dc.creator | Leão, Márcia Regina Moreira | |
dc.creator | Pino, Elisabete Maria de Gouveia Dal | |
dc.creator | Lima, Robson Santos | |
dc.creator | Lazarian, A. | |
dc.date.accessioned | 2015-03-16T16:13:39Z | |
dc.date.accessioned | 2018-07-04T17:04:06Z | |
dc.date.available | 2015-03-16T16:13:39Z | |
dc.date.available | 2018-07-04T17:04:06Z | |
dc.date.created | 2015-03-16T16:13:39Z | |
dc.date.issued | 2013 | |
dc.identifier | Latin American Regional IAU Meeting, 14, 2013, Florianópolis. | |
dc.identifier | 0185-1101 | |
dc.identifier | http://www.producao.usp.br/handle/BDPI/48524 | |
dc.identifier.uri | http://repositorioslatinoamericanos.uchile.cl/handle/2250/1644215 | |
dc.description.abstract | For a molecular cloud clump to form stars some
transport of magnetic flux is required from the
denser, inner regions to the outer regions of the
cloud, otherwise this can prevent the collapse. Fast
magnetic reconnection which takes place in the presence
of turbulence can induce a process of reconnection
diffusion (RD). Extending earlier numerical
studies of reconnection diffusion in cylindrical
clouds, we consider more realistic clouds with spherical
gravitational potentials and also account for the
effects of the gas self-gravity. We demonstrate that
within our setup RD is efficient. We have also identified
the conditions under which RD becomes strong
enough to make an initially subcritical cloud clump
supercritical and induce its collapse. Our results indicate
that the formation of a supercritical core is
regulated by a complex interplay between gravity,
self-gravity, the magnetic field strength and nearly
transonic and trans-Alfv´enic turbulence, confirming
that RD is able to remove magnetic flux from collapsing
clumps, but only a few of them become nearly
critical or supercritical, sub-Alfv´enic cores, which is
consistent with the observations. Besides, we have
found that the supercritical cores built up in our simulations
develop a predominantly helical magnetic
field geometry which is also consistent with observations.
Finally, we have evaluated the effective values
of the turbulent reconnection diffusion coefficient and found that they are much larger than the numerical
diffusion, especially for initially trans-Alfv´enic
clouds, ensuring that the detected magnetic flux removal
is due to to the action of the RD rather than
to numerical diffusivity. | |
dc.language | eng | |
dc.publisher | International Astronomical Union | |
dc.publisher | Florianópolis | |
dc.relation | Latin American Regional IAU Meeting, 14 | |
dc.rights | restrictedAccess | |
dc.title | The role of reconnection diffusion in the gravitational collapse of turbulent cloud cores | |
dc.type | Actas de congresos | |