisms - sensitivity of the pore filling to the bulk thermodynamic state and electric field effect - are combined. We show by Monte Carlo simulation that the composition can be controlled both in a continuous and in a jumpwise way. Near the bulk demixing instability, we demonstrate a field induced population inversion in the pore. The conditions for the realization of this method should be best met with colloids, but being based on robust and generic mechanisms, it should also be applicable to some molecular fluids.Comment: 9 pages, 5 figure

    Investigation of dynamic stresses in detona- tion technical note no. 7

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    Axial and hoop stress calculation in blast loaded thin walled cylindrical pressure vessel
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