Ejs Open Source Motion of Charge Particle in Electric & Magnetic Field in 3D

reference:

this is a remix of Charge Trajectories in 3D Electrostatic Fields Model written by Andrew Duffy http://www.compadre.org/osp/items/detail.cfm?ID=9997

with help from Charged particle motion in static Electric/Magnetic field by Fu-Kwun Hwang http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1431.0

zoom in and out graphics are taken from creative commons license http://findicons.com/icon/86740/zoom_in?width=16#

this is remixed to support content learning of small part of electromagnetism similar to Escape from Centauri 7 http://gli.lsl.nie.edu.sg/projects_centauri.html.

But the link Escape from Centauri 7 here is about learning to scientist :) the goal is different.

whereas the applet is more suited for inquiry learning for content knowledge with a shorter time frame, perhaps 1.5 hours during practical periods. Here, becoming a scientist is also "achieved" but not as explicit as Escape from Centauri 7.

/htdocs/ntnujava/ejsuser/14019/users/sgeducation/lookang/Chargein3DEnBfield_pkg/Chargein3DEnBfield.propertiesFull screen applet or Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list

Download EJS jar file(1364.4kB):double click downloaded file to run it. (98 times by 31 users) , Download EJS source View EJS source

This model is created with the following 6 equations., derivation and checked by lookang

dx/dt = vx

dy/dt = vy

dz/dt = vz

dvx/dt = q*(Ex+(vy*Bz-vz*By))/m

dvy/dt = q*(Ey+(vz*Bx-vx*Bz))/m

dvz/dt = q*(Ez+(vx*By-vy*Bx))/m

Newton's 2nd Law F = ma,

because cross product is v^B in x direction is (vy*Bz-vz*By), refer to cross product literature

q*Ex + (vy*Bz-vz*By)*q = m*dvx/dt

because cross product is v^B in y direction is -(vx*Bz-vz*Bx), refer to cross product literature

q*Ey + (vz*Bx-vx*Bz)*q = m*dvy/dt

because cross product is v^B in z direction is (vx*By-vy*Bx), refer to cross product literature

q*Ez + (vx*By-vy*Bx)*q = m*dvz/dt

A Charge in Electric and Magnetic Fields by Andrew Duffy

In this simulation, you can investigate a charged particle, and the forces exerted on that charged particle by electric and/or magnetic fields. First, see how the charge behaves when exposed to just an electric field. Then, see how the charge behaves when exposed to just a magnetic field. Finally, if you'd like, turn both fields on and see what happens.

Activities by Andrew Duffy

Start with no initial velocity, and with just the electric field turned on. What does the charged particle do? If you reverse the sign on the charged particle, what happens?

Now, give the charged particle an initial velocity in the x-direction. Try turning on the electric field in just the x-direction, and then in just the y-direction. What do you observe about the motion of the charged particle in these cases? Write down the expression for the force the electric field exerts on the charged particle. Are your observations consistent with this expression?

Once again, start with no initial velocity, and with just the magnetic field turned on. What does the charged particle do? If you reverse the sign on the charged particle, what happens?

Now, give the charged particle an initial velocity in the x-direction. Try turning on the magnetic field in just the x-direction, and then in just the z-direction. What do you observe about the motion of the charged particle in these cases? Write down the expression for the force the magnetic field exerts on the charged particle. Are your observations consistent with this expression?

Finally, turn on both electric and magnetic fields, and see what kind of motions you can get.