Home▸Articles▸Electromagnetism

Magnetic Field & Lorentz Force Explorer: A Deep Dive into Charged Particle Dynamics

An interactive simulation that illuminates how charged particles move in magnetic fields, revealing the underlying physics through a live demonstration of the Lorentz force.

mysimulator teamUpdated June 2026≈ 4 min read▶ Open the simulation

What is the Lorentz Force?

The Lorentz force (F) is the force exerted on a charged particle moving through an electromagnetic field. It combines both electric and magnetic forces, but when only a magnetic field is present, it simplifies to F = qv × B, where q is the charge of the particle, v is its velocity vector, and B is the magnetic field strength. This force causes particles to move in curved paths due to the perpendicular interaction between the particle's motion and the magnetic field lines.

The Lorentz force is fundamental in understanding phenomena such as cathode ray tubes, mass spectrometers, and the operation of particle accelerators.

How Does the Biot-Savart Law Apply?

The Biot-Savart law describes how a magnetic field (B) is generated by an electric current. It states that the magnetic field dB at a point due to a small segment of wire carrying current I is given by dB = μ0/4π * (I dl × r)/r^3, where μ0 is the permeability of free space, dl is the vector representing the length element of the wire, and r is the position vector from the wire element to the point where the field is being calculated.

In this simulation, a series of current loops are used to create a complex magnetic field. The Biot-Savart law is applied iteratively for each loop segment to compute the total magnetic field at any given point in space.

live demo · related simulation● LIVE

Why Does This Simulation Matter?

This simulation provides an intuitive and interactive way to understand how charged particles behave in complex magnetic fields. By manipulating parameters such as current direction, particle charge, velocity, and mass, learners can observe the effects of these variables on the particle's trajectory.

Moreover, it serves as a practical tool for educators and researchers to explore and explain fundamental concepts in electromagnetism, making abstract physics principles more tangible.

Real-World Applications

The Lorentz force and magnetic fields are crucial in various technologies. For example, in mass spectrometry, charged particles are deflected by magnetic fields to separate different isotopes based on their masses.

In particle accelerators like the Large Hadron Collider (LHC), precise control of magnetic fields is essential for guiding and accelerating subatomic particles at high speeds.

Frequently asked questions

How does changing the current direction in a loop affect the simulation?

Changing the current direction in a loop reverses the magnetic field it generates, which can cause the charged particle's trajectory to curve in the opposite direction or even reverse its path.

What is the significance of the Biot-Savart law in this simulation?

The Biot-Savart law is crucial because it allows for the calculation of the magnetic field produced by each current loop, which then influences the Lorentz force acting on the charged particle. This ensures that the simulation accurately reflects real-world physics.

Can this simulation be used to study other types of fields?

While the simulation is specifically designed for magnetic fields, similar principles can be applied using the Biot-Savart law and Lorentz force in electric fields. However, the interaction would differ as only magnetic fields cause a perpendicular force on moving charges.

How does the mass of the test charge affect its motion?

The mass of the test charge influences how easily it can be deflected by the Lorentz force. A higher mass means less acceleration for a given force, resulting in a more gradual change in trajectory.

Try it live

Everything above runs in your browser — open Magnetic Field & Lorentz Force Explorer (2D) and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.

▶ Open Magnetic Field & Lorentz Force Explorer (2D) simulation

What did you find?

Add reproduction steps (optional)