simulations.objects
Class ElectricDipole

java.lang.Object
  simulations.objects.BaseObject
      simulations.objects.ElectricDipole

Direct Known Subclasses:

ElectricOscillatingDipole

public class ElectricDipole

extends BaseObject

This is a quasi-static electric dipole moving at constant velocity that can be extended to a time varying radiating electric dipole (see for example ElectricOscillatingDipole). In this routine we set the time derivative and the second time derivative of the dipole moment vector to zero, even though we have in the expressions for the electric and magnetic field the full radiation correct terms for a point electric dipole. To do radiaton terms we have to put in correct expressions for the time derivatives of the dipole moment, as in ElectricOscillatingDipole. Important note: for color coding purposes, where we want to color code the DLIC according to the magnitude of the electric field, we multiply the overall electric field of this dipole by one factor of the radius and scale it by 1/100. If you want this dipole to interact with other electromagnetic objects you must compensate for this!!!!

Version:

1.0

Author:

Andreas Sunquist

Field Summary

Vec3	p The dipole moment of the dipole.
double	t The time.
Vec3	v The constant velocity of the dipole.
Vec3	x The position of the dipole.

Constructor Summary

ElectricDipole(Vec3 x, Vec3 p)
Create an electric dipole with zero velocity at t = 0.

ElectricDipole(Vec3 x, Vec3 v, Vec3 p)
Create an electric dipole with non-zero velocity at t = 0.

Method Summary

Vec3	Bfield(Vec3 x, Vec3 B) Compute the magnetic field at position x and time t
Vec3	Efield(Vec3 x, Vec3 E) Compute the electric field at position x and time t
void	Evolve(double dt) Evolve the dipole time and position.
Vec3	getDDP(double dtretarded) Get the second time derivative of dipole moment vector of the dipole.
Vec3	getDP(double dtretarded) Get the time derivative of dipole moment vector of the dipole.
Vec3	getP(double dtretarded) Get the dipole moment vector.
double	getT() Get the time.

Methods inherited from class simulations.objects.BaseObject

Bfield, Efield, Pfield, Pfield

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

x

public Vec3 x

The position of the dipole.

v

public Vec3 v

The constant velocity of the dipole.

p

public Vec3 p

The dipole moment of the dipole.

t

public double t

The time.

Constructor Detail

ElectricDipole

public ElectricDipole(Vec3 x,
                      Vec3 p)

Create an electric dipole with zero velocity at t = 0.

ElectricDipole

public ElectricDipole(Vec3 x,
                      Vec3 v,
                      Vec3 p)

Create an electric dipole with non-zero velocity at t = 0.

Method Detail

getT

public double getT()

Get the time. This allows us the find the current time for this dipole.

getP

public Vec3 getP(double dtretarded)

Get the dipole moment vector. Here we always return the constant dipole moment vector p, which does not evolve in time. To extend this to non-quasi-static dipoles or radiating dipoles, this method must be overridden. See for example ElectricOscillatingDipole

getDP

public Vec3 getDP(double dtretarded)

Get the time derivative of dipole moment vector of the dipole. Here we set this to zero, so that we have a quasi-static electric dipole. To extend this to non-quasi-static dipoles, this method must be overridden, see for example ElectricOscillatingDipole

getDDP

public Vec3 getDDP(double dtretarded)

Get the second time derivative of dipole moment vector of the dipole. Here we set this to zero, so that we have a quasi-static electric dipole. To extend this to non-quasi-static dipoles, this method must be overridden, see for example ElectricOscillatingDipole

Evolve

public void Evolve(double dt)

Evolve the dipole time and position. This needs to be improved if the dipole is not moving with constant speed.

Overrides:

Evolve in class BaseObject

Parameters:

dt - the time step

Efield

public Vec3 Efield(Vec3 x,
                   Vec3 E)

Compute the electric field at position x and time t

Specified by:

Efield in class BaseObject

Parameters:

x - the position of the observer

E - the electric field at the observer's position

Returns:

E the electric field at the observer's position

Bfield

public Vec3 Bfield(Vec3 x,
                   Vec3 B)

Compute the magnetic field at position x and time t

Specified by:

Bfield in class BaseObject

Parameters:

B - the magnetic field at the observer's position

Returns:

B the magnetic field at the observer's position