|
|
|
|
|
| Dubrulle, B; Marie, Louis; Normand, C; Richard, D; Hersant, F; Zahn, Jp. |
| We discuss the possibility that astrophysical accretion disks are dynamically unstable to non-axisymmetric disturbances with characteristic scales much smaller than the vertical scale height. The instability is studied using three methods: one based on the energy integral, which allows the determination of a sufficient condition of stability, one using a WKB approach, which allows the determination of the necessary and sufficient condition for instability and a last one by numerical solution. This linear instability occurs in any inviscid stably stratified differential rotating fluid for rigid, stress-free or periodic boundary conditions, provided the angular velocity Omega decreases outwards with radius r. At not too small stratification, its growth rate... |
| Tipo: Text |
Palavras-chave: Accretion; Accretion disks hydrodynamic instabilities turbulence. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/00253/36469/35013.pdf |
| |
|
|
| Auzende, Jean-marie; Boespflug, Xavier; Bougault, Henri; Dosso, Laure; Foucher, Jean-paul; Joron, Jean-louis; Ruellan, Etienne; Sibuet, Jean-claude. |
| Three cruises (POP 1, SEAPSO 3 and SEAPSO 4) carried out during the "Tour du Monde" of the R.V. Jean Charcot allow us to obtain new structural and geochemical data for the Okinawa, North Fiji and Lau basins. Taken together, the structural and geochemical data illustrate a difference in evolution stages of these sites. The less evolved stage is represented by the Okinawa basin, where accretion is evidenced only by volcanic intrusion into a thinned continental crust. The most evolved stage is illustrated in the North Fiji basin, where the present-day accretion can be directly compm·ed to the East Pacific Ridge. The Lau basin displays an intem1ediate stage with a complex system of accretionary ridges. This difference in the evolution stage is translated in... |
| Tipo: Text |
Palavras-chave: Ouest Pacifique; Bassins arriere arc; Structure; Accretion; Geochimie; West Pacific; Back arc basins; Structure; Accretion; Geochemistry. |
| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00119/23058/20893.pdf |
| |
|
|
| Gallais, Flora; Graindorge, David; Gutscher, Marc-andre; Klaeschen, Dirk. |
| The rollback of a segmented slab of oceanic lithosphere is typically accompanied by vertical lithospheric tear fault(s) along the lateral slab edge(s) and by strike slip movement in the upper plate, defined as a STEP fault (Subduction Tear Edge Propagator). The Neogene evolution of the Central Mediterranean is dominated by the interaction between the slow Africa–Eurasia convergence and the SE-ward rollback of the Ionian slab, that leads to the back-arc opening of the Tyrrhenian Sea. Here, we present post-stack time migrated and pre-stack depth migrated Archimede (1997) multichannel seismic lines, that were acquired offshore eastern Sicily, at the foot of the Malta escarpment. First, we identify the recent deformation along the lateral ramp of the Calabrian... |
| Tipo: Text |
Palavras-chave: Tear fault; Rollback; Accretion; Multi-channel seismic reflection. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00118/22878/21386.pdf |
| |
|
|
|
