SCIENTIFIC OBJECTIVES OF THE NOVEL FORMATION FLYING MISSION ASPIICS

摘要

Formation flyers open new perspectives and allow to conceive giant, externally-occulted coronagraphs using a two-component space system with the external occulter on one spacecraft and the optical instrument on the other spacecraft at approximately 100-150 m from the first one. ASPIICS (Association de Satellites Pour l'Imagerie et l'Interfromtrie de la Couronne Solaire) is a mission proposed to ESA in the framework of the PROBA-3 demostration program of formation flying (presently in phase A). ASPIICS is composed of a single coronagraph which performs high spatial resolution imaging of the corona as well as 2-dimensional spectroscopy of several emission lines from the coronal base out to 3 R{sub}⊙. ASPIICS will address the question of the coronal heating and the role of waves by characterizing propagating fluctuations (waves and turbulence) in the solar wind acceleration region and by looking for oscillations in the intensity and Doppler shift of spectral lines. The combined imaging and spectral diagnostics capabilities available with ASPIICS will allow to map the velocity field of the corona both in the sky plane (directly on the images) and along the line of sight by measuring the Doppler shifts of emission lines. ASPIICS will thus attempt to determine how the different components of the solar wind, slow and fast are accelerated. ASPIICS will observe the corona during the maximum of solar activity, insuring the characterization of many Coronal Mass Ejections by rapidly alternating high resolution imaging and spectroscopy. In addition, ASPIICS will attempt to characterize the topology of the magnetic field in the corona.