Quadrupole / Penning-Style Trap
A static electric quadrupole Φ ∝ x²−y² creates a saddle potential; combined with a uniform axial magnetic field, Lorentz forces can confine charged particle orbits in the plane. Three test charges with different initial conditions illustrate bounded epicyclic motion — a qualitative cousin of Penning traps, not a radio-frequency Paul trap.
Who it's for: Students linking E×B dynamics to mass spectrometry hardware.
Key terms
- Penning trap
- Quadrupole potential
- Lorentz force
- Magnetron motion
How it works
Classical charged-particle dynamics in a static electric saddle plus uniform magnetic field: a qualitative cousin of Penning/Paul traps used in mass spectrometry.
Frequently asked questions
- Why no RF drive?
- Paul traps require time-varying fields for a ponderomotive pseudopotential; this page keeps Φ static for transparent classical trajectories.
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