Point charge with full electromagnetic field and dynamics. More...

#include <PointCharge.hpp>

Inheritance diagram for Phyth::Electromagnetics::PointCharge:

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Collaboration diagram for Phyth::Electromagnetics::PointCharge:

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Public Member Functions
	PointCharge (const Quantity< Kilogram > mass, const Vector3< Quantity< Meter > > &position, const Quantity< Coulomb > charge_value)
	Construct a point charge.

void	SetComputeForcesFunction (const std::function< void(PointCharge *)> &func) noexcept
	Set the force computation function.

Vector3< Quantity< NewtonPerCoulomb > >	GetElectricFieldAt (const Vector3< Quantity< Meter > > &point) const override
	Get the electric field at a point using Liénard-Wiechert formulas.

Vector3< Quantity< Tesla > >	GetMagneticFieldAt (const Vector3< Quantity< Meter > > &point) const override
	Get the magnetic field at a point using Liénard-Wiechert formulas.

Quantity< Volt >	GetElectricPotentialAt (const Vector3< Quantity< Meter > > &point) const override
	Get the electric potential at a point.

void	ApplyElectricFieldForce (const Vector3< Quantity< NewtonPerCoulomb > > &field)
	Apply force from an electric field: F = q * E.

void	ApplyMagneticFieldForce (const Vector3< Quantity< Tesla > > &field)
	Apply force from a magnetic field: F = q * v cross B.

void	ApplyLorentzForce (const Vector3< Quantity< NewtonPerCoulomb > > &electric_field, const Vector3< Quantity< Tesla > > &magnetic_field)
	Apply the full Lorentz force: F = q * (E + v cross B)

Quantity< Coulomb >	GetTotalChargeValue () const override
	Get the total charge value.

Quantity< Meter >	GetMinimumDistanceTo (const Vector3< Quantity< Meter > > &point) const override
	Get the minimum distance from a point to the charge location.

void	Integrate () noexcept override
	Integrate dynamics using velocity Verlet.

Public Member Functions inherited from Phyth::Mechanics::Particle
	Particle (const Quantity< Kilogram > &mass, const Vector3< Quantity< Meter > > &position) noexcept
	Construct a particle with mass and initial position.

virtual	~Particle ()=default

void	ApplyForce (const Vector3< Quantity< Newton > > &force)
	Accumulate an external force on the particle.

constexpr const auto &	GetPosition () const noexcept

void	SetPosition (const Vector3< Quantity< Meter > > &position) noexcept
	Set the particle position (m)

constexpr auto	GetMass () const noexcept

void	SetMass (const Quantity< Kilogram > &mass) noexcept
	Set the particle mass (kg)

constexpr const auto &	GetVelocity () const noexcept

void	SetVelocity (const Vector3< Quantity< MeterPerSecond > > &velocity) noexcept
	Set the particle velocity (m/s)

constexpr bool	IsFixed () const noexcept

void	SetFixed (const bool fixed) noexcept
	Set whether the particle is fixed (immovable)

constexpr const auto &	GetExternalForce () const noexcept

void	SetExternalForce (const Vector3< Quantity< Newton > > &external_force) noexcept
	Manually set the external force (N)

void	SetComputeForcesFunction (const std::function< void(Particle *)> &func) noexcept
	Set the user-defined force computation function.

Quantity< Joule >	GetPotentialEnergy (const Quantity< Meter > y_ref=0) const
	Compute gravitational potential energy relative to a reference height.

Quantity< Joule >	GetKineticEnergy () const noexcept
	Compute kinetic energy.

Quantity< Joule >	GetTotalEnergy (const Quantity< Meter > y_ref=0) const noexcept
	Compute total mechanical energy.

Public Member Functions inherited from Phyth::Electromagnetics::ChargeSource
virtual	~ChargeSource ()=default

virtual Quantity< CoulombPerCubicMeter >	GetChargeDensityAt (const Vector3< Quantity< Meter > > &point) const
	Get the charge density at a point.

