choclo.prism.magnetic_e

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choclo.prism.magnetic_e#

choclo.prism.magnetic_e(easting, northing, upward, prism_west, prism_east, prism_south, prism_north, prism_bottom, prism_top, magnetization_east, magnetization_north, magnetization_up)[source]#

Easting component of the magnetic field due to a prism

Returns the easting component of the magnetic field due to a single rectangular prism on a single computation point.

Parameters:
easting, northing, upwardfloat

Easting, northing and upward coordinates of the observation point. Must be in meters.

prism_west, prism_east, prism_south, prism_north, prism_bottom, prism_topfloat

The boundaries of the prism. Must be in meters.

magnetization_eastfloat

The East component of the magnetization vector of the prism. Must be in \(A m^{-1}\).

magnetization_northfloat

The North component of the magnetization vector of the prism. Must be in \(A m^{-1}\).

magnetization_upfloat

The upward component of the magnetization vector of the prism. Must be in \(A m^{-1}\).

Returns:
b_efloat

Easting component of the magnetic field generated by the prism on the observation point in \(\text{T}\). Return numpy.nan if the observation point falls in a singular point: prism vertices, prism edges or interior points.

Notes

Computes the easting component of the magnetic field \(\mathbf{B}(\mathbf{p})\) generated by a rectangular prism \(R\) with a magnetization vector \(M\) on the observation point \(\mathbf{p}\) as follows:

\[B_x(\mathbf{p}) = \frac{\mu_0}{4\pi} \left( M_x u_{xx} + M_y u_{xy} + M_z u_{xz} \right)\]

Where \(u_{ij}\) are:

\[u_{ij} = \frac{\partial^2}{\partial i \partial j} \int\limits_R \frac{1}{\lVert \mathbf{p} - \mathbf{q} \rVert} dv\]

with \(i,j \in \{x, y, z\}\). Solutions of the second derivatives of these integrals are given by [Nagy2000]:

\[\begin{split}u_{xx} &= \Bigg\lvert\Bigg\lvert\Bigg\lvert - \arctan \left( \frac{yz}{xr} \right) \Bigg\rvert_{X_1}^{X_2} \Bigg\rvert_{Y_1}^{Y_2} \Bigg\rvert_{Z_1}^{Z_2} \\ u_{xy} &= \Bigg\lvert\Bigg\lvert\Bigg\lvert \ln (z + r) \Bigg\rvert_{X_1}^{X_2} \Bigg\rvert_{Y_1}^{Y_2} \Bigg\rvert_{Z_1}^{Z_2} \\ u_{xz} &= \Bigg\lvert\Bigg\lvert\Bigg\lvert \ln (y + r) \Bigg\rvert_{X_1}^{X_2} \Bigg\rvert_{Y_1}^{Y_2} \Bigg\rvert_{Z_1}^{Z_2}\end{split}\]

References