b_theta

CurvCoords.b_thetaSource

Poloidal covariant basis \(\mathbf{b}_\theta\).

\(\mathbf{b}_\theta\) is defined as follows:

\[\mathbf{b}_\theta = \frac{\partial \mathbf{r}}{\partial \theta}\]

where \(\mathbf{r}\) is the position vector of the center grids.

The shape array of \(\mathbf{b}_\rho\) is (L, M, N, 3), which follows the order of (\(\rho, \theta, \zeta\)) grid resolution at the first three dimensions, and the last dimension is the coordinate of \((x, y, z)\).