Public Member Functions inherited from Phyth::Electromagnetics::MagneticSource
virtual	~MagneticSource ()=default

Private Member Functions
Vector3< Quantity< Meter > >	GetPositionAtOffset (const Quantity< Second > &offset) const
	Get position at a time offset in the past.

Vector3< Quantity< MeterPerSecond > >	GetVelocityAtOffset (const Quantity< Second > &offset) const
	Get velocity at a time offset in the past.

Vector3< Quantity< MeterPerSecondSquared > >	GetAccelerationAtOffset (const Quantity< Second > &offset) const
	Get acceleration at a time offset in the past.

Quantity< Second >	SolveRetardedTimeOffset (const Vector3< Quantity< Meter > > &point) const
	Solve for the retarded time offset using Newton's method.

Quantity< Second >	SolveRetardedTimeOffsetBisection (const Vector3< Quantity< Meter > > &point, Quantity< Second > dt_low, Quantity< Second > dt_high) const
	Solve for the retarded time offset using bisection method.

Private Attributes
Quantity< Coulomb >	charge_value_

TimeHistory< Vector3< Quantity< Meter > > >	position_history_ {}

TimeHistory< Vector3< Quantity< MeterPerSecond > > >	velocity_history_ {}

TimeHistory< Vector3< Quantity< MeterPerSecondSquared > > >	acceleration_history_ {}

Additional Inherited Members
Protected Attributes inherited from Phyth::Mechanics::Particle
Quantity< Kilogram >	mass_

Vector3< Quantity< MeterPerSecond > >	velocity_ {}

bool	fixed_ {false}

Vector3< Quantity< Newton > >	external_force_ {}

Vector3< Quantity< Meter > >	position_

std::function< void(Particle *)>	compute_forces_func_

Detailed Description

Point charge with full electromagnetic field and dynamics.

PointCharge represents a moving charged particle that produces electric and magnetic fields via the Liénard-Wiechert potentials. It inherits from Particle for dynamics and implements both ChargeSource and MagneticSource interfaces.

The electric field consists of two components:

Velocity field (Coulomb-like, falls as 1/r^2)
Acceleration field (radiation, falls as 1/r)

Example: auto charge = std::make_shared<PointCharge>( 1.0_kg, Vector3<Quantity<Meter>>(0_m, 0_m, 0_m), 1.0_C );

// Add a force function (e.g., Lorentz force) charge->SetComputeForcesFunction([](PointCharge* q) { Vector3<Quantity<NewtonPerCoulomb>> E(0_V/m, 0_V/m, -1.0_V/m); q->ApplyElectricFieldForce(E); });

// In simulation loop: charge->Integrate(); auto E = charge->GetElectricFieldAt(point); auto B = charge->GetMagneticFieldAt(point);

Note: The field and potential diverge at the charge location. Querying at the charge position throws an exception.

Definition at line 43 of file PointCharge.hpp.

Constructor & Destructor Documentation

◆ PointCharge()

Phyth::Electromagnetics::PointCharge::PointCharge	(	const Quantity< Kilogram >	mass,
		const Vector3< Quantity< Meter > > &	position,
		const Quantity< Coulomb >	charge_value
	)

inlineexplicit

Construct a point charge.

Parameters

mass	Mass of the particle (kg)
position	Initial position (m)
charge_value	Electric charge (Coulombs)

Definition at line 54 of file PointCharge.hpp.

Member Function Documentation

◆ ApplyElectricFieldForce()

void Phyth::Electromagnetics::PointCharge::ApplyElectricFieldForce ( const Vector3< Quantity< NewtonPerCoulomb > > & field )

inline

Apply force from an electric field: F = q * E.

Parameters

field Electric field intensity at the charge position

Definition at line 223 of file PointCharge.hpp.

◆ ApplyLorentzForce()

void Phyth::Electromagnetics::PointCharge::ApplyLorentzForce	(	const Vector3< Quantity< NewtonPerCoulomb > > &	electric_field,
		const Vector3< Quantity< Tesla > > &	magnetic_field
	)

inline

Apply the full Lorentz force: F = q * (E + v cross B)

Parameters

electric_field	Electric field intensity (N/C)
magnetic_field	Magnetic flux density (Tesla)

Definition at line 242 of file PointCharge.hpp.

