Period increase and amplitude modification in the kink oscillations of a small-scale EUV loop

Solar Orbiter/EUI High Resolution Imager observations (2 s cadence) uncover the first case of simultaneous sub-minute period and amplitude growth in transverse kink oscillations at the apex of a bundle of Quiet-Sun coronal small-scale EUV loop. The event occurs in four episodes and each episode starts with both period and amplitude growth for a couple of cycles and ends with a sudden reset in both oscillation period and amplitude values. During each episode, the oscillation period increases–most plausibly due to rising density within the flux tube, as evidenced by concurrent intensity increase and theoretical expectations–while the amplitude also grows, potentially driven by a localized heating pulse or nearby activity (though verification is limited by SDO’s far-side perspective and EUI’s field-of-view) that repeats to energy injection into the standing kink wave. The observed episodic abrupt reset of the oscillation period and amplitude suggests repeated magnetic reconfiguration of the loop system, possibly driven by intermittent magnetic reconnection. The kink and Alfvén speeds, magnetic field strength, and total energy of the kink wave is estimated.