Suppression of amplitude of 5-min oscillations in sunspots due to the lack of acoustic sources

K. Parchevsky, Alexander Kosovichev

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Acoustic waves on the Sun are excited by subsurface turbulent convection. However, in sunspots the excitation is suppressed because strong magnetic field inhibits convection. We use 3D simulations of acoustic waves to investigate how the suppression of excitation sources affects the distribution of acoustic power in sunspot regions. These simulations show that the amplitude of acoustic oscillations is approximately 4 times lower in the region with suppressed sources in comparison with the quiet Sun. This is in good agreement with observations of 5-min oscillations in sunspots. Hence, the observed reduced oscillation power in sunspots can be explained almost entirely by the suppression of acoustic sources in sunspot areas. These results challenge the current paradigm that the extinction of 5-min oscillations in sunspots is caused by absorption and transformation into other types of MHD waves in sunspot magnetic fields.

Original languageEnglish (US)
Title of host publicationSOHO 18/GONG 2006/HELAS I Beyond the spherical Sun
Volume624 SP
StatePublished - Oct 1 2006
Externally publishedYes
EventSOHO 18/GONG 2006/HELAS I Beyond the spherical Sun - Sheffield, United Kingdom
Duration: Aug 7 2006Aug 11 2006

Other

OtherSOHO 18/GONG 2006/HELAS I Beyond the spherical Sun
CountryUnited Kingdom
CitySheffield
Period8/7/068/11/06

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering

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