Fig. 1
From: Magnetic field stretching at the top of the shell of numerical dynamos
Snapshot from dynamo model 4: a radial magnetic field \(B_r\) (in colors) and the tangential flow \(\vec {u}_h\) (black arrows). The upper and lower polygons denote the zoom-in zones shown in Figs. 2 and 3, respectively. b The frozen-flux SV, c radial vorticity \(\omega _r\), d tangential divergence \(\delta _h\), e advective SV and f stretching SV. All plots are at a radial level just below the Ekman boundary layer (\(r_{\text {e}}\) in Table 1). All variables are non-dimensional. The global statistics for this snapshot are: St/Ad=1.18; \({\mathcal {P}}/{\mathcal {T}}=0.36\); \(H_u=0.89\); \({\text{corr}}(|B_r|,\delta _h^-)=0.46\); \({\text{corr}}(|B_r|,\delta _h^+)=-0.20\)