simulations.experiments.magnetostatics
Class TeachSpinExperiment

java.lang.Object
  simulations.experiments.BaseExperiment
      simulations.experiments.magnetostatics.TeachSpinExperiment

public class TeachSpinExperiment

extends BaseExperiment

Experiment consists of two ring currents, one above the other. The top one represents the small magnet in the teach spin experiment, and the bottom one represents the bottom current ring in the teach spin experiment. In this experiment we let the current in the bottom current ring vary sinusoidally with time, I(t) = I0 sin (omega * t) and calculate the corresponding motion of the magnet due to this changing current in a purely magnetostatic fashion (that is there is no currrent induced anywhere in this problem due to a changing magnetic flux through any ring--e.g. there are no induced electric fields or currents of importance). We also assume that this magnet motion is quasi-static--that is it is very slow compared to the natural frequency of oscillation of the magnet on the spring from which it is suspended, so that the magnetic force on the dipole simply results in a displacement from equilibrium that is proportional to the force.

Version:

1.0

Author:

Michael Danziger, John Belcher

Field Summary

private EMCollection	collection the EMCollection consisting of the dipole and the current ring
double	deltaR the amplitude of the motion of the magnet
double	dIdt the current time rate of change of current in the ring
CurrentRing	dipole the dipole in the Teach Spin experiment
double	I the current current in the ring
double	I0 the amplitude of the sinusoidal variation in the current in the lower current ring
double	I1 the amplitude of the sinusoidal variation in the current in the lower current ring
double	omega the constant current in the magnetic dipole
double	R the radius of the lower current ring in pixels
CurrentRing	ring the lower ring in the Teach Spin experiment
double	t the time
double	v the current velocity of the magnet along the z-axis
double	z the current position of the magnet along the z-axis
double	z0 the initial position of the magnet on the z-axis
double	Z0 the fixed position of the lower current ring center along the z-axis

Fields inherited from class simulations.experiments.BaseExperiment

eps, FieldMotionType, FieldType, FluidFlowSpeed, Fnorm, Fpower, numberSmallSteps

Constructor Summary

TeachSpinExperiment(double R, double deltaR, double I1, double z0, double Z0, double I0, double omega)
constructor for the experiment

Method Summary

void	ConstructEMSource() Constructs the EMSource representing the two current rings in the experiment with the given initial conditions
void	Evolve(double dt) Evolves the experiment by a time step "dt"
void	Evolve(double dt, double maxStep) Evolves the experiment.
BaseObject	getEMSource() returns the collecton of BaseObjects constructed in ConstructEMSource()
double	getFlowSpeed(Vec3 r, Vec RegionFlow) Method to find the flow speed in a given region when we are determining that speed according to region.
double	getHue(double TargetHue, Vec3 r, Vec RegionColor) Method to find the hue in a given region when we are coloring according to region (Color Mode 4).

Methods inherited from class java.lang.Object

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

Field Detail

R

public double R

the radius of the lower current ring in pixels

deltaR

public double deltaR

the amplitude of the motion of the magnet

I0

public double I0

the amplitude of the sinusoidal variation in the current in the lower current ring

I1

public double I1

the amplitude of the sinusoidal variation in the current in the lower current ring

omega

public double omega

the constant current in the magnetic dipole

z0

public double z0

the initial position of the magnet on the z-axis

Z0

public double Z0

the fixed position of the lower current ring center along the z-axis

z

public double z

the current position of the magnet along the z-axis

v

public double v

the current velocity of the magnet along the z-axis

I

public double I

the current current in the ring

dIdt

public double dIdt

the current time rate of change of current in the ring

t

public double t

the time

ring

public CurrentRing ring

the lower ring in the Teach Spin experiment

dipole

public CurrentRing dipole

the dipole in the Teach Spin experiment

collection

private EMCollection collection

the EMCollection consisting of the dipole and the current ring

Constructor Detail

TeachSpinExperiment

public TeachSpinExperiment(double R,
                           double deltaR,
                           double I1,
                           double z0,
                           double Z0,
                           double I0,
                           double omega)

constructor for the experiment

Parameters:

R - the radius of the lower current ring

deltaR - the amplitude of the variation in the height of the magnet

I1 - the constant current in the magnet

z0 - the initial position of the magnet above the lower current ring

Z0 - the initial position of the lower current ring along the z-axis

I0 - the amplitude of the variation in the current in the lower current ring

omega - the angular frequency of the time variation in current

Method Detail

ConstructEMSource

public void ConstructEMSource()

Constructs the EMSource representing the two current rings in the experiment with the given initial conditions

Specified by:

ConstructEMSource in class BaseExperiment

getEMSource

public BaseObject getEMSource()

Description copied from class: BaseExperiment

returns the collecton of BaseObjects constructed in ConstructEMSource()

Specified by:

getEMSource in class BaseExperiment

Evolve

public void Evolve(double dt,
                   double maxStep)

Evolves the experiment. This is easy because we have an analytic expression for the position of the magnet as a function of time and the current in the ring as a function of time. The state of the EMSource representing the ring and magnet must be updated to reflect the change

Evolve

public void Evolve(double dt)

Evolves the experiment by a time step "dt"

Specified by:

Evolve in class BaseExperiment

getHue

public double getHue(double TargetHue,
                     Vec3 r,
                     Vec RegionColor)

Method to find the hue in a given region when we are coloring according to region (Color Mode 4).

Specified by:

getHue in class BaseExperiment

Parameters:

TargetHue - This is the target hue from the renderer.

r - This is the vector postion of the point in the image.

RegionColor - This is the varous hues for the regions.

Returns:

The hue for the part of the image map at r.

getFlowSpeed

public double getFlowSpeed(Vec3 r,
                           Vec RegionFlow)

Method to find the flow speed in a given region when we are determining that speed according to region. This method is used when we have set experiment.FieldMotionType to one of either Constants.FIELD_MOTION_VREFIELD or Constants.FIELD_MOTION_VRBFIELD.

Specified by:

getFlowSpeed in class BaseExperiment

Parameters:

r - This is the vector postion of the point in the image.

RegionFlow - This is the flow speeds for the regions.

Returns:

The flow speed for the part of the image map at r.