# geoana.em.tdem.TransientPlaneWave.magnetic_field#

TransientPlaneWave.magnetic_field(xyz)#

Magnetic field for the harmonic planewave at a set of gridded locations.

Parameters:
xyz(…,, 3) numpy.ndarray

Gridded xyz locations

Returns:
(n_t, …, 3) numpy.array of float

Magnetic field at all frequencies for the gridded locations provided.

Examples

Here, we define a transient planewave in the x-direction in a wholespace.

```>>> from geoana.em.tdem import TransientPlaneWave
>>> import numpy as np
>>> from geoana.utils import ndgrid
>>> from mpl_toolkits.axes_grid1 import make_axes_locatable
>>> import matplotlib.pyplot as plt
```

Let us begin by defining the transient planewave in the x-direction.

```>>> time = 1.0
>>> orientation = 'X'
>>> sigma = 1.0
>>> simulation = TransientPlaneWave(
>>>     time=time, orientation=orientation, sigma=sigma
>>> )
```

Now we create a set of gridded locations and compute the electric field.

```>>> x = np.linspace(-1, 1, 20)
>>> z = np.linspace(-1000, 0, 20)
>>> xyz = ndgrid(x, np.array([0]), z)
>>> h_vec = simulation.magnetic_field(xyz)
>>> hy = h_vec[..., 1]
```

Finally, we plot the x-oriented magnetic field.

```>>> plt.pcolor(x, z, hy.reshape(20, 20), shading='auto')
>>> cb = plt.colorbar()
>>> cb.set_label(label= 'Magnetic Field (\$A/m\$)')
>>> plt.ylabel('Z coordinate (\$m\$)')
>>> plt.xlabel('X coordinate (\$m\$)')
>>> plt.title('Magnetic Field of a Transient Planewave in the x-direction in a Wholespace')
>>> plt.show()
```