4.3.1 What are the velocity and magnetic vectors in the solar photosphere?
- Requires simultaneous observations from PHI and an instrument on the ground or another satellite.
- Simultaneous observations at different viewing angles.
4.3.2 What is the 3D geometry of the solar surface in convective and magnetic features?
- Study the undulating 3D structure of the visible solar surface (Lites et al., 2004).
- Wilson depression appearing in magnetic structures such as faculae, pores and sunspots (Solanki, 2003).
- Exact estimate of the height difference of the surface layer of different structures.
- Local helioseismology of active regions (Gizon and Birch, 2005).
4.3.3 How does the brightness of magnetic features change over the solar disk?
- Variation across the disk of the contrast of magnetic features relative to the quiet Sun (Topka et al., 1997; Ortiz et al., 2002; Hirzberger and Wiehr, 2005).
4.3.4 What is the long-term behaviour of active regions?
- Study sunspot evolution during co-rotation phase.
- Study the large-scale flows (e.g. sunspot moat flows) in and around active regions.
- Magnetic oscillations in sunspots and active regions.
4.3.5 How do magnetic fields emerge on the solar surface (coalescence, magnetic loops, convective collapse?).
- See e.g. Lamb et al., 2008; Centeno et al., 2007; Martínez González & Bellot Rubio, 2009; Nagata et al., 2008.