**5. Penumbral characterization and co-processes**

Ichimoto et al. [17] observed the dynamical processes of strongly magnetized plasma through the twisting motions of penumbral filaments. When magnetic reconnection happens, Katsukawa et al. [18] observed penumbral microjets in chromospheric layers above the penumbra (**Figure 7**). With less than 0.4 Mm width and a life span less than 1 minute, they are by all means small features around sunspots. They are similar to limb's spicules, dynamic fibrils in active regions and quiet Sun's mottles. They might be involved in the thermal source of the sunspot's coronal connectivity.

Scharmer et al. [19] used the Crisp Imaging SpectroPolarimeter (CRISP) on the Swedish 1 m Solar Telescope in La Palma, Spain, to study the neutral carbon line (C I) of downward Doppler velocities in the penumbral area of a sunspot. Evidence directs to (dark) downflows that can reach 8 km/s in the blueshift, with an estimated horizontal magnetic direction, while (bright) outward flows have about 50 degrees angle with the surface.

Howe et al. [20] compared Doppler surface measurements with global and local helioseismology (MDI, GONG). They show that subsurface shear fine-tuning just below the surface is hard to reconcile across methods in high accuracy levels while quite agreeing at equator for good accuracy levels. Zonal flow patterns agree largely across methods about rotation-rate residuals allowing for multiscale sources generating wave signals discrepancies.

**Figure 7.** *Penumbral microjet and dark filaments [18].*
