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LYOT, SFSA, Juillet 2007 1
LYOT : LYman Orbiting Telescopes
à bord de la mission franco-chinoise SMESE (Small Explorer for solar Erupions)
Frédéric Auchère, Jean-Claude VialInstitut d’Astrophysique Spatiale
T. Appourchaux, K. Bocchialini, M. Derouich (I.A.S.)
P. Lamy (L.A.M.), S. Koutchmy (I.A.P.) U. Schühle (MPS), E. Antonucci, S. Fineschi (Obs. Turin), M. Romolli
(Univ. Florence)
Autres collaborations : ORB, CSL, RAL, LESIA, LERMA, …
LYOT, SFSA, Juillet 2007 4
Mécanisme d’initiation des CMEs et Eruptions : reconnexion magnétique
from Anzer et Pneumann (1982)
LYOT, SFSA, Juillet 2007 5
Initiation des Coronal Mass Ejections
(CMEs) (1)
Source instability which leads to the CME ?
4 critical parameters concerning the acting forces: * initial acceleration* non-radial motions * transverse (latitudinal) expansion* initial radial expansion
• Must be measured below 2 Rs
LYOT, SFSA, Juillet 2007 6
Initiation des Coronal Mass Ejections
(CMEs) (2)
Source instability which leads to the CME ?
Several models(e.g. flux rope, Amari et al. 2003, breakout model, Aulanier et al. 2001)
None have been validated
LYOT, SFSA, Juillet 2007 7
Magnetic field in the corona
Corona cannot befully understood withoutthe magnetic field
Measured at the surfaceNot measuredin the corona
LYOT, SFSA, Juillet 2007 8
Measurements of the coronal magnetic field
Bommier & Sahal (1982)
Rotation polarisation Dépolarisation (B < 50 G pour L)
Hanle effect
LYOT, SFSA, Juillet 2007 9
Further studies
Structure of the transition between chromosphere and corona
Spatial and temporal variability of the La irradiance
Origin of solar energetic particles (SEPs)
Factor 3 variability at 30.4 nm(~L)SEM/SOHO
LYOT, SFSA, Juillet 2007 11
LYOT (and SMESE payload) performances
Wavelength/ Energy
Field of View
Spatial (pixel)
resolution
Watching-mode
Cadence
Event-mode
cadence
Daily data
volume
LYOT : Limager
121.6 nm Full Disk 1.1 arcsec 10 s 0.2 s
LYOT :Lcoronagraph
121.6 nm 5*5 solar radii
2.3 arcsec 20 s 2 s 29 Gb
DESIR :Infra-red Telescope
35 ≤ 1 ≤ 80 m100≤ 2 ≤ 250 m
Full Disk 50 arcsec at 35 m
100 ms 100 ms 5 Gb
HEBS 10-500keV200keV-10MeV10MeV-600MeV
Full Disk Full disk 1 s 32 ms 1.75 Gb
LYOT, SFSA, Juillet 2007 12
Mission Requirements (1)
Continuous observations : SS (6-18) orbit
Altitude : 650 – 750 km (radiation belts vs. geocorona)
TM : compatible with continuous imaging at 10 s rate (+ compression) : ~ 35 Gbits/day
Power : 100 W
Volume : ~ 60*60*30 cm3
LYOT, SFSA, Juillet 2007 13
Mission Requirements (2)
P/L mass :< 70 kg
Sun-pointed stabilized platform
Pointing stability : 0.4 arcsec/s for LYOT ; with a dedicated internal P/L servo mechanism, a platform stability of 36 arcsec/s is OK.
Pointing accuracy : 30 arcsec
Roll of the S/C (polarization measurements) : ~ twice a week
LYOT, SFSA, Juillet 2007 14
Mission Requirements (3)
Duration : 2 years minimum; 3 optimum
Time : ASAP after solar maximum of cycle 24 « scheduled « for 2011-2012 ?
Operations : no special requirement but internal reactivity to events (flag signal thru an Internal Data Handling Processor; mass memory ~16 Gb)
Data available ASAP to the community through SMC
LYOT, SFSA, Juillet 2007 15
Situation du projet
Proposition LYOT : avril 2000 (7 ans déjà …)
Prospective CNES : 2002 -> 2004
Mars-Septembre 2006 : Phase 0/A
Septembre 2006 – Juin 2007 : Phase APRR : 7 juin 2007Steering Committee : 6 juillet 2007
Phase B en 2008 ?
Lancement en 2012-2013 ? Cf. le calendrier solaire
LYOT, SFSA, Juillet 2007 19
The SMESE French-Chinese Team
China: PMO : Purple Mountain Observatory, CASNJU : Nanjing University CSSAR : Center for Space Science and Applied Research (Beijing)NAOC : National Astronomical Observatory, CAS (Beijing)CNSA : Chinese National Space Agency
France : LESIA/OP : Laboratoire d’Etudes Spatiales et d’Instrumentation en Astrophysique (Paris Observatory)IAS : Institut d‘Astrophysique Spatiale (Orsay)CNES : Centre National d‘Etudes Spatiales
Collaborations with other Institutes (LAM, LPCE, Torino/Firenze, CSL, ORB, RAL, SSL, Brazil, GSFC ...)