Large scale coherent magnetohydrodynamic oscillations in a sunspot.

ABSTRACT: Although theoretically predicted, the simultaneous excitation of several resonant modes in sunspots has not been observed. Like any harmonic oscillator, a solar magnetic flux tube can support a variety of resonances, which constitute the natural response of the system to external forcing. Apart from a few single low order eigenmodes in small scale magnetic structures, several simultaneous resonant modes were not found in extremely large sunspots. Here we report the detection of the largest-scale coherent oscillations observed in a sunspot, with a spectrum significantly different from the Sun's global acoustic oscillations, incorporating a superposition of many resonant wave modes. Magnetohydrodynamic numerical modeling agrees with the observations. Our findings not only demonstrate the pos

SUBMITTER: Stangalini M 

PROVIDER: S-EPMC8789893 | biostudies-literature | 2022 Jan

REPOSITORIES: biostudies-literature