Fun with applets!

It may be difficult to separate "theory" from "application," but let''s see if this helps facilitate the discussion.
Post Reply
longstreet
Posts: 165
Joined: Sun Aug 07, 2005 5:35 am
Real name:
Contact:

Fun with applets!

Post by longstreet » Sun Oct 23, 2005 8:35 am

I love this guys physics applets, and I just found one that can be used to get a visual on what's happening in a fusor. It simply shows particles reacting to an undescript vector field; so no charge, collision, etc... This is NOT a fusor simulator, but it is interesting.

Here is the link to the applet page: http://www.falstad.com/vector3d/

An applet should come up automatically, and it has a default with particles falling into point. First, change the "display" drop-down to force setting: "Display: Particles (Force)", rather than "Display: Particles (Vel.)". Now you can play with different field types. Basically anything that doesn't have the word "single" or "rotational" will give you fusor type stuff, except the complicated stuff at the bottom of the list.

I prefer the "1/r^2 sphere" field. Try changing sphere size and field strength!

have fun!
Carter

Captain_Proton
Posts: 52
Joined: Sat Nov 10, 2001 1:21 am
Real name:

Re: Fun with applets!

Post by Captain_Proton » Sun Oct 23, 2005 10:56 pm

This is excellent! What a great find...

Q
Posts: 200
Joined: Mon Jan 12, 2004 10:45 pm
Real name:

Re: Fun with applets!

Post by Q » Mon Oct 24, 2005 2:24 am

yes, very interesting! especially when you expiriment with the "field strength" and "sphere size". the different modes of operation that it demonstrates has given me a few ideas...
Q

longstreet
Posts: 165
Joined: Sun Aug 07, 2005 5:35 am
Real name:
Contact:

Re: Fun with applets!

Post by longstreet » Mon Oct 24, 2005 6:26 am

It seems that 1/r^2 is the potential, which is wronge for a point source. Potential is 1/r. So, it's not exactly like a fusor's field.

Carter

Starfire
Posts: 1482
Joined: Wed Oct 24, 2001 6:14 pm
Real name:

Re: Fun with applets!

Post by Starfire » Mon Oct 24, 2005 1:58 pm

Great one Carter - should put in ' Links'

Have you tried some of the others?
http://www.falstad.com/mathphysics.html

User avatar
Richard Hull
Moderator
Posts: 12499
Joined: Fri Jun 15, 2001 1:44 pm
Real name: Richard Hull

Re: Fun with applets!

Post by Richard Hull » Mon Oct 24, 2005 5:46 pm

Very nice!

Did anyone look at it max'd out on field and on particles and on both. Is the formation of a crude star seen real, or imagined by optical illusion within the cube??

Looking at the thing crosseyed will help or with averted vision.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

longstreet
Posts: 165
Joined: Sun Aug 07, 2005 5:35 am
Real name:
Contact:

Re: Fun with applets!

Post by longstreet » Mon Oct 24, 2005 6:24 pm

Yes John. He has many great wave applets.

Richard, I think that "star" forms because the box is not spherical. There are simple more particles along those axis so it looks like a star. The diaginal is sqrt(3) times longer than from face to face. I don't think it's the same as "star mode" in a fusor.

longstreet
Posts: 165
Joined: Sun Aug 07, 2005 5:35 am
Real name:
Contact:

Re: Fun with applets!

Post by longstreet » Mon Oct 24, 2005 9:41 pm

Try this... Set the size of sphere to max size, set particle number to max, and set force to zero and reset so everything is still. Then *slowly* increase the force to the max. Nice little oscillation there.

edit: also try the above with force at zero. Then just tap the up arrow so force is at lowest non-zero value. Wait till a nice ball forms in the middle and then set the force to max.

Carter

Q
Posts: 200
Joined: Mon Jan 12, 2004 10:45 pm
Real name:

Re: Fun with applets!

Post by Q » Tue Oct 25, 2005 2:39 am

yeah, the 1/r^2 field would be more accurate for a gravitational field, but the visualization does help a few gears to turn in the ol' noggin.

Q

Post Reply