A less idealized central force

This is the 3rd in a series that started with the gravitational potential, and then the harmonic.  While those are the two biggies, what we are looking at next behaves more like something you would see in real life, and doesn’t have solutions that can be written down with simple formulas.

For this entry in our series, I reached into my hat and pulled out the lorentz distribution from basic physics.  It it finite in all ranges from the very small, all the way out to infinity, and dare I say beyond.

These images range from a stream of slow particles which converge directly to the center of the force field, through a range of velocities, until the force is just a blip to be zoomed over, producing just a slight deflection.

Some features to note.  The intermediate images have more features and details than either the harmonic or gravitational wells.  That is directly related to the cut offs in the force.  Only the harmonic and gravitational potentials have elliptical orbits, all other potentials have more complicated and complex shapes.

Eventually, however the streams get fast enough that there are no major deflections and no bound orbits.  That just shows up as a narrow beam of deflected particles.

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Central force images #2

This is the second in a series profiling the solutions to common central force fields from physics.  Check out the the first one on the Newtonian gravitational force field.

These are even more plain than the gravitational well.  That’s because these are for the harmonic potential.  One of the things that distinguishes this potential is that all orbits are bound and elliptical in shape.

Contrasting that with the gravitational potential, there are 3 orbit shapes for that force: elliptical, parabolic, and hyperbolic.  You can see the effects in the image.  There is a relatively dark area bounded by the parabolic orbit, with a diffuse bright spot near the tip of the parabola.  This is due to the tightly curved hyperbolic orbits nearby.  The bright spot fades out into a dim patch further out as the trajectories become straighter the further they are from the center of the field.

Both of these fields have infinities which means that they valid only as approximations to actual forces.  The harmonic field has the most severe, it extends out to infinity and no particle can escape from it’s pull.  It doesn’t matter how fast our test particles are moving, they will never escape the grasp of the central pull.

Newtonian gravity has the opposite problem.  The force becomes infinitely strong as you approach the central point.  This causes problems for the differential equation solver and leads to the lower two images with kinked up trajectories and the rays radiating from the central point.

In our next installment I’ll be showing a field without those infinities and see how it stacks up.

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These aren’t all that pretty

Any guesses as to what these are?

Rather than focus on chaotic dynamics I wanted to see how I could explore the differences between the classical central forces.  This one is newtonian gravity.

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Islands of stability

This time I mapped the pendulum angle and time onto the surface of a cone to create a tunnel effect.  For the parameter space I’m looking at, you can really see how the paths will converge for a while and then suddenly diverge wildly.

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Sensitive dependence on initial conditions

This next demo highlights the butterfly effect.  These curves show the same pendulum as before, this version has the time axis wrapped around the center of the screen and the exponential of the angle as the radius.  All the pendulums start at a very similar initial position and for some driving functions they diverge wildly and others they all stay pretty close.

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Ensemble #2

This is more of what I was thinking of when I started down this route.

These are ensembles of particle paths in a chaotic dynamical system.  Not only are these ensemble pictures beautiful, but they highlight some interesting mathematics and physics.

But what I’ve really been after is a better source of semi regular noise.  The sinusoidal waves and interpolation between random points have been good, but for really entrancing fluid random motion, I need a chaotic semi-periodic source to feed into the other visualizations.

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Ensemble #1

I’m continuing with the envelope series, this time with an ensemble of states of a damped driven pendulum.  One of the “classic” chaotic systems.  This one isn’t in a chaotic regime, but striking none the less.

 

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More envelopes

This time I’m not taking up all of the screen.  Still working with polynomials and trigonometric functions.

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sine waves and envelopes

Still just playing with more effects.  This is a bunch of sine waves layered up to create an envelope effect.

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I hadn’t thought of stacking multiple iterations on top of each other

I just stumbled on these IFS renderings on art from code.  They produce a really nice effect.

It's rectangles all the way up.

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