Main Objective:
To determine how magnetic flux from the internetwork interacts with the magnetic network and eventually becomes part of the network.
Scientific Justification: It is known that the internetwork is a very important, if not the main, source of flux for the network. A significant fraction of internetwork flux merges with network patches of the same polarity, while other internetwork features cancel out with opposite-polarity network patches. The balance between these two processes determines the contribution of the internetwork to the network, but it is poorly known. Solar Orbiter will carry out a 6-hour continuous observation of several supergranular cells at the disk center to shed light on this process. As a side product, the evolution of network/internetwork features will be followed by Solar Orbiter using vector magnetograms that include linear polarization measurements. The observations will also allow to study the effects of cancellations of network and internetwork features at the boundary of the network, which are known to produce local brightenings in the chromosphere and transition region above. The contribution of these events to chromospheric and coronal heating will be assessed using EUI and SPICE.
Hinode is needed to perform magnetic/dynamic stereoscopy in the photosphere together with Solar Orbiter. At the time of the observations, the two spacecraft will be separated by about 60 degrees, and the spatial resolutions provided by the Hinode/SP in the normal map mode and SO/PHI will be exactly the same. We therefore request normal mode SP observations of the tracked supergranular cells during the six hours of Solar Orbiter observations. Hinode/EIS will help investigate changes in the upper atmosphere due to flux cancellations at the network boundaries, together with EUI and SPICE. To this end, we request fast cadence narrow rasters covering the center of one of the tracked supergranular cells. |
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