## Program 15: Electromagnetic and Gravitational Field Radiation

### Introduction and Purpose

The purpose of this program is to study how an electro_magnatic field or gravitational field propagates

This program is base around the question: How do electro_magnetic and gravity fields propagate ?

Operation Input to the program are 4 parameters:

1. Theory #. 1 = is Theory behind MTW page 111 figure 4.6. 2 = Origin centered propagation or radiation.
2. Path #. 1 = Straight line to the left. 2 = Straight lines one to the left and one to the right. 3 = curved.
3. Relative speed of field.Minumum value is 1.1. 50 or more means infinite.
4. For path (movement) 3 the radius of the curve.
The first 2 parameters are obligatoir. The parameters 3 & 4 are an option.

The display shows:

1. The position of the particle as green dots.
2. The field as brown and white dots.
Operation.
1. Select Theory 1 and Path 1
2. Select Theory 2 and Path 1.
3. Compare and observe at the end that the field lines in Theory 1 are highly symetric and the field lines of Theory 2 have a tendency to move to the right. Observe that the size of the draw field is the same (at each generation)
4. Select Theory 1 and Path 1
5. Select Theory 1 and Path 2.
6. Compare and observe that the disturbance is centered around the point where the velocity change occured. Observe that the field behind the disturbance is the same for both. Observe that the field with in the disturbance is 180 degrees rotated.
7. Select Theory 2 and Path 1
8. Select Theory 2 and Path 2.
9. Compare and observe that the disturbance is centered around the point where the velocity change occured. Observe that the field behind the disturbance is the same for both. Observe that the field with in the disturbance is 180 degrees rotated. Observe that the field lines through the disturbance are slightly bended.
10. Select Theory 2 and Path 3. Try this one for standard radius (100) and for radius = 50.

In order to retrieve the source select:RADIATE.BAS
To the the program listing select:RADIATE.HTM

## Technical Data

The program keeps track where the particle is by using 3 arrays: X(20), Y(20), R(20) and Angl(20)
X(5) represents the x position of the particle at t= 5.
Y(5) represents the y position of the particle at t= 5.
R(5) is zero at t=5 and is then increased each cycle.
Angl(5) represents the direction of movement. Used for path 3