BEGIN:VCALENDAR
VERSION:2.0
PRODID:https://murmitoyen.com/events/vanille/udem/
X-WR-TIMEZONE:America/Montreal
BEGIN:VEVENT
UID:69e1a16281efc
DTSTAMP:20260416T225634
DTSTART:20121213T113000
SEQUENCE:0
TRANSP:OPAQUE
DTEND:20121213T123000
URL:https://murmitoyen.com/events/vanille/udem/detail/166726
LOCATION:Université de Montréal - Pavillon Roger-Gaudry\, 2900\, chemin d
 e la Tour\, Montréal\, QC\, Canada\, H3T 1J6
SUMMARY:Understanding the solar tachocline: testing the magnetic confinemen
 t scenario with numerical simulations
DESCRIPTION:Antoine Strugarek\, CEA SaclayRésumé/abstract:Among the many 
 fascinating aspects of the solar dynamics\, the structure of the tachoclin
 e (thin region located at 0.7 solar radius in the interior of the Sun) has
  been puzzling the solar physicists for many years. In particular\, its ex
 treme thinness (less than 5% of the solar radius) has not been satisfactor
 ily explained yet. Some theoretical models have been proposed to explain i
 ts structure\, among which one postulated the existence of a (fossil) magn
 etic field\, buried in the radiative interior of the Sun\, that would conf
 ine the tachocline to a thin layer. We present pioneer 3D MHD global solar
  simulations coupling the turbulent convective zone and the radiative zone
  that have been carried out to test this scenario. Essential features of t
 he Sun\, such as differential rotation\, meridional circulation and intern
 al waves excitation are recovered. We find that an initially confined axis
 ymmetric dipolar fossil field does not confine the tachocline and couples 
 the convection zone to the solar interior. The three- dimensional convecti
 ve motions are shown to play an essential role in the transport of magneti
 c field and the failure of the confinement scenario. Because of its axisym
 metry\, the dipolar field is moreover able to transport the mean angular m
 omentum radially\, accelerating the loss of confinement of the tachocline.
  Other primordial magnetic field configurations are also considered. We fi
 nd a similar evolution of the solar interior in the case of an inclined di
 pole (with respect to the rotation axis of the star). The special case of 
 a perpendicular dipolar magnetic field results in a significantly differen
 t evolution compared the aligned dipolar case. Nevertheless\, the magnetic
  confinement scenario for the tachocline fails in the three cases\, in the
  parameter regime we have exploredCe séminaire est présenté par le grou
 pe astronomie et astrophysique du Département de physique de l'Universit
 é de Montréal.
END:VEVENT
BEGIN:VTIMEZONE
TZID:America/Montreal
X-LIC-LOCATION:America/Montreal
END:VTIMEZONE
END:VCALENDAR