Initial conditions

Perturbations

Explore the perturbation functions from struphy.initial.perturbations used to seed simulations. Each plot is generated from the corresponding class during the site build, sampled over the logical domain.

Perturbation · basis: norm

CoaxialWaveguideElectric_r

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`m`	1	Number of Modes a1, a2 : float inner and outer radius of Hollow Cylinder a, b : float Parameters of Electric field
`a1`	1	—
`a2`	2	—
`a`	1	—
`b`	-0.28	—

Perturbation · basis: norm

CoaxialWaveguideElectric_theta

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`m`	1	Number of Modes a1, a2 : float inner and outer radius of Hollow Cylinder a, b : float Parameters of Electric field
`a1`	1	—
`a2`	2	—
`a`	1	—
`b`	-0.28	—

Perturbation · basis: norm

CoaxialWaveguideMagnetic

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`m`	1	Number of Modes a1, a2 : float inner and outer radius of Hollow Cylinder a, b : float Parameters of Electric field
`a1`	1	—
`a2`	2	—
`a`	1	—
`b`	-0.28	—

Perturbation

Erf_z

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`amp`	0.0001	Amplitude of the velocity on each side.
`delta`	0.06666666666666667	Characteristic size of the shear layer
`given_in_basis`	null	In which basis the perturbation is represented (see base class).
`comp`	0	Which component (0, 1 or 2) of vector is perturbed (=0 for scalar-valued functions)

Perturbation · basis: physical

ITPA_density

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`n0`	0.00720655	ITPA profile density
`c`	[0.49123,0.298228,0.198739,0.521298]	4 ITPA profile coefficients
`comp`	0	—

Perturbation · basis: physical

ManufacturedSolutionPotential

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`dimension`	1D	Defines the manufactured solution to be selected ('1D' or '2D').
`b0`	1	Magnetic field (default: 1.0).

Perturbation · basis: physical

ManufacturedSolutionVelocity

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`species`	Ions	'Ions' or 'Electrons'.
`dimension`	1D	Defines the manufactured solution to be selected ('1D' or '2D').
`b0`	1	Magnetic field (default: 1.0).
`comp`	0	Which component (0, 1 or 2) of vector is perturbed (=0 for scalar-valued functions)

Perturbation · basis: physical

ManufacturedSolutionVelocity_2

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`species`	Ions	'Ions' or 'Electrons'.
`dimension`	1D	Defines the manufactured solution to be selected ('1D' or '2D').
`b0`	1	Magnetic field (default: 1.0).
`comp`	0	Which component (0, 1 or 2) of vector is perturbed (=0 for scalar-valued functions)

Perturbation

ModesCos

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`ls`	[2]	Mode numbers in x-direction (kx = l2pi/Lx).
`ms`	[3]	Mode numbers in y-direction (ky = m2pi/Ly).
`ns`	null	Mode numbers in z-direction (kz = n2pi/Lz).
`amps`	[0.0001]	Amplitude of each mode. Lx, Ly, Lz : float Domain lengths.
`Lx`	1	—
`Ly`	1	—
`Lz`	1	—
`given_in_basis`	null	In which basis the perturbation is represented (see base class).
`comp`	0	Which component (0, 1 or 2) of vector is perturbed (=0 for scalar-valued functions)
`perb_domain`	[null,null,null]	Subdomain in which the pertrubation is applied to: ((x_min, x_max), (y_min, y_max), (z_min, z_max)). None means apply perturbation to all domain in that direction

Perturbation

ModesCosCos

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`ls`	[2]	—
`ms`	[3]	—
`amps`	[0.0001]	—
`theta_x`	null	—
`theta_y`	null	—
`pfuns`	["Id"]	—
`pfuns_params`	[0]	—
`Lx`	1	—
`Ly`	1	—
`Lz`	1	—
`given_in_basis`	null	—
`comp`	0	—

Perturbation

ModesCosSin

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`ls`	[2]	—
`ms`	[3]	—
`amps`	[0.0001]	—
`theta_x`	null	—
`theta_y`	null	—
`pfuns`	["Id"]	—
`pfuns_params`	[0]	—
`Lx`	1	—
`Ly`	1	—
`Lz`	1	—
`given_in_basis`	null	—
`comp`	0	—

