Damping

class micromagneticmodel.Damping(**kwargs)

Damping dynamics term.

\[\frac{\text{d}\mathbf{m}}{\text{d}t} = -\frac{\gamma_{0} \alpha} {1 + \alpha^{2}} \mathbf{m} \times (\mathbf{m} \times \mathbf{H}_\text{eff})\]

Parameters:

alpha (numbers.Real, dict, discretisedfield.Field) – If a single positive value numbers.Real is passed, a spatially constant parameter is defined. For a spatially varying parameter, either a dictionary, e.g. alpha={'region1': 1e5, 'region2': 5e5} (if the parameter is defined “per region”) or discretisedfield.Field is passed.

Examples

1. Defining the damping dynamics term using scalar.

>>> import micromagneticmodel as mm
...
>>> damping = mm.Damping(alpha=0.01)

2. Defining the damping dynamics term using dictionary.

>>> damping = mm.Damping(alpha={'region1': 0.01, 'region2': 0.005})

3. Defining the damping dynamics term using discretisedfield.Field.

>>> import discretisedfield as df
...
>>> region = df.Region(p1=(0, 0, 0), p2=(5e-9, 5e-9, 5e-9))
>>> mesh = df.Mesh(region=region, n=(5, 5, 5))
>>> alpha = df.Field(mesh, nvdim=1, value=0.012)
>>> damping = mm.Damping(alpha=alpha)

4. An attempt to define the damping dynamics term using a wrong value.

>>> damping = mm.Damping(alpha=-5)  # negative value
Traceback (most recent call last):
...
ValueError: ...

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Methods

__add__	Binary + operator.
__dir__	Default dir() implementation.
__eq__	Relational operator ==.
__iter__	Iterator.
__repr__	Representation string.
dmdt

Properties

alpha	Descriptor allowing setting attributes with a value described as descriptor or a dictionary.
name	Name.

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