**3. The Sun convection zone and the processes of upwelling matter**

Nandy et al. [7] studying the mass conservation of the Sun Convection Zone (SCZ) looked into modeling of flow transfer within meridional latitudes and inner tachocline structures. They found that the mass conservation must include toroidal fields in opposite direction at higher latitudes, to compensate the sunspot nursery at lower latitudes. What they also found is that the poloidal fields within the SCZ also drive mass transfer from equator to high latitudes. Their simulation also demonstrated that the mass transfer actually happens *through* the tachocline. It seems that the toroidal field is somehow passing through the tachocline at low latitudes (creating sunspots), but not its opposite direction equivalent at high altitudes (absence of sunspots). Is the tachocline generating a toroidal field constraint larger at high latitudes? It seems (**Figure 4**) that the combination of poloidal and toroidal field simulation adds explanations about the sunspots appearance in the lower latitudes, as the poloidal field/mass movement is outward at low latitude, and inward at high latitude [7]. In that condition, the threshold for sunspot generation used by Nandy et al. [7] is 105 G above the base of the SCZ. and tachocline (gray) redrawn from Nandy et al. [7].

*Introductory Chapter: The Sun and Its Phenomenal Material Flux DOI: http://dx.doi.org/10.5772/intechopen.104926*

#### **Figure 4.**

*Flow directions in toroidal fields (blue/red), poloidal fields (black lines), redrawn after [7].*

Hathaway and Rightmire [9] studied the 1996–2009 period's magnetic maps made every 96 minutes from the MDI sensor (discontinued in 2011, follow-up by hmi.stanford.edu) on-board SOHO (soho.nascom.nasa.gov). MDI imaged the line-of-sight magnetic field by measuring the difference of polarization on both side of a Nickel absorption line in the Sun's atmosphere. They found that the surface

meridional (following N-S meridians) flow velocities away from the equator are in the range of 0–15 m/s (**Figure 5**), negligible near to differential rotation (~170 m/s), granulation (~300 m/s), and supergranulation (~3000 m/s). The velocity is however responsible for the rate of polar magnetism reversion, thus the Sun cycle life span and its activity overall. Zhao and Kosovichev [10] studied the interior of a sunspot region using time-distance helioseismology [11] on a dataset of 512 uninterrupted dopplergrams at 1-minute cadence on August 7 and 8, 2000, from MDI, following the data preparation from Giles [12]. Vortical flows in the subphotospheric zone have been estimated through inverse modeling, leading to suggest that kinetic and magnetic helicity extends from surface to depth. Such connectivity could be a source of great energy buildup and enters into the making of solar flares.
