Identification, physical structure and variability of the coronal sources of the fast and slow solar wind
Abstract
In spite of the numerous and continuous improvements in our understanding of the mechanisms governing the solar corona and its dynamics, none of the previous missions to the Sun have been able to fully explore the interface region where the solar wind originates and heliospheric structures are formed with sufficient observational capabilities to link solar wind structures back to their source regions at the Sun.
Thanks to the powerful combination of in-situ and remote-sensing instruments and the unique inner-heliospheric mission design, the upcoming solar and heliospheric missions will definitely contribute to address the central scientific question: how does the Sun create and control the heliosphere? Answering this fundamental question means to address, in particular, the interrelated question: how and where do the solar wind plasma streams originate in the corona? To answer these questions it is essential to perform in-situ measurements of the solar wind plasma, magnetic fields, waves and energetic particles close enough to the Sun to prevent any modification of the observed properties due to the subsequent transport and propagation processes. The Solar Orbiter spacecraft will approach the Sun to within 0.28 AU, leading also to a significant improvement in spatial resolution of the remote-sensing instruments. Simultaneous high-resolution imaging and spectroscopic observations of the Sun in and out of the ecliptic plane will allow to relate in-situ measurements by the Solar Orbiter itself, as well as by the Solar Probe Plus, back to their source regions and structures on the Sun, also providing unprecedented close-up views of the Sun's polar regions at solar latitudes higher than 30(°) . This proximity to the Sun will also give the advantage of flying in near synchronization with the Sun's rotation allowing observations of the solar surface and heliosphere from a near co-rotating vantage point. In these observations, both the on-disc inner corona and the outer corona will be nearly frozen for several days in the plane of the sky, and this can be used to disentangle the evolution of coronal structures and solar rotation effects on medium-term scales. This presentation will discuss the capability of remote-sensing instruments to provide information on the physical properties, fine structure and variability of different coronal regions, with both closed and open magnetic configuration, that can help to get a firmer identification of the source regions of the fast and slow solar wind streams.- Publication:
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40th COSPAR Scientific Assembly
- Pub Date:
- 2014
- Bibcode:
- 2014cosp...40E3181S