◆ ApplyMagneticFieldForce()

void Phyth::Electromagnetics::PointCharge::ApplyMagneticFieldForce ( const Vector3< Quantity< Tesla > > & field )

inline

Apply force from a magnetic field: F = q * v cross B.

Parameters

field Magnetic flux density at the charge position

Definition at line 232 of file PointCharge.hpp.

◆ GetAccelerationAtOffset()

Vector3< Quantity< MeterPerSecondSquared > > Phyth::Electromagnetics::PointCharge::GetAccelerationAtOffset ( const Quantity< Second > & offset ) const

inlineprivate

Get acceleration at a time offset in the past.

Definition at line 309 of file PointCharge.hpp.

◆ GetElectricFieldAt()

Vector3< Quantity< NewtonPerCoulomb > > Phyth::Electromagnetics::PointCharge::GetElectricFieldAt ( const Vector3< Quantity< Meter > > & point ) const

inlineoverridevirtual

Get the electric field at a point using Liénard-Wiechert formulas.

The electric field is: E = k_E * q * (hat_R - beta) / (gamma^2 * R^2 * (1 - hat_R dot beta)^3)

k_E * q * (hat_R cross ((hat_R - beta) cross beta_dot)) / (c * R * (1 - hat_R dot beta)^3)

The first term is the velocity field (1/r^2), the second is the acceleration field (radiation, 1/r).

Parameters

point Position to evaluate the field (meters)

Returns: Electric field intensity E (N/C)

Exceptions

std::runtime_error If point is at the charge location

Implements Phyth::Electromagnetics::ChargeSource.

Definition at line 95 of file PointCharge.hpp.

◆ GetElectricPotentialAt()

Quantity< Volt > Phyth::Electromagnetics::PointCharge::GetElectricPotentialAt ( const Vector3< Quantity< Meter > > & point ) const

inlineoverridevirtual

Get the electric potential at a point.

The Liénard-Wiechert potential is: V = k_E * q / (R - hat_R dot beta * R)

Parameters

point Position to evaluate the potential (meters)

Returns: Electric potential V (Volts)

Exceptions

std::runtime_error If point is at the charge location or the denominator factor approaches zero

Implements Phyth::Electromagnetics::ChargeSource.

Definition at line 182 of file PointCharge.hpp.

◆ GetMagneticFieldAt()

Vector3< Quantity< Tesla > > Phyth::Electromagnetics::PointCharge::GetMagneticFieldAt ( const Vector3< Quantity< Meter > > & point ) const

inlineoverridevirtual

Get the magnetic field at a point using Liénard-Wiechert formulas.

The magnetic field is related to the electric field by: B = (hat_R / c) cross E

Parameters

point Position to evaluate the field (meters)

Returns: Magnetic flux density B (Tesla)

Exceptions

std::runtime_error If point is at the charge location

Implements Phyth::Electromagnetics::MagneticSource.

Definition at line 151 of file PointCharge.hpp.

◆ GetMinimumDistanceTo()

Quantity< Meter > Phyth::Electromagnetics::PointCharge::GetMinimumDistanceTo ( const Vector3< Quantity< Meter > > & point ) const

inlineoverridevirtual

Get the minimum distance from a point to the charge location.

Parameters

point Position to compute distance from

Returns: Distance to the charge location (meters)

Implements Phyth::Electromagnetics::ChargeSource.

Definition at line 264 of file PointCharge.hpp.

◆ GetPositionAtOffset()

Vector3< Quantity< Meter > > Phyth::Electromagnetics::PointCharge::GetPositionAtOffset ( const Quantity< Second > & offset ) const

inlineprivate

Get position at a time offset in the past.

Definition at line 291 of file PointCharge.hpp.

◆ GetTotalChargeValue()

Quantity< Coulomb > Phyth::Electromagnetics::PointCharge::GetTotalChargeValue ( ) const

inlineoverridevirtual

Get the total charge value.

