Charged Particle in Electric & Magnetic Fields
Fire a charged particle into a uniform magnetic field (a closed cyclotron circle), add a uniform electric field (a bending parabola), or combine both to see the guiding center drift sideways — adjust charge sign, mass, speed, and both fields.
Preview — sign up free to change the numbers yourself
What you can adjust
- Scenario
- 0 – 3
- Charge
- -5 – 5 C
- Mass
- 0.1 – 10 kg
- Initial speed
- 0.5 – 20 m/s
- Launch direction
- 0 – 360 °
- Electric field (vertical)
- -10 – 10 V/m
- Magnetic field (out of plane)
- -5 – 5 T
Pick a named regime to set charge, mass, speed, direction, and both fields at once — pick Custom to use the sliders below.
Negative or positive — flips which way the particle curves in the magnetic field. Only used when Scenario is Custom.
Only used when Scenario is Custom.
Only used when Scenario is Custom.
0° = launched along +x. The magnetic circle's shape doesn't depend on this, only where it starts. Only used when Scenario is Custom.
0 = off. With the magnetic field also on, a nonzero value here makes the circle's center drift sideways (E-cross-B drift). Only used when Scenario is Custom.
Positive = out of the screen (⊙), negative = into the screen (⊗). Set to 0 with the electric field on to see a pure parabola instead of a circle. Only used when Scenario is Custom.
About this simulation
What it shows
A charged particle moves through a magnetic field, an electric field, or both. Its path is a circle, a parabola, or a circle that drifts sideways.
The key idea
A magnetic field bends a moving charge into a circle, and an electric field pushes it steadily in one direction. With both fields at right angles the circle drifts sideways at a speed E/B, whatever the charge or mass.
Try this
Set Scenario to E×B drift (both fields): the circular path slides steadily sideways instead of closing on itself.