We report a quasi-periodic pulsation ( QPP ) event simultaneously detected from the spatial displacements of coronal loop at both EUV images and microwave emission during the preflare phase of a C1.1 flare on 2016 March 23 .
Using the motion magnification technique , a low-amplitude transverse oscillation with the growing period is discovered in a diffuse coronal loop in Atmospheric Imaging Assembly ( AIA ) image sequences at wavelength of 171 Å , and the initial oscillation period is estimated to be \sim 397 s with a slow growth rate of 0.045 .
At the same time , a QPP with growing periods from roughly 300 s to nearly 500 s is discovered in the microwave flux in the same active region .
Based on the imaging observations measured at EUV wavelengths by the AIA and at microwave 17 GHz by Nobeyama Radioheliograph , the diffuse coronal loop and the microwave radiation source are found to be connected through a hot loop seen in AIA images at wavelength of 94 Å .
The growing period of the QPP should be related to the modulation of LRC-circuit oscillating process in a current-carrying plasma loop .
The existence of electric currents may imply the non-potentialities in the source region during the preflare phase .