Returns: The charge of the particle (Coulombs)

Implements Phyth::Electromagnetics::ChargeSource.

Definition at line 253 of file PointCharge.hpp.

◆ GetVelocityAtOffset()

Vector3< Quantity< MeterPerSecond > > Phyth::Electromagnetics::PointCharge::GetVelocityAtOffset ( const Quantity< Second > & offset ) const

inlineprivate

Get velocity at a time offset in the past.

Definition at line 300 of file PointCharge.hpp.

◆ Integrate()

void Phyth::Electromagnetics::PointCharge::Integrate ( )

inlineoverridevirtualnoexcept

Integrate dynamics using velocity Verlet.

Overrides Particle::Integrate to also update history buffers for retarded field computations.

Reimplemented from Phyth::Mechanics::Particle.

Definition at line 274 of file PointCharge.hpp.

◆ SetComputeForcesFunction()

void Phyth::Electromagnetics::PointCharge::SetComputeForcesFunction ( const std::function< void(PointCharge *)> & func )

inlinenoexcept

Set the force computation function.

Parameters

func	Function that applies forces to the charge via ApplyForce()

This wraps the Particle::SetComputeForcesFunction to accept PointCharge pointers directly.

Definition at line 72 of file PointCharge.hpp.

◆ SolveRetardedTimeOffset()

Quantity< Second > Phyth::Electromagnetics::PointCharge::SolveRetardedTimeOffset ( const Vector3< Quantity< Meter > > & point ) const

inlineprivate

Solve for the retarded time offset using Newton's method.

Solves R(t_ret) = c * (t - t_ret) for t_ret. Falls back to bisection if Newton fails.

Definition at line 323 of file PointCharge.hpp.

◆ SolveRetardedTimeOffsetBisection()

Quantity< Second > Phyth::Electromagnetics::PointCharge::SolveRetardedTimeOffsetBisection	(	const Vector3< Quantity< Meter > > &	point,
		Quantity< Second >	dt_low,
		Quantity< Second >	dt_high
	)		const

inlineprivate

Solve for the retarded time offset using bisection method.

Fallback when Newton's method fails to converge.

Exceptions

std::runtime_error If no solution exists in the interval

Definition at line 375 of file PointCharge.hpp.

Member Data Documentation

◆ acceleration_history_

TimeHistory<Vector3<Quantity<MeterPerSecondSquared> > > Phyth::Electromagnetics::PointCharge::acceleration_history_ {}

private

Definition at line 287 of file PointCharge.hpp.

◆ charge_value_

Quantity<Coulomb> Phyth::Electromagnetics::PointCharge::charge_value_

private

Definition at line 283 of file PointCharge.hpp.

◆ position_history_

TimeHistory<Vector3<Quantity<Meter> > > Phyth::Electromagnetics::PointCharge::position_history_ {}

private

Definition at line 285 of file PointCharge.hpp.

◆ velocity_history_

TimeHistory<Vector3<Quantity<MeterPerSecond> > > Phyth::Electromagnetics::PointCharge::velocity_history_ {}

private

Definition at line 286 of file PointCharge.hpp.

The documentation for this class was generated from the following file:

include/Phyth/Elements/Electromagnetics/FieldSources/PointCharge.hpp

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ PointCharge()

Member Function Documentation

◆ ApplyElectricFieldForce()

◆ ApplyLorentzForce()

◆ ApplyMagneticFieldForce()

◆ GetAccelerationAtOffset()

◆ GetElectricFieldAt()

◆ GetElectricPotentialAt()

◆ GetMagneticFieldAt()

◆ GetMinimumDistanceTo()

◆ GetPositionAtOffset()

◆ GetTotalChargeValue()

◆ GetVelocityAtOffset()

◆ Integrate()

◆ SetComputeForcesFunction()

◆ SolveRetardedTimeOffset()

◆ SolveRetardedTimeOffsetBisection()

Member Data Documentation

◆ acceleration_history_

◆ charge_value_

◆ position_history_

◆ velocity_history_