field provider uniform_rotating#

Describes the entry uniform_rotating at version 0.1.0, registered by mime.fields._uniform_rotating.UniformRotating.

At a glance#

  • field provider uniform_rotating, version 0.1.0, namespace mime

  • Nodes: UniformRotatingNode

  • The equations are on the node page: equations

  • Derivative: exact

  • Validity: none declared

What it models, and when not to use it#

A uniform field turning about an axis#

What it models. A magnetic field that is the same at every point and turns right-handed about a fixed axis at a commanded frequency, with a commanded amplitude: an idealisation of the field a rotating-magnet or coil rig makes over a body small against it. UniformRotating(rotation_axis=..., initial_direction=...) as an apparatus’s field, driven through its two commands, frequency and amplitude. The field points along the initial direction, less its part along the axis, at the start of the run. A reader’s slot takes no points, since the field does not depend on them, and the gradient it publishes is zero everywhere. Its time is the step count times the timestep, never a running sum of timesteps.

It publishes the flux density and the gradient, so it feeds Magnetic.Torque (which reads the flux density) and Magnetic.Force (which reads the gradient, zero here, and so delivers nothing beside it).

When not to use it.

  • Where the field varies across the body or with the body’s place: a uniform field has no gradient, no pull and no near field. A source with a position, such as the point dipole, is the model for that.

  • For a source that the body reacts on: this field has no source mounted anywhere, so it takes no reaction. A body’s moment turns in it and the field is not turned back.

  • For a frequency that changes during the run, taken as a sweep: the phase is the present frequency times the time since the start, not the integral of the frequency, so a change of frequency changes the phase at once, and the field’s direction jumps with it. A frequency held constant, or changed where a jump of phase is acceptable, is what it is for.

  • For a field’s delivery by coils or magnets with a bandwidth, a lag, a saturation or a nonuniformity: it is the ideal field, and the commanded amplitude is the amplitude delivered. Nothing here bounds how far a rig’s field is from that.

Its derivative is exact, as the generated section states.

Versions. uniform_rotating 0.1.0 is its first.

Settings#

Setting

Type

Default

Dimension

Role

Default’s kind

initial_direction

Annotated[DirectionLike, Direction]

{"required": true}

marked Direction

design

none

rotation_axis

Annotated[DirectionLike, Direction]

{"required": true}

marked Direction

design

none

Each role and default’s kind is the entry’s setting_roles (mime.registry.SettingRole); a setting that declares none is required.

Roles, reads and deliveries#

Publishes:

Interface

Output

field.magnetic.flux_density

flux_density

field.magnetic.gradient

gradient

Nodes it builds#

Declared in builds; the node walk compares it with what a round-trip case builds.

Gradient status#

The derivative through this entry is exact, the derivative of what it computes.

Validity#

none declared

References#

none declared

Other declarations#

Class variable

Type

Value

commands

ClassVar[Mapping[str, Command]]

too long to show; see `mime registry --json`

flags

ClassVar[frozenset[Capability]]

["provision=evaluated", "uniform"]

moving

ClassVar[bool]

false

outside_parts

ClassVar[bool]

false

parts

ClassVar[Mapping[str, str | None]]

{}

turns_at

ClassVar[str | None]

frequency