Perturbation

ModesSin

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`ls`	[2]	Mode numbers in x-direction (kx = l2pi/Lx).
`ms`	[3]	Mode numbers in y-direction (ky = m2pi/Ly).
`ns`	null	Mode numbers in z-direction (kz = n2pi/Lz).
`amps`	[0.0001]	Amplitude of each mode.
`theta`	null	Phase of each mode.
`pfuns`	["Id"]	"Id" or "localize" define the profile functions. localize multiply the sinus by :math: `tanh((\eta_3 - 0.5)/\delta)/cosh((\eta_3 - 0.5)/\delta)` to localize it around 0.5. :math: `\delta` is given by the input parameter pfuns_params
`pfuns_params`	[0]	The parameter needed by the profile function Lx, Ly, Lz : float Domain lengths.
`Lx`	1	—
`Ly`	1	—
`Lz`	1	—
`given_in_basis`	null	In which basis the perturbation is represented (see base class).
`comp`	0	Which component (0, 1 or 2) of vector is perturbed (=0 for scalar-valued functions)

Perturbation

ModesSinCos

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`ls`	[2]	—
`ms`	[3]	—
`amps`	[0.0001]	—
`theta_x`	null	—
`theta_y`	null	—
`pfuns`	["Id"]	—
`pfuns_params`	[0]	—
`Lx`	1	—
`Ly`	1	—
`Lz`	1	—
`given_in_basis`	null	—
`comp`	0	—

Perturbation

ModesSinSin

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`ls`	[2]	—
`ms`	[3]	—
`amps`	[0.0001]	—
`theta_x`	null	—
`theta_y`	null	—
`pfuns`	["Id"]	—
`pfuns_params`	[0]	—
`Lx`	1	—
`Ly`	1	—
`Lz`	1	—
`given_in_basis`	null	—
`comp`	0	—

Perturbation · basis: physical

RestelliAnalyticSolutionPotential

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`a`	1	Minor radius of torus (default: 1.).
`R0`	2	Major radius of torus (default: 2.).
`B0`	10	On-axis (r=0) toroidal magnetic field (default: 10.).
`Bp`	12.5	Poloidal magnetic field (default: 12.5).
`alpha`	0.1	(default: 0.1)
`beta`	1	(default: 1.0) References ---------- [1] Juan Vicente Gutiérrez-Santacreu, Omar Maj, Marco Restelli: Finite element discretization of a Stokes-like model arising in plasma physics, Journal of Computational Physics 2018.

Perturbation · basis: physical

RestelliAnalyticSolutionVelocity

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`a`	1	Minor radius of torus (default: 1.).
`R0`	2	Major radius of torus (default: 2.).
`B0`	10	On-axis (r=0) toroidal magnetic field (default: 10.).
`Bp`	12.5	Poloidal magnetic field (default: 12.5).
`alpha`	0.1	(default: 0.1)
`beta`	1	(default: 1.0)
`comp`	0	Which component (0, 1 or 2) of vector is perturbed (=0 for scalar-valued functions) References ---------- [1] Juan Vicente Gutiérrez-Santacreu, Omar Maj, Marco Restelli: Finite element discretization of a Stokes-like model arising in plasma physics, Journal of Computational Physics 2018.

Perturbation · basis: physical

RestelliAnalyticSolutionVelocity_2

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`a`	1	Minor radius of torus (default: 1.).
`R0`	2	Major radius of torus (default: 2.).
`B0`	10	On-axis (r=0) toroidal magnetic field (default: 10.).
`Bp`	12.5	Poloidal magnetic field (default: 12.5).
`alpha`	0.1	(default: 0.1)
`beta`	1	(default: 1.0)
`comp`	0	Which component (0, 1 or 2) of vector is perturbed (=0 for scalar-valued functions) References ---------- [1] Juan Vicente Gutiérrez-Santacreu, Omar Maj, Marco Restelli: Finite element discretization of a Stokes-like model arising in plasma physics, Journal of Computational Physics 2018.

Perturbation · basis: physical

RestelliAnalyticSolutionVelocity_3

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`a`	1	Minor radius of torus (default: 1.).
`R0`	2	Major radius of torus (default: 2.).
`B0`	10	On-axis (r=0) toroidal magnetic field (default: 10.).
`Bp`	12.5	Poloidal magnetic field (default: 12.5).
`alpha`	0.1	(default: 0.1)
`beta`	1	(default: 1.0)
`comp`	0	Which component (0, 1 or 2) of vector is perturbed (=0 for scalar-valued functions) References ---------- [1] Juan Vicente Gutiérrez-Santacreu, Omar Maj, Marco Restelli: Finite element discretization of a Stokes-like model arising in plasma physics, Journal of Computational Physics 2018.

Perturbation

Shear_x

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`amp`	0.0001	—
`delta`	0.06666666666666667	Characteristic size of the shear layer
`given_in_basis`	null	In which basis the perturbation is represented (see base class).
`comp`	0	Which component (0, 1 or 2) of vector is perturbed (=0 for scalar-valued functions)

Perturbation

Shear_y

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`amp`	0.0001	—
`delta`	0.06666666666666667	Characteristic size of the shear layer
`given_in_basis`	null	In which basis the perturbation is represented (see base class).
`comp`	0	Which component (0, 1 or 2) of vector is perturbed (=0 for scalar-valued functions)

Perturbation

Shear_z

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`amp`	0.0001	—
`delta`	0.06666666666666667	Characteristic size of the shear layer
`given_in_basis`	null	In which basis the perturbation is represented (see base class).
`comp`	0	Which component (0, 1 or 2) of vector is perturbed (=0 for scalar-valued functions)

Perturbation · basis: physical

TokamakManufacturedSolutionVelocity

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`comp`	0	Which component of the solution ('0', '1' or '2').
`a`	1	Minor radius of torus (default: 1.).
`R0`	2	Major radius of torus (default: 2.).
`B0`	10	On-axis (r=0) toroidal magnetic field (default: 10.).
`Bp`	12.5	Poloidal magnetic field (default: 12.5).
`alpha`	0.1	(default: 0.1)
`beta`	1	(default: 1.0) References ---------- [1] Juan Vicente Gutiérrez-Santacreu, Omar Maj, Marco Restelli: Finite element discretization of a Stokes-like model arising in plasma physics, Journal of Computational Physics 2018.

Perturbation · basis: physical

TokamakManufacturedSolutionVelocity_1

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`comp`	0	Which component of the solution ('0', '1' or '2').
`a`	1	Minor radius of torus (default: 1.).
`R0`	2	Major radius of torus (default: 2.).
`B0`	10	On-axis (r=0) toroidal magnetic field (default: 10.).
`Bp`	12.5	Poloidal magnetic field (default: 12.5).
`alpha`	0.1	(default: 0.1)
`beta`	1	(default: 1.0) References ---------- [1] Juan Vicente Gutiérrez-Santacreu, Omar Maj, Marco Restelli: Finite element discretization of a Stokes-like model arising in plasma physics, Journal of Computational Physics 2018.

Perturbation · basis: physical

TokamakManufacturedSolutionVelocity_2

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`comp`	0	Which component of the solution ('0', '1' or '2').
`a`	1	Minor radius of torus (default: 1.).
`R0`	2	Major radius of torus (default: 2.).
`B0`	10	On-axis (r=0) toroidal magnetic field (default: 10.).
`Bp`	12.5	Poloidal magnetic field (default: 12.5).
`alpha`	0.1	(default: 0.1)
`beta`	1	(default: 1.0) References ---------- [1] Juan Vicente Gutiérrez-Santacreu, Omar Maj, Marco Restelli: Finite element discretization of a Stokes-like model arising in plasma physics, Journal of Computational Physics 2018.

Perturbation

TorusModesCos

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`ms`	[2]	Poloidal mode numbers.
`ns`	[1]	Toroidal mode numbers.
`amps`	[0.1]	Amplitudes of each mode (m_i, n_i).
`pfuns`	["sin"]	"sin" or "cos" or "exp" to define the profile functions.
`pfun_params`	null
`given_in_basis`	null	In which basis the perturbation is represented (see base class).
`comp`	0	Which component (0, 1 or 2) of vector is perturbed (=0 for scalar-valued functions)

Perturbation

TorusModesSin

Documentation ↗

Perturbation value u

Coordinates: eta1–eta2 · value 0.5

Perturbation value u

Coordinates: eta1–eta3 · value 0.5

Perturbation value u

Coordinates: eta2–eta3 · value 0.5

Coordinate-line profiles

Each line varies one logical coordinate while the other two remain fixed at 0.5.

eta1(other coordinates = 0.5)

eta2(other coordinates = 0.5)

eta3(other coordinates = 0.5)

Parameters

Parameter	Value	Description
`ms`	null	Poloidal mode numbers.
`ns`	null	Toroidal mode numbers.
`amps`	[0.0001]	Amplitudes of each mode (m_i, n_i).
`pfuns`	["sin"]	"sin" or "cos" or "exp" to define the profile functions.
`pfun_params`	null
`given_in_basis`	null	In which basis the perturbation is represented (see base class).
`comp`	0	Which component (0, 1 or 2) of vector is perturbed (=0 for scalar-valued functions)