jeudi 21 décembre 2017, par Leon Golub (Harvard-Smithsonian Center for Astrophysics, USA)
Lundi 8 janvier 2018 à 11h00 , Lieu : Salle de confĂ©rence du bâtiment 17
We have designed a novel wide field, dual-use EUV imager to observe the dynamics of solar coronal streamers and other large-scale structures from the solar surface out to at least 3 R_sol. The COSIE instrument is proposed for implementation on the ISS, with the objectives of : 1.) understanding the dynamics of the Transition Corona, the region of the upper corona in which the plasma beta changes from low to high and the atmosphere transitions from being dominated by magnetically confined closed structures to high beta with generally open radially-directed regions with outflowing solar wind streams, and 2.) providing new tools for space weather forecasting via early detection of coronal mass ejections (CMEs), tracking of CMEs during their main acceleration phase and early path changes, and modeling of the CME magnetic configuration at event initiation. The imaging channel has 500X greater sensitivity than existing EUV imagers and is capable of detecting streamers out to at least 2.5 R_sol and CMEs to substantially greater distances. A novel feature of COSIE is that the observing mode is switchable between ultra-high sensitivity direct EUV imaging and a global spectroscopic imaging mode. The overlapped spectra can be unfolded to provide spectral resolution of 20,000 over the 185-206Ă… passband covering a wide coronal temperature range, as well as providing full-Sun density images every 10 seconds. The sensitivity and field of view of the design are flexible and many observing locations are feasible, including L1, L4 and L5.
