Broadening of the Drumhead Mode Spectrum due to In-Plane Thermal Fluctuations of Two-Dimensional Trapped Ion Crystals in a Penning Trap

The authors theoretically and numerically investigate the in-plane motion of two-dimensional ion crystals stored in Penning traps. They find that the thermal fluctuations in the in-plane positions of ions, described by normal modes whose potential energy is several hundred times larger than their kinetic energy, strongly contribute to the spectral broadening of the transverse drumhead motion.