The HElium Resonance Scattering in the Corona and HELiosphere (HERSCHEL)
Abstract
The HERSCHEL (HElium Resonance Scattering in the Corona and Heliosphere) sounding-rocket payload has been selected in 2003 in the Living with a Star (LWS) Targeted Research and Technology program. The HERSCHEL experiment is designed to investigate the helium coronal abundance and solar wind acceleration by obtaining simultaneous observations of the electron, proton and helium solar coronae. The HERSCHEL instrument package consists of the Extreme Ultraviolet Imaging Telescope (EIT) for on-disk coronal observations and the Ultraviolet and Visible-light Coronagraphic Imager (UVCI) for off-limb observations of the corona. The UVCI is an externally occulted, reflecting coronagraph with an off-axis Gregorian telescope. UVCI will be able to take coronal images at heliocentric heights comprised between 1.2 to 3.5 solar radii of a) K-corona polarized brightness (pB); b) H I Lyman-a, 121.6 nm, line-emission; c) He II Lyman-a, 30.4 nm, line. Synthetic images obtained from coronal models and the expected instrument response will be presented. The key element in the UVCI instrument concept is that the mirrors with multilayer coatings optimized for 30.4 nm still have good reflectivity at 121.6 nm and in the visible. The optical design concept for the UVCI instrument will be discussed, together with its expected optical and throughput performances.
- Publication:
-
35th COSPAR Scientific Assembly
- Pub Date:
- 2004
- Bibcode:
- 2004cosp...35.4567F