.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "auto_examples/em/plot_static_magnetic_fields_from_pole_source.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_auto_examples_em_plot_static_magnetic_fields_from_pole_source.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_examples_em_plot_static_magnetic_fields_from_pole_source.py:


Total magnetic fields: Dipole and Pole sources
==============================================

In this example, we plot anomalous total magnetic field
from a magnetic dipole and pole targets. These targets are
excited by Earth magnetic fields.
We can vary the direction of the Earth magnetic field, and
magnetic moment of the target.

:author: Seogi Kang (`@sgkang <https://github.com/sgkang>`_)
:date: Aug 19, 2018

.. GENERATED FROM PYTHON SOURCE LINES 15-25

.. code-block:: default



    import numpy as np
    import matplotlib.pyplot as plt
    from matplotlib.colors import LogNorm
    from scipy.constants import mu_0, epsilon_0

    from geoana import utils, spatial
    from geoana.em import static








.. GENERATED FROM PYTHON SOURCE LINES 26-31

Setup
-----

define the location, orientation, and source, physical properties of the
wholespace and source parameters

.. GENERATED FROM PYTHON SOURCE LINES 31-41

.. code-block:: default


    mu = mu_0  # permeability of free space (this is the default)
    location = np.r_[0., 0., -10.]  # location of the dipole or pole

    # dipole parameters
    moment = 1
    # inclination and declination (e.g. Vancouver)
    inclination, declination = 67., 0.









.. GENERATED FROM PYTHON SOURCE LINES 42-47

Magnetostatic Dipole and Loop
-----------------------------

Here, we build the geoana magnetic dipole and poie in a wholespace
using the parameters defined above.

.. GENERATED FROM PYTHON SOURCE LINES 47-68

.. code-block:: default


    def id_to_cartesian(inclination, declination):
        ux = np.cos(inclination/180.*np.pi)*np.sin(declination/180.*np.pi)
        uy = np.cos(inclination/180.*np.pi)*np.cos(declination/180.*np.pi)
        uz = -np.sin(inclination/180.*np.pi)
        return np.r_[ux, uy, uz]

    orientation = id_to_cartesian(inclination, declination)

    dipole = static.MagneticDipoleWholeSpace(
        location=location,
        orientation=orientation,
        moment=moment
    )

    pole = static.MagneticPoleWholeSpace(
        location=location,
        orientation=orientation,
        moment=moment
    )








.. GENERATED FROM PYTHON SOURCE LINES 69-74

Evaluate magnetic fields
--------------------------

Next, we construct a grid where we want to plot the magentic fields and
evaluate

.. GENERATED FROM PYTHON SOURCE LINES 74-84

.. code-block:: default


    x = np.linspace(-36, 36, 100)
    y = np.linspace(-36, 36, 100)
    xyz = utils.ndgrid([x, y, np.r_[1.]])

    # evaluate the magnetic field
    b_vec_dipole = dipole.magnetic_flux_density(xyz)
    b_vec_pole = pole.magnetic_flux_density(xyz)
    b_total_dipole = dipole.dot_orientation(b_vec_dipole)
    b_total_pole = pole.dot_orientation(b_vec_pole)







.. GENERATED FROM PYTHON SOURCE LINES 85-87

and define plotting code to plot an image of the amplitude of the vector
field / flux as well as the streamlines

.. GENERATED FROM PYTHON SOURCE LINES 88-100

.. code-block:: default



    def plot_amplitude(ax, v):
        plt.colorbar(
            ax.pcolormesh(
                x, y, v.reshape(len(x), len(y), order='F')
            ), ax=ax
        )
        ax.axis('square')
        ax.set_xlabel('y (east,  m)')
        ax.set_ylabel('x (north,  m)')








.. GENERATED FROM PYTHON SOURCE LINES 101-103

Create subplots for plotting the results. Loop over frequencies and plot the
electric and magnetic fields along a slice through the center of the dipole.

.. GENERATED FROM PYTHON SOURCE LINES 104-121

.. code-block:: default


    fig, ax = plt.subplots(1, 2, figsize=(12, 5))

    # plot dipole vector potential
    plot_amplitude(ax[0], b_total_dipole)

    # plot loop vector potential
    plot_amplitude(ax[1], b_total_pole)


    # set the titles
    ax[0].set_title("Total field: dipole")
    ax[1].set_title("Total field: pole")

    # format so text doesn't overlap
    plt.tight_layout()
    plt.show()



.. image-sg:: /auto_examples/em/images/sphx_glr_plot_static_magnetic_fields_from_pole_source_001.png
   :alt: Total field: dipole, Total field: pole
   :srcset: /auto_examples/em/images/sphx_glr_plot_static_magnetic_fields_from_pole_source_001.png
   :class: sphx-glr-single-img






.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 0.292 seconds)


.. _sphx_glr_download_auto_examples_em_plot_static_magnetic_fields_from_pole_source.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example




    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: plot_static_magnetic_fields_from_pole_source.py <plot_static_magnetic_fields_from_pole_source.py>`

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: plot_static_magnetic_fields_from_pole_source.ipynb <plot_static_magnetic_fields_from_pole_source.ipynb>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_