The Parallel Dipole Line Magnetic Trap: Experiment from The 2017 International Physics Olympiad, Indonesia

We present a laboratory experiment of a new type of natural magnetic trap called parallel dipole line trap which was recently featured as the experimental problem in the 2017 International Physics Olympiad (IPhO), Indonesia. The key feature of the trap is the recently-discovered 1-D "camelback" potential along the longitudinal axis [1]. The trap consists of a pair of transversely magnetized cylindrical magnets and a graphite rod as the trapped object. It serves as a "particle in 1-D potential" system that enables rich experiments covering diverse topics such as mechanics (harmonic and damped oscillator), electromagnetism (magnetostatics, diamagnetic levitation) and fluid dynamics (Stokes drag). Possible applications as seismometer and tiltmeter to monitor volcano were also presented. The experiment was well received by the IPhO international team leaders and could be used as a new and fascinating laboratory exercise with a fairly simple and affordable setup. [1] O. Gunawan, Y. Virgus, Appl. Phys. Lett. 106, 062407 (2015); J. Appl. Phys. 121, 133902 